The remission concept in type 1 diabetes and its significance in immune intervention

The influence of sodium metavanadate on the process of diabetogenesis in BB rats

Vanadium has been shown to be beneficial in the oral treatment of animal models of type 1 and type 2 diabetes. The aim of the study was to evaluate the short-term effects of sodium metavanadate in prediabetic BB-DP rats. To do this, 96 rats were divided into 4 equal groups. Groups V1, V2, V3 were treated with sodium metavanadate (0.1, 0.2 and 0.3 mg/ml respectively) and sodium chloride (0.5 mg/ml) in drinking water for 7 days. Group C received only sodium chloride (0.5 mg/ml). Blood glucose (BG), glycosuria, ketonuria, body weight and insulinemia were determined. The age of onset of diabetes was significantly higher for groups V2, V3 compared to group C, (p<0.05) and depends on the metavanadate concentration (V3 vs. V1, p=0.006). The incidence of diabetes was lower in the rats treated with metavanadate than in the control group, but this difference was not statistically significant. In diabetic rats, the BG at the onset was higher in group C than in groups V, p<0.05. Insulinemia, at the onset of the treatment as well as immediately after its cessation showed a drop in the treatment groups, proportionally to the dosage of vanadium, but later increased slowly and continuously until the end of the experiment. In conclusion, metavanadate delays the development of diabetes in BB-DP rats, but does not prevent its onset. A milder form of diabetes occurs in diabetic rats treated with metavanadate. The effects depend on the metavanadate concentration and 0.2 mg/ml is preferable.

Severe autoimmune hepatitis in patients with previous spontaneous recovery of a flare

BACKGROUND/AIMS

Autoimmune hepatitis can present acutely and pursues a variable, usually progressive course. Spontaneous remissions have been described, but their influence on the course of subsequent attacks has not yet been studied.

METHODS

Charts from 1980 to 2000 were reviewed. Cases of autoimmune hepatitis were further examined to identify those with prior episodes of transient elevation of the serum aminotransferase activities of unknown etiology.

RESULTS

Fifty-one patients with autoimmune hepatitis were identified, nine of whom (18%) had experienced a transient episode of elevated aminotransferase activities which had resolved spontaneously. The median period of time separating the two flares was 10 months (range: 4 months-23 years). The median age at diagnosis was 41 years in both groups. More than 75% of the patients in either group suffered from a type 1 autoimmune hepatitis. Importantly, patients with spontaneous recovery of a previous episode had a higher serum alanine transaminase activity (P<0.02), were less likely to respond to immunosuppressive therapy (78 versus 98%, P=0.077) and required transplantation more frequently (22 versus 0%, P=0.028). Histologically, these patients did not have more fibrosis than patients without previous flare.

CONCLUSIONS

More than 10% of autoimmune hepatitis may begin with a spontaneously resolving episode. However, the spontaneous recovery of a previous attack should not falsely reassure: a subsequent flare of autoimmune hepatitis can still be severe.

Influence of streptozotocin-induced diabetes in rats on the lithium content of tissue and the effect of dietary lithium supplements on this diabetic condition

To study the effects of lithium supplementation on the diabetic condition, we measured the lithium concentration in the liver, kidney, and muscle from streptozotocin (STZ)-induced diabetic male Sprague-Dawley (SD) rats that were either treated or untreated with peroral lithium carbonate (0.3 mg/mL). The data showed that the lithium content of the liver and muscle was significantly lower in STZ rats than in normal control rats (0.22 +/- 0.05 v 1.30 +/- 0.15, P < .01, and 0.79 +/- 0.30 v 2.48 +/- 2.00 microg/g, respectively). After 4 weeks of lithium carbonate supplementation, we found that (1) the lithium content of the liver and muscle returned to the normal range, (2) the extent of STZ-mediated destruction of beta cells in the pancreas decreased, (3) fasting blood glucose (FBG) and 2-hour postprandial blood glucose (PBG) decreased (P < .05), (4) among the indicators of oxidative stress and antioxidant defenses, blood lipid peroxidate (LPO) decreased and erythrocyte superoxide dismutase (RBC-SOD) and glutathione (GSH) returned to normal, and (5) hepatic LPO decreased and glutathione peroxidase (GSH-Px) increased. These results suggest that the restoration of lithium to control levels in the liver and muscle of diabetic animals is associated not only with decreased blood glucose but also with reduced oxidative stress, and consequently with the protection of insulin-secreting pancreatic islet cells.

Partial preservation of pancreatic beta-cells by vanadium: evidence for long-term amelioration of diabetes

Streptozotocin (STZ)-diabetic rats treated with vanadium can remain euglycemic for up to 20 weeks following withdrawal from vanadium treatment. In this study, we examined the effects of short-term vanadium treatment in preventing or reversing the STZ-induced diabetic state. Male Wistar rats were untreated (D) or treated (DT) with vanadyl sulfate for 1 week before administering STZ. Treatment was subsequently maintained for 3 days (DT3) or 14 days (DT14) post-STZ, after which vanadium was withdrawn. At 4 to 5 weeks post-STZ and following long-term withdrawal from vanadium, DT14 rats demonstrated levels of food and fluid intake and glucose tolerance that were not significantly different from those of age-matched untreated nondiabetic rats, and had significantly reduced glycemic levels in the fed state compared with D and DT3 groups. The proportion of animals that were euglycemic (fed plasma glucose < 9.0 mmol/L) was significant in DT14 (five of 10) relative to D (one of 10) and DT3 (one of 10) (P = .01). All euglycemic animals had an improved pancreatic insulin content that, albeit low (12% of control), was strongly linked to euglycemia in the fed state (r = -.91, P < .0001). Moreover, the highly significant correlation persisted with the analysis of untreated STZ-rats alone (r = -.95, P < .0001). Similarly, improvements in glucose tolerance and insulin secretory function in euglycemic rats were strongly correlated with small changes in residual insulin content. Hence, as vanadium pretreatment did not prevent STZ-induced beta-cytotoxicity, the vanadium-induced amelioration of the diabetic state appears to be secondary to the preservation of a functional portion of pancreatic beta cells that initially survived STZ toxicity. The partial preservation of pancreatic beta cells, albeit small in proportion to the total insulin store, was both critical and sufficient for a long-term reversal of the diabetic state. These results suggest that apparently modest effects in preserving residual pancreatic insulin content can have profound consequences on glucose homeostasis and may bear important implications for interventions that have "limited" protective effects on beta cells.