Dose-dependent effects of oral misoprostol on renal function in alcoholic cirrhosis

Treatment and management of ascites and hepatorenal syndrome: an update

Ascites and renal dysfunction are frequent complications experienced by patients with cirrhosis of the liver. Ascites is the pathologic accumulation of fluid in the peritoneal cavity, and is one of the cardinal signs of portal hypertension. The diagnostic evaluation of ascites involves assessment of its granulocyte count and protein concentration to exclude complications such as infection or malignoma and to allow risk stratification for the development of spontaneous peritonitis. Although sodium restriction and diuretics remain the cornerstone of the management of ascites, many patients require additional therapy when they become refractory to this treatment. In this situation, the treatment of choice is repeated large-volume paracentesis. Alteration in splanchnic hemodynamics is one of the most important changes underlying the development of ascites. Further splanchnic dilation leads to changes in systemic hemodynamics, activating vasopressor agents and leading to decreased renal perfusion. Small alterations in renal function influence the prognosis, which depends on the cause of renal failure. Prerenal failure is evident in about 70% of patients, whereas in about 30% of patients the cause is hepatorenal syndrome (HRS), which is associated with a worse prognosis. Therefore, effective therapy is of great clinical importance. Recent data indicate that use of the new definition of acute kidney injury facilitates the identification and treatment of patients with renal insufficiency more rapidly than use of the current criteria for HRS. In this review article, we evaluate approaches to the management of patients with ascites and HRS.

Minimizing risks of NSAIDs: cardiovascular, gastrointestinal and renal

Nonsteroidal anti-inflammatory drugs (NSAIDs) are effective in treating inflammation, pain and fever, but their cardiovascular, renal and gastrointestinal toxicity can result in significant morbidity and mortality to patients. Techniques for minimizing the adverse risks of NSAIDs include avoiding use of NSAIDs where possible, particularly in high-risk patients; keeping NSAID dosages low; prescribing modified-release and enteric-coated NSAIDs; prescribing cyclooxygenase-2-selective inhibitors where appropriate; monitoring for early signs of side effects; prescribing treatments designed to minimize NSAID side effects; and developing new therapeutic strategies beyond the inhibition of cyclooxygenase. All of the above strategies can be useful in reducing the risk of NSAID complications. The optimal use and management of NSAIDs involves an individualized paradigm approach to establish efficacy with optimal tolerability given the patient risk factors for adverse events.

Review article: current management of renal dysfunction in the cirrhotic patient

The United Network for Organ Sharing database revealed that over the last 4-5 years, an average of 1800 patients were removed from the cadaveric waiting list annually because of patients' death and an additional 400-500 were removed from the list because of the severity of their illnesses. The pre-transplant evaluation process, therefore, requires careful and continued assessment of the patient's pulmonary, cardiac and renal function among others. This article describes a systematic approach to the evaluation and management of renal dysfunction complicating the course of advanced liver disease, the pathogenic mechanisms and current recommendations for the treatment of hepatorenal syndrome, and the indications for combined liver-kidney transplantation.

Misoprostol therapeutics revisited

Misoprostol, a prostaglandin E1 analog, is a racemate of four stereoisomers. On administration it rapidly de-esterifies to its active form, misoprostolic acid. Misoprostolic acid is 85% albumin bound and has a half-life of approximately 30 minutes. It is excreted in urine as inactive metabolites. No significant drug interactions have been reported. Besides its gastrointestinal protective and uterotonic activities, misoprostol regulates various immunologic cascades. It inhibits platelet-activating factor and leukocyte adherence, and modulates adhesion molecule expression. It protects against gut irradiation injury, experimental gastric cancer, enteropathy, and constipation. It improves nutrient absorption in cystic fibrosis. Misoprostol has utility in acetaminophen and ethanol hepatotoxicity, hepatitis, and fibrosis. It is effective in asthmatics and aspirin-sensitive asthmatic and allergic patients. It lowers cholesterol and severity of peripheral vascular diseases, prolongs survival of cardiac and kidney transplantation, synergizes cyclosporine, and protects against cyclosporine-induced renal damage. It works against drug-induced renal damage, interstitial cystitis, lupus nephritis, and hepatorenal syndrome. It is useful in periodontal disease and dental repair. Misoprostol enhances glycosoaminoglycan synthesis in cartilage after injury. It prevents ultraviolet-induced cataracts and reduces intraocular pressure in glaucoma and ocular hypertension. It synergizes antiinflammatory and analgesic effects of diclofenac or colchicine and has been administered to treat trigeminal neuralgic pain. It reduces chemotherapy-induced hair loss and recovery time from burn injury, and is effective in treating sepsis, multiple sclerosis, and pancreatitis.

