Playing with Biophysics: How a Symphony of Different Electromagnetic Fields Acts to Reduce the Inflammation in Diabetic Derived Cells.

Several factors, such as ischemia, infection and skin injury impair the wound healing process. One common pathway in all these processes is related to the reactive oxygen species (ROS), whose production plays a vital role in wound healing. In this view, several strategies have been developed to stimulate the activation of the antioxidative system, thereby reducing the damage related to oxidative stress and improving wound healing. For this purpose, complex magnetic fields (CMFs) are used in this work on fibroblast and monocyte cultures derived from diabetic patients in order to evaluate their influence on the ROS production and related wound healing properties. Biocompatibility, cytotoxicity, mitochondrial ROS production and gene expression have been evaluated. The results confirm the complete biocompatibility of the treatment and the lack of side effects on cell physiology following the ISO standard indication. Moreover, the results confirm that the CMF treatment induced a reduction in the ROS production, an increase in the macrophage M2 anti-inflammatory phenotype through the activation of miRNA 5591, a reduction in inflammatory cytokines, such as interleukin-1 (IL-1) and IL-6, an increase in anti-inflammatory ones, such as IL-10 and IL-12 and an increase in the markers related to improved wound healing such as collagen type I and integrins. In conclusion, our findings encourage the use of CMFs for the treatment of diabetic foot.

A structured therapeutic education program for children and adolescents with type 1 diabetes: an analysis of the efficacy of the "Pediatric Education for Diabetes" project.

BACKGROUND: Therapeutic education for Type 1 Diabetes involves the process of transmitting knowledge and developing the skills and behavior required to treat the disease. guidelines agree on stressing the importance of therapeutic educational intervention in teaching self-management skills to children and adolescents with Type 1 Diabetes (T1D). This study presents the results of the "Pediatric Education for Type 1 Diabetes (T1D)" (PED) project, specifically designed for children and adolescents aged 6 to 16, and structured on guidelines indications, as part of a broader clinical-educational intervention for Type 1 diabetes. METHODS: Twenty-four patients with Type 1 diabetes (mean age: 12,13 y; SD=1.48 y; range 9-14) were studied in a 12-month PED structured project followed by an educational summer camp. All the activities were designed and organized by a multidisciplinary team (dietitian, pediatric diabetologist, nurse, psychologist and adult diabetologist). Glycated hemoglobin (HbA1C), knowledge about Type 1 Diabetes (T1D) (self-monitoring and nutrition), self-management (self-monitoring, nutrition and flexibility of medical treatment), and wellbeing were used as outcome measures. RESULTS: Data suggest that the PED had a positive impact on all the targeted levels indicated for recommended care. CONCLUSIONS: The results of this study seem to confirm the effectiveness in altering the three levels of "knowing," "know-how" and "wellbeing" required to optimize the quality of life of young patients with Type 1 diabetes. In addition, the proposed model, where a pediatric diabetologist always cooperates with an adult diabetologist, seems to be a permanent solution to the transitional gap widely discussed in the literature.

Intensive Risk Factor Management and Cardiovascular Autonomic Neuropathy in Type 2 Diabetes: The ACCORD Trial.

OBJECTIVE: The effects of preventive interventions on cardiovascular autonomic neuropathy (CAN) remain unclear. We examined the effect of intensively treating traditional risk factors for CAN, including hyperglycemia, hypertension, and dyslipidemia, in individuals with type 2 diabetes (T2D) and high cardiovascular risk participating in the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial. RESEARCH DESIGN AND METHODS: CAN was defined as heart rate variability indices below the fifth percentile of the normal distribution. Of 10,251 ACCORD participants, 71% (n = 7,275) had a CAN evaluation at study entry and at least once after randomization. The effects of intensive interventions on CAN were analyzed among these subjects through generalized linear mixed models. RESULTS: As compared with standard intervention, intensive glucose treatment reduced CAN risk by 16% (odds ratio [OR] 0.84, 95% CI 0.75-0.94, P = 0.003)-an effect driven by individuals without cardiovascular disease (CVD) at baseline (OR 0.73, 95% CI 0.63-0.85, P < 0.0001) rather than those with CVD (OR 1.10, 95% CI 0.91-1.34, P = 0.34) (P interaction = 0.001). Intensive blood pressure (BP) intervention decreased CAN risk by 25% (OR 0.75, 95% CI 0.63-0.89, P = 0.001), especially in patients ≥65 years old (OR 0.66, 95% CI 0.49-0.88, P = 0.005) (P interaction = 0.05). Fenofibrate did not have a significant effect on CAN (OR 0.91, 95% CI 0.78-1.07, P = 0.26). CONCLUSIONS: These data confirm a beneficial effect of intensive glycemic therapy and demonstrate, for the first time, a similar benefit of intensive BP control on CAN in T2D. A negative CVD history identifies T2D patients who especially benefit from intensive glycemic control for CAN prevention.

