History Of The Hepatic Encephalopathy Biology Essay


Substances absorbed into the blood stream from the intestine pass through the liver where toxins are normally removed. In hepatic encephalopathy, toxins are not removed as liver function is impaired and also some toxins may bypass the liver through portal systemic connections. Toxins entering systemic circulation reach the brain and affect its function [4] .

Abnormalities of ammonia metabolism are more frequently implicated in the pathophysiology of HE. Ammonia is produced in the gut from dietary proteins by the action of urease positive micro organisms in the gut and is then converted to urea by the liver, which is excreted out of the body through urine [5] . In liver cell failure ammonia conversion to urea is impaired. This results in an increase in ammonia levels. Excess Ammonia from the blood reaches the brain, as it is able to cross the blood brain barrier and affects the normal functioning of the brain, resulting in symptoms and signs of hepatic encephalopathy [6] .

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In addition, a number of other possible mechanisms are proposed - Production of false neuro transmitters, activation of GABA- BZD receptors by ligands of endogenous origin, altered cerebral metabolism, disturbed activity of Na/K ATPase , increased level of short chain fatty acids and increased levels of aromatic amino acids with decreased levels of branched chain amino acids are other possible mechanisms [7] . These pathogenic mechanisms of HE are due to complicated interplay of many factors, not just one.

Apart from supportive care, the management of hepatic encephalopathy is directed towards decreasing the nitrogen load from gut. This includes dietary protein restriction, synthetic sugars (e.g. lactulose), antibiotics and synbiotics. Whereas, extra intestinal elimination of ammonia is improved by L-Ornithine L-Aspartate, Oral zinc.,etc. Other modes of treatment are counteracting the central neurotransmitters and long term therapies like liver assist devices or liver transplantation [8] .

Prevention of the generation and absorption of ammonia in the gut is the primary focus of the treatment for HE. Another approach to this problem is to promote the excretion of waste nitrogen. This is by enhancing what remains of the liver capacity for ureagenic and glutamine synthesis, or by providing substances that fix ammonia and get excreted in the urine.

Non absorbable dissacharides like Lactulose are considered the drugs of first choice for treating HE. They act on the colon, shortening intestinal transit time and decreasing colon pH, which reduces the absorption of nonionized ammonia and increases the assimilation of ammonia by bacteria [9] . Since only 15% of ammonia production originates from the colon, the contribution of Lactulose to the reduction of hyperammonemia is limited.

LOLA has been shown to reduce blood ammonia concentration and improve psychometric performance in patients with hyperammonemia and hepatic encephalopathy. LOLA treatment stimulates ammonia detoxification, particularly in skeletal muscle. Control studies showed both oral and intravenous administration reduce ammonia levels and improve encephalopathy in patients with cirrhosis [10] .

Synbiotics are the combination of probiotics and prebiotics. Synbiotics acidify the gut lumen and inhibits the growth of urease producing pathogenic bacteria. It also normalizes the intestinal flora by promoting the growth of beneficial bacteria [11] .

The mechanism of action of LOLA and synbiotics are different. The combination of both may be more effective in improving the clinical features of Hepatic Encephalopathy. But LOLA and Synbiotics are not used commonly due to reservations in their therapeutic benefits.

Since the combination of LOLA and Synbiotics are less studied, it was proposed to evaluate the efficacy and tolerability of LOLA and Synbiotic in Grade II/III Hepatic Encephalopathy.

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Liver disease constitutes one of the main causes of mortality worldwide [12] . Liver plays a pivotal role in detoxification of ammonia. Ammonia is the endproduct of protein catabolism. Ammonia may also originate from dietary proteins by the activity of urease producing micro organisms in the gut or by intestinal and renal glutaminase [13] . Nearly 85% of total blood ammonia may be generated by intestinal glutamine deamination, whereas, as little as 10-15% may originate from the deamination of proteins by the gut macrobiota.

The liver and muscle play central roles in ammonia detoxification by converting it to urea (liver) and glutamine (liver and muscle). Urea is excreted by the kidneys. The importance of muscle glutamine formation as a means of removing ammonia from the bloodstream is stressed recently, implying the crucial role of skeletal muscle in ammonia detoxification.

However, in liver cell failure ammonia conversion to urea is impaired. This results in an increased ammonia levels. Ammonia from the blood reaches the brain and affects the normal functioning of the brain resulting in symptoms and signs of hepatic encephalopathy5.

Hepatic encephalopathy :

Definition :

Hepatic encephalopathy (HE) is a potentially reversible, progressive, neuropsychiatric disease, that develops as a result of fulminant hepatitis or cirrhosis, or a portosystemic shunt. HE manifests as a spectrum of abnormalities involving cognition, attention, functional ability, personality and intellect [14] . HE may be present in 50%-70% of all patients with cirrhosis and most manifestations are reversible with medical treatment2.

Epidemiology :

The risk of developing hepatic encephalopathy is 20% per year, and at any time about 30-45% of people with cirrhosis exhibit evidence of overt encephalopathy. The prevalence of minimal hepatic encephalopathy detectable on formal neuropsychological testing is 60-80%; this increases the likelihood of developing overt encephalopathy in the future [15] . HE is divided into two primary components: Overt HE (OHE) and minimal HE (MHE). It has been estimated that OHE is present in 30-45% of patients, with an annual risk of development in 20% of patients with cirrhosis.

