Autoimmunity during alpha-interferon therapy for chronic hepatitis C

Neuroprotective effect of quercetin on the duodenum enteric nervous system of streptozotocin-induced diabetic rats

BACKGROUND

In diabetes mellitus (DM), hyperglycemia promotes changes in biochemical mechanisms that induce oxidative stress. Oxidative stress has been closely linked to adverse consequences that affect the function of the gastrointestinal tract caused by injuries to the enteric nervous system (ENS) that in turn cause neurodegeneration and enteric glial loss. Therapeutic approaches have shown that diet supplementation with antioxidants, such as quercetin, reduce oxidative stress.

AIMS

This work sought to evaluate neurons and enteric glial cells in the myenteric and submucosal plexuses of the duodenum in diabetic rats supplemented with quercetin.

METHODS

The duodenum of 24 rats, including a control group (C), control quercetin supplementation group (CQ), diabetic group (D), and diabetic quercetin supplementation group (DQ), were used to investigate whole mounts of muscular and submucosal layers subjected to immunohistochemistry to detect vasoactive intestinal peptide in the myenteric layer and double-staining for HuC-D/neuronal nitric oxide synthase (nNOS) and HuC-D/S100.

RESULTS

A reduction of the general neuronal population (HuC/D) was found in the myenteric and submucosal plexuses (p < 0.001) in the D and DQ groups. The nitrergic subpopulation (nNOS) decreased only in the myenteric plexus (p < 0.001), and glial cells decreased in both plexuses (p < 0.001) in the D and DQ groups. In diabetic rats, quercetin supplementation reduced neuronal and glial loss. Diabetes promoted an increase in the cell body area of both the general and nitrergic populations. Quercetin supplementation only prevented neuronal hypertrophy in the general population.

CONCLUSION

Supplementation with quercetin eased the damage caused by diabetes, promoting a neuroprotective effect and reducing enteric glial loss in the duodenum.

[Interferon therapy and autoimmunity]

The treatment of viral hepatitis or malignomas with interferon (IFN) can increase the incidence of autoimmune disease. This paper reviews published case and study reports. The incidence of overt autoimmune diseases under IFN treatment is about 3%. Autoantibodies can be detected in 23% of the patients. Autoimmune thyroid diseases are the most frequent ones, but nearly all autoimmune diseases can occur. Beside benign and reversible courses chronic developments and lethal outcomes are possible. Actual concepts concerning the pathogenesis of IFN-associated autoimmunity include induction of MHC and other molecules as well as the modulation of lymphocyte functions. Clinical and paraclinical controls are necessary under treatment with IFN and during follow-up.

Interferon-alpha-2a. A review of its pharmacological properties and therapeutic use in the management of viral hepatitis

Interferon-alpha-2a is a recombinant interferon with antiviral, antitumour and immunomodulatory properties. Clinical studies have demonstrated that the drug offers therapeutic benefit in patients with some forms of chronic viral hepatitis. Remission, as measured by clearance of viral DNA and hepatitis B 'e' antigen (HBeAg), and normalisation of serum alanine aminotransferase levels, is observed in approximately 30 to 45% of patients with chronic hepatitis B receiving interferon-alpha-2a (2.5 to 18MU administered 3 times/week); about 5 to 15% of untreated controls remit spontaneously every year. Complete recovery [with loss of hepatitis B surface antigen (HBsAg)] is usually noted in < 20% of treated individuals. Similar response rates have been reported in the relatively small number of children evaluated to date. Although numerous studies have shown that interferon-alpha-2a (at various dosages) induces biochemical amelioration of chronic hepatitis C in approximately 50 to 75% of patients, relapse is common. Thus, long term remission may only be observed in about 15 to 30% of treated patients. On the other hand, this disorder remits spontaneously in only a few patients. The role of interferon-alpha-2a in the treatment of chronic hepatitis D remains unclear. Although preliminary data suggest it may be beneficial, cessation of therapy is generally followed by relapse. As with other types of interferons, most patients receiving interferon-alpha-2a experience an 'influenza-like' syndrome, which tends to diminish with continuing therapy. Other effects such as fatigue, lethargy, anorexia and weight loss are usually dose-limiting. Serum neutralising antibodies develop in approximately 10 to 20% of treated patients. Thus, although response rates are less than optimal, interferon-alpha-2a is a drug of first choice amongst the limited therapeutic options available for the management of well-compensated chronic viral hepatitis B or C.

Silicone breast implants: immunotoxic and epidemiologic issues

Silicone gel implants for breast augmentation and reconstruction have been in use since 1962. Significant local complications include capsular contracture, rupture, gel "bleed", and spread of the implant material to regional lymph nodes (1-7) as well as histologic findings of foreign body granulomas in the capsular tissue and in lymph nodes (7-9). Through magnetic resonance spectroscopy and atomic emission spectroscopy, silicon compounds were found in the blood of some women with silicone breast implants; silicone and silica have also been found in liver (10). Well-publicized case reports have raised significant concerns regarding an association between implants and systemic disease. However, despite the availability of silicone implants for over 30 years, controlled epidemiological studies were not carried out until 1992. Currently available epidemiologic data are extremely limited. In part, because the majority of implants were used after 1981, the incidence of long-term problems is not yet known. In 1992, due to the unavailability of studies demonstrating the safety of implants, the U.S. Food and Drug Administration advised that silicone breast implants should be used only in reconstructive surgery and as part of clinical trials (11). This decision spurred a wave of research on the bioreactivity of silicone and clinical observations of patients with implants. Herein, we review the adverse immune effects following contact with silicone as well as the epidemiologic data available.