Diabetes-related microvascular and macrovascular diseases in the physical therapy setting

Characterization of Vitreous and Aqueous Proteome in Humans With Proliferative Diabetic Retinopathy and Its Clinical Correlation

Aims:

Proliferative diabetic retinopathy (PDR) is associated with microvascular complications that cause biochemical changes in the human retina and alter the proteome of vitreous humor and aqueous humor (AH).

Methods:

Human vitreous humor and AH of PDR subjects were collected. Subjects who had surgery for epiretinal membrane or macular hole served as controls. Protein profiles were obtained and analyzed after running the samples on a liquid chromatography-mass spectrometry/mass spectrometry.

Results:

In vitreous humor, 16 unique proteins were noted in PDR patients, but not in controls. Those were associated mainly with coagulation, complement, and kallikrein-kinin systems. Under coagulation, fibrinogen and prothrombin proteins were more evident and may emphasize the importance of angiogenesis in the development of PDR. Vitreous proteins showed replicative presence in AH too. As for AH samples, we detected 10 proteins found in PDR patients, which were related to transport, coagulation, and inflammatory responses.

Conclusions:

We found 57 proteins in human vitreous and 39 proteins in AH. Identification of these proteins that are involved in various pathways will be helpful to understand diabetic retinopathy pathogenesis and to develop proteome as a biomarker for PDR.

Sirtuin 1 and 7 mediate resveratrol-induced recovery from hyper-anxiety in high-fructose-fed prediabetic rats

Hyperglycaemia in diabetes is either caused by reduced availability of insulin (type 1 diabetes, T1D) or insulin resistance to the cells (type 2 diabetes, T2D). In recent years, the prevalence of T2D has increased to an alarming proportion, encompassing 95 percent of the total diabetic burden, probably due to economy-driven changes in lifestyle. Recent epidemiological studies show comorbid depression, anxiety and related mental illness. To explore the molecular mechanisms underlying this comorbid conditions, we used Sprague-Dawley rats on high-fructose diet for 8 weeks to induce prediabetic condition. Rats with this metabolic syndrome also showed hyper-anxiety when they were subjected to anxiety-related behavioural assays. Rats were administered with resveratrol, an activator of sirtuins, and metformin, a standard antidiabetic drug, simultaneously with fructose. We observed that resveratrol was more effective in protecting from both the metabolic (prediabetic) and affective (anxiety) disorders than metformin. Molecular studies showed that recovery was associated with the upregulation of few nuclear sirtuins that act epigenetically - Sirt 1 and 7, which were significantly attenuated in the striatum of prediabetic rats. In conclusion, our study showed that hyper-anxiety associated with prediabetic condition is ameliorated by resveratrol through modulation of sirtuins, which is more or less similar to metformin.

Stimulation of β-adrenergic receptors plays a protective role via increased expression of RAF-1 and PDX-1 in hyperglycemic rat pancreatic islet (RIN-m5F) cells

INTRODUCTION

It is a widely held view that a progressive reduction of beta-cell mass occurs in the progression of diabetes. RAF-1 kinase and pancreas duodenal homeobox 1 (PDX-1) are major factors that promote survival of cells and maintain normal insulin functions. In this study we investigated the effect of a β-adrenergic receptor agonist and antagonist on RAF-1 and PDX-1, and their respective effects on apoptosis and insulin release in RIN-m5F cells.

MATERIAL AND METHODS

RIN-m5F cells were cultured in normal (5 mM) and high (25 mM) glucose to mimic diabetic conditions, followed by treatment with 5 µM, 10 µM and 20 µM of isoproterenol and isoproterenol + propranolol for 6, 12 and 24 h. Western blotting and reverse transcription analysis were performed to examine the expression of RAF-1 and PDX-1. Annexin-V-FITC and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assays were used to investigate apoptosis. ELISA was used to measure insulin levels. Reverse transcription polymerase chain reaction was conducted to investigate the expression of genes.

RESULTS

Stimulation of β-adrenergic receptors with isoproterenol significantly induced RAF-1 and PDX-1 genes in a concentration-dependent and time-independent manner. Changes were significant both at protein and mRNA levels. Up-regulation of RAF-1 and PDX-1 was accompanied by improved insulin levels and reduced apoptosis. Concentrations of 10 µM and 20 µM for 12 and 24 h were more effective in achieving significant differences in the experimental and control groups. Propranolol reversed the effect of isoproterenol mostly at maximum concentrations and time periods.

CONCLUSIONS

A positive effect of a β-adrenergic agonist on RAF-1 and PDX-1, reduction in β-cell apoptosis and improved insulin contents can help to understand the pathogenesis of diabetes and to develop novel approaches for the β-cell dysfunction in diabetes.

Biomarkers Associated with Ischemic Stroke in Diabetes Mellitus Patients

Diabetes is an established risk factor for ischemic stroke, but the associated molecular mechanisms remain to be fully elucidated. This study investigated the role of plasma and platelet microRNAs and their targeting proteins in the activation of platelets and their association with the occurrence of ischemic stroke in patients with type 2 diabetes mellitus (T2DM). Results showed that the expressions of platelet and plasma miR-144 and miR-223 were significantly altered in T2DM patients with or without ischemic stroke compared to that in healthy controls, but these changes were more significant in T2DM patients with ischemic stroke. The expressions of P2Y12 and IRS-1 as well as phosphorylation levels of IRS-1, PI3K, and Akt in platelets were significantly altered in T2DM patients with or without ischemic stroke. The expression of platelet miR-144 and miR-223 significantly correlated with their plasma levels, P2Y12 and IRS-1 expression, blood glucose concentration, and platelet activation rate. High glucose concentration significantly elevated P-selectin, miR-144 and P2Y12 expression and significantly reduced miR-223 and IRS-1 expression in UT-7 cells. Overexpression of miR-223 and blocking of miR-144 expression significantly normalized the effects of high glucose concentration in UT-7 cells. In conclusion, hyperglycemia may activate platelets through miR-144 and miR-223 to downregulate IRS-1 and upregulate P2Y12 expression in the platelets of T2DM patients through an IRS-1-PI3K-Akt signaling. Low platelet and plasma miR-223 expression in addition to high platelet and plasma miR-144 expression are risk factors for ischemic stroke in T2DM patients.

Hierarchical Bayesian Logistic Regression to forecast metabolic control in type 2 DM patients

In this work we present our efforts in building a model able to forecast patients' changes in clinical conditions when repeated measurements are available. In this case the available risk calculators are typically not applicable. We propose a Hierarchical Bayesian Logistic Regression model, which allows taking into account individual and population variability in model parameters estimate. The model is used to predict metabolic control and its variation in type 2 diabetes mellitus. In particular we have analyzed a population of more than 1000 Italian type 2 diabetic patients, collected within the European project Mosaic. The results obtained in terms of Matthews Correlation Coefficient are significantly better than the ones gathered with standard logistic regression model, based on data pooling.

Evaluation of lorcaserin on progression of prediabetes to type 2 diabetes and reversion to euglycemia

OBJECTIVES

Lorcaserin is a selective 5-HT2C (5-hydroxytryptamine 2C) receptor agonist indicated for weight management. Here, we assess the impact of lorcaserin on progression from prediabetes to type 2 diabetes (T2D) and on reversion from prediabetes to euglycemia.