Nomenclature of HE: [16] 

Type A Encephalopathy associated with acute liver failure

Type B Encephalopathy associated with portosystemic bypass and no intrinsic hepatocellular disease

Type C Encephalopathy associated with cirrhosis and portal hypertension or portosystemic shunts

1 Episodic HE

a Precipitated

b Spontaneous

c Recurrent

2 Persistent HE

a Mild

b Severe

c Treatment-dependent

3 Minimal HE

Clinical features:

The earliest clinical signs of hepatic encephalopathy (stage 1) are often subtle psychiatric and behavioural changes [17] , [18] . These changes are primarily due to mild impairment of intellectual function that reflect predominantly bilateral forebrain, parietal, and temporal dysfunction. In early stages of hepatic encephalopathy the presence of pronounced intellectual impairment may be masked by relatively well preserved verbal ability [19] , [20] .

Grading - West Haven Classification:

Stage 0

no abnormality detected

Stage 1

trivial lack of awareness, euphoria, anxiety, shortened attention span, impairment of addition or subtraction

Stage 2

lethargy, disorientation for time, obviuos personality changes, inappropriate behaviour

Stage 3

somnolence to semistupor, but responsing to stimuli, confusion, gross disorientation, bizarre behaviour

Stage 4

coma, tests of mental status not possible


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The differential diagnosis of hepatic encephalopathy includes

Alcohol intoxication and withdrawal syndromes,

Wernicke's encephalopathy,

Korsakoff's syndrome,

Intoxication with sedative/hypnotic drugs,

Other metabolic encephalopathies (for example, hypernatraemia or hyponatraemia, uraemia, hyperglycaemia or hypoglycaemia, hypercapnia),

Wilson's disease,

Consequences of head trauma (for example, subdural haematoma)

Organic intracranial lesions. .

Diagnosis :

Laboratory investigations:

When encephalopathy is attributable to hepatic encephalopathy alone, abnormal results of serum biochemical tests reflect the underlying liver disease. Routine laboratory test results aid in the differential diagnosis of encephalopathies (for example, uraemia, hypoglycaemia, hypercapnia) and in the detection of factors that may precipitate hepatic encephalopathy (for example, hypokalaemic metabolic alkalosis).

Blood venous ammonia [22] concentrations are measured in hepatic encephalopathy; but not considered as a reliable index of the efficacy of treatments for hepatic encephalopathy. [23] 

Brain imaging

Computed tomography is not useful for the diagnosis of hepatic encephalopathy. It should be done, however, in each case in which the differential diagnosis includes intracranial bleeding, especially the presence of a subdural haematoma.

Psychometric tests

Simple psychometric tests include orientation to time, person, and place, recall of current events, subtraction of serial sevens, handwriting, and figure drawing. Of the many quantitative psychometric tests available, one that is easy to apply and has been extensively used in the assessment of early hepatic encephalopathy is a modification of the Reitan trail making test, known as the number connection test [24] . Repeated application of this test can be useful, but care must be taken to exclude an effect of learning and age on test scores.

Tests used for psychometric assessment are- Digit symbol, trail making tests like Line Tracing test and Number Connection Test, Figure connection Test etc.

Line tracing test :

This test is considered as a measure of psychomotor speed . In LTT subjects are required to complete a course drawn on paper without touching or crossing the edges as fast and accurate as possible. the normal value is > 120 seconds.

Number connection test:

This test is considered as a measure of psychomotor speed and visual attention. In the number connection test, the subjects were asked to connect numbers 1 to 25 on the printed paper consecutively as quickly as possible. Normal range falls between 15-30 seconds.


The EEG abnormalities that occur in hepatic encephalopathy are nonspecific, being found in other metabolic encephalopathies. The main EEG abnormalities in hepatic encephalopathy are a progressive bilaterally synchronous decrease in wave frequency and an increase in wave amplitude. A good correlation between the clinical stage of hepatic encephalopathy and the degree of abnormality of the EEG is not invariable [25] .


The pathophysiology of hepatic encephalopathy is intricate and exact mechanisms leading to HE are not clearly understood. Hepatic encephalopathy pathogenesis has many components which include ammonia, inflammatory cytokines, benzodiazepine like compounds and manganese like substances which impair neuronal function [26] .. Evidence regarding other concurrent factors has emerged over the years and it is thought that these factors either work alone or in synergy to cause astrocytes to swell and fluid to accumulate in brain which causes the symptoms of HE [27] .

The ammonia theory

The role of ammonia has dominated explanations for the pathogenesis of HE but it cannot single handedly explain all the neurological changes seen in HE. Ammonia is a weak base with a pKa of 9.25 .

. Ammonia is produced predominantly from dietary nitrogenous components, bacterial metabolism of these nitrogenous products in the colon and in small intestine from glutamine by glutaminase enzyme [28] .While ammonia is produced by many tissues, most results from the activity of urease producing gut flora and is released into the portal vein after absorption by the intestinal epithelium . Urease is a bacterial enzyme produced mainly by gram negative enterobacteria, that catalyzes the hydrolysis of urea to carbamate and ammonia.

