Age-matched Non-diabetic Controls Research Articles

Skeletal muscle myosin heavy chain expression and 3D capillary network changes in streptozotocin-induced diabetic female mice.

It is not well-understood how type 1 diabetes (T1DM) affects skeletal muscle histological phenotype, particularly capillarisation. This study aimed to analyze skeletal muscle myosin heavy chain (MyHC) fibre type changes and 3D capillary network characteristics in experimental T1DM mice. Female C57BL/6J-OlaHsd mice were categorized into streptozotocin (STZ)-induced diabetic (n = 12) and age-matched non-diabetic controls (n =12). The muscle fibre phenotype of the soleus, gluteus maximus, and gastrocnemius muscles were characterized based on the expression of MyHC isoforms, while capillaries of the gluteus maximus were assessed with immunofluorescence staining, confocal laser microscopy and 3D image analysis. STZ-induced diabetic mice exhibited elevated glucose levels, reduced body weight, and prolonged thermal latency, verifying the T1DM phenotype. In both T1DM and non-diabetic mice, the gluteus maximus and gastrocnemius muscles predominantly expressed fast-twitch type 2b fibers, with no significant differences noted. However, the soleus muscle in non-diabetic mice had a greater proportion of type 2a fibers and comparable type 1 fiber densities (26.2 ± 14.6% vs 21.9 ± 13.5%) relative to diabetic mice. T1DM mice showed reduced fiber diameters (P = 0.026), and the 3D capillary network analysis indicated a higher capillary length per muscle volume in the gluteus maximus of diabetic mice compared to controls (P < 0.05). Overall, T1DM induced significant changes in the skeletal muscle, including shifts in MyHC fibre types, decreased fibre diameters, and increased relative capillarisation, possibly due to muscle fibre atrophy. Our findings emphasize the superior detail provided by the 3D analytical method for characterizing skeletal muscle capillary architecture, highlighting caution in interpreting 2D data for capillary changes in T1DM.

Characterization of sensory and motor dysfunction and morphological alterations in late stages of type 2 diabetic mice.

Diabetic neuropathy is the most common complication of diabetes and lacks effective treatments. Although sensory dysfunction during the early stages of diabetes has been extensively studied in various animal models, the functional and morphological alterations in sensory and motor systems during late stages of diabetes remain largely unexplored. In the current work, we examined the influence of diabetes on sensory and motor function as well as morphological changes in late stages of diabetes. The obese diabetic Leprdb/db mice (db/db) were used for behavioral assessments and subsequent morphological examinations. The db/db mice exhibited severe sensory and motor behavioral defects at the age of 32 weeks, including significantly higher mechanical withdrawal threshold and thermal latency of hindpaws compared with age-matched nondiabetic control animals. The impaired response to noxious stimuli was mainly associated with the remarkable loss of epidermal sensory fibers, particularly CGRP-positive nociceptive fibers. Unexpectedly, the area of CGRP-positive terminals in the spinal dorsal horn was dramatically increased in diabetic mice, which was presumably associated with microglial activation. In addition, the db/db mice showed significantly more foot slips and took longer time during the beam-walking examination compared with controls. Meanwhile, the running duration in the rotarod test was markedly reduced in db/db mice. The observed sensorimotor deficits and motor dysfunction were largely attributed to abnormal sensory feedback and muscle atrophy as well as attenuated neuromuscular transmission in aged diabetic mice. Morphological analysis of neuromuscular junctions (NMJs) demonstrated partial denervation of NMJs and obvious fragmentation of acetylcholine receptors (AChRs). Intrafusal muscle atrophy and abnormal muscle spindle innervation were also detected in db/db mice. Additionally, the number of VGLUT1-positive excitatory boutons on motor neurons was profoundly increased in aged diabetic mice as compared to controls. Nevertheless, inhibitory synaptic inputs onto motor neurons were similar between the two groups. This excitation-inhibition imbalance in synaptic transmission might be implicated in the disturbed locomotion. Collectively, these results suggest that severe sensory and motor deficits are present in late stages of diabetes. This study contributes to our understanding of mechanisms underlying neurological dysfunction during diabetes progression and helps to identify novel therapeutic interventions for patients with diabetic neuropathy.

