␤-Cell dysfunction is an important factor in the development of hyperglycemia of type-2 diabetes mellitus, and pancreatic islet amyloidosis (IA) has been postulated to be one of the main contributors to impaired insulin secretion. The aim of this study was to evaluate the correlation of IA with metabolic parameters and its effect on islets of Langerhans remodeling and relative endocrine-cell volume in baboons. We sequenced the amylin peptide, determined the fibrillogenic propensities, and evaluated pancreatic histology, clinical and biochemical characteristics, and endocrine cell proliferation and apoptosis in 150 baboons with different metabolic status. Amylin sequence in the baboon was 92% similar to humans and showed superimposable fibrillogenic propensities. IA severity correlated with fasting plasma glucose (FPG) (r ‫؍‬ 0.662, P < 0.001) and HbA1c (r ‫؍‬ 0.726, P < 0.001), as well as with free fatty acid, glucagon values, decreased homeostasis model assessment (HOMA) insulin resistance, and HOMA-B. IA severity was associated with a decreased relative ␤-cell volume, and increased relative ␣-cell volume and hyperglucagonemia. These results strongly support the concept that IA and ␤-cell apoptosis in concert with ␣-cell proliferation and hypertrophy are key determinants of islets of Langerhans ''dysfunctional remodeling'' and hyperglycemia in the baboon, a nonhuman primate model of type-2 diabetes mellitus. The most important determinants of IA were age and FPG (R 2 ‫؍‬ 0.519, P < 0.0001), and different FPG levels were sensitive and specific to predict IA severity. Finally, a predictive model for islet amyloid severity was generated with age and FPG as required variables.amyloid deposits ͉ non-human primates ͉ insulin resistance ͉ islet of Langerhans ͉ type-2 diabetes mellitus T ype-2 diabetes mellitus (T2DM) is a chronic metabolic disorder characterized by insulin resistance in liver, muscle, and adipose tissue, as well as progressive ␤-cell dysfunction leading to hyperglycemia (1-3). Hyperglycemia and islet amyloidosis (IA) have been implicated in the progressive loss of ␤ cells in T2DM (4, 5). The prevalence of IA has been reported to range from 40 to 90% in T2DM individuals, and from 7% to 33% in nondiabetic controls (6 -11). Islet amyloid pancreatic polypeptide (IAPP) is the major constituent of pancreatic amyloid deposits (12, 13). In humans, monkeys, and cats, but not in mice and rats, IAPP has an amyloidogenic-promoting region, which resides within amino acids 20 to 29. Abnormalities in IAPP processing and secretion have been proposed as important contributors to the formation of IA (14 -17). Of note, IA and ␤-cell apoptosis have been observed in normal human islets transplanted into diabetic nude mice, as well as in the liver of type-1 diabetic patients transplanted with human islets (18,19).IA can cause ␤-cell death by occupying extracellular space, thereby impairing nutrients and oxygen uptake. In addition, small IAPP oligomers can form nonselective ion-permeable membrane pores, leading to increased...

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ObjectiveObesity is associated to high insulin and glucagon plasma levels. Enhanced β–cell function and β–cell expansion are responsible for insulin hypersecretion. It is unknown whether hyperglucagonemia is due to α-cell hypersecretion or to an increase in α-cell mass. In this study, we investigated the dynamics of the β-cell and α-cell function and mass in pancreas of obese normoglycemic baboons.MethodsPancreatic β- and α-cell volumes were measured in 51 normoglycemic baboons divided into 6 groups according to overweight severity or duration. Islets morphometric parameters were correlated to overweight and to diverse metabolic and laboratory parameters.ResultsRelative α-cell volume (RαV) and relative islet α-cell volume (RIαV) increased significantly with both overweight duration and severity. Conversely, in spite of the induction of insulin resistance, overweight produced only modest effects on relative β-cell volume (RβV) and relative islet β-cell volume (RIβV). Of note, RIβV did not increase neither with overweight duration nor with overweight severity, supposedly because of the concomitant, greater, increase in RIαV. Baboons' body weights correlated with serum levels of Interleukin-6 and Tumour Necrosis Factor-α soluble Receptors (IL-6sR and sTNF-R1), demonstrating that overweight induces abnormal activation of the signaling of two cytokines known to impact differently β- and α-cell viability and replication.ConclusionIn conclusion, overweight and insulin resistance induce in baboons a significant increase in α-cell volumes (RαV, RIαV) while have minimal effects on the β-cells. This study suggests that an increase in the α-cell mass may precede the loss of β-cells and the transition to overt hyperglycemia and diabetes.

von Willebrand's disease (VWD) is the most commonly inherited bleeding disorder. For a long time, it has been said that VWD was absent in some countries due to ethnical differences. Information about the prevalence of VWD in Mexico remains unclear, owing largely to poor awareness and diagnosis of the disease. The aim of this study was to objectively diagnose VWD in a cohort of highly selected Mexican patients with a chronic history of bleeding. Mexican Mestizos were recruited between July 2010 and August 2011. Included were 133 adult and paediatric patients with a high suspicion of VWD. Fifty-three were diagnosed with VWD: 47 (88.7%) with type 1 VWD, four (7.5%) with type 2a VWD and two (3.8%) with type 3 VWD. Mean age for female patients was 19.5 years (range 3-44 years) and 18.5 years (range 4-63 years) for male patients. Mean age at start of bleeding symptoms was 8.8 years (range 1-61). The most frequent clinical symptoms were epistaxis (84.9%), ecchymosis (79.2%), haematomas (71.7%), gum bleeds (62.3%) and petechia (50.9%). Severe transoperative or postoperative bleeding was found in 17 patients (32.1%). Twenty-six women at childbearing age had a history of abnormal gynaecological bleeding. Our results clearly demonstrate the presence of VWD in Mexican and underscore the importance of a more detailed description of VWD. Efforts to increase the awareness and diagnosis of VWD could help in better identification of patients with bleeding disorders and lead to early, appropriate management with safe and efficacious therapies such as desmopressin and plasma concentrates.

The kallikrein-kinin (K-K) (contact) system is activated during acute and chronic relapsing phases of enterocolitis induced in genetically susceptible Lewis rats by intramural injection of peptidoglycan-polysaccharide (PG-APS). Using the selective plasma kallikrein inhibitor P8720, we investigate whether activation of the K-K system plays a primary role in chronic granulomatous intestinal and systemic inflammation in this model. Group I (negative control) received human serum albumin intramurally. Group II (treatment) received PG-APS intramurally and P8720 orally. Group III (positive control) received PG-APS intramurally and albumin orally. P8720 attenuated the consumption of the contact proteins, high molecular weight kininogen (P<0.03), and factor XI (P<0.04) in group II vs. group III. P8720 decreased chronic intestinal inflammation measured by blinded gross (P<0.01) and histologic (P<0.0005) scores as well as systemic complications (arthritis, splenomegaly, hepatomegaly, leukocytosis, and acute-phase reaction) (P<0.01) in group II as compared with group III. We conclude that relapsing chronic enterocolitis and systemic complications are in part due to plasma K-K system activation, and that inhibition of this pathway is a potential therapeutic approach to human inflammatory bowel disease and associated extraintestinal manifestations.