Eventually this ammonia from gastrointestinal tract enters portal circulation for its final destination of urea cycle in the liver to be converted as urea which will subsequently be excreted by kidneys [29] . Humans excrete over 20 pounds of urea a year and first pass hepatic clearance of ammonia is around 80%

Under normal conditions, ammonia is eliminated through urea formation in the liver but in patients with acute liver failure, brain and muscle cells are also involved in the metabolism [30] . Ammonia crosses the blood-brain barrier, where it acts on impaired astroctyes and results in a cascade of pathopysiologic neurochemical events [31] . In Brain, astrocytes are the only cells capable of metabolizing ammonia and express the enzyme glutamine synthase for the conversion of ammonia into glutamine. So, ammonia detoxification in astrocytes leads to accumulation of glutamine which being an osmolyte, causes movement of water inside the astrocyte and causes cerebral edema i-e 'Trojan horse' hypothesis39, [32] , [33] 

Some of the studies had shown the ammonia induced expression of aquaporin water channel on astrocytes [34] . This has been seen in autopsies of patients with cirrhosis in which brain tissue had shown swollen astrocytes with enlarged nuclei along with displacement of chromatin to the perimeter of the cell, this condition is known as Alzheimer type II astrocytosis [35] .

Acute insult of ammonia leads to calcium dependent glutamate release from astrocytes, which causes increased neuronal activity (as seen in Type A HE). A prolonged exposure to ammonia leads to glutamine induced osmotic stress, which causes compensatory release of myoinositol and taurine from the astrocytes, which may lead to down regulation of glutamate receptors and neuroinhibitory state of HE (as seen in Type C HE).

Elevated intracellular ammonia levels also results in altered neurotransmission by agonizing GABA tone. [36] Hyper ammonia lead to abnormal cerebral blood flow and glucose metabolism and this had been seen in studies of single photon emission tomographic (SPECT) in which redistribution of blood flow form cerebral cortex to subcortical regions had been demonstrated. This abnormality leads to different HE features.42, [37] 

Inflammation [38] 

Majority of the cirrhotic patients in the presence of infection develop the HE. This association of markers of inflammatory response in state of systemic inflammatory response (SIRS) and HE, has been demonstrated in different studies [39] , [40] .TNF causes Astrocytes to release inflammatory cytokines (i-e IL-1, IL-6) which impairs the endothelial Blood-Brain barrier and increases ammonia diffusion into astrocytes [41] .

Neurosteroids and GABA/Benzodiazepine receptor complex theory

Neurosteroids increase chloride influx and thereby enhance GABAergic tone, causing symptoms in patients with Type C HE [42] , [43] . Increased sensitivity of the trasnslocator proteins also enhances the activation of GABA-GRC complex, hence causing inhibition of neurotransmission [44] . Increased GABAergic tone has been associated with the pathogenesis of HE and this was proved by the reports which had revealed the beneficial effects of benzodiazepine antagonist (Flumazenil) [45] .

There is an excess of benzodiazepine like compounds in HE that are derived from synthesis by intestinal flora, dietary vegetables and medications [46] . A study by Stewart et al group had shown that ammonia itself bind to the GABA receptor complex [47] . It may also potentiate benzodiazepines by up regulating expression of peripheral type benzodiazepine receptor that trigger synthesis of neuro-steroids, which are strong GABA agonists [48] .

BCCA and false neurotransmitter theory:

. Aromatic as well as branch chain amino acids share a common transport mechanism into the CNS and as a consequence of increased of aromatic amino acids in cirrhosis, neuronal levels may be increased leading to the production of false neurotransmitter subsequently leading to HE [49] .

Serotonin theory:

In cirrhotic patients it has been seen that serotonin metabolism is altered hence leading to serotonergic synaptic deficit. Serotonergic pathway in brain is important for regulation of sleep, locomotion and circadian rhythmicity. Serotonin metabolism is intricately and selectively sensitive to the degree of portosystemic shunting and hyperammonaemia, therefore suggesting a role for serotonin in early neuropsychiatric symptoms of HE [50] .

Zinc theory:

Zinc (Zn) element is a component/substrate of urea cycle enzymes. It is assumed that this element is reduced in patients with liver cirrhosis. Zn supplementation increases activities of ornithine transcarbamalyse increasing excretion of ammonia ions. Interestingly till now there is conflicting evidence for this hypothesis of Zn supplementation in He patients [51] .

Oxidative and nitrosative stress

Exposure of astrocytes to ammonia, inflammatory cytokines, hyponatremia and benzodiazepines leads to enhanced production of RNS & ROS via the Calcium dependent N-methyl-D-aspartate (NMDA) pathway. RNS and ROS cause tyrosine nitration, leading to altered BBB permeability and astrocyte swelling [52] .

Manganese theory [53] 

In normal healthy individuals, Manganese is cleared by liver and excreted into the bile. Manganese stimulates the Translocator proteins located on astrocytes, leading to enhanced neurosteroid synthesis. In cirrhotic patients, it accumulates in the basal ganglia because of decreased excretion of Manganese due to portosystemic shunting and promotes formation of Alzheimer's type 2 astrocytes. Brain magnetic resonance imaging (MRI) in cirrhotic patients has shown changes, which are due to accumulation of Manganese in basal ganglia particularly in the palladium, putamen and caudate nucleus.

Neuropathology [54] 

Structural changes in neurons, as assessed by light microscopy, are not found in the brains of patients who had hepatic encephalopathy when they died. However, in patients who die with cirrhosis and portal-systemic shunts, an increase in the number and size of astrocytes, particularly Alzheimer type 2 astrocytes is commonly found. Such changes may be induced by raised concentrations of ammonia, but they are not a feature of the brain in fulminant hepatic failure

Precipitating factors [55] :

The Most of HE episodes are precipitated by an event rather than spontaneous, with infection anywhere in body being the common, though its frequency is decreasing. Hence careful history and examination are necessary to identify the precipitating or contributing factors for HE, most of the time these factors are evident.