Prevalence and Risk Factors of Erectile Dysfunction in Patients with Type 2 Diabetes Mellitus in Erbil-Iraq

Background and Objectives: Erectile dysfunction is a highly prevalent disease. It affects multiple aspects of health and can have a serious adverse effect on both the patients and their partners. Diabetes mellitus is a metabolic disorder associated with many chronic complications including erectile dysfunction. The aim of this study was to find out the prevalence and risk factors of erectile dysfunction in patients with type 2 diabetes mellitus. Patients and Methods: A cross-sectional study had been done on 100 adult male patients with type 2 diabetes mellitus, attending endocrinology outpatient at Erbil Teaching Hospital between June and December 2021, and another 50 age-matched non-diabetic controls. Each one of them underwent detailed history taking, clinical examination, and relevant biochemical study. Results: Sixty-three diabetic patients (63%) had erectile dysfunction compared to 6 nondiabetic subjects (12%). Mild, mild-to-moderate, moderate, and severe erectile dysfunction among these patients were 17 (27%), 21 (33.3%), 16 (25.4%), and 9 (14.3%), respectively. Among diabetics, erectile dysfunction was significantly associated with age, obesity, glycated hemoglobin level, duration of diabetes, presence of hypertension, dyslipidemia, and neuropathy (p= 0.001, 0.005, &lt;0.001, 0.038, 0.02, 0.017 and 0.025 respectively) Conclusion: Erectile dysfunction was significantly more prevalent in patients with type 2 diabetes than in non-diabetic patients. Being older than 50 years old, obesity, glycated hemoglobin level higher than 9, diabetes more than 10 years duration, presence of hypertension, dyslipidemia, and neuropathy were significantly in favor of a higher prevalence of erectile dysfunction in this group.

1753-P: Islet GLP-1R Protein Expression Is Reduced in Humans with Cystic Fibrosis–Related Diabetes

Impaired insulin secretion underlies the development of cystic fibrosis-related diabetes (CFRD). Glucagon like peptide-1 (GLP-1) is produced in islet α cells, and potentiates insulin secretion by binding GLP-1 receptors (GLP-1Rs) on β cells. In CFRD, α-cell mass is increased. Despite this, we hypothesized that levels of GLP-1 and/or its signaling components are reduced in CFRD, thereby contributing to deficits in insulin secretion. To address our hypothesis, paraffin-embedded pancreas sections from humans with CFRD and age-matched nondiabetic controls (from nPOD) underwent immunohistochemistry to quantify protein levels of active GLP-1 and GLP-1R (n=5-6/group). Spatial transcriptomics (NanoString) was also performed to assess differentially expressed α- and/or β-cell genes between CFRD and control pancreas (n=3/group; 15 CFRD + 9 control islets). GLP-1 immunoreactivity was unchanged between CFRD and control pancreas (0.33±0.15 vs 0.51±0.15, % GLP-1 area/pancreas area; p=0.4), however islet GLP-1R immunoreactivity was significantly reduced (4.35±1.21 vs 18.70±0.50, % GLP-1R area/islet area; p=0.004). Surprisingly, few α- or β-cell genes were differentially expressed between CFRD and control islets. However, a gene set test (ROAST) to assess transcripts involved in GLP-1 production/signaling revealed that those in α cells (GCG, PCSK1, PCSK2, DPP-4) significantly changed in mixed directions (up- or down-regulated; p=0.001). No such perturbation was seen in the β-cell gene set (INS, GLP1R, DPP-4, PLCG1, PIP4P2, ITPR3, ADCY1, ADCY6, PRKACA, RAPGEF4; p=0.4). In sum, our data suggest CFRD is not associated with altered intra-islet GLP-1 levels, however α-cell genes that modulate GLP-1 levels are dysregulated. Also, islet GLP-1R protein levels are reduced, though expression of genes downstream of GLP-1R is unchanged. Thus, interventions to restore protein levels of islet GLP-1R and/or promote intracellular signaling beyond GLP-1R may improve β-cell function in CFRD. Disclosure R. Vemireddy: None. J.J. Castillo: None. B.S. Fountaine: None. T.K. Bammler: None. J. MacDonald: None. R.L. Hull-Meichle: Research Support; Casma Therapeutics, Cystic Fibrosis Foundation, NIH - National Institutes of Health. Employee; Veterans Administration. Research Support; Veterans Administration. S. Gharib: None. S. Zraika: None. Funding National Institutes of Health (P30DK089507, P30DK017047)

340-OR: ADA Presidents' Select Abstract: Structural Neuroimaging and Cognitive Function in Long-Duration Type 1 Diabetes

