Diabetes remission and glycemic response to pre-bariatric surgery diet.

BACKGROUND: Before bariatric surgery, some patients with type 2 diabetes mellitus (T2DM) experience improvement in blood glucose control and reduced insulin requirements while on a preoperative low-calorie diet (LCD). We hypothesized that patients who exhibit a significant glycemic response to this diet are more likely to experience remission of their diabetes in the postoperative period. MATERIALS AND METHODS: Insulin-dependent T2DM patients undergoing bariatric surgery between August 2006 and February 2011 were eligible for inclusion. Insulin requirements at day 0 and 10 of the LCD were compared. Patients with a ≥ 50% reduction in total insulin dosage to maintain appropriate blood glucose control were considered rapid responders to the preoperative LCD. All others were non-rapid responders. We analyzed T2DM remission rates up to 1 y postoperatively. RESULTS: A total of 51 patients met inclusion criteria and 29 were categorized as rapid responders (57%). The remaining 22 were considered non-rapid responders (43%). The two groups did not differ demographically. Rapid responders had greater T2DM remission rates at 6 (44% versus 13.6%; P = 0.02) and 12 mo (72.7% versus 5.9%; P < 0.01). In patients undergoing laparoscopic gastric bypass, rapid responders showed greater excess weight loss at 3 mo (40.1% versus 28.2%; P < 0.01), 6 mo (55.2% versus 40.2%; P < 0.01), and 12 mo (67.7% versus 47.3%; P < 0.01). CONCLUSIONS: Insulin-dependent T2DM bariatric surgery patients who display a rapid glycemic response to the preoperative LCD are more likely to experience early remission of T2DM postoperatively and greater weight loss.

Degradation of the disease-associated prion protein by a serine protease from lichens.

The disease-associated prion protein (PrP(TSE)), the probable etiological agent of the transmissible spongiform encephalopathies (TSEs), is resistant to degradation and can persist in the environment. Lichens, mutualistic symbioses containing fungi, algae, bacteria and occasionally cyanobacteria, are ubiquitous in the environment and have evolved unique biological activities allowing their survival in challenging ecological niches. We investigated PrP(TSE) inactivation by lichens and found acetone extracts of three lichen species (Parmelia sulcata, Cladonia rangiferina and Lobaria pulmonaria) have the ability to degrade prion protein (PrP) from TSE-infected hamsters, mice and deer. Immunoblots measuring PrP levels and protein misfolding cyclic amplification indicated at least two logs of reductions in PrP(TSE). Degradative activity was not found in closely related lichen species or in algae or a cyanobacterium that inhabit lichens. Degradation was blocked by Pefabloc SC, a serine protease inhibitor, but not inhibitors of other proteases or enzymes. Additionally, we found that PrP levels in PrP(TSE)-enriched preps or infected brain homogenates are also reduced following exposure to freshly-collected P. sulcata or an aqueous extract of the lichen. Our findings indicate that these lichen extracts efficiently degrade PrP(TSE) and suggest that some lichens could have potential to inactivate TSE infectivity on the landscape or be a source for agents to degrade prions. Further work to clone and characterize the protease, assess its effect on TSE infectivity and determine which organism or organisms present in lichens produce or influence the protease activity is warranted.