Dietary protein Overload

GI Bleeding (most common)


Electrolyte imbalance


Infection / Sepsis



In a patient with chronic hepatocellular disease an episode of hepatic encephalopathy usually resolves if overall hepatocellular function remains relatively well maintained and a precipitating factor can be identified and corrected. Alternatively, if an obvious precipitating factor cannot be identified, a poor prognosis is likely.

About 50% of patients with cirrhosis die within one year of their first episode of hepatic encephalopathy and about 80% within five years, not as a direct consequence of hepatic encephalopathy, but as a consequence of chronic hepatocellular failure [56] .

Treatment of HE [57] , [58] 

HE treatment has evolved over the last 5 decades and multiple key management principles which parallel the pathophysiology of the disease . they are-

Management of precipitating factors,

Reduction of ammonia

Modulation of intestinal flora

Modulation of neurotransmission

Correction of nutritional deficiencies

Reduction of inflammation/infection

Many treatment options are available for the treatment of HE with the mainstay to eliminate the underlying factors that precipitate HE. It is recommended that all patients should receive the empiric therapy for HE, based on the principle of reducing the production and absorption of ammonia.

Nutritional intervention [59] 

In the past, dietary protein restriction was considered an important component of the treatment of HE. Recent evidence however suggests that excessive restriction can raise serum ammonia levels, as a result of reduced muscular ammonia metabolism. It has also been seen that majority of the patients with advanced liver disease had severe protein calorie malnutrition due to multifactorial reasons including the decreased oral intake,catabolic state etc. A high-protein diet is therefore recommended for improving the symptoms of HE.

The European society for Parenteral and Enteral nutrition recommended an energy intake of 35/40 kcal/kg body weight per day and that patients must eat at least 1.2g/kg of protein daily along with Branched-chain amino acids (BCAA's) and vegetable-based protein.Vegetable and dairy based proteins are preferred to animal proteins because of a high calorie-to-nitrogen ratio. Vegetable based proteins increase colonic motility and enhances intestinal nitrogen clearance. They also reduce colonic PH, which prevents ammonia absorption into gut.(Zinc increases the activity of ornithine transcarbamylase (an enzyme in urea cycle) so zinc supplementation is also recommended for HE especially in patients who don't show any response to lactulose or neomycin.

Nonadsorable disaccharides [60] 

Nonadsorable disaccharides like Lacutlose and Lactitol [61] are considered the first line therapy for HE. They are metabolized by the colonic bacteria and form by products that reduce the colonic pH, hence interfering with mucosal uptake of glutamine and reducing the synthesis and absorption of ammonia.

Other proposed mechanism of lactulose in HE are modification of the colonic flora which in turn results in shift of urease containing bacteria with lactobacillus. There is a fourfold increase in fecal nitrogen excretion due to increase stool volume. It also helps in reduction of formation potentially toxic short chain fatty acids e.g propionate or butyrate.

The recommended dose of lactulose is about 15-30ml given twice a day. Lactitol, an alternative to lactulose is considered equally effective and is used in patients intolerant of lactulose, but it is not available in some countries. Lactulose can also be administered orally through a nasogastric tube to unresponsive patients as well as rectally through enemas. The most common side effects associated with over use include dehydration, electrolyte imbalance and abdominal cramping [62] .

Antibiotics [63] 

Patients intolerant to nonabsorable disaccharides are generally treated with antibiotics, to suppress the bacteria involved in ammonia genesis. There are few antibiotics which have been used for the treatment of HE which had shown limited benefit, which include neomycin, metronidazole, oral vancomycin, oral fluroquinolones like Norfloxacin [64] and very recently Rifaximin. In fact neomycin was used for treatment of HE for many years based on earlier studies then in early 1990's a double blind randomized controlled trial had no improvement in HE. And also because of its limited systemic absorption which would lead to ototoxicity and nephrotoxicity has lost its use in HE in liver cirrhosis.

Rifaximin, a minimally absorbed oral antibiotic has been approved by FDA for the treatment of chronic HE, on the basis of results of a multicenter, randomized, controlled trials and metanalysis. Recently a RCT had shown benefit in prevention of recurrent hepatic encephalopathy over period of 6 months follow up.. Some small studies have also reported the effectiveness of vancomycin and metronidazole, but the data to support their use is not enough.


Zinc deficiency has been reported in patients with liver cirrhosis and related neurologic dysfunction. Moreover, reduced zinc concentrations inversely correlate with blood ammonia and experimental studies showed that zinc supplementation improves ammonia detoxification through urea genesis by increasing liver ornithine transcarbamylase activity [65] . Existing RCTs on oral zinc supplementation to cirrhotic patients, however, have shown conflicting results.

Branch chain amino acids (BCCA) [66] :

As it has been hypothesized that in liver cirrhosis, there has been reversal of aromatic amino acids (AAA) to BCCA which could lead to encephalopathy in patients with cirrhosis. Encephalopathy is presumably caused by increase in levels of AAA for monoamine neurotransmission which lead to transformed neuronal excitability and causing HE. Hence numbers of studies have been done to evaluate the effects of BCCA on HE. BCCA can be given orally as well as in infusion form.