MicroRNA-21/PDCD4 Proapoptotic Signaling From Circulating CD34+ Cells to Vascular Endothelial Cells: A Potential Contributor to Adverse Cardiovascular Outcomes in Patients With Critical Limb Ischemia.

OBJECTIVE: In patients with type 2 diabetes (T2D) and critical limb ischemia (CLI), migration of circulating CD34+ cells predicted cardiovascular mortality at 18 months after revascularization. This study aimed to provide long-term validation and mechanistic understanding of the biomarker. RESEARCH DESIGN AND METHODS: The association between CD34+ cell migration and cardiovascular mortality was reassessed at 6 years after revascularization. In a new series of T2D-CLI and control subjects, immuno-sorted bone marrow CD34+ cells were profiled for miRNA expression and assessed for apoptosis and angiogenesis activity. The differentially regulated miRNA-21 and its proapoptotic target, PDCD4, were titrated to verify their contribution in transferring damaging signals from CD34+ cells to endothelial cells. RESULTS: Multivariable regression analysis confirmed that CD34+ cell migration forecasts long-term cardiovascular mortality. CD34+ cells from T2D-CLI patients were more apoptotic and less proangiogenic than those from control subjects and featured miRNA-21 downregulation, modulation of several long noncoding RNAs acting as miRNA-21 sponges, and upregulation of the miRNA-21 proapoptotic target PDCD4. Silencing miR-21 in control CD34+ cells phenocopied the T2D-CLI cell behavior. In coculture, T2D-CLI CD34+ cells imprinted naive endothelial cells, increasing apoptosis, reducing network formation, and modulating the TUG1 sponge/miRNA-21/PDCD4 axis. Silencing PDCD4 or scavenging reactive oxygen species protected endothelial cells from the negative influence of T2D-CLI CD34+ cells. CONCLUSIONS: Migration of CD34+ cells predicts long-term cardiovascular mortality in T2D-CLI patients. An altered paracrine signaling conveys antiangiogenic and proapoptotic features from CD34+ cells to the endothelium. This damaging interaction may increase the risk for life-threatening complications.

Bone marrow as a target and accomplice of vascular complications in diabetes.

Peripheral vascular complications are common in diabetic patients. While pathogenic mechanisms have received much consideration, only recently regenerative processes captured attention. There is now a consensus that the bone marrow is a source of reparative cells and that this healing mechanism is lost in people with diabetes, especially in those suffering from ischemic complications. This failure was thought to occur due to a negative impact of diabetes on the mobilization of stem/progenitor cells with angiogenic properties from the bone marrow to the circulation. Moreover, those patients showing severely reduced bone marrow cell mobilization also bared a very high risk for adverse cardiovascular events. More recently, the structural integrity of the bone marrow was recognized to be altered because of the rarefaction of local microvasculature and innervation, thus mirroring anatomical features that typically occur in peripheral tissues. Ensuing hypoxia, nutrient starvation, and creation of an acidic and oxidative environment concur in causing the depletion of stem/progenitor cells in the endosteal niche and in forcing stromal cells to activate an adipogenesis program. Moreover, stem/progenitor cells acquire a pathogenic phenotype and, once mobilized, can pass harmful signalling molecules to vascular cells of peripheral tissues thereby contributing to ischemic complications. These new pieces of evidence indicate that the bone marrow should deserve more attention in the current care of critical limb ischemia and diabetic foot. Owing to powerful reserve capacities, the bone marrow integrity could be preserved and even rescued using rehabilitation programs and pharmacological treatments with consequent benefit for local and whole-organism homeostasis.

