Extravascular modified lipoproteins: a role in the propagation of diabetic retinopathy in a mouse model of type 1 diabetes

Aims/hypothesis: We aimed to determine whether plasma lipoproteins, after leakage into the retina and modification by glycation and oxidation, contribute to the development of diabetic retinopathy in a mouse model of type 1 diabetes.

Methods: To simulate permeation of plasma lipoproteins intoretinal tissues, streptozotocin-induced mouse models of diabetes and non-diabetic mice were challenged with intravitreal injection of human ‘highly-oxidised glycated’ low-density lipoprotein (HOG-LDL), native- (N-) LDL, or the vehicle PBS.Retinal histology, electroretinography (ERG) and biochemical markers were assessed over the subsequent 14 days.

Results: Intravitreal administration of N-LDL and PBS had noeffect on retinal structure or function in either diabetic or non-diabetic animals. In non-diabetic mice, HOG-LDL elicited a transient inflammatory response without altering retinal function,but in diabetic mice it caused severe, progressive retinal injury, with abnormal morphology, ERG changes, vascular leakage, vascular endothelial growth factor overexpression, gliosis, endoplasmic reticulum stress, and propensity to apoptosis.

Conclusions/interpretation: Diabetes confers susceptibility to retinal injury imposed by intravitreal injection of modified LDL. The data add to the existing evidence that extravasated, modified plasma lipoproteins contribute to the propagation of diabetic retinopathy. Intravitreal delivery of HOG-LDL simulates a stress known to be present, in addition to hyperglycaemia, in human diabetic retinopathy once blood retinal barriers are compromised.

The impact of body fat on three dimensional motion of the paediatric foot during walking

Childhood obesity is commonly associated with a pes planus foot type and altered lower limb joint function during walking. However, limited information has been reported on dynamic intersegment foot motion with the level of obesity in children. The aim of this study was to explore the relationships between intersegment foot motion during gait and body fat in boys age 7 to 11 years. Fat mass was measured in fifty-five boys using air displacement plethysmography. Three-dimensional gait analysis was conducted on the right foot of each participant using the 3DFoot model to capture angular motion of the shank, calcaneus, midfoot and metatarsals. Two multivariate statistical techniques were employed; principle component analysis reduced the multidimensional nature of gait analysis, and multiple linear regression analysis accounted for potential confounding factors. Higher fat mass predicted greater plantarflexion of the calcaneus during the first half and end of stance phase and at the end of swing phase. Greater abduction of the calcaneus throughout stance and swing was predicted by greater fat mass. At the midfoot, higher fat mass predicted greater dorsiflexion and eversion throughout the gait cycle. The findings present novel information on the relationships between intersegment angular motion of the foot and body fat in young boys. The data indicates a more pronated foot type in boys with greater body fat. These findings have clinical implications for pes planus and a predisposition for pain and discomfort during weight bearing activities potentially reducing motivation in obese children to be physically active.

Characterization of pro- and anti-angiogenic factors in models of diabetic retinopathy

Dissertação de mestrado, Ciências Biomédicas, Departamento de Ciências Biomédicas e Medicina, Universidade do Algarve, 2015

Role of oxidative stress-induced systemic and cavernosal molecular alterations in the progression of diabetic erectile dysfunction

Background Erectile dysfunction (ED) is a prevalent complication of diabetes, and oxidative stress is an important feature of diabetic ED. Oxidative stress-induced damage plays a pivotal role in the development of tissue alterations. However, the deleterious effects of oxidative stress in the corpus cavernosum with the progression of diabetes remain unclear. The aim of this study was to evaluate systemic and penile oxidative stress status in the early and late stages of diabetes. Methods Male Wistar streptozotocin-diabetic rats (and age-matched controls) were examined 2 (early) and 8 weeks (late) after the induction of diabetes. Systemic oxidative stress was evaluated by urinary H2O2 and the ratio of circulating reduced/oxidized glutathione (GSH/GSSG). Penile oxidative status was assessed by H2O2 production and 3-nitrotyrosine (3-NT) formation. Cavernosal endothelial nitric oxide synthase (eNOS) was analyzed by quantitative immunohistochemistry. Dual immunofluorescence was also performed for 3-NT and α-smooth muscle actin (α-SMA) and eNOS–α-SMA. Results There was a significant increase in urinary H2O2 levels in both diabetic groups. The plasma GSH/GSSG ratio was significantly augmented in late diabetes. In cavernosal tissue, H2O2 production was significantly increased in late diabetes. Reactivity for 3-NT was located predominantly in cavernosal smooth muscle (SM) and was significantly reduced in late diabetes. Quantitative immunohistochemistry revealed a significant decrease in eNOS levels in cavernosal SM and endothelium in late diabetes. Conclusions The findings indicate that the noxious effects of oxidative stress are more prominent in late diabetes. Increased penile protein oxidative modifications and decreased eNOS expression may be responsible for structural and/or functional deregulation, contributing to the progression of diabetes-associated ED.