Agents used for GABA hypothesis pathway [67] :

GABA receptor complex is the principal inhibitory network in nervous system and seems to be a contributor to neuronal inhibition in HE. This GABA receptor complex contains barbiturates and benzodiazepine receptor sites, chloride channels and a GABA binding site. In cirrhosis, there is an evidence for increase in benzodiazepine receptor ligands in subjects with HE, therefore effects of benzodiazepine receptor antagonist have been evaluated. Flumazenil, a GABAA receptor antagonist also improves the symptoms in patients with grade 3 or 4 HE but its use is limited due to adverse effects. It has been seen that response to treatment with flumazenil is rapid onset with few minutes and then with few hours, more than half of these patients deteriorated with 2-3 hours. Because of its short duration effect and variable results of different studies, flumazenil cannot be recommended as routine therapy.

Acarbose [68] 

A hypoglycemic agent and an intestinal α-glucosidase inhibitor which causes decrease in blood ammonia levels and improves mild HE in patients with cirrhosis. It has also been hypothesized that Acarbose promotes the proliferation of intestinal saccharolytic bacterial flora while reducing proteolytic flora that produce mercaptans, benzodiazepine like substances and ammonia as well.

Benzyl benzoate:

Sodium benzoate, sodium phenyl acetate and sodium phenyl butyrate are ammonia excretors , shown to improve HE but clear efficacy has not been established yet. Sodium phenyl acetate and Ammonal are the only drugs approved by the Food and Drug Administration for the treatment of acute hyperammonemia and associated encephalopathy in patients with urea cycle disorders [69] 

L-Ornithine L-Aspartate [70] , [71] , [72] 

Chemical stucture of L-Ornithine L-Aspartate


L-ornithine-L-aspartate (LOLA) is a stable salt composed of two natural amino acids. LOLA provides critical substrates for ureagenesis and glutamine synthesis, the two primary mechanisms by which the body rids itself of excess ammonia. According to the results of published studies, LOLA is more effective than placebo in reducing blood ammonia and in ameliorating patient mental status and psychometric performance.

L-Ornithine [73] :

L-ornithine is a "non-protein," non-essential amino acid. Amino acids are the building blocks that make up protein structures, such as animal muscle tissue. L-ornithine is considered non-essential because our bodies make it from the amino acid L-arginine.

Physiological role:

Ornithine is essential for making urea, which removes nitrogen and ammonia from the body, eliminating toxins. The body uses L-ornithine to synthesize arginine, proline and other amino acids.


Natural sources include meat, fish, dairy and eggs.

L-Aspartate [74] , [75] :

L-Aspartic acid is a non-essential amino acidused for the synthesis of L-Asparagine, proteins, pyrimidine and purine nucleoties, and neurotransmitter NMDA.. It is glycogenis in nature and plays active role in transamination and deamination reactions.

Physiological role:

Helps in the formation of carbamyl phosphate and arginosuccinic acid in the urea cycle. The potassium or magnesium salt of aspartic acid is useful in physiological cellular functions.


Found in plenty in plants, especially in sprouting seeds. .It is also found in dairy, beef, poultry, sugar cane and molasses.

Mechanism of action of LOLA in HE:

Urea cycle plays a key role in ammonia metabolism and its excretion by forming urea in periportal hepatocytes or synthesis of glutamine in perivenous hepatocytes. But in cirrhosis, the activities of carbamyl phosphate synthetase enzyme (Urea synthesis) and of glutamine synthesis (glutamine synthesis) are impaired which in turn lead to increased level of ammonia. Therefore L-Ornithine and L-Aaspartate has been used for reducing the ammonia levels by increasing the metabolism of ammonia to glutamine.

Figure :

CO2 + NH3

Carbomoyl phosphate synthase




Ornithine Carbomoyl transferase

Arginosuccinate synthase



Arginosuccinate lyase






Ornithine is a specific activator of ornithine carbamyl transferase and carbamylphosphate synthetase, and, in addition, is a substrate for ureagenesis. These reactions are carried out mainly in the periportal portion of the hepatic lobules. Aspartate combines with citrulline to form Argino-succinate in the urea cycle.

Figure :


Glutamate semialdehyde


Alpha ketoglutarate




Alpha ketoglutarate

Glutamine Synthase




Aspartate and ornithine, after conversion to alfa-ketoglutarate, are substrates for glutamine synthesis, which is performed exclusively by a small population of perivenous hepatocytes, the so-called perivenous scavenger cells and in skeletal muscle.

The ammonia lowering effect resulting from the stimulation of these two basic mechanisms of ammonia detoxification has been studied in animals and was confirmed in humans in clinical trials.

Pharmacokinetics :

LOLA is available both as oral and intravenous formulations. The bioavailability of LOLA when administered orally is 82.2 ± 28%. After absorbtion L-Ornithine L-aspartate is cleaved into l-ornithine and L-Aspartate. Elimination half life is 40 minutes, some L-Aspartate appears unchanged in urine. The recommended dose of L-Ornithine L-Aspartate is 20 g by infusion and 6 g orally LOLA crosses the blood brain barrier.

Toxicology tests and Adverse reactions:

Toxicology tests on rats and dogs gave no effect even at 1500 mg/kg. it does not have teratogenic effects. Adverse reactions are minimal. 5%of mild gastro-intestinal disturbances (nausea, vomiting) occurs with infusion therapy.