Correction to: Bone marrow pericyte dysfunction in individuals with type 2 diabetes.

Unfortunately, three errors were made in the conversion of HbA1c to per cent values.

Bone marrow pericyte dysfunction in individuals with type 2 diabetes.

AIMS/HYPOTHESIS: Previous studies have shown that diabetes mellitus destabilises the integrity of the microvasculature in different organs by damaging the interaction between pericytes and endothelial cells. In bone marrow, pericytes exert trophic functions on endothelial cells and haematopoietic cells through paracrine mechanisms. However, whether bone marrow pericytes are a target of diabetes-induced damage remains unknown. Here, we investigated whether type 2 diabetes can affect the abundance and function of bone marrow pericytes. METHODS: We conducted an observational clinical study comparing the abundance and molecular/functional characteristics of CD146+ pericytes isolated from the bone marrow of 25 individuals without diabetes and 14 individuals with uncomplicated type 2 diabetes, referring to our Musculoskeletal Research Unit for hip reconstructive surgery. RESULTS: Immunohistochemistry revealed that diabetes causes capillary rarefaction and compression of arteriole size in bone marrow, without changing CD146+ pericyte counts. These data were confirmed by flow cytometry on freshly isolated bone marrow cells. We then performed an extensive functional and molecular characterisation of immunosorted CD146+ pericytes. Type 2 diabetes caused a reduction in pericyte proliferation, viability, migration and capacity to support in vitro angiogenesis, while inducing apoptosis. AKT is a key regulator of the above functions and its phosphorylation state is reportedly reduced in the bone marrow endothelium of individuals with diabetes. Surprisingly, we could not find a difference in AKT phosphorylation (at either Ser473 or Thr308) in bone marrow pericytes from individuals with and without diabetes. Nonetheless, the angiocrine signalling reportedly associated with AKT was found to be significantly downregulated, with lower levels of fibroblast growth factor-2 (FGF2) and C-X-C motif chemokine ligand 12 (CXCL12), and activation of the angiogenesis inhibitor angiopoietin 2 (ANGPT2). Transfection with the adenoviral vector carrying the coding sequence for constitutively active myristoylated AKT rescued functional defects and angiocrine signalling in bone marrow pericytes from diabetic individuals. Furthermore, an ANGPT2 blocking antibody restored the capacity of pericytes to promote endothelial networking. CONCLUSIONS/INTERPRETATION: This is the first demonstration of pericyte dysfunction in bone marrow of people with type 2 diabetes. An altered angiocrine signalling from pericytes may participate in bone marrow microvascular remodelling in individuals with diabetes.

Can Nurse-Based Management Screening Ensure Adequate Outcomes in Patients With Gestational Diabetes? A Comparison of 2 Organizational Models.

BACKGROUND: Gestational diabetes mellitus (GDM) is an impaired glucose tolerance with onset or first recognition during pregnancy. The purpose of this study is to evaluate the clinical outcomes of a blood glucose monitoring protocol implemented by nurses and dietitians in a diabetes team to the previously established protocol of direct monitoring of GDM patients by a diabetologist. METHODS: Two groups of patients were formed: The first group was based on a traditional protocol (P1: 230 patients) with patients' blood glucose constantly checked by a diabetologist. In the second structured group (P2: 220 patients) patients were referred to a diabetologist only if they required insulin therapy. RESULTS: The number of medical visits (P2: 1.28 ± 0.70 vs P1: 3.27 ± 1.44; P < .001) and the percentage of patients with hypoglycemia (P2: 6.8% vs P1: 15.2%; P < .006) were found to be lower in group P2 than in group P1. In both groups, a direct relationship was found between a parental history of diabetes and the risk of GDM (odds ratio [OR]: P1 = 2.2 [1.17-4.12]; P2 = 2.5 [1.26-5.12]). In group P1, it was observed that hyperweight gain in patients who were already overweight before becoming pregnant significantly increased the risk of macrosomia (OR: 3.11 [1.39-25.7]), whereas this was not detected in patients in group P2. In group P2, a correlation was found between macrosomia and insulin therapy (OR: 0.066 vs 0.34). In group P1 and group P2, a correlation was observed between insulin therapy and a family history of diabetes (OR: 2.20 vs 2.27), and a body mass index of greater than 30 kg/m in group P2 (OR: 3.0 vs 1.47). CONCLUSIONS: The data we collected show that creating a structured protocol for GDM management reduces the number of medical visits required by patients without increasing the risk of hypoglycemia, macrosomia, or hyperweight gain during pregnancy.

