Macrophage migration inhibitory factor is an important mediator in the pathogenesis of gastric inflammation in rats

Methimazole prevents stress and chemical induced gastropathy in rats

This investigation was undertaken to study the effect of methimazole (MMI) on gastric acid secretion and stress and chemically induced gastric ulcer in rats. Acid secretion studies were undertaken using pylorus-ligated rats pretreated with MMI (10-100 mg/kg, i.p.). The effect of orally administered MMI on water-immersion restraint (WIR) stress, indomethacin and ethanol-induced gastric ulcers was also tested. The level of myeloperoxidase (MPO), non-protein sulfhydryls (NP-SH) and gastric wall mucus was measured in the glandular stomach of rats following ethanol-induced gastric lesions. There was a dose-dependent inhibition of gastric acid secretion and ulcerogen induced gastric lesion formation in the MMI treated rats. Our morphological and histological studies showed a complete prevention of ethanol-induced lesions in the rats treated with high dose (100 mg/kg) of MMI. A significant attenuation of ethanol-induced increase in gastric MPO activity, depletion of NP-SH and reduction of gastric wall mucus was also observed in MMI treated rats. These findings clearly suggest the involvement of endogenous pro-inflammatory agents and oxidative stress in mediating the gastroprotective effect of MMI.

Liver function disturbances following laparoscopic cholecystectomy: incidence and significance

BACKGROUND

Unexplained disturbances of liver function parameters after laparoscopic cholecystectomy have been reported in a few previous studies. We aimed to assess the incidence of these disturbances, and their relation to age, sex, duration of surgery, and type of gallbladder inflammation, as well as their clinical significance.

PATIENTS AND METHODS

All patients undergoing laparoscopic cholecystectomy at Dallah Hospital, Riyadh, Saudi Arabia, during the year 2001 were prospectively evaluated. In all the patients, six parameters of liver function (direct bilirubin, indirect bilirubin, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, and gamma-glutamyltransferase) were assessed before and 24 hours after surgery. Patients with suspected chronic liver disease or common bile duct pathology were excluded. Patients who showed more than a 100% increase in at least one parameter (group I) were compared with those who did not (group II) regarding age, sex, duration of surgery, and type of gallbladder inflammation.

RESULTS

Of the patients, 67.1% showed more than a 100% increase in at least one parameter of liver function. No significant difference was noticed between the two groups regarding age, duration of surgery, or type of gallbladder inflammation. Female patients, however, showed a significantly higher incidence of liver function changes (P = .011). No clinical adverse reactions were reported in those who showed liver function changes.

CONCLUSION

Changes in liver function parameters after laparoscopic cholecystectomy are common, carrying no clinical sequalae. They are more common in female patients and are not related to age, duration of surgery, or the acuteness of gallbladder inflammation. Assessment of direct bilirubin and alkaline phosphatase is sufficient for the routine evaluation of these patients postoperatively.

Macrophage migration inhibitory factor (MIF) plays a pivotal role in immunity against Salmonella typhimurium

The cytokine macrophage migration inhibitory factor (MIF) exerts a multitude of biological functions. Notably, it induces inflammation at the interface between the immune system and the hypothalamus-pituitary-adrenal stress axis. The role of MIF in infectious diseases is not understood completely. Here, we show that MIF-deficient (MIF(-/-)) knockout mice fail to control an infection with wild-type Salmonella typhimurium. Increased susceptibility was accompanied by a reduced Th1 response, demonstrated by decreased levels of IL-12, IFNgamma, and tumor necrosis factor alpha. In Salmonella-infected MIF(-/-) mice, levels of IL-1beta were markedly increased. Additionally, infected MIF(-/-) mice showed elevated serum levels of nitric oxide and corticosterone as compared with control mice. Our results point to MIF as a key mediator in the host response to S. typhimurium. MIF not only promotes development of a protective Th1 response but ameliorates disease by altering levels of reactive nitrogen intermediates and corticosteroid hormones, which both exert immunosuppressive functions.

Macrophage migration inhibitory factor in drug-induced liver injury: a role in susceptibility and stress responsiveness

Idiosyncratic drug-induced hepatitis may depend upon many factors including a balance between pro- and anti-inflammatory mediator production levels. Using a guinea pig model of liver injury induced by bioactivation of the anesthetic drug, halothane, we found that toxicity was commensurate with an increase in serum macrophage migration inhibitory factor (MIF), a pro-inflammatory signal and counter-regulator of glucocorticoids, but only in susceptible animals. The pathogenic role of MIF was further investigated using a murine model in which liver injury was induced by the reactive metabolite of another drug, acetaminophen (APAP). MIF leakage from the liver into the sera preceded peak increases in toxicity following APAP administration. MIF null (-/-) mice were significantly less susceptible to this toxicity at 8 h. At 48 h following a 300 mg/kg dose, complete lethality was observed in wild-type mice, while 46% survival was noted in MIF-/- mice. The decreased hepatic injury in MIF-/- mice correlated with a reduction in mRNA levels of interferon-gamma and a significant increase in heat shock protein expression, but was unrelated to the APAP-protein adduct formation in the liver. These findings support MIF as a critical pro-toxicant signal in drug-induced liver injury with potentially important and novel effects on heat shock protein responsiveness.