METHODS

This is a post hoc analysis of pooled data from two Phase 3 studies, BLOOM and BLOSSOM (N = 6136), evaluating the impact of lorcaserin on weight and glycemic parameters over 52 weeks in the subpopulation of obese/overweight subjects with prediabetes, alternately defined by fasting plasma glucose (FPG) 100-125 mg/dl or glycated hemoglobin (HbA1c) 5.7-6.4% at baseline.

RESULTS

At Week 52, in the subpopulation with prediabetes, nearly twice as many lorcaserin-treated subjects achieved ≥5% weight loss versus placebo (HbA1c: 55.6% vs. 27.5%, p < 0.001; FPG: 52.8% vs. 28.8%, p < 0.001), and a significantly lower percentage of lorcaserin-treated subjects progressed to T2D versus placebo based on HbA1c (lorcaserin 3.2%, placebo 5.0%, p = 0.032) but not FPG (lorcaserin 1.6%, placebo 2.6%, p = 0.227). A significantly greater proportion of lorcaserin-treated subjects versus placebo also reverted to euglycemia based on both HbA1c (lorcaserin 40%, placebo 29.5%, p < 0.001) and FPG (lorcaserin 52.4%, placebo 46.5%, p = 0.047).

CONCLUSION

In subjects with prediabetes, lorcaserin may contribute to weight loss and improve glycemic parameters, and thus may help with preventing progression to T2D and promoting reversion to euglycemia.

CLINICAL TRIAL REGISTRATION

www.clinicaltrials.gov identifiers are NCT00395135 (BLOOM) and NCT00603902 (BLOSSOM).

Association of Diabetes Related Complications with Heart Rate Variability among a Diabetic Population in the UAE

Microvascular, macrovascular and neurological complications are the key causes of morbidity and mortality among type II diabetes mellitus (T2DM) patients. The aim of this study was to investigate the alterations of cardiac autonomic function of diabetic patients in relation to three types of diabetes-related complications. ECG recordings were collected and analyzed from 169 T2DM patients in supine position who were diagnosed with nephropathy (n = 55), peripheral neuropathy (n = 64) and retinopathy (n = 106) at two hospitals in the UAE. Comparison between combinations of patients with complications and a control diabetic group (CONT) with no complication (n = 34) was performed using time, frequency and multi-lag entropy measures of heart rate variability (HRV). The results show that these measures decreased significantly (p<0.05) depending on the presence and type of diabetic complications. Entropy, (median, 1st- 3rd interquartile range) for the group combining all complications (1.74,1.37-2.09) was significantly lower than the corresponding values for the CONT group (1.77, 1.39-2.24) with lag-1 for sequential beat-to-beat changes. Odds ratios (OR) from the entropy analysis further demonstrated a significantly higher association with the combination of retinopathy and peripheral neuropathy versus CONT (OR: 1.42 at lag 8) and an even OR for the combination of retinopathy and nephropathy (OR: 2.46 at lag 8) compared to the other groups with complications. Also, the OR of low frequency power to high frequency power ratio (LF/HF) showed a higher association with these diabetic-related complications compared to CONT, especially for the patient group combining all complications (OR: 4.92). This study confirms that the type of microvascular or peripheral neuropathy complication present in T2DM patients have different effects on heart rate entropy, implying disorders of multi-organ connectivity are directly associated with autonomic nervous system dysfunction. Clinical practice may benefit from including multi-lag entropy for cardiac rhythm analysis in conjunction with traditional screening methods in patients with diabetic complications to ensure better preventive and treatment outcomes in the Emirati Arab population.

Machine Learning and Data Mining Methods in Diabetes Research

The remarkable advances in biotechnology and health sciences have led to a significant production of data, such as high throughput genetic data and clinical information, generated from large Electronic Health Records (EHRs). To this end, application of machine learning and data mining methods in biosciences is presently, more than ever before, vital and indispensable in efforts to transform intelligently all available information into valuable knowledge. Diabetes mellitus (DM) is defined as a group of metabolic disorders exerting significant pressure on human health worldwide. Extensive research in all aspects of diabetes (diagnosis, etiopathophysiology, therapy, etc.) has led to the generation of huge amounts of data. The aim of the present study is to conduct a systematic review of the applications of machine learning, data mining techniques and tools in the field of diabetes research with respect to a) Prediction and Diagnosis, b) Diabetic Complications, c) Genetic Background and Environment, and e) Health Care and Management with the first category appearing to be the most popular. A wide range of machine learning algorithms were employed. In general, 85% of those used were characterized by supervised learning approaches and 15% by unsupervised ones, and more specifically, association rules. Support vector machines (SVM) arise as the most successful and widely used algorithm. Concerning the type of data, clinical datasets were mainly used. The title applications in the selected articles project the usefulness of extracting valuable knowledge leading to new hypotheses targeting deeper understanding and further investigation in DM.

miRNAs: Nanomachines That Micromanage the Pathophysiology of Diabetes Mellitus

Diabetes mellitus (DM) refers to a combination of heterogeneous complex metabolic disorders that are associated with episodes of hyperglycemia and glucose intolerance occurring as a result of defects in insulin secretion, action, or both. The prevalence of DM is increasing at an alarming rate, and there exists a need to develop better therapeutics and prognostic markers for earlier detection and diagnosis. In this review, after giving a brief introduction of diabetes mellitus and microRNA (miRNA) biogenesis pathway, we first describe various in vitro and animal model systems that have been developed to study diabetes. Further, we elaborate on the significant roles played by miRNAs as regulators of gene expression in the context of development of diabetes and its secondary complications. The different approaches to quantify miRNAs and their potential to be used as therapeutic targets for alleviation of diabetes have also been discussed.

Carvedilol and antioxidant proteins in a type I diabetes animal model

BACKGROUND

Patients with diabetes are at a high risk of developing both micro- and macrovascular disease. Hyperglycaemia seems to be the main factor in the pathogenesis of diabetic cardiomyopathy, often based on increased oxidative stress. Carvedilol, a β-adrenergic blocker, has intrinsic antioxidant properties and was previously described to be effective in the protection of cardiac mitochondria against oxidative stress. The objective of this study was to evaluate the effect of carvedilol on hyperglycaemia-induced oxidative damage and mitochondrial abnormalities in cardiac and skeletal muscle in streptozotocin-treated rats.

MATERIALS AND METHODS

Body mass, blood glucose, the level of protein carbonylation, caspase-9- and caspase-3-like activities, mitochondrial proteins, the status of antioxidant defence system and stress-related proteins were evaluated in streptozotocin vs streptozotocin + carvedilol (1 mg/kg/day)-treated rats.

RESULTS

The results showed that carvedilol decreased blood glucose in streptozotocin-treated animals. Content of catalase in the heart and SOD2, SOD1 and catalase in skeletal muscle were increased by carvedilol treatment in streptozotocin-treated animals. At this particular time point, streptozotocin-induced hyperglycaemia did not cause caspase activation or increase in protein carbonylation status. The data showed that carvedilol increased the level of antioxidant enzymes, what may contribute to preserve cell redox balance during hyperglycaemia. We also showed here for the first time that carvedilol effects on streptozotocin-treated rats are tissue dependent, with a more predominant effect on skeletal muscle.