Quality of life of hypertensive and diabetic patients: Who suffers the most?

Objective: Quality of life was measured using the EQ-5D index for Portugal and a Self-Assessed Ranking of Health (SARH) to understand which patients suffer the most decrease in quality of life: diabetics or hypertensive. Method: Using the National Health Survey (NHS), two analyses were conducted on 5649 respondents. The EQ-5D index was calculated by matching questions in the NHS with its dimensions. The SARH was calculated based on a specific question in the NHS. Results: Differences between diseases do not occur using the EQ-5D index. Using the SARH, type 1 diabetics suffer the most while hypertensive suffers the least.

Angiotensin II favors progression to heart failure in diabetic hearts: role of myocardial fatty acid oxidation downregulation

Purpose: Diabetic myocardium is particularly vulnerable to develop heart failure in response to chronic stress conditions including hypertension or myocardial infarction. We have recently observed that angiotensin II (Ang II)-mediated downregulation of the fatty acid oxidation pathway favors occurrence of heart failure by myocardial accumulation of lipids (lipotoxicity). Because diabetic heart is exposed to high levels of circulating fatty acid, we determined whether insulin resistance favors development of heart failure in mice with Ang II-mediated myocardial remodeling.Methods: To study the combined effect of diabetes and Ang II-induced heart remodeling, we generated leptin-deficient/insulin resistant (Lepob/ob) mice with cardiac targeted overexpression of angiotensinogen (TGAOGN). Left ventricular (LV) failure was indicated by pulmonary congestion (lung weight/tibial length>+2SD of wild-type mice). Myocardial metabolism and function were assessed during in vitro isolated working heart perfusion.Results: Forty-eight percent of TGAOGN mice without insulin resistance exhibited pulmonary congestion at the age of 6 months associated with increased myocardial BNP expression (+375% compared with WT) and reduced LV power (developed pressure x cardiac output; -15%). The proportion of mice presenting heart failure was markedly increased to 71% in TGAOGN mice with insulin resistance (TGAOGN/Lepob/ob). TGAOGN/Lepob/ob mice with heart failure exhibited further increase of BNP compared with failing non-diabetic TGAOGN mice (+146%) and further reduction of cardiac power (-59%). Mice with insulin resistance alone (Lepob/ob) did not exhibit signs of heart failure or LV dysfunction. Myocardial fatty acid oxidation measured during in vitro perfusion was markedly increased in non-failing hearts from Lepob/ob mice (+380% compared with WT) and glucose oxidation decreased (-72%). In contrast, fatty acid and glucose oxidation did not differ from Lepob/ob mice in hearts from TGAOGN/Lepob/ob mice without heart failure. However, both fatty acid and glucose oxidation were markedly decreased (-47% and -48%, respectively, compared with WT/Lepob/+) in failing hearts from TGAOGN/Lepob/ob mice. Reduction of fatty acid oxidation was associated with marked reduction of protein expression of a number of regulatory enzymes implied in fatty acid oxidation.Conclusions: Insulin resistance favors the progression to heart failure during chronic exposure of the myocardium to Ang II. Our results are compatible with a role of Ang II-mediated downregulation of fatty acid oxidation, potentially promoting lipotoxicity.

Pathologic ventricular hypertrophy in the offspring of diabetic mothers : a retrospective study