MCP-1 Feedback Loop Between Adipocytes and Mesenchymal Stromal Cells Causes Fat Accumulation and Contributes to Hematopoietic Stem Cell Rarefaction in the Bone Marrow of Patients With Diabetes.

Fat accumulates in bone marrow (BM) of patients with diabetes. In this study, we investigated the mechanisms and consequences of this phenomenon. BM mesenchymal stromal cells (BM-MSCs) from patients with type 2 diabetes (T2D) constitutively express adipogenic markers and robustly differentiate into adipocytes (ADs) upon in vitro induction as compared with BM-MSCs from subjects without diabetes. Moreover, BM-ADs from subjects with T2D (T2D BM-ADs) paracrinally stimulate a transcriptional adipogenic program in BM-MSCs. Antagonism of MCP-1, a chemokine pivotally expressed in T2D BM-ADs, prevented the T2D BM-AD secretome from converting BM-MSCs into ADs. Mechanistic validation of human data was next performed in an obese T2D mouse model. Systemic antagonism of MCP-1 improved metabolic control, reduced BM fat, and increased osteocyte density. It also indirectly re-established the abundance of long-term versus short-term hematopoietic stem cells. We reveal a diabetic feedback loop in which 1) BM-MSCs are constitutively inclined to make ADs, and 2) mature BM-ADs, via secreted MCP-1, relentlessly fuel BM-MSC determination into new fat. Pharmacological inhibition of MCP-1 signaling can contrast this vicious cycle, restoring, at least in part, the balance between adipogenesis and hematopoiesis in BM from subjects with T2D.

Proinsulin-expressing dendritic cells in type 2 neuropathic diabetic patients with and without foot lesions.

Diabetic neuropathy is the most common complication of diabetes and is frequently associated with foot ischemia and infection, but its pathogenesis is controversial. We hypothesized that proinsulin expression in peripheral blood mononuclear cells is a process relevant to this condition and could represent a link among hyperglycemia, nerve susceptibility, and diabetic foot lesions. We assessed proinsulin expression by using flow cytometry in dendritic cells from control participants and patients with type 2 diabetes with or without peripheral neuropathy or accompanied by diabetic foot. Among 32 non-neuropathic and 120 neuropathic patients with type 2 diabetes, we performed leg electromyography and found average sensory sural nerve conduction velocities of 48 ± 4 and 30 ± 4 m/s, respectively ( P < 0.03). Of those with neuropathy, 42 were without lesions, 39 had foot lesions, and 39 had neuroischemic foot lesions (allux oximetry <30 mmHg). In this well-defined diabetic population, but not in nondiabetic participants, a progressively increasing level of peripheral blood dendritic cell proinsulin expression was detected, which directly correlated with circulating TNF-α levels ( P < 0.002) and multiple conduction velocities of leg nerves ( P < 0.05). These results are consistent with the hypothesis that, in type 2 diabetes, proinsulin-expressing blood cells, possibly via their involvement in innate immunity, may play a role in diabetic peripheral neuropathy and foot lesions.-Sambataro, M., Sambado, L., Trevisiol, E., Cacciatore, M., Furlan, A., Stefani, P. M., Seganfreddo, E., Durante, E., Conte, S., Della Bella, S., Paccagnella, A., dei Tos, A. P. Proinsulin-expressing dendritic cells in type 2 neuropathic diabetic patients with and without foot lesions.

Treatment of diabetic foot ulcers with Therapeutic Magnetic Resonance (TMR®) improves the quality of granulation tissue.