CONCLUSIONS

Based on data showing modulation of the antioxidant network in the heart, carvedilol may be beneficial in diabetic patients without advanced disease complications, delaying their progression.

Ashanti pepper (Piper guineense Schumach et Thonn) attenuates carbohydrate hydrolyzing, blood pressure regulating and cholinergic enzymes in experimental type 2 diabetes rat model

BACKGROUND

Ashanti pepper (Piper guineense Schumach et Thonn) seed is well known in folkloric medicine in the management of type 2 diabetes (T2DM) with little or no scientific documentation for its action. This study investigated the effect of Ashanti pepper seed on some enzymes relevant to carbohydrate hydrolysis, blood regulation and the cholinergic system, as well as the blood glucose level, lipid profile, antioxidant parameters, and hepatic and renal function markers in T2DM rats.

METHODS

T2DM was induced by feeding rats with high-fat diet (HFD) for 14 days followed by a single intraperitoneal dose of 35 mg/kg body weight of streptozotocin (STZ). Three days after STZ induction, diabetic rats were placed on a dietary regimen containing 2%-4% Ashanti pepper.

RESULTS

Reduced blood glucose level with decreased α-amylase, α-glucosidase and angiotensin I converting enzyme (ACE) activities were observed in Ashanti pepper seed and acarbose-treated rat groups when compared to that of the diabetic control rat group. Furthermore, the results revealed that inclusion of 2%-4% Ashanti pepper seed in diabetic rat fed group diets may ameliorate the lipid profile, antioxidant status, and hepatic and renal function in T2DM rats as much as in the acarbose-treated groups. In addition, a chromatographic profile of the seed revealed the presence of quercitrin (116.51 mg/g), capsaicin (113.94 mg/g), dihydrocapsaicin (88.29 mg/g) and isoquercitrin (74.89 mg/g).

CONCLUSIONS

The results from this study clearly suggest that Ashanti pepper could serve as a promising source of phenolic compounds with great alternative therapeutic potentials in the management of T2DM.

Contribution of redox-dependent activation of endothelial Nlrp3 inflammasomes to hyperglycemia-induced endothelial dysfunction

Recent studies indicate that inflammasomes serve as intracellular machinery to initiate classical cytokine-mediated inflammatory responses and play a crucial role in the pathogenesis of cardiovascular diseases. However, whether or not the activation of endothelial inflammasomes directly causes cell dysfunction or tissue injury without recruitment of inflammatory cells is unknown. We explored the role of endothelial cell inflammasome activation in mediating tight junction disruption, a hallmark event of endothelial barrier dysfunction leading to endothelial hyperpermeability in diabetes. We used confocal microscopy to study the formation and activation of NOD-like receptor family pyrin domain containing-3 (Nlrp3) inflammasomes and expression of tight junction proteins in coronary arteries of streptozotocin-treated diabetic wild type and Nlrp3 gene-deleted mice. We found that Nlrp3 ablation prevented inflammasome activation and tight junction disassembly in the coronary arterial endothelium of diabetic mice. Similarly, Nlrp3 gene silencing prevented high glucose-induced down-regulation of tight junction proteins in cultured mouse vascular endothelial cells (MVECs). The high glucose-induced tight junction disruption and consequent endothelial permeability were attributed to increased release of the high mobility group box protein-1 (HMGB1), which is dependent on enhanced Nlrp3 inflammasome activity. Mechanistically, reducing reactive oxygen species (ROS) production abolished high glucose-induced inflammasome activation, tight junction disruption, and endothelial hyperpermeability in MVECs. Collectively, the ROS-dependent activation of endothelial Nlrp3 inflammasomes by hyperglycemia may be an important initiating mechanism to cause endothelial dysfunction. These effects could contribute to the early onset of endothelial injury in diabetes.

KEY MESSAGE

Endothelial tight junction disruption in diabetes requires Nlrp3 inflammasomes. High glucose activates Nlrp3 inflammasome in endothelial cells via ROS production. Activation of endothelial inflammasome by high glucose triggers release of HMGB1. Blockade of Nlrp3/HMGB1 axis inhibits high glucose-induced endothelial permeability.

Nailfold capillary abnormalities are associated with type 2 diabetes progression and correlated with peripheral neuropathy

Diabetes mellitus (DM) is associated with a state of chronic hyperglycemia with a highly increased risk of vascular complications. The current study aimed to investigate microcirculation abnormalities in patients with type 2 DM and those with pre-DM using nailfold videocapillaroscopy (NVC) and evaluate the possible correlation with microvascular complications.A total of 115 patients with type 2 DM, 41 patients with pre-DM, and 37 healthy subjects without diabetes were enrolled. All subjects underwent NVC to evaluate capillary density, length, morphology, distribution, presence of enlarged loops or hemorrhages, and blood flow. NVC score was used to quantitate the aforementioned characteristics.Patients with type 2 DM showed significantly increased alterations including reduced capillary length (29.6%), irregular distribution (35.7%), and abnormal morphology (59.1%), while the corresponding NVC scores were comparable to those of control subjects. In addition, subjects with pre-DM had a significantly higher NVC score and greater alterations in distribution (26.8%) and morphology (48.8%) than control subjects. NVC score was positively correlated with diabetic peripheral neuropathy (DPN) and the number of microvascular complications.NVC identified a high frequency of microcirculation abnormalities in subjects with pre-DM or type 2 DM compared to those in the control group. NVC score was also capable of detecting microvascular complications in patients with type 2 DM and was correlated with DPN and the number of microvascular complications.

Spinal cord stimulation in experimental chronic painful diabetic polyneuropathy: Delayed effect of High-frequency stimulation

Background

Spinal cord stimulation (SCS) has been shown to provide pain relief in painful diabetic polyneuropathy (PDPN). As the vasculature system plays a great role in the pathophysiology of PDPN, a potential beneficial side‐effect of SCS is peripheral vasodilation, with high frequency (HF) SCS in particular. We hypothesize that HF‐SCS (500 Hz), compared with conventional (CON) or low frequency (LF)‐SCS will result in increased alleviation of mechanical hypersensitivity in chronic experimental PDPN.

Methods

Diabetes was induced in 8‐week‐old female Sprague–Dawley rats with an intraperitoneal injection of 65 mg/kg of streptozotocin (n = 44). Rats with a significant decrease in mechanical withdrawal response to von Frey filaments over a period of 20 weeks were implanted with SCS electrodes (n = 18). Rats were assigned to a cross‐over design with a random order of LF‐, CON‐, HF‐ and sham SCS and mechanical withdrawal thresholds were assessed with von Frey testing.

Results

Compared with sham treatment, the average 50% WT score for 5 Hz was 4.88 g higher during stimulation (p = 0.156), and 1.77 g higher post‐stimulation (p = 0.008). CON‐SCS resulted in 50% WT scores 5.7 g, and 2.51 g higher during (p = 0.064) and after stimulation (p < 0.004), respectively. HF‐SCS started out with an average difference in 50% WT score compared with sham of 1.87 g during stimulation (p = 0.279), and subsequently the steepest rise to a difference of 5.47 g post‐stimulation (p < 0.001).

