Anti-sickling effect of MX-1520, a prodrug of vanillin: an in vivo study using rodents.

Vanillin, a food additive, covalently binds with sickle haemoglobin (Hb S), inhibits cell sickling and shifts the oxygen equilibrium curve towards the left. These effects would potentially benefit patients with sickle cell disease (SCD). However, vanillin has no therapeutic effect if given orally because orally administered vanillin is rapidly decomposed in the upper digestive tract. To overcome this problem, a vanillin prodrug, MX-1520, which is biotransformed to vanillin in vivo, was synthesized. Studies using transgenic sickle mice, which nearly exclusively develop pulmonary sequestration upon exposure to hypoxia, showed that oral administration of MX-1520 prior to hypoxia exposure significantly reduced the percentage of sickled cells in the blood. The survival time under severe hypoxic conditions was prolonged from 6.6 +/- 0.8 min in untreated animals to 28.8 +/- 12 min (P < 0.05) and 31 +/- 7.5 min (P < 0.05) for doses of 137.5 and 275 mg/kg respectively. Intraperitoneal injection of MX-1520 to bypass possible degradation in the digestive tract showed that doses as low as 7 mg/kg prolonged the survival time and reduced the percentage of sickled cells during hypoxia exposure. These results demonstrate the potential for MX-1520 to be a new and safe anti-sickling agent for patients with SCD.

A dithiocarbamate analogue decreases intraislet cell infiltration and the incidence of diabetes mellitus in the genetic diabetes-prone BB rat.

SUMMARY: Dithiocarbamates are a class of agents that have interesting biologic properties including the ability to limit the production and/or action of nitric oxide (NO). These agents are also potential immunosuppressant agents. Since immunosuppressant agents have been examined for remission of disease in clinical trials, we wanted to examine whether a dithiocarbamate analogue, NOX-200, might inhibit diabetogenesis in the genetic diabetes-prone BB rat model. Immunohistochemical analysis revealed inducible NO synthase (iNOS) gene expression in pancreatic islets of both normoglycemic and hyperglycemic diabetes-prone BB rats but not in diabetes-prone BB rats at the early age of 30 days or in diabetes-resistant BB rats. A qualitative decrease in immunostaining for iNOS was also observed in the pancreata of drug-treated animals. Long-term treatment with NOX-200, used alone or in combination with low-dose cyclosporine (CsA), significantly reduced the incidence of diabetes mellitus. In the subset of animals that became diabetic, NOX-200 did not alter either the time to onset of hyperglycemia or the level of hyperglycemia, insulinopenia, or lymphocytic cell infiltration into the pancreas. In contrast, in animals that did not develop hyperglycemia, treatment with NOX-200 decreased inflammatory cell infiltration into the pancreas equipotent to that seen using CsA. These studies demonstrate the potential therapeutic efficacy of dithiocarbamates to oppose the development of autoimmune insulin-dependent diabetes mellitus by limiting inflammatory cell activation/infiltration.

Chronic or delayed treatment with an oral dithiocarbamate analog decreases glycation and protects diabetic arteries.

In the present study, we examined the efficacy of a dithiocarbamate-based compound, denoted as NOX-700, on diabetes-induced endothelial dysfunction and glycosylation of hemoglobin (Hb). Streptozotocin-induced diabetic rats received 3 mg/ml NOX-700 in drinking water beginning at 72 h or 4 weeks and continued to 8 weeks. Oxidative and glycooxidative stress were examined by electrophoretic mobility shift assay (EMSA) for nuclear factor-kappaB (NF-kappaB) in nuclear fractions of aortic homogenates and by glycosylated Hb, respectively. Vascular reactivity was examined in aortic ring segments ex vivo. Treatment with NOX-700 inhibited glycosylated Hb formation when given long-term or after delayed administration. NOX-700 improved endothelium-dependent relaxation to acetylcholine but did not alter reactivity to norepinephrine or nitroglycerin, suggesting selective protection of the endothelium. Nuclear factor-kappaB (NF-kappaB) nuclear binding activity was significantly increased in diabetic aortas and abrogated by NOX-700. Thus, vascular protection by NOX-700 is believed to be mediated, in part, by an antioxidant mechanism and decreased protein glycation.

A novel nitric oxide scavenger in combination with cyclosporine A ameliorates experimental autoimmune encephalomyelitis progression in mice.

Immunotherapy improves experimental autoimmune encephalomyelitis (EAE), a model of multiple sclerosis (MS), while excessive production of nitric oxide (NO) has been implicated in the pathogenesis of this disease. Here, we show that disease progression in SJL/J mice with EAE is improved after treatment with either a subtherapeutic dose of cyclosporine A (CsA) or NOX-100, a nitric oxide scavenger. Importantly, the impact of subtherapeutic doses of CsA in combination with NOX-100 on disease progression in EAE was greater than that attained with either agent alone and led to near total protection. CNS inflammation and gene expression of proinflammatory cytokines and iNOS were also significantly reduced after treatment. These observations point to the potential therapeutic utility of NOX-100 as a dose-reducing agent for CsA in the treatment of MS.