Diabetic foot ulcers (DFUs) often result in severely adverse outcomes, such as serious infections, hospitalization, and lower extremity amputations. In last few years, to improve the outcome of DFUs, clinicians and researchers put their attention on the application of low intensity pulsating electro-magnetic fields through Therapeutic Magnetic Resonance (TMR®). In our study, patients with DFUs have been divided into two groups: The Sham Group treated with non-functioning TMR® device, and the Active Group treated with a functioning device. Biopsies were recovered from ulcers before and after a 15-day treatment with both kind of TMR® device. To recognize signs of inflammation or healing process, the harvested biopsies were subjected to histological and molecular analyses. The histological analysis showed a change in cell population after treatment with TMR®: an increase of fibroblasts and endothelial cells with a reduction of inflammatory cells. After TMR® application, the gene expression profile analysis revealed an improvement in extracellular matrix components such as matrix metalloproteinases, collagens and integrins, a reduction in pro-inflammatory interleukins, and an increase in growth factors expression. In conclusion, our research has identified histological and molecular features of reduced inflammation and increased cell proliferation during the wound healing process in response to TMR® application.

Enteral nutrition at home and in nursing homes: an 11-year (2002-2012) epidemiological analysis.

BACKGROUND: Home enteral nutrition (HEN) is a well-established extra-hospital therapy that can reduce the risk of malnutrition, ensure the rapid discharge of patients from hospital and significantly reduce health care expenditure. The data reported in this study allow us to understand the relationships between mortality, the place of treatment either at patients' homes (PH) or in nursing homes (NHR) and nutritional status. METHODS: Patients were analyzed according to age, gender, underlying disease, the Karnofsky Index, type of enteral access device (nasogastric tube or percutaneous endoscopic gastrostomy), weight and Body Mass Index (BMI). The duration of HEN therapy was then calculated and the outcome was established on patient mortality or survival. RESULTS: Over an 11-year period, 3246 subjects were administered HEN therapy. The mean duration of HEN therapy was equal to 312±487 days at PH and 398±573 in NHR. The mean incidence is 406±58 patients/million inhabitants/year at PH and 319±44 in NHR (mean prevalence rate: 464±129 cases/million inhabitants at PH compared to 478±164 in NHR). Analysis of variance was used for continuous variables. The study reveals that >8% (8.6% at PH; 8.5% in NHR) of patients die within 10 days of starting HEN therapy. CONCLUSIONS: The study shows a progressive increase in HEN therapy and highlights clinical, organizational and ethical issues, which also need to be analyzed in relation to the progressively aging population.

Sensory neuropathy hampers nociception-mediated bone marrow stem cell release in mice and patients with diabetes.

AIMS/HYPOTHESIS: Upon tissue injury, peripheral sensory neurons release nociceptive factors (e.g. substance P [SP]), which exert local and systemic actions including the recruitment of bone marrow (BM)-derived haematopoietic stem and progenitor cells (HSPCs) endowed with paracrine pro-angiogenic properties. We herein explore whether diabetic neuropathy interferes with these phenomena. METHODS: We first investigated the presence of sensory neuropathy in the BM of patients with type 2 diabetes by immunohistochemistry and morphometry analyses of nerve size and density and assessment of SP release by ELISA. We next analysed the association of sensory neuropathy with altered HSPC release under ischaemia or following direct stimulation with granulocyte colony-stimulating factor (G-CSF). BM and circulating HSPCs expressing the neurokinin 1 receptor (NK1R), which is the main SP receptor, were measured by flow cytometry. We finally assessed whether an altered modulation of SP secretion interferes with the mobilisation and homing of NK1R-HSPCs in a mouse model of type 2 diabetes after limb ischaemia (LI). RESULTS: Nociceptive fibres were reduced in the BM of patients and mice with type 2 diabetes. Patients with neuropathy showed a remarkable reduction in NK1R-HSPC mobilisation under ischaemia or upon G-CSF stimulation. Following LI, diabetic mice manifested an altered SP gradient between BM, peripheral blood and limb muscles, accompanied by a depressed recruitment of NK1R-HSPCs to the ischaemic site. CONCLUSIONS/INTERPRETATION: Sensory neuropathy translates into defective liberation and homing of reparative HSPCs. Nociceptors may represent a new target for treatment of diabetic complications.

Prognostic significance of circulating and endothelial progenitor cell markers in type 2 diabetic foot.