Conclusions

We demonstrated a delayed effect of HF‐SCS on mechanical hypersensitivity in chronic PDPN animals compared with LF‐, or CON‐SCS.

Significance

This study evaluates the effect of SCS frequency (5–500 Hz) on mechanical hypersensitivity in the chronic phase of experimental PDPN. High frequency (500 Hz) – SCS resulted in a delayed effect‐ on pain‐related behavioural outcome in chronic PDPN.

Potential regulatory mechanisms of lncRNA in diabetes and its complications

Long non-coding RNAs (lncRNAs) are transcripts longer than 200 nucleotides without protein-coding potential. Although these molecules were initially considered as "junk products" of transcription without biological relevance, recent advances in research have shown that lncRNA plays an important role, not only in cellular processes such as proliferation, differentiation, and metabolism, but also in the pathological processes of cancers, diabetes, and neurodegenerative diseases. In this review, we focus on the potential regulatory roles of lncRNA in diabetes and the complications associated with diabetes.

Cordyceps militaris Treatment Preserves Renal Function in Type 2 Diabetic Nephropathy Mice

Diabetic nephropathy is derived from long-term effects of high blood glucose on kidney function in type 2 diabetic patients. Several antidiabetic drugs and herbal medications have failed to prevent episodes of DN. Hence, this study aimed to further investigate the renal injury-reducing effect of antidiabetic CmNo1, a novel combination of powders of fruiting bodies and mycelia of Cordyceps militaris. After being administered with streptozotocin-nicotinamide and high-fat-diet, the diabetic nephropathy mouse model displayed elevated blood glucose and renal dysfunction markers including serum creatinine and kidney-to-body weight ratio. These elevated markers were significantly mitigated following 8 weeks CmNo1 treatment. Moreover, the chronic hyperglycemia-induced pathological alteration in renal tissue were also ameliorated. Besides, immunohistochemical study demonstrated a substantial reduction in elevated levels of carboxymethyl lysine, an advanced glycation end product. Elevated collagenous deposition in DN group was also attenuated through CmNo1 administration. Moreover, the enhanced levels of transforming growth factor-β1, a fibrosis-inducing protein in glomerulus were also markedly dampened. Furthermore, auxiliary risk factors in DN like serum triglycerides and cholesterol were found to be increased but were decreased by CmNo1 treatment. Conclusively, the results suggests that CmNo1 exhibit potent and efficacious renoprotective action against hyperglycemia-induced DN.

Hyperglycaemia-induced reciprocal changes in miR-30c and PAI-1 expression in platelets

Type 2 diabetic mellitus (DM2) is associated with accelerated thrombotic complications and is characterized by high levels of plasminogen activator inhibitor-1 (PAI-1). Recent studies show that human platelets have high levels of miR-30c and synthesize considerable active PAI-1. The underlying mechanism of how PAI-1 expression is upregulated in DM2 is poorly understood. We now report that hyperglycaemia-induced repression of miR-30c increases PAI-1 expression and thrombus formation in DM2. Bioinformatic analysis and identification of miRNA targets were assessed using luciferase assays, quantitative real-time PCR and western blots invitro and in vivo. The changes in miR-30c and PAI-1 levels were identified in platelets from healthy and diabetic individuals. We found that miR-30c directly targeted the 3′ UTR of PAI-1 and negatively regulated its expression. miR-30c was negatively correlated with glucose and HbA1c levels in DM2. In HFD-fed diabetic mice, increasing miR-30c expression by lenti-miR-30c significantly decreased the PAI-1 expression and prolonged the time to occlusion in an arterial thrombosis model. Platelet depletion/reinfusion experiments generating mice with selective ablation of PAI-1 demonstrate a major contribution by platelet-derived PAI-1 in the treatment of lenti-miR-30c to thrombus formation. These results provide important implications regarding the regulation of fibrinolysis by platelet miRNA under diabetic mellitus.

Erythrocyte oxidative stress is associated with cell deformability in patients with retinal vein occlusion

Essentials Retinal vein occlusion (RVO), characterized by blood hyperviscosity, has an unclear pathogenesis. We aimed to find out if hemorheological profile is altered by oxidative stress in RVO patients. Red blood cell (RBC) oxidative stress is associated to whole blood viscosity and RBC deformability. Reactive oxygen species alter RBC membrane rigidity, playing a key role in RVO pathogenesis.

SUMMARY

Background Retinal vein occlusion (RVO) is characterized by vision loss resulting from hypoperfusion and hypoxia of the retina. RVO pathogenesis is not yet fully understood, although blood hyperviscosity has been observed. Erythrocyte deformability plays a key role in determining blood viscosity, and it is critical to microvascular perfusion and oxygen delivery. It has been shown that oxidative stress-induced erythrocyte membrane fluidity alterations are linked to the progression of cardiovascular diseases. Objectives To determine whether erythrocytes from RVO patients show signs of oxidative stress, and whether this condition can modify the hemorheologic profile in these patients. Patients and Methods We analyzed the entire hemorheologic profile and erythrocyte oxidative stress - reactive oxygen species (ROS) production and membrane lipid peroxidation - in 128 RVO patients and 128 healthy subjects, matched for age and sex. Fluorescence anisotropy was used to evaluate the fluidity of erythrocyte membranes. Results In RVO patients, erythrocyte oxidative stress was present and positively correlated with whole blood viscosity and erythrocyte deformability. Multivariate linear regression analysis after adjustment for age, cardiovascular risk factors, medications, leukocyte number and mean corpuscular volume indicated that erythrocyte-derived ROS and erythrocyte lipid peroxidation were significantly and positively correlated with erythrocyte membrane viscosity and deformability. Moreover, in vitro experiments demonstrated that ROS have a key role in erythrocyte membrane fluidity. Conclusions Our findings indicate that erythrocyte oxidative stress plays a key role in the pathogenesis of RVO, and pave the way to new therapeutic interventions.

Human Recombinant Antithrombin (ATryn®) Administration Improves Survival and Prevents Intravascular Coagulation After Intraportal Islet Transplantation in a Piglet Model

Human islet transplantation is a viable treatment option for type 1 diabetes mellitus (T1DM). However, pancreatic islet inflammation after transplantation induced by innate immune responses is likely to hinder graft function. This is mediated by incompatibility between islets and the blood interface, known as instant blood-mediated inflammatory reaction (IBMIR). Herein we hypothesized that portal venous administration of islet cells with human recombinant antithrombin (ATryn®), a serine protease inhibitor (serpin), which plays a central role in the physiological regulation of coagulation and exerts indirect anti-inflammatory activities, may offset coagulation abnormalities such as disseminated intravascular coagulation (DIC) and IBMIR. The current prospective, randomized experiment was conducted using an established preclinical pig model. Three groups were constituted for digested pancreatic tissue transplantation (0.15 ml/kg): control, NaCl 0.9% (n = 7); gold standard, heparin (25 UI/kg) (n = 7); and human recombinant ATryn® (500 UI/kg) (n = 7). Blood samples were collected over time (T0 to 24 h), and biochemical, coagulation, and inflammatory parameters were evaluated. In both the control and heparin groups, one animal died after a portal thrombosis, while no deaths occurred in the ATryn®-treated group. As expected, islet transplantation was associated with an increase in plasma IL-6 or TNF-α levels in all three groups. However, DIC was only observed in the control group, an effect that was suppressed after ATryn® administration. ATryn® administration increased antithrombin activity by 800%, which remained at 200% for the remaining period of the study, without any hemorrhagic complications. These studies suggest that coadministration of ATryn® and pancreatic islets via intraportal transplantation may be a valuable therapeutic approach for DIC without risk for islets and subjects.