L'hypertrophie ventriculaire pathologique chez les nouveau-nés des mères diabétiques une étude rétrospective RESUME Objectif L'incidence du diabète chez les femmes enceintes ne cesse de croître, de même que les complications chez leurs nouveau-nés. C'est pourquoi, nous avons étudié la population de mères diabétiques suivies dans notre établissement entre les années 2003-2005 dans le but d'analyser spécifiquement le problème d'hypertrophie ventriculaire pathologique (HVP) chez les nouveau-nés de cette population. Méthode et résultats Dans notre étude rétrospective comprenant 87 grossesses de femmes diabétiques (92 nouveau-nés), 16 présentaient un diabète de type 1, 17 de type 2 et 54 ont développé un diabète gestationnel (DG). Le médian des hémoglobines glycquées (HbAlc) pour cette population est de 5.8% (5.3-6.5) : 17 avaient une HbAlc au-dessus de la norme, dont 2 souffrant d'une cardiomyopathie congénitale (CMC) et six d'une HVP. Un total de 75 nouveaux-nés étaient normaux, cinq avaient une CMC et 12 une HVP (1/12 décédé post-natalement, 1/12 mort-né, 2/12 nécessitant un accouchement prématuré, 8/12 normaux). Les 16 mères avec un diabète de type 1 accouchèrent de trois nouveau-nés avec une CMC et de 50% avec une HVP, comprenant un enfant décédé et un prématuré né par césarienne à cause d'une HVP. Dans le groupe des 17 nouveau-nés issus d'une mère connue pour un diabète de type 2, un cas présentait une CMC et 25% des cas une HVP. Parmi les 54 grossesses avec un DG, on dénombre un cas de CMC et un cas de HVP. Conclusion Les grossesses de mères souffrant d'un diabète de type 1 et de type 2 comportent toutes deux un risque augmenté de développement d'une HVP comparées à celles de mères ayant développé un diabète gestationnel. Les contrôles glycémiques sont insuffisants pour éviter la survenue d'une HVP. Comme aucun autre paramètre prédictif n'a pu été défini jusqu'alors, nous concluons qu'un suivi échographique rapproché de ces grossesses peut prévenir des complications périnatales sévères.

Renal responses to three types of renin-angiotensin system blockers in patients with diabetes mellitus on a high-salt diet: a need for higher doses in diabetic patients?

Objective Activation of the renal renin-angiotensin system in patients with diabetes mellitus appears to contribute to the risk of nephropathy. Recently, it has been recognized than an elevation of prorenin in plasma also provides a strong indication of risk of nephropathy. This study was designed to examine renin-angiotensin system control mechanisms in the patient with diabetes mellitus.Methods We enrolled 43 individuals with type 2 diabetes mellitus. All individuals were on a high-salt diet to minimize the contribution of the systemic renin-angiotensin system. After an acute exposure to captopril (25 mg), they were randomized to treatment with either irbesartan (300 mg) or aliskiren (300 mg) for 2 weeks.Results All agents acutely lowered blood pressure and plasma aldosterone, and increased renal plasma flow and glomerular filtration rate. Yet, only captopril and aliskiren acutely increased plasma renin and decreased plasma angiotensin II, whereas irbesartan acutely affected neither renin nor angiotensin II. Plasma renin and angiotensin II subsequently did increase upon chronic irbesartan treatment. When given on day 14, irbesartan and aliskiren again induced the above hemodynamic, renal and adrenal effects, yet without significantly changing plasma renin. Irbesartan at that time did not affect plasma angiotensin II, whereas aliskiren lowered it to almost zero.Conclusion The relative resistance of the renal renin response to acute (irbesartan) and chronic (irbesartan and aliskiren) renin-angiotensin system blockade supports the concept of an activated renal renin-angiotensin system in diabetes, particularly at the level of the juxtaglomerular cell, and implies that diabetic patients might require higher doses of renin-angiotensin system blockers to fully suppress the renal renin-angiotensin system. J Hypertens 29: 2454-2461 (C) 2011 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins.

Coronary artery disease screening in diabetic patients: how good is guideline adherence?

INTRODUCTION: Diabetic patients are at high risk for coronary artery disease (CAD), which is the leading cause of death in this population. The Swiss Society of Endocrinology-Diabetology (SSED) recommends CAD screening for diabetic patients with > or = 2 additional cardiovascular risk factors (CVRF), by stress echocardiography (SE) or myocardial perfusion imaging (MPI). The aim of this study was to assess the application of these guidelines and the treatment of CVRF in the diabetes outpatient clinics of the five Swiss University Hospitals. METHODS: The study was initiated in Lausanne and the study questionnaires were circulated to the endocrinologists of the five Swiss University Hospitals. Practitioners were asked to include consecutive patients attending the diabetes outpatient clinics over one month. Prevalence of CAD, screening methods for CAD, prevalence of CVRF, biological analyses over the last 6 months and medical therapy were recorded. RESULTS: A total of 302 subjects were included. The mean age was 53 +/- 14 years, 68% had type 2 diabetes, 27% type 1 and 5% other types. Among T2DM with > or = 2 CVRF, 45% were screened for CAD according to SSED guidelines. In T2DM 25% had blood pressure < or = 130/80 mm Hg, 15% a lipid profile within target, 23% HbA1c < or = 7.0%. Overall, 2% achieved all 3 targets. CONCLUSIONS: Only 45% of T2DM with > or = 2 CVRF were screened for CAD according to SSED guidelines and 2% of T2DM had proper control over all CVRF. Efforts are still necessary to improve CAD prevention and screening of diabetic patients in Swiss University Hospitals.