Effects of misoprostol on lipoprotein (a) levels of ovariectomized rats

OBJECTIVE

To determine the effects of misoprostol on plasma lipoprotein (a) concentrations of ovariectomized rats.

DESIGN

Controlled prospective study.

SETTING

Animal research laboratory.

ANIMAL(S)

Four-month-old female Sprague-Dawley rats.

INTERVENTION(S)

Blood samples were obtained before and 60 days after ovariectomy, and the rats were divided into three groups. Group I (five rats) was treated with vehicle (water); groups II and III (nine and eight rats, respectively) were treated with oral misoprostol at 100 and 200 microg/kg/d, respectively, for 60 days, after which blood was drawn again.

MAIN OUTCOME MEASURE(S)

Serum lipoprotein (a) levels.

RESULT(S)

The median lipoprotein (a) level before ovariectomy was 10.8 mg/dL (range, 10.6-46.5 mg/dL). Sixty days after ovariectomy, the level increased significantly to 15.9 mg/dL (range, 10.6-36.9 mg/dL). After treatment, there was no change in lipoprotein (a) levels in the vehicle-treated group (range, 16.3-21.1 mg/dL); however, the lipoprotein (a) levels decreased significantly in the group treated with 100 microg/kg/d of misoprostol, from 15.4 mg/dL to 10.8 mg/dL, and in the group treated with 200 microg/kg/d of misoprostol, from 17.1 mg/dL to 10.6 mg/dL.

CONCLUSION(S)

Misoprostol caused a significant decrease in lipoprotein (a) levels.

Effects of misoprostol on bone loss in ovariectomized rats

This study was performed to investigate whether misoprostol (prostaglandin E1 analogue) (Cytotec, Searle, England) is effective for restoration of bone loss. Four-month-old parous female Sprague-Dawley rats (n = 30) were subjected either to bilateral ovariectomy (OVX, 24 rats) or to sham surgery (sham, 6 rats). The OVX rats were divided into four groups 60 days after the surgery. Six of them were killed, and dual-energy X-ray absorption (Norland xr-36, Norland Corporation, Fort Atkinson, WI, USA) measurements were performed, called pretreatment OVX group. The remaining groups (each had 6 rats) treated orally with 0 (control), 100, 200 micrograms/kg/day misoprostol for 60 days. All rats were killed 60 days after having treatment, and bone loss of the lumbar spine was measured by dual-energy X-ray absorption. The bone mineral density was decreased by 25.4% in control group and 23.6% in pretreatment group compared to sham group, but restored by 86% and 96% in groups treated with 100 and 200 micrograms/kg/day misoprostol, respectively. These results suggest that misoprostol restores bone loss in the lumbar spine of OVX rats in a dose-dependent manner.

Ascites and hepatorenal syndrome: pathophysiology and management

Ascites, a late manifestation of cirrhosis of the liver, causes increased morbidity and mortality. The renin-angiotensin-aldosterone system, the sympathetic nervous system, and arginine vasopressin are responsible for sodium and water retention in patients with cirrhosis. Fluid localizes to the peritoneal cavity mainly as a result of portal hypertension. Recent developments in the understanding of the pathophysiologic mechanisms of ascites include the role of inadequate renal prostaglandin production in the development of the hepatorenal syndrome and the possible role of nitric oxide in the pathogenesis of the renal complications of cirrhosis. The aim of medical therapy is to achieve a negative sodium balance and, consequently, fluid loss. Large-volume paracentesis is safe and effective in the management of tense ascites, but use of diuretic agents should be continued to prevent reaccumulation of ascites. Liver transplantation, transjugular intrahepatic portosystemic shunts, or LeVeen shunts should be considered in selected patients with persistent ascites. In patients with diuretic-resistant or diuretic-refractory ascites, a thorough assessment must be performed to exclude potentially reversible causes. The hepatorenal syndrome has an associated grave prognosis, especially in patients who are not candidates for liver transplantation.