A murine model of type 2 diabetes mellitus developed using a combination of high fat diet and multiple low doses of streptozotocin treatment mimics the metabolic characteristics of type 2 diabetes mellitus in humans

INTRODUCTION

A murine model of type 2 diabetes mellitus was used to compare the antidiabetic effects of the dipeptidyl peptidase-4 (DPP4) inhibitor vildagliptin and biguanide, metformin.

METHODS

Swiss albino mice (n=20 males; n=25 females) were given high fat diet (HFD) ad libitum for 3weeks followed by low dose (40mgkg^-1 body weight, bw daily) of streptozotocin (STZ) intraperitoneally five times from the 22nd day of treatment onwards, with HFD continued up to 26th day. Controls (n=15 males; n=15 females) were fed normal balanced diet without administration of STZ. Successful induction of diabetes mellitus was confirmed by testing for fasting blood glucose, intraperitoneal glucose tolerance and intraperitoneal insulin sensitivity. Diabetic mice were administered vildagliptin (10mgkg^-1 bw daily) and metformin (50mgkg^-1 bw daily) orally for 4weeks. Control, diabetic, vildagliptin and metformin-treated diabetic mice were evaluated for alterations in lipid profile using blood serum and histopathology and oxidative stress using tissues including liver, kidney and heart.

RESULTS

Diabetic mice showed significant alterations in lipid profile, tissue histopathology, impaired glucose tolerance, lower insulin sensitivity and elevated lipid peroxidation and protein carbonylation, with depressed catalase activity, when compared to age and gender-matched controls. Metformin and vildagliptin ameliorated the abovementioned diabetic conditions, with vildagliptin found to be more effective.

DISCUSSION

A murine model developed by the combination of HFD and multiple low dose of STZ mimics the metabolic characteristics of type 2 diabetes mellitus in humans, and may be useful for antidiabetic drug screening.

Proteasome Activators, PA28α and PA28β, Govern Development of Microvascular Injury in Diabetic Nephropathy and Retinopathy

Diabetic nephropathy (DN) and diabetic retinopathy (DR) are major complications of type 1 and type 2 diabetes. DN and DR are mainly caused by injury to the perivascular supporting cells, the mesangial cells within the glomerulus, and the pericytes in the retina. The genes and molecular mechanisms predisposing retinal and glomerular pericytes to diabetic injury are poorly characterized. In this study, the genetic deletion of proteasome activator genes, PA28α and PA28β genes, protected the diabetic mice in the experimental STZ-induced diabetes model against renal injury and retinal microvascular injury and prolonged their survival compared with wild type STZ diabetic mice. The improved wellbeing and reduced renal damage was associated with diminished expression of Osteopontin (OPN) and Monocyte Chemoattractant Protein-1 (MCP-1) in the glomeruli of STZ-injected PA28α/PA28β double knockout (Pa28αβDKO) mice and also in cultured mesangial cells and retinal pericytes isolated from Pa28αβDKO mice that were grown in high glucose. The mesangial PA28-mediated expression of OPN under high glucose conditions was suppressed by peptides capable of inhibiting the binding of PA28 to the 20S proteasome. Collectively, our findings demonstrate that diabetic hyperglycemia promotes PA28-mediated alteration of proteasome activity in vulnerable perivascular cells resulting in microvascular injury and development of DN and DR.

Vasoregression: A Shared Vascular Pathology Underlying Macrovascular And Microvascular Pathologies?

Vasoregression is a common phenomenon underlying physiological vessel development as well as pathological microvascular diseases leading to peripheral neuropathy, nephropathy, and vascular oculopathies. In this review, we describe the hallmarks and pathways of vasoregression. We argue here that there is a parallel between characteristic features of vasoregression in the ocular microvessels and atherosclerosis in the larger vessels. Shared molecular pathways and molecular effectors in the two conditions are outlined, thus highlighting the possible systemic causes of local vascular diseases. Our review gives us a system-wide insight into factors leading to multiple synchronous vascular diseases. Because shared molecular pathways might usefully address the diagnostic and therapeutic needs of multiple common complex diseases, the literature analysis presented here is of broad interest to readership in integrative biology, rational drug development and systems medicine.

Modulatory influence of Parkia biglobosa protein isolate on testosterone and biomarkers of oxidative stress in brain and testes of streptozotocin-induced diabetic male rats

Parkia biglobosa seed an important household spice commonly consumed in Nigeria is believed to possess antioxidant activity that may exert modulatory effects in diabetes and diabetic complications. This study investigated the modulatory potential of Parkia biglobosa protein isolate (PBPi) on serum testosterone (sTT) level as well as its influence on biomarkers of oxidative stress in brain and testes of streptozotocin-induced diabetic male rats. Animals were made diabetic by single intraperitoneal administration of streptozotocin (STZ; 60 mg/kg body weight). PBPi (200 or 400 mg/kg body weight) was given orally by gavage or insulin (5 U/kg, i.p.) was administered daily to STZ-induced diabetic rats for 28 days. The results revealed a significant elevation in thiobarbituric acid reactive substances (TBARS) levels in the brain and testes of diabetic rats. This was closely associated with a concomitant reduction in levels of sTT and reduced testes weight, a noticeable decline in the glutathione-S-transferase (GST), superoxide dismutase (SOD) and catalase (CAT) as well as total glutathione (Total GSH) level in the brain and testes of diabetic rats. Interestingly, treatment with PBPi efficiently prevented the alterations witnessed in the serum sTT and also ameliorated various alterations in the biomarkers of oxidative stress (TBARS, Total GSH, GST, SOD and CAT) in brain and testes of diabetic rats. These results provide evidence that PBPi could protect the brain and testicular tissues against oxidative stress induced by STZ, via modulation of serum testosterone concentration and also by enhancing antioxidant defence system in STZ-diabetic rats.

Effects of pomegranate juice consumption on oxidative stress in patients with type 2 diabetes: a single-blind, randomized clinical trial

Increased free radicals production due to hyperglycemia produces oxidative stress in patients with diabetes. Pomegranate juice (PJ) has antioxidant properties. This study was conducted to determine the effects of PJ consumption in oxidative stress in type 2 diabetic patients. This study was a randomized clinical trial performed on 60, 40-65 years old diabetic patients. The patients were randomly allocated either to PJ consumption group or control. Patients in PJ group consumed 200 ml of PJ daily for six weeks. Sex distribution and the mean age were not different between two groups. After six weeks intervention, oxidized LDL and anti-oxidized LDL antibodies decreased and total serum antioxidant capacity and arylesterase activity of paraoxonase increased significantly in the PJ-treated group compared to the control group. Our data have shown that six weeks supplementation of PJ could have favorable effects on oxidative stress in patients with type 2 diabetes (T2D).