L-Ornithine L-Aspartate is primarily indicated in conditions like Hepatic encephalopathy, Hepatitis, Jaundice, Liver cirrhosis and can also be given in adjunctive therapy as an alternative drug of choice inTuberculosis.

Contraindications :

LOLA is not recommended for patients with severe renal function due to the increased formation of urea.

Drug interactions:

LOLA is not known to have interaction with other medications.

Synbiotics [76] 

Colonic bacteria clearly play a major role in the pathogenesis of major complications in patients with liver cirrhosis. By producing ammonia and endotoxins they can cause hepatic encephalopathy , and their translocation from the gut to the peritoneal cavity is the major mechanism for spontaneous bacterial peritonitis. There are also new studies suggesting a possible connection between bacterial translocation and bleeding from esophageal varices.

Some of the therapeutic measures for the treatment and prevention of complications in cirrhotic patients, such as antibiotics and lactulose, are partially directed against gut bacteria. Synbiotics refer to nutritional supplements combining Probiotics and Prebiotics that are thought to act together; i.e. synergism.

Probiotics [77] 

'Probiotics' is derived from a Greek word meaning "for life". They are live organisms, when ingested in adequate amounts, exerts a beneficial effect to the host. They are non-pathogenic organisms isolated from the same species as its intended host, having a demonstrable beneficial effect on the host. There are several commercially available supplements containing viable micro-organisms with probiotic properties.

Probiotics include lactobaccillus, Bacillus, propionibacterium, saccharomyces etc.


Prebiotics are "non-digestible food ingredients that beneficially affect the host by selectively stimulating the growth and/or activity of one or a limited number of bacteria in the colon".

Some of the prebiotics commonly used are -





Breast milk oligosaccharides


Synbiotics have to be administered orally. Synbiotics have been shown to be resistant to the action of gastric juice and intestinal juice including bile. They can therefore pass unaffected through the upper GI tract and colonize in the lower GI tract when taken orally. Probiotics are not hydrolyzed or absorbed in the stomach or small intestine, whereas, it is selective for beneficial commensal bacteria in the large intestine.

Fermentation of the substrate induces beneficial luminal/systemic effects within the host. the daily dose related to body weight or to the gastrointestinal mucosal surface is generally much larger in experimental animals and in pediatric cases. In the majority of studies, the daily dose used in humans has been 1 billion lactic acid bacteria (LAB) once or twice per day, up to 10 billion organisms/day. Larger doses delivered more impressive results.

Mechanism of action:

1. Decreases total ammonia in the portal blood by:

(a) decreasing bacterial urease activity,

(b) decreasing ammonia absorption by decreasing pH,

(c) decreasing intestinal permeability,

(d) improving nutritional status of gut epithelium.

2. It Reduces inflammation and oxidative stress in the hepatocyte, leading to increased hepatic clearance of ammonia and other toxins.

3. Decreases uptake of other toxins.

The probiotic bacteria, among which the most common are the lactose fermenting Lactobacilli, inhibit the growth of pathogenic bacteria by acidifying the gut lumen, competing for nutrients, and by producing antimicrobial substances. They adhere to the gut mucosa and by that are thought to prevent bacterial translocation from the gut.

Therapeutic use:

In recent years there is a growing interest in the effect of probiotic bacteria on gut flora and prevention of infection. They were found to prevent pediatric infectious diarrhea and antibiotic-associated diarrhea- especially those caused by Clostridium difficile.

These effects of probiotics raised the idea that they may have a role in the treatment and prevention of cirrhosis complications. A recent study examined the effect of probiotics on patients with minimal chronic hepatic encephalopathy.

Hepatic encephalopathy was reversed in 50% of the patients receiving probiotics. These patients also demonstrated a significant reduction of blood levels of ammonia, bilirubin and ALT, and of pathologic bacteria in stool cultures. This study showed promising results but was carried out on a relatively small population. Furthermore, the effect of probiotics on the prevention of hepatic encephalopathy and other major complications of cirrhosis has not been studied yet. Therefore, more studies are needed to establish the role of probiotics in patients with cirrhosis.

Study drug: L-Ornithine L-Aspartate + Synbiotic (NOVOZEN)

The study drug is a combination of L-Ornithine L-Aspartate and Synbiotics.

Product information:


Outer capsule contains- L-Ornithine L-Aspartate 150 mg

Inner capsule contains-

Streptococcus faecalis T- 110- 30 million

Clostridium butyricum TOA- 2 million

Bacillus mesentricus TOA- 1 million

Lactobacillus spoogenes- 50 million

Dosage : One capsule twice daily for 14 days

Rationale of conducting the study-

Hyperammonemia in patients with advanced liver disease arises by multiple mechanisms. Prevention of the generation and absorption ammonia in the gut has been the primary focus of the treatments for HE. Another approach to this problem is to promote the excretion of waste nitrogen. This can be approached by enhancing what remains of the liver capacity for ureagenic and glutamine synthesis, or by providing substances that fix ammonia and get excreted in the urine.

L-ornithine L-aspartate (LOLA) is a substrate for the metabolism and conversion of ammonia to urea and glutamine. Its effects are mediated as follows:

L-Ornithine, an intermediate of the urea cycle, promotes urea synthesis.

LOLA promotes glutamine synthesis in skeletal muscle, wich is used as a substrate for glutamate production by glutamine synthetase. Both L-ornithine and L-aspartate are substrates for transamination reactions that result in the production of glutamate. [78] 

Experimental studies with animals show that LOLA is effective in lowering blood ammonia concentration and preventing of cerebral edema in acute liver failure; studies with humans in which LOLA was compared with disaccharides or a placebo, show that it is an effective treatment for hepatic encephalopathy [79] .