Cognitive decline is an increasingly important complication in people with type 1 diabetes (T1D) as they age. We previously reported that compared with nondiabetic people, those with long-duration T1D have impaired cognitive function, similar to people with type 2 diabetes. To characterize factors associated with cognitive decline in people with T1D, 52 participants of the Joslin Medalist Study (“Medalists”) with T1D≥50 years, and 20 age-matched nondiabetic controls, underwent clinical evaluation, cognitive assessments, and neuroimaging (Alzheimer Disease Neuroimaging Initiative-3 protocol). Compared to controls, Medalists had 49.4 (±21.9) cm3 (p=0.03) lower total brain volume, and 2.7 (±0.8) cm3, 3.0 (±1.5) cm3 and 3.1 (±1.5) cm3 lower volumes (p&amp;lt;0.05), respectively, in the deep gray matter region (thalamus, putamen, caudate and globus pallidus), the Alzheimer disease signature region (hippocampus, parahippocampus, entorhinal cortex, inferior parietal lobule, precuneus and cuneus), and the occipital lobe. No significant differences were observed in frontal, temporal, or parietal lobe volumes. In assessing small vessel disease, the number of white matter hyperintensities (WMHs) or microvascular hemorrhages did not differ between Medalists and controls, nor did regional cerebral blood flow measures (via arterial spin labeling). Among Medalists, reduced total and all regional brain volumes were associated (p&amp;lt;0.05) with worse motor skills, female sex, lower education status, increased age, and longer diabetes duration. Increased WMHs were associated with worse renal function and higher coronary artery calcification scores. Volumes did not associate with other cognitive domains (recall, working memory, or executive function). These findings suggest that cognitive decline in people with long-duration T1D is related mainly to abnormalities in parenchymal CNS rather than neurovascular changes. Definitive confirmation of this finding by brain histopathology is underway. Disclosure H. Shah: None. M. Desalvo: None. A. Haidar: None. S. Jangolla: None. M. Yu: None. J. Gauthier: None. N.A. Ziemniak: None. I. Wu: None. T. Billah: None. L. Ning: None. A. Adam: None. Y. Rathi: None. G.L. King: Research Support; Janssen Research &amp; Development, LLC. Funding National Institute of Diabetes and Digestive and Kidney Diseases (3P30DK036836-34S1); Thomas J. Beatson, Jr. Foundation

Association Between Optical Coherence Tomography Angiography Findings and Inner Retinal Thickness in Diabetic Patients.

To investigate the association between optical coherence tomography angiography (OCTA) findings and inner retinal thickness (IRT) in diabetic patients. This retrospective study included 23 eyes of 23 diabetic patients with retinopathy (group 1), 30 eyes of 30 diabetic patients without retinopathy (group 2), and 27 eyes of 27 non-diabetic age-matched controls (group 3). Foveal avascular zone (FAZ) area (mm²), average vessel density (%) in the parafoveal region, and average IRT in the parafoveal region (μm) were calculated using 6x6 mm OCTA images. Correlations between IRT and OCTA findings were analyzed. The mean FAZ area was 0.32±0.11 mm² in group 1, 0.29±0.08 mm² in group 2, and 0.22±0.09 mm² in group 3. There were statistically significant differences between groups 1 and 3 (p&lt;0.001) and between groups 2 and 3 (p=0.001). Average IRT was 108.02±9.42 µm in group 1, 110.12±11.01 µm in group 2, and 114.41±5.21 µm in group 3, with statistically significant differences between groups 1 and 3 (p=0.003) and between groups 2 and 3 (p=0.014). In both group 1 and group 2, average IRT was correlated with FAZ area (r=-0.320 and -0.512, respectively). The inner retina is significantly thinner in diabetic patients with and without retinopathy compared to controls. Quantitative OCTA findings and IRT are correlated in diabetic patients, suggesting that both structures are compromised in patients with diabetes with or without retinopathy. Microvascular changes in FAZ detected by OCTA might precede neurodegenerative changes.

The Positive Association of Plasma Levels of Vitamin C and Inverse Association of VCAM-1 and Total Adiponectin with Bone Mineral Density in Subjects with Diabetes.