Selenium levels and Glutathione peroxidase activity in the plasma of patients with type II diabetes mellitus

Selenium, an essential trace element, is involved in the complex system of defense against oxidative stress through selenium-dependent glutathione peroxidases (GPx) and other selenoproteins. Because of its antioxidant properties, selenium or its selenospecies at appropriate levels could hinder oxidative stress and so development of diabetes. In this vein, quantitative speciation of selenium in human plasma samples from healthy and diabetic patients (controlled and non-controlled) was carried out by affinity chromatography (AF) coupled on-line to inductively coupled plasma mass spectrometry (ICP-MS) and isotope dilution analysis (IDA). Similarly, it is well known that patients with diabetes who exhibit poor control of blood glucose show a decreased total antioxidant activity. Thus, we evaluated the enzymatic activity of GPx in diabetic and healthy individuals, using the Paglia and Valentine enzymatic method, observing a significant difference (p<0.05) between the three groups of assayed patients (healthy (n=24): 0.61±0.11U/ml, controlled diabetic (n=38): 0.40±0.12U/ml and non-controlled diabetic patients (n=40): 0.32±0.09U/ml). Our results show that hyperglycemia induces oxidative stress in diabetic patients compared with healthy controls. What is more, glycation of GPx experiments demonstrated that it is the degree of glycation of the selenoenzyme (another species of the Se protein) what actually modulates its eventual activity against ROS in type II diabetes mellitus patients.

Clinical Effectiveness of Liraglutide in Type 2 Diabetes Treatment in the Real-World Setting: A Systematic Literature Review

INTRODUCTION

In clinical trials, liraglutide has proven to be an effective drug for the treatment of type 2 diabetes mellitus (T2DM). The real-world effectiveness of liraglutide has been investigated in numerous studies. The aim of this systematic literature review is to collate evidence on the real-world clinical effectiveness of liraglutide.

METHODS

A review of publications from Medline, EMBASE, the Cochrane Library, and conference proceedings was conducted to identify observational studies that assessed the clinical effectiveness of liraglutide in real-world clinical practice. This review was conducted according to the National Institute of Health and Care Excellence (NICE) guidance. No language or time limits were applied, except to the conference proceedings (2013-2015). Endpoints for data extraction were decided a priori. Study quality appraisal was done for full-text journal articles.

RESULTS

Of 124 publications included in the review, 43 were full-text articles. Liraglutide significantly reduces glycated hemoglobin (HbA1c) within 6 months of initiating treatment (mean change in HbA1c from baseline: -0.9% to -2.2%; HbA1c <7.0%: 29.5-65.0%). The NICE composite endpoint (HbA1c reduction ≥1% and weight reduction ≥3%) was met in 16.9-47.0% of patients with liraglutide treatment. Liraglutide therapy led to a mean change in absolute weight from baseline of -1.3 to -8.65 kg. Liraglutide treatment was well tolerated in patients with T2DM. The rate of occurrence of hypoglycemia with liraglutide monotherapy was ≤0.8%. Hypoglycemia was more common in patients taking antidiabetic medications (0.0-15.2%) together with liraglutide. The beneficial glycemic and weight effect of liraglutide therapy in patients with T2DM was maintained for at least 12 months.

CONCLUSION

Evidence from observational studies reflecting real-world clinical practice demonstrates that liraglutide therapy improves glycemic control with a low risk of hypoglycemia, and is associated with significant weight loss in patients with T2DM. These observations are consistent with clinical trial findings.

FUNDING

Novo Nordisk A/S, Søborg, Denmark.

Therapeutic Efficacy of Stem Cells Transplantation in Diabetes: Role of Heme Oxygenase

The growing data obtained from in vivo studies and clinical trials demonstrated the benefit of adult stem cells transplantation in diabetes; although an important limit is represented by their survival after the transplant. To this regard, recent reports suggest that genetic manipulation of stem cells prior to transplantation can lead to enhanced survival and better engraftment. The following review proposes to stimulate interest in the role of heme oxygenase-1 over-expression on transplantation of stem cells in diabetes, focusing on the clinical potential of heme oxygenase protein and activity to restore tissue damage and/or to improve the immunomodulatory properties of transplanted stem cells.

Angiogenesis and Inflammation Crosstalk in Diabetic Retinopathy

Diabetic retinopathy (DR) is one of the most prevalent microvascular complications of diabetes and one of the most frequent causes of blindness in active age. Etiopathogenesis behind this important complication is related to several biochemical, hemodynamic and endocrine mechanisms with a preponderant initial role assumed by polyol pathways, increment of growth factors, accumulation of advanced glycation end products (AGE), activation of protein kinase C (PKC), activation of the renin-angiotensin-aldosterone system (RAAS), and leukostasis. Chronic and sustained hyperglycemia works as a trigger to the early alterations that culminate in vascular dysfunction. Hypoxia also plays an essential role in disease progression with promotion of neovascularization and vascular dystrophies with vitreous hemorrhages induction. Thus, the accumulation of fluids and protein exudates in ocular cavities leads to an opacity augmentation of the cornea that associated to neurodegeneration results in vision loss, being this a devastating characteristic of the disease final stage. During disease progression, inflammatory molecules are produced and angiogenesis occur. Furthermore, VEGF is overexpressed by the maintained hyperglycemic environment and up-regulated by tissue hypoxia. Also pro-inflammatory mediators regulated by cytokines, such as tumor necrosis factor (TNF-α) and interleukin-1 beta (IL-1β), and growth factors leads to the progression of these processes, culminating in vasopermeability (diabetes macular edema) and/or pathological angiogenesis (proliferative diabetic retinopathy). It was found a mutual contribution between inflammation and angiogenesis along the process. J. Cell. Biochem. 117: 2443-2453, 2016. © 2016 Wiley Periodicals, Inc.

Effect of obesity and glycated hemoglobin on oxygen saturation in ambulatory type 2 diabetic individuals: A pilot study

AIMS

Tissue hypoxia is an important contributor to diabetic complications. Glycation of hemoglobin (Hb) and obesity are major determinant of oxygen saturation (SpO2) in blood. Hence, the present study was planned to evaluate the effect of obesity on SpO2 in a wide range of glycated hemoglobin (HbA1c) levels in ambulatory type 2 diabetic patients.

MATERIAL AND METHODS

A cohort of 60 subjects irrespective of diabetic status were recruited and clustered in group I (HbA1c <6.5) and group II (HbA1c ≥6.5) depending on HbA1c. Anthropometry and routine biochemical parameters were measured. HbA1c (%) were estimated by high performance liquid chromatography (HPLC) respectively. SpO2 (%) levels were measured by pulse oximetry. Pearson correlation, bivariate regression and student 't' test were used for statistical analysis.