The efficacy of LOLA for reducing serum ammonia level and increasing hepatic neuropsychiatric status in encephalopathy has been studied for many years.

The study done by Pérez Hernández JL, supports the adoption of LOLA infusion as a treatment for clinical encephalopathy in patients with liver failure, because it has been shown to improve neuropsychiatric status and decrease serum levels of ammonia with a low incidence of adverse effects [80] 

According to the study done by Blanco Vela CI, LOLA was shown to be superior to a placebo for management of HE.  LOLA is effective not only in reducing hyperammonemia and the severity of this disease, but also in improving the patient's perceived quality of life [81] .

As per the study done by JL Poo et al ,oral administration of lactulose or L-ornithine - L-aspartate to Mexican patients with cirrhosis and hyperammonemic encephalopathy significantly reduced serum ammonia levels in study groups and additionally improved mental status parameters, number connection test, asterixis scores, and EEG activity in the group receiving L-ornithine-L-aspartate. [82] 

126 patients with hyperammonemia and hepatic encephalopathy were enrolled in a double blin randomized controlled trial conducted by Kircheis G, Nilius R, Held C et al. it was found that OA infusion appears to be a safe, effective treatment of chronic (persistent) manifest HE in cirrhotic patients [83] 

Oral L-ornithine-L-aspartate is a safe, well-tolerated treatment with a good compliance rate and a beneficial therapeutic effect in patients with cirrhosis and stable, overt, chronic hepatic encephalopathy. [84] 

Synbiotics modulatev gut flora and decrease ammonia producing bacteria and is found to be useful in HE. Synbiotics is a combination of prebiotic and probiotic.

Prebiotic- non digestible dietary supplement stimulating the growth and or activity of beneficial organisms and suppressing potentially deleterious bacteria.

Probiotic- live microbial feed supplement, which beneficially affects the host by improving the host's intestinal microbial balance.

 McGee RG, et al conducted a meta-analysis based on 7 clinical trials of probiotics in which 550 participants were randomized. 4 of the 7 trials compared a probiotic with placebo or no treatment in 245 participants, another trial compared a probiotic with lactulose in 40 participants , and the remaining 2 trials compared a probiotic with both placebo and lactulose in 265 participants. Each trial used different types of probiotics. Duration of administration of the experimental intervention varied from 10 days to 180 days. Probiotics appeared to reduce plasma ammonia concentration when compared with placebo or no intervention [85] .

97 outpatients diagnosed with hepatic cirrhosis were treated with synbiotics. The author concluded that synbiotics or fermentable fiber can be instituted as an alternative to use of non-absorbable disaccharides, such as lactulose, for the management of MHE in patients with cirrhosis, since, significant reductions in viable counts of potentially pathogenic gut flora occured with both treatments [86] .

Meta-analysis of nine studies which used prebiotics, probiotics and synbiotics were undertaken by Shukla S et al. It was found that, they significantly reduced the pooled relative risk (RR) of no improvement of MHE (RR 0.40, 95% CI 0.32-0.50; P<0.001). Upon subgroup analysis, five studies with lactulose showed significant reduction of risk of no improvement of MHE (RR 0.34, 95% CI 0.24-0.47; P<0.0001) with no inter-trial heterogeneity. In two trials each of probiotics and synbiotics, their use was associated with significant beneficial effects (RR 0.41, 95% CI 0.26-0.65; P<0.0001 and RR of 0.51, 95% CI 0.32-0.80; P=0.004 respectively). There were no major adverse events though probiotics and synbiotics were better tolerated than lactulose.The use of prebiotics, probiotics and synbiotics was associated with significant improvement in minimal hepatic encephalopathy [87] .

The safety and efficacy of synbiotics and LOLA therapy in the management of hepatic encephalopathy have been established by the above studies. The mechanism of action of synbiotics and lola are different. A combination of both may be more effective in improving the clinical features of encephalopathy. Since no studies has been conducted to evaluate this combination, this study has been undertaken to evaluate the efficacy and tolerability of lola and synbiotic in patients with HE Grade II/III.


To evaluate the efficacy and tolerability of L-Ornithie L-Aspartate +synbiotics in patients with Grade II/III Hepatic encephalopathy


Study design: A randomized, open label, comparative study

Study centre: Department of Hepatology,

Rajiv Gandhi Government General hospital,

Madras medical college.

Study period: June 2011 - july 2012

Study duration : 2 weeks

Study population: Patients with Grade II/III Hepatic encephalopathy in Rajiv Gandhi

Government General Hospital

Sample size: 40 (20+20)

Inclusion criteria:

Age- 20 to 50 years

Sex- both genders

Cirrhosis of liver with grade II/III hepatic encephalopathy

Subject willing to give Written informed consent

Subject is capable and willing to comply with all study procedures

Exclusion criteria:

Patients with Hepatic encephalopathy (grade 1, 4 )

Hepatic encephalopathy due to metabolic causes, intracranial disorders and toxins

H/O Hypersensitivity to any of the component's study medication

H/O Recent GI bleed (<6 weeks)

H/O Infection / recent (<6 weeks) antibiotic use

Subject has active malignancy

Subject with alcoholic cirrhosis who still consumes alcohol

Subject has electrolyte imbalance

Subject has significant systemic illness

Subject participated in an investigational drug or device study within 30 days prior to study screening

Subject has been diagnosed with HIV as determined by medical history

Pregnant or lactating women

Subject is anemic, as defined by Hb level of <8 gm/dL

Study procedure:

The study was conducted after obtaining the approval from Institutional Ethics Committee. Patients with clinical features of Grade II/III Hepatic Encephalopathy admitted for treatment as inpatient in the Department of Hepatology and their Caregivers were briefed about the study purpose and procedures.