Objective. We studied circulating precursor cells (CPC) in type 2 diabetes mellitus (T2DM) with neuropathic foot lesions with or without critical limb ischemia and relationships between endothelial precursor cells (EPC) and peripheral neuropathy. Methods and Subjects. We measured peripheral blood CD34, CD133, and CD45 markers for CPC and KDR, CD31 markers for EPC by citofluorimetry and systemic neural nociceptor CGRP (calcitonin gene related protein) by ELISA in 8 healthy controls (C) and 62 T2DM patients: 14 with neuropathy (N), 20 with neuropathic foot lesions (N1), and 28 with neuroischemic recent revascularized (N2) foot lesions. Timing of lesions was: acute (until 6 weeks), healed, and not healed. Results. CD34+ and CD133+ were reduced in N, N1, and N2 versus C, and CD34+ were lower in N2 versus N1 (P = 0.03). In N2 CD34+KDR+ remain elevated in healed versus chronic lesions and, in N1 CD133+31+ were elevated in acute lesions. CGRP was reduced in N2 and N1 versus C (P < 0.04 versus C 26 ± 2 pg/mL). CD34+KDR+ correlated in N2 with oximetry and negatively in N1 with CGRP. Conclusions. CD34+ CPC are reduced in diabetes with advanced complications and diabetic foot. CD34+KDR+ and CD31+133+ EPC differentiation could have a prognostic and therapeutic significance in the healing process of neuropathic and neuroischemic lesions.

Lipid accumulation in overweight type 2 diabetic subjects: relationships with insulin sensitivity and adipokines.

Adipokines are known to play a fundamental role in the etiology of obesity, that is, in the impaired balance between increased feeding and decreased energy expenditure. While the adipokine-induced changes of insulin resistance in obese diabetic and nondiabetic subjects are well known, the possible role of fat source in modulating insulin sensitivity (IS) remains controversial. The aim of our study was to explore in overweight type 2 diabetic patients (T2DM) with metabolic syndrome IS in different energy storage conditions (basal and dynamic) for relating it to leptin and adiponectin. Sixteen T2DM (5/11 F/M; 59 ± 2 years; 29.5 ± 1.1 kg/m(2)) and 16 control (CNT 5/11; 54 ± 2; 29.1 ± 1.0) underwent an oral glucose tolerance test. Fasting IS was measured by QUICKI, while the dynamic one with OGIS. The insulinogenic index (IGI) described beta cell function. Also, the lipid accumulation product parameter (LAP) was assessed. LAP accounts for visceral abdominal fat and triglycerides, and it is known to be related to IS. Possible interrelationships between LAP and adipokines were explored. In T2DM and CNT, adiponectin (7.4 ± 0.5 vs. 7.8 ± 0.9 µg/mL), leptin (13.3 ± 3.0 vs. 12.4 ± 2.6 ng/mL), and QUICKI (0.33 ± 0.01 vs. 0.33 ± 0.01) were not different (P > 0.40), at variance with OGIS (317 ± 11 vs. 406 ± 13 mL/min/m(2); P = 0.006) and IGI (0.029 ± 0.005 vs. 0.185 ± 0.029 × 10(3) pmolI/mmolG; P = 0.00001). LAP was 85 ± 15 cm × mg/dL in T2DM and 74 ± 10 in CNT (P > 0.1), correlated with OGIS in all subjects (R = -0.42, P = 0.02) and QUICKI (R = -0.56, P = 0.025) in T2DM. Leptin correlated with QUICKI (R = -0.45, P = 0.009), and adiponectin correlated with OGIS (R = 0.43, P = 0.015). In overweight T2DM, insulin sensitivity in basal condition appears to be multifaceted with respect to the dynamic one, because it should be more fat-related. Insulin sensitivity appears to be incompletely described by functions of fasting glucose and insulin values alone and the use of other indices, such as LAP could be suggested.

Inherited apolipoprotein A-V deficiency in severe hypertriglyceridemia.

