Immunosuppressive therapy in pancreas and islet transplant: Need for simultaneous assessment of insulin sensitivity and secretion

Diabetes mellitus is a metabolic disease possible to treat via pancreas/islet transplantation but most immunosuppressive drugs are diabetogenic. In this letter, we review current up to date methods to assess insulin action and secretion (using the surrogate indexes) suggesting their use in large studies in populations of pancreas/ islets transplanted patients.

Pioglitazone does not modify ANP levels of type 2 diabetic patients

Background: The atrial natriuretic peptide (ANP) regulates fluid volume redistribution between heart and the pulmonary vessels. In diabetic patients the physiological action of ANP appears to be seriously altered. Methods: 12 subjects (gender 6M/6F, age 47 ± 2 years, BMI 29.1 ± 0.1 kg/m2), with type 2 diabetes and under stable conditions, were studied after one month of pioglitazione treatment (30 mg/die) by means of isotonic blood volume expansion. Results: After one month of pioglitazone treatment the meta- bolic profile of the subjects improved (decrease dia- stolic blood pressure: p = 0.05, total cholesterol: p = 0.01, triglycerides: p = 0.03 and blood glucose: p = 0.01) as the expansion of their plasma volume was found associated with the decrease of hematocrit (p < 0.05). The statistical comparison before versus after pioglitazone showed a significant decrease in the ba- sal aldosterone levels post-treatment (p < 0.04). Nonetheless ANP plasma levels were similar before and after therapy. Conclusions: The inappropriately high concentrations of ANP induced by hyperglyce-mia and the abnormal responses to a physiological sti- mulus like an isotonic blood volume expansion are not reverted by one month of pioglitazone. This is in contrast with the brisk improvement of the metabolic profile seen for the same period of treatment. ANP secretion is modified by fluid load in diabetic patients. This anomaly is not reverted by pioglitazone.

Plasma Citrulline: A New Marker of Gut Epithelium Alteration in Obese Patients?

Objectives: In the last decade gut microbial diversity was associated with the pathogenesis of obesity in humans. Plasma citrulline was a simple and accurate biomarker for the severity of intestinal failure and was associated with short bowel syndrome and alteration of gut permeability, being developed as an alternative to D-xylose tolerance test for the diagnosis of an abnormal small intestinal absorption of nutrients. This study was performed to ascertain whether obesity might be associated with dysregulation of epithelial gut function. Methods: Fifteen obese individuals (5 M/10 F;BMI 37.4 ± 6.1 Kg/m2;42 ± 6 yrs) and 15 healthy gender- and age-matched controls (6 M/9 F BMI: 22.7 ± 2.1 Kg/m2;39 ± 7 yrs) underwent D-xylose load (25 g) and plasma citrulline, plasma insulin, glucose and lipid profile testing. Results: Plasma citrulline was significantly lower in the obese group (p = 0.045) with respect to controls, whilst total cholesterol, LDL and trygliceri- des concentration, insulin level and HOMA-IR were significantly higher in obese patients. In contrast, after D-xylose load no difference in serum xylose was found between the two groups (p = ns). Conclusions: Obese patients show a decreased citrulline concentration with respect to lean subjects. Since citrulline is a known marker of intestinal health, alterations in the gut epithelium are likely to be associated with the obesity syndrome. We propose to measure citrulline level in obese patients on a routine basis.