Liver cirrhosis induces renal and liver phospholipase A2 activity in rats

Maintenance of renal function in liver cirrhosis requires increased synthesis of arachidonic acid derived prostaglandin metabolites. Arachidonate metabolites have been reported to be involved in modulation of liver damage. The purpose of the present study was to establish whether the first enzyme of the prostaglandin cascade synthesis, the phospholipase A2(PLA2) is altered in liver cirrhosis induced by bile duct excision. The mRNA of PLA2(group I and II) and annexin-I a presumptive inhibitor of PLA2 enzyme was measured by PCR using glyceraldehyde 3-phosphate dehydrogenase (GAPDH) as an internal standard. The mean mRNA ratio of group II PLA2/GAPDH was increased in liver tissue by 126% (P < 0.001) and in kidney tissue by 263% (P < 0.006) following induction of liver cirrhosis. The increase in group II PLA2 mRNA in cirrhotic animals was reflected by an increase in PLA2 protein and enzyme activity in both liver and kidney tissues. Since the mRNA of group I PLA2 was not detectable and Group IV PLA2 activity measured in liver and kidney tissue samples was very low and not changed following induction of cirrhosis, it is likely that the major PLA2 activity measured in liver and kidney corresponds to group II PLA2 enzyme. The mean mRNA ratio of annexin-I/GAPDH was increased in liver tissue by 115% (P < 0.05) but unchanged in kidney tissue following induction of cirrhosis. The protein content of annexin-I and -V were not affected by bile duct excision in liver and kidney tissue indicating that upregulation of group II PLA2 activity was not due to downregulation of annexin-I or -V. Group II PLA2 activity of glomerular mesangial cells stimulated by interleukin-1 beta was enhanced by bile juice and various bile salts. In conclusion, activity of group II PLA2 is upregulated partly due to enhanced transcription and translation in cirrhosis and is furthermore augmented by elevated levels of bile salts.

The effects of chronic administration of indomethacin and misoprostol on renal function in cirrhotic patients with and without ascites

BACKGROUND

Non-steroidal anti-inflammatory drugs (NSAIDs) often cause renal dysfunction in cirrhotic patients with ascites through inhibition of prostaglandin synthesis. However, their renal effects in cirrhotic patients without ascites are controversial. In addition, the role of prostaglandins in cirrhotic patients with ascites and in non-ascitic cirrhotic patients receiving NSAIDs also remains elusive. Thus we evaluated the chronic renal effects of indomethacin and misoprostol in 9 cirrhotic patients with ascites (protocol 1) and 21 cirrhotic patients without ascites (protocol 2).

METHODS

The patients of protocol 1 received 200 micrograms of misoprostol every 6 h for 7 consecutive days. In protocol 2, 11 patients received 25 mg indomethacin three times a day for 7 consecutive days. The other 10 patients received 25 mg indomethacin three times a day plus 200 micrograms misoprostol every 6 h for 7 consecutive days. Renal function tests, plasma renin activity, and plasma aldosterone concentration were measured before and after treatment.

RESULTS

In protocol 1, misoprostol tended to reduce the urinary sodium excretion (p = 0.08). In protocol 2, indomethacin alone greatly impaired renal plasma flow (p < 0.05), creatinine clearance (p < 0.05), blood urea nitrogen (p < 0.05), and serum creatinine (p = 0.06) in 11 patients. Similar magnitudes of renal dysfunction were observed in the other 10 patients despite the concomitant misoprostol treatment.

CONCLUSION

Chronic administration of misoprostol may have caused a negative natriuretic effect in cirrhotic patients with ascites. In cirrhotic patients without ascites chronic administration of indomethacin may induce a renal dysfunction that cannot be reversed by misoprostol.

The effect of misoprostol on indomethacin-induced renal dysfunction in well-compensated cirrhosis

BACKGROUND/AIMS

Indomethacin has been shown to have adverse effects on renal function in patients with well-compensated alcoholic cirrhosis. The aim of this study was to determine whether an oral prostaglandin E1 analogue, misoprostol, could prevent this indomethacin-induced renal dysfunction.

METHODS

Six patients with well-compensated alcoholic cirrhosis were studied. Renal hemodynamics and tubular function were assessed by clearance techniques before and after an oral dose of (i) 50 mg of indomethacin alone (I50), and (ii) a combination of I50 and 200 micrograms of misoprostol.

RESULTS

I50 produced a significant reduction in glomerular filtration rate, a fall in effective renal plasma flow and an increase in renal vascular resistance. Two hundred micrograms of misoprostol was able to abolish the deleterious renal effects of indomethacin totally, yielding an increase in glomerular filtration rate and effective renal plasma flow and a decrease in renal vascular resistance as well as an increase in urinary volume and urinary sodium excretion. These beneficial effects were maximal in the hour immediately following medication, but were only transient, and this may be a limiting factor in its clinical use.

CONCLUSIONS

If the beneficial renal effects of misoprostol could be confirmed after chronic administration, then the vasodilatory, natriuretic and diuretic potential of 200 micrograms of misoprostol could be of potential therapeutic value in patients with well-compensated alcoholic cirrhosis who require non-steroidal anti-inflammatory drug therapy.