RESULTS

Blood concentration of HbA1c was <6.5 in 29 participants and ≥6.5 in 31 participants. Plasma fasting and post prandial glucose, HbA1c as well as Hb levels were significantly (p<0.50) higher in diabetics as compared to non diabetics. Waist circumference (WC) (r=-400; p=0.026) and body mass index (BMI) (r=-381; p=0.034) showed a significant negative correlation with SpO2 in diabetic patients. On adjusting HbA1c in group II, SpO2 was found to independently and inversely associated with WC (p=0.042) and BMI (p=0.049).

CONCLUSIONS

Obesity was found to be a strong independent contributor to reduction in oxygen carrying capacity in ambulatory type 2 diabetic subjects. However there is no effect of glycated Hb on SpO2 in the same population.

Microvasular and macrovascular complications in diabetes mellitus: Distinct or continuum?

Diabetes and related complications are associated with long-term damage and failure of various organ systems. The line of demarcation between the pathogenic mechanisms of microvascular and macrovascular complications of diabetes and differing responses to therapeutic interventions is blurred. Diabetes induces changes in the microvasculature, causing extracellular matrix protein synthesis, and capillary basement membrane thickening which are the pathognomic features of diabetic microangiopathy. These changes in conjunction with advanced glycation end products, oxidative stress, low grade inflammation, and neovascularization of vasa vasorum can lead to macrovascular complications. Hyperglycemia is the principal cause of microvasculopathy but also appears to play an important role in causation of macrovasculopathy. There is thought to be an intersection between micro and macro vascular complications, but the two disorders seem to be strongly interconnected, with micro vascular diseases promoting atherosclerosis through processes such as hypoxia and changes in vasa vasorum. It is thus imperative to understand whether microvascular complications distinctly precede macrovascular complications or do both of them progress simultaneously as a continuum. This will allow re-focusing on the clinical issues with a unifying perspective which can improve type 2 diabetes mellitus outcomes.

Medication Adherence and the Occurrence of Complications in Patients with Newly Diagnosed Hypertension

BACKGROUND AND OBJECTIVES

In this retrospective cohort study, we sought to elucidate the relationship between medication adherence (MA) and the incidence of complications in patients with newly diagnosed hypertension.

SUBJECTS AND METHODS

Using claims data from the National Health Insurance Service, we measured health outcomes based on levels of MA, analyzed the incidence of complications in patients with a good MA, and clarified factors that may affect or predict MA.

RESULTS

In 2008, a total of 4294773 patients were diagnosed with hypertension and were subsequently prescribed anti-hypertensive medications. In the present study, we enrolled 564782 patients who met our inclusion/exclusion criteria. The 40-59% medication possession ratio (MPR) group had a 1.36 times higher risk of developing complications (95% confidence interval [CI]: 1.27-1.45) than did the MPR≥ 80% group, as revealed through Cox's proportional hazards analysis. Similarly, the <20% MPR group was 2.01 times more likely to develop complications than the good MA group (95% CI: 1.82-2.23). Overall, patients who had a lower level of MA had a higher risk of developing complications.

CONCLUSION

Our results demonstrate that MA is tightly correlated with hypertension health outcomes. Improving MA could be one strategy for reducing the risk of cerebrovascular disease complications and the loss of productivity in these patients.

Resveratrol shows neuronal and vascular-protective effects in older, obese, streptozotocin-induced diabetic rats

Diabetes-induced CVD is the most significant complication of prolonged hyperglycaemia. The aim of this study was to determine whether resveratrol, a polyphenol antioxidant compound, when administered at a dose that can be reasonably obtained through supplementation could prevent the development of cardiovascular complications in older, obese, diabetic rats. Diabetes was induced in 6-month old, obese, male Wistar rats via a single intravenous dose of streptozotocin (65 mg/kg). Randomly selected animals were administered resveratrol (2 mg/kg) via oral gavage daily for 8 weeks. Body weights, blood glucose levels, food intake and water consumption were monitored, and assessments of vascular reactivity, tactile allodynia and left ventricular function were performed. Resveratrol therapy significantly improved tactile allodynia and vascular contractile functionality in diabetic rats (P<0·05). There were no significant changes in standardised vasorelaxation responses, plasma glucose concentrations, water consumption, body weight, left ventricular hypertrophy, kidney hypertrophy, heart rate or left ventricular compliance with resveratrol administration. Resveratrol-mediated improvements in vascular and nerve function in old, obese, diabetic rats were associated with its reported antioxidant effects. Resveratrol did not improve cardiac function nor mitigate the classic clinical symptoms of diabetes mellitus (i.e. hyperglycaemia, polydypsia and a failure to thrive). This suggests that supplementation with resveratrol at a dose achievable with commercially available supplements would not produce significant cardioprotective effects in people with diabetes mellitus.

Higher Risk of Thyroid Disorders in Young Patients with Type 1 Diabetes: A 12-Year Nationwide, Population-Based, Retrospective Cohort Study

BACKGROUND

The association between type 1 diabetes and thyroid autoimmunity has been studied in various populations, but seldom on Taiwanese children and adolescents. Therefore, the aim of this study was to examine the incidence of autoimmune thyroid disorders in Taiwanese children and adolescent patients with type 1 diabetes, based on data from a nationwide, population-based, health claims database.

METHODS

Using Taiwan's National Health Insurance Research Database, we identified 3,652 patients with type 1 diabetes between 2000 and 2012. A comparison cohort was assembled, which consisted of five patients without type 1 diabetes, based on frequency matching for sex and 3-year age interval, for each patient with type 1 diabetes. Both groups were followed until diagnosis of thyroid disorders or the end of the follow-up period. Poisson regression models were used to calculate incidence rate ratios for the thyroid disorders between the type 1 diabetes cohort and the comparison cohort.

RESULTS

Simple and unspecified goiter (International Classification of Diseases, 9th Revision, Clinical Modification [ICD-9-CM] code 240), thyrotoxicosis (ICD-9-CM code 242), unspecified hypothyroidism (ICD-9-CM code 244.9), and thyroiditis (ICD-9-CM code 245) showed significantly higher incidences in the type 1 diabetes cohort compared with the control cohort, with incidence rate ratios of 2.74, 6.95, 6.54, 16.07, respectively.

CONCLUSIONS

Findings from this nationwide, population-based cohort study showed that the incidences of autoimmune thyroid disorders were significantly higher in Taiwanese children and adolescents with type 1 diabetes compared with those without the disease.

Serum and Urinary Orosomucoid in Young Patients With Type 1 Diabetes: A Link Between Inflammation, Microvascular Complications, and Subclinical Atherosclerosis

Orosomucoid is an acute-phase serum protein that is upregulated in urine samples of patients with diabetic nephropathy. We assessed serum and urinary orosomucoid levels in children and adolescents with type 1 diabetes and their relation to microvascular complications and carotid intima-media thickness (CIMT). Sixty patients with type 1 diabetes were divided into 2 groups according to the presence of microvascular complications and compared with 60 healthy controls. High-sensitivity C-reactive protein (hs-CRP), hemoglobin A1c (HbA1c), urinary albumin-creatinine ratio (UACR), serum and urinary orosomucoid, and CIMT were assessed. Both serum and urinary orosomucoid levels were significantly increased in patients with and without microvascular complications compared with controls, and the highest levels were in patients with complications (P < .001). Serum and urinary orosomucoid were higher in patients with microalbuminuria than normoalbuminuric group (P < .001). The cutoff value of urinary orosomucoid at 2825 ng/mL could differentiate patients with and without microvascular complications. Serum and urinary orosomucoid were positively correlated. Multiple regression analysis showed that HbA1c, UACR, hs-CRP, and CIMT were independently related to orosomucoid. We suggest that orosomucoid is a significant independent factor for diabetic microvascular complications and can be considered as an early marker of renal injury. High orosomucoid levels in type 1 diabetes reflect endothelial dysfunction and subclinical atherosclerosis.