OBJECTIVE: Mutations in LPL or APOC2 genes are recognized causes of inherited forms of severe hypertriglyceridemia. However, some hypertrigliceridemic patients do not have mutations in either of these genes. Because inactivation or hyperexpression of APOA5 gene, encoding apolipoprotein A-V (apoA-V), causes a marked increase or decrease of plasma triglycerides in mice, and because some common polymorphisms of this gene affect plasma triglycerides in humans, we have hypothesized that loss of function mutations in APOA5 gene might cause hypertriglyceridemia. METHODS AND RESULTS: We sequenced APOA5 gene in 10 hypertriglyceridemic patients in whom mutations in LPL and APOC2 genes had been excluded. One of them was found to be homozygous for a mutation in APOA5 gene (c.433 C>T, Q145X), predicted to generate a truncated apoA-V devoid of key functional domains. The plasma of this patient was found to activate LPL in vitro less efficiently than control plasma, thus suggesting that apoA-V might be an activator of LPL. Ten carriers of Q145X mutation were found in the patient's family; 5 of them had mild hypertriglyceridemia. CONCLUSIONS: As predicted from animal studies, apoA-V deficiency is associated with severe hypertriglyceridemia in humans. This observation suggests that apoA-V regulates the secretion and/or catabolism of triglyceride-rich lipoproteins. Mutations in APOA5 gene might be the cause of severe hypertriglyceridemia in subjects in whom mutations in LPL or APOC2 genes have been excluded. We detected a nonsense mutation in APOA5 gene (Q145X) in a boy with hyperchylomicronemia syndrome. This is the first observation of a complete apoA-V deficiency in humans.

Insulin sensitivity correlates with glycogen synthesis rate, but not with von Willebrand factor in type 2 diabetes.

BACKGROUND: Whether insulin resistance in type 2 (non-insulin-dependent) diabetes is due to compromised endothelial insulin migration or to impaired intracellular hormone action or both is unclear. Coexistent microalbuminuria reflects possible endothelial pathogenesis in insulin resistance. METHODS: Insulin sensitivity (S(I)) was calculated from an intravenous glucose tolerance test in 23 type 2 albuminuric (AER+), 11 type 2 normoalbuminuric (AER-), and 17 control subjects. Cultured fibroblasts from skin biopsies from these subjects were used to study intracellular insulin action on glycogen synthesis. Endothelial damage in type 2 diabetes was evaluated by plasma concentrations of von Willebrand factor (vWf). Results: S(I) and glycogen synthesis in fibroblasts were lower in AER+ and AER- than in controls. Glycogen synthesis in vitro was related to S(I) in vivo (r=0.55, P<0.001). vWf was 169+/-12% in AER+ and 140+/-5% in AER-, P<0.051. No correlation was observed between vWf and S(I) or plasma insulin clearance. CONCLUSIONS: This study demonstrates that reduced insulin-mediated glucose removal in type 2 diabetes is strictly associated with a decreased glycogen synthesis of cultured skin fibroblasts in vitro, but not with markers of endothelial damage in vivo.

Nitric oxide modulation of renal and cardiac hemodynamics in type 2 diabetes.

OBJECTIVE: To evaluate endothelial function in type 2 diabetic patients with and without diabetic nephropathy. METHODS: We studied the effects of systemic infusion of the nitric oxide (NO) synthase inhibitor NG-monomethyl-l-arginine (L-NMMA) on cardiovascular and renal hemodynamics in six type 2 diabetic patients with microalbuminuria (D2-MA), six type 2 diabetic patients with normoalbuminuria (D2-NA) and five control subjects. Both type 2 diabetic patients and control subjects had mild arterial hypertension. RESULTS: L-NMMA infusion decreased the cardiac index in all groups. A reduction in glomerular filtration rate (GFR) and an increase in filtration fraction were observed only in controls. Renal plasma flow decreased in controls and D2-NA patients and renal vascular resistance increased in all groups. CONCLUSIONS: The effect of L-NMMA on cardiac output was similar in controls and type 2 diabetic patients with and without diabetic nephropathy. In contrast, the effect on GFR was impaired in both diabetic groups, suggesting that glomerular NO homeostasis is altered in type 2 diabetes. Moreover the discrepancy, in diabetic patients, between cardiac and renal effects during L-NMMA infusion suggests that the modulation of glomerular hemodynamics is independent from NO-regulated cardiac output.