Acute and repeated dose (28 days) toxicity studies in rats and dogs of recombinant batroxobin, a snake venom thrombin-like enzyme expressed from Pichia pastoris.

Recombinant batroxobin is a thrombin-like enzyme of Bothrops atrox moojeni venom. To evaluate its toxicological effect, it was highly expressed in Pichia pastorisand successfully purified to homogeneity from culture broth supernatant following Good Manufacturing Practice (GMP). The maximum tolerated dose of the recombinant batroxobin was examined in Sprague-Dawley (SD) rat and Beagle dogs following Good Laboratory Practice (GLP) regulations. The approximate lethal dose of recombinant batroxobin was 10 National Institute of Health (NIH) u/kg in male and female rats. Slight test substance-related effects were clearly in male and female dogs at more than 10 NIH u/kg. The maximum tolerated dose (MTD) was considered to be greater than 30 NIH u/kg in dogs. To investigate the repeated dose toxicity of batroxobin, the test item was intravenously administered to groups of SD rat and Beagle dog every day for 4 weeks. We observed that all animals survived the duration of the study without any effects on their mortality. There were no effects in both rats and dogs regarding their clinical signs, body weight, food consumption, ophthalmological examination, urinalysis, hematology, clinical chemistry, organ weightand gross post mortem examinations. The no adverse effect level (NOAEL) of recombinant batroxobin for both males and females is considered to be greater than 2.5 NIH u/kgin rats and 1 NIH u/kg in dogs, respectively. No toxic effects were noted in target organs. In conclusion, these results show a favorable preclinical profile and may contribute clinical development of recombinant batroxobin.

Antihyperglycemic effect of short-term arginyl-fructose supplementation in subjects with prediabetes and newly diagnosed type 2 diabetes: randomized, double-blinded, placebo-controlled trial.

BACKGROUND: A previous study reported that arginyl-fructose may have great value as a functional food with antioxidant and antidiabetic activities. However, there have been few clinical studies on the efficacy of arginyl-fructose supplementation for blood glucose control. METHODS: In this double-blind, placebo-controlled study, 60 Korean subjects with prediabetes or type 2 diabetes mellitus were randomly assigned to placebo or test groups. The test group subjects received 1500 mg/day arginyl-fructose. Fasting serum levels of glucose, hemoglobin A1c, insulin, and free fatty acids were measured by 2-hour oral glucose tolerance tests at baseline and after the 6-week intervention. Eleven subjects dropped out or were excluded during the trial. The data for the remaining 49 were statistically analyzed using Student's t-test and paired t-test. RESULTS: After the 6-week intervention, the test group showed significant reductions in serum glucose levels at 30 minutes (-19.4 ± 5.62 mg/dL) and 60 minutes (-15.4 ± 7.01 mg/dL) and reduced glucose area under the curve (-27.4 ± 8.59 mg/dL) compared with those of the placebo control group. The changes (differences from baseline) in serum glucose levels at 60 minutes and glucose area under the curve in the test group differed significantly from those in the control group even after adjusting for baseline values. In contrast, glucose-related biomarkers including hemoglobin A1c, insulin, and C-peptide levels were not significantly improved by the dietary intervention with arginyl-fructose. CONCLUSIONS: Arginyl-fructose supplementation (1500 mg/day) may be beneficial for reducing postprandial blood glucose levels in patients with prediabetes or type 2 diabetes mellitus. TRIAL REGISTRATION: ClinicalTrials.gov NCT02285231 . Registered 11 May 2014.