Impact of Diabetic Complications on Balance and Falls: Contribution of the Vestibular System

Diabetes causes many complications, including retinopathy and peripheral neuropathy, which are well understood as contributing to gait instability and falls. A less understood complication of diabetes is the effect on the vestibular system. The vestibular system contributes significantly to balance in static and dynamic conditions by providing spatially orienting information. It is noteworthy that diabetes has been reported to affect vestibular function in both animal and clinical studies. Pathophysiological changes in peripheral and central vestibular structures due to diabetes have been noted. Vestibular dysfunction is associated with impaired balance and a higher risk of falls. As the prevalence of diabetes increases, so does the potential for falls due to diabetic complications. The purpose of this perspective article is to present evidence on the pathophysiology of diabetes-related complications and their influence on balance and falls, with specific attention to emerging evidence of vestibular dysfunction due to diabetes. Understanding this relationship may be useful for screening (by physical therapists) for possible vestibular dysfunction in people with diabetes and for further developing and testing the efficacy of interventions to reduce falls in this population.

Design of Potent and Highly Selective Inhibitors for Human β-Secretase 2 (Memapsin 1), a Target for Type 2 Diabetes

Structure-based design and syntheses of potent and highly selective BACE2 inhibitors are described.

Design, synthesis and evaluation of very potent and selective β-secretase 2 (memapsin 1, BACE 2) inhibitors are described. The inhibitors were designed specifically to interact with the S2′-site of β-secretase 2 to provide >170 000-fold selectivity over β-secretase (BACE 1) and >15 000-fold selectivity over cathepsin D. BACE 2 is implicated in type 2 diabetes. The studies serve as an important guide to selective BACE 2 inhibitors.

Endurance, interval sprint, and resistance exercise training: impact on microvascular dysfunction in type 2 diabetes

Type 2 diabetes (T2D) alters capillary hemodynamics, causes capillary rarefaction in skeletal muscle, and alters endothelial and vascular smooth muscle cell phenotype, resulting in impaired vasodilatory responses. These changes contribute to altered blood flow responses to physiological stimuli, such as exercise and insulin secretion. T2D-induced microvascular dysfunction impairs glucose and insulin delivery to skeletal muscle (and other tissues such as skin and nervous), thereby reducing glucose uptake and perpetuating hyperglycemia and hyperinsulinemia. In patients with T2D, exercise training (EX) improves microvascular vasodilator and insulin signaling and attenuates capillary rarefaction in skeletal muscle. EX-induced changes subsequently augment glucose and insulin delivery as well as glucose uptake. If these adaptions occur in a sufficient amount of tissue, and skeletal muscle in particular, chronic exposure to hyperglycemia and hyperinsulinemia and the risk of microvascular complications in all vascular beds will decrease. We postulate that EX programs that engage as much skeletal muscle mass as possible and recruit as many muscle fibers within each muscle as possible will generate the greatest improvements in microvascular function, providing that the duration of the stimulus is sufficient. Primary improvements in microvascular function occur in tissues (skeletal muscle primarily) engaged during exercise, and secondary improvements in microvascular function throughout the body may result from improved blood glucose control. We propose that the added benefit of combined resistance and aerobic EX programs and of vigorous intensity EX programs is not simply "more is better." Rather, we believe the additional benefit is the result of EX-induced adaptations in and around more muscle fibers, resulting in more muscle mass and the associated microvasculature being changed. Thus, to acquire primary and secondary improvements in microvascular function and improved blood glucose control, EX programs should involve upper and lower body exercise and modulate intensity to augment skeletal muscle fiber recruitment. Under conditions of limited mobility, it may be necessary to train skeletal muscle groups separately to maximize whole body skeletal muscle fiber recruitment.

Effects of a Novel Therapeutic Intervention in Patients With Diabetic Peripheral Neuropathy

OBJECTIVE

To determine the effect of a novel therapeutic intervention called intraneural facilitation on balance measures and a neuropathy scale in patients with diabetic peripheral neuropathy.

DESIGN

Prospective pre- and posttest, single group clinical trial.

SETTING

Outpatient physical therapy clinic.

PARTICIPANTS

Patients with diabetic peripheral neuropathy (N=13).

INTERVENTION

Subjects received 10 sessions of intraneural facilitation.

MAIN OUTCOME MEASURES

The modified Total Neuropathy Scale, the NeuroCom SMART Balance Master system computerized dynamic posturography (CDP) that includes the Sensory Organization Test (SOT) and the limits of stability (LOS), and the Activities-specific Balance and Confidence (ABC) scale.

RESULTS

Subjects in this study showed significant improvement in the modified Total Neuropathy Scale, SOT, and 1 component in the LOS test (movement velocity). There were no significant differences in the ABC scale or in 4 components of the LOS test, which were reaction time, end point excursion, maximum excursion, and directional control.

CONCLUSIONS

Intraneural facilitation improved objective balance measures and neuropathy symptoms in patients with diabetic peripheral neuropathy. Further study is needed to determine long-term benefits of this intervention.

The usefulness of quantifying intraepidermal nerve fibers density in the diagnostic of diabetic peripheral neuropathy: a cross-sectional study

BACKGROUND

Distal symmetric polyneuropathy (DSPN) is the most common complication of type 2 diabetes mellitus (T2DM) and the most common form of peripheral neuropathy. DSPN increases the risk of foot ulceration up to seven-fold, and is a significant risk factor in more than 60 % of the amputations of the lower limbs in patients with T2DM. The aims of our study were to evaluate the difference in the density of intraepidermal nerve fibers (IENF) in patients with respectively without DSPN, to evaluate the strength of the relationship between the symptomatology of the DSPN and IENF density and to define a cutoff value of the IENF density for the diagnosis of DSPN.

METHODS

We enrolled, according to a consecutive, population-based method, 36 patients with T2DM admitted in our Clinic. For all patients, we measured HbA1c, lipid profile, body mass index and we assessed the presence and severity of DSPN using the evaluation of clinical symptoms, nerve conduction velocity and IENF density quantification.

RESULTS

The presence of neuropathy was significantly associated with a decreased density of IENF for both the proximal (11.6 vs. 14.9 fibers/mm; p = 0.014) and the distal biopsies (7.2 vs. 8.6 fibers/mm; p = 0.020). The optimal threshold value of IENF density (the point with the maximum sum of specificity and sensitivity), according to our model, was 10.1 fibers/mm.

CONCLUSIONS

Skin biopsy followed by IENF density quantification is a valid, reliable tool for the diagnosis of DSPN.