Acute painful diabetic neuropathy: an uncommon, remittent type of acute distal small fibre neuropathy.

INTRODUCTION: Acute painful diabetic neuropathy (APDN) is a distinctive diabetic polyneuropathy and consists of two subtypes: treatment-induced neuropathy (TIN) and diabetic neuropathic cachexia (DNC). The characteristics of APDN are (1.) the small-fibre involvement, (2.) occurrence paradoxically after short-term achievement of good glycaemia control, (3.) intense pain sensation and (4.) eventual recovery. In the face of current recommendations to achieve quickly glycaemic targets, it appears necessary to recognise and understand this neuropathy. METHODS AND RESULTS: Over 2009 to 2012, we reported four cases of APDN. Four patients (three males and one female) were identified and had a mean age at onset of TIN of 47.7 years (±6.99 years). Mean baseline HbA1c was 14.2% (±1.42) and 7.0% (±3.60) after treatment. Mean estimated time to correct HbA1c was 4.5 months (±3.82 months). Three patients presented with a mean time to symptom resolution of 12.7 months (±1.15 months). One patient had an initial normal electroneuromyogram (ENMG) despite the presence of neuropathic symptoms, and a second abnormal ENMG showing axonal and myelin neuropathy. One patient had a peroneal nerve biopsy showing loss of large myelinated fibres as well as unmyelinated fibres, and signs of microangiopathy. CONCLUSIONS: According to the current recommendations of promptly achieving glycaemic targets, it appears necessary to recognise and understand this neuropathy. Based on our observations and data from the literature we propose an algorithmic approach for differential diagnosis and therapeutic management of APDN patients.

Chronic kidney disease in type 2 diabetic patients followed-up by primary care physicians in Switzerland: prevalence and prescription of antidiabetic drugs.

QUESTION UNDER STUDY: The aim of this study was to assess the prevalence of chronic kidney disease (CKD) among type 2 diabetic patients in primary care settings in Switzerland, and to analyse the prescription of antidiabetic drugs in CKD according to the prevailing recommendations. METHODS: In this cross-sectional study, each participating physician was asked to introduce anonymously in a web database the data from up to 15 consecutive diabetic patients attending her/his office between December 2013 and June 2014. Demographic, clinical and biochemical data were analysed. CKD was classified with the KDIGO nomenclature based on estimated glomerular filtration rate (eGFR) and urinary albumin/creatinine ratio. RESULTS: A total of 1 359 patients (mean age 66.5 ± 12.4 years) were included by 109 primary care physicians. CKD stages 3a, 3b and 4 were present in 13.9%, 6.1%, and 2.4% of patients, respectively. Only 30.6% of patients had an entry for urinary albumin/creatinine ratio. Among them, 35.6% were in CKD stage A2, and 4.1% in stage A3. Despite prevailing limitations, metformin and sulfonylureas were prescribed in 53.9% and 16.5%, respectively, of patients with advanced CKD (eGFR <30 ml/min). More than a third of patients were on a dipeptidyl-peptidase-4 inhibitor across all CKD stages. Insulin use increased progressively from 26.8% in CKD stage 1-2 to 50% in stage 4. CONCLUSIONS: CKD is frequent in patients with type 2 diabetes attending Swiss primary care practices, with CKD stage 3 and 4 affecting 22.4% of cases. This emphasizes the importance of routine screening of diabetic nephropathy based on both eGFR and urinary albumin/creatinine ratio, the latter being largely underused by primary care physicians. A careful individual drug risk/benefit balance assessment is mandatory to avoid the frequently observed inappropriate prescription of antidiabetic drugs in CKD patients.

Travels and adventures in México : in the course of fourneys of upueard of 2500 miles, performed on foot...

UANL

The foot of the cross; or the sorrows of Mary

UANL

Insulino-mimetic and anti-diabetic effects of zinc

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.