Written informed consent obtained from subjects willing to participate in the study, in the prescribed format in regional language prior to the performance of any study related procedures. If the patient was illiterate, left thumb impression was sought. This was done in the presence of an impartial witness.

The subjects were screened by case history, clinical examination and laboratory investigations. Subjects who fulfill the inclusion and exclusion criteria were recruited for the study. They were randomized to either of the study groups and treated for a period of 2 weeks.

Figure :


(Laboratory investigations, psychometric tests, clinical examination)


(Inclusion and Exclusion criteria)












Laboratory investigations

Complete hemogram

Blood sugar

Blood Urea

Serum creatinine

Serum electrolytes

Serum bilirubin,



Alkaline phosphatase,

Total proteins

Serum ammonia,

Neuropsychological testing:

Psychometric performance is assessed using

-Line Tracing Test (figure : )

-Number Connection Test (figure : )






The laboratory parameters were analyzed with the physical examination and clinical features. Patients who fulfilled the inclusion and exclusion criteria were enrolled for study and the demographic profiles with address and contact number were recorded.


The enrolled patients were randomized into either Control group or Test group and received the respective therapy by simple randomization.

Treatment plan:

Group A(20 pts) :

Standard therapy - Syp. Lactulose 2 tsp thrice daily for 2 weeks

Tab. Norfloxacin 400 mg twice daily for 7 days ,

Group B(20 pts) :

Test drug with Standard therapy

- Cap. L-Ornithine L-Aspartate + Synbiotic (NOVOZEN) twice daily

for 2 weeks along with

- Standard therapy


Day 0 (Baseline visit/Visit 1):

Clinical examination was done

Blood invetigations done

Psychometric performance assessed with Line Tracing and Number Connection Test

Test control and standard drugs issued for respective groups

Day 7 (Visit 2):

Empty drug sachets were received

Drugs issued for next week

Clinical examination was done

Patient was assessed with line tracing test and number connection test.

Day 14: [Visit 3]

Received the empty sachets

Clinical examination was done

Blood investigations were done

Patients were assessed with line tracing test and number connection test.

Adverse drug effects :

Patients were enquired Adverse events and the same recorded. Patients were adviced to report to investigator as soon as possible in case of any adverse drug effects or occurrence other illness or consumption of concomitant medications

Withdrawal from Study

In case of adverse effect related to study medication is observed by the physician or reported during the study period, the patient will be withdrawn from the study. Patient will be given appropriate treatment . During the trial the subject can withdraw his/her voluntary consent.

Statistical analysis:

The obtained Data was analyzed statistically. Distribution of age was analysed using ANOVA method. Sex distribution was analyzed by Chi square test.

All the laboratory parameters were performed on Day 0 and Day 14. The difference inbetween the groups before and after treatment were analysed using student's paired t-test. Whereas the difference between the Control and Test groups on Day 0 and Day 14 were analyzed using One Way ANOVA method.

The Line Tracing and Number Connection test were performed by the patient on Day 0, Day 7 and Day 14. Therefore it is analyzed by Repeated measures of ANOVA method. The difference between the Control and the Test groups on the three visits were analyzed using Student's unpaired t-test. p Value of less than 0.05 is considered to be significant.

Results table



No. of patients

Mean age

Standard deviation

One way Anova

F test










Figure : 1

Table -1 shows

Age distribution among control and test groups

There is no significant difference ( p = o.463) between the mean age of patients in the control and test group

Figure -1 shows the age distribution of patients in the control and test group

Table -2 : Gender distribution

Study Group

No. Of Patients

Sex Distribution

























Figure : 2

Table -2 shows

The distribution of male and female patients in the 2 study groups

The male and female population were equal in both groups

Male population was more in both groups

Figure -2 shows diagrammatic representation of sex distribution of patients in control and test group

Table -3 : Blood sugar


Day 0

Day 14


















Figure : 3

Table- 3 shows

The mean blood sugar values in control and test groups.

The mean blood sugar value at the baseline and at the end of the study did not change significantly ( p= 0.661) in both groups.

Figure- 3 is the diagrammatic representation of mean blood sugar of both the study groups.

Table -4 : Blood urea:


Before treatment

After treatment


















Figure -4

Table- 4 shows

The mean Blood Urea levels in control and test groups.

The mean Blood Urea levels at the baseline and at the end of the study did not change significantly ( p= 0.295) in both groups.

Figure- 4 is the diagrammatic representation of mean blood urea levels of both the study groups

Table -5 :Serum creatinine


Before Treatment

After Treatment















One Way Anova



Figure :5

Table -5 shows

The mean Serum Creatinine values in control and test groups.

The mean Serum Creatinine value at the baseline and at the end of the study did not change significantly ( p= 0.106) in both groups.

Figure- 5 is the diagrammatic representation of mean Serum Creatinine values of both the study groups

Table -6 : Serum Sodium


before treatment

after treatment