Context. Population studies have shown a trend in decreasing vitamin C status and increasing prevalence of osteoporosis in patients with diabetes and non-diabetic people. Dietary vitamin C consumption is linked to improvement in bone mineral density (BMD) in epidemiological studies. VCAM-1 and adiponectin are known to activate osteoclasts, which increase bone loss. Aim: This study examined whether there is any association between the circulating level of vitamin C and BMD and whether the beneficial effect of vitamin C on BMD was linked to a simultaneous decrease in circulating levels of adiponectin and VCAM-1 in subjects with diabetes. Methods: Patients with diabetes (T2D, n = 74) and age-matched non-diabetic controls (n = 26) were enrolled in this study. Fasting blood levels of glycemia, adiponectin, VCAM-1, inflammation biomarkers, and vitamin C were determined in both groups. The BMD of the lumbar spine (L1–L4), left femur, and right femur was determined using a DXA scan in subjects with diabetes. Results: Patients with diabetes had lower levels of vitamin C and higher levels of VCAM-1 and inflammatory cytokines. There was a significant positive association between vitamin C blood levels and lumbar spine BMD as well as a significant negative association between total adiponectin and VCAM-1 levels with that of vitamin C and lumbar BMD in patients with diabetes. Total adiponectin and VCAM-1 also showed a negative association with BMD of both the right and left femurs. The inter-relationship among the circulating levels of vitamin C and VCAM-1 and BMD was strong and is a novel finding. Conclusions: This study reports a positive association of circulating vitamin C levels and the BMD and that the beneficial effects of vitamin C on BMD could be linked to a simultaneous lowering in circulating VCAM-1 and total adiponectin levels. Thus, dietary vitamin C consumption has potential to lower inflammation and the risk of osteoporosis in subjects with diabetes.

Behavioral defects and downregulation of hippocampal BDNF and nNOS expression in db/db mice did not improved by chronic TGF-β2 treatment.

Epidemiological evidence suggests that there is a link between diabetes and mood disorders, such as depression and anxiety. Although peripheral or central inflammation may explain this link, the molecular mechanisms are not fully understood and few effective treatments for diabetes or mood disorders are available. In the present study, we aimed to determine whether transforming growth factor (TGF)-β2, an anti-inflammatory substance, might represent a potential therapeutic agent for diabetes-related mood behaviors. TGF-β2 expression in the hippocampus is affected by anxiolytic drugs and stress exposure, it is able to cross the blood-brain barrier, and it is as an exercise-induced physiological adipokine that regulates glucose homeostasis. Therefore, we hypothesized that a chronic TGF-β2 infusion would ameliorate diabetes-related glucose intolerance and mood dysregulation. To determine the effects of the chronic administration of TGF-β2 on diabetes, we implanted osmotic pumps containing TGF-β2 into type 2 diabetic mice (db/db mice), and age-matched non-diabetic control wild type mice and db/db mice were infused with vehicle (PBS), for 12 consecutive days. To assess anxiety-like behaviors and glucose homeostasis, the mice underwent elevated plus maze testing and intraperitoneal glucose tolerance testing. Hippocampal and perigonadal visceral white adipose tissue perigonadal white adipose tissue samples were obtained 12 days later. Contrary to our hypothesis, TGF-β2 infusion had no effect on diabetes-related glucose intolerance or diabetes-related behavioral defects, such as inactivity. In db/db mice, the expression of inflammatory markers was high in pgWAT, but not in the hippocampus, and the former was ameliorated by TGF-β2 infusion. The expression of brain-derived neurotrophic factor and neuronal nitric oxide synthase, important regulators of anxiety-like behaviors, was low in db/db mice, but TGF-β2 infusion did not affect their expression. We conclude that although TGF-β2 reduces the expression of pro-inflammatory markers in the adipose tissue of diabetic mice, it does not ameliorate their obesity or mood dysregulation.

Age-Influenced Receptors of Advanced Glycation End Product Overexpression Associated With Osteogenic Differentiation Impairment in Patients With Type 2 Diabetes.

Preclinical studies have found impaired osteogenic differentiation to be associated with type 2 diabetes (T2DM), which is related to skeletal accumulation of advanced glycation end products (AGEs). Our previous study also showed impaired osteogenic differentiation in peripheral blood-derived mononuclear cells (PBMC) isolated from patients with long-standing T2DM, which is conceivably due to the overexpression of receptor of advance glycation end products (RAGE) and the enhancement of cellular apoptosis. However, the existence of RAGE overexpression in earlier stages of diabetes remains unclear, as do the factors influencing that RAGE overexpression. This cross-sectional study enrolled 40 patients with T2DM treated with metformin monotherapy and 30 age-matched non-diabetic controls (NDM) to investigate the overexpression of RAGE in PBMC derived from patients with earlier stage diabetes, as well as to explore its determining factors. Almost all (90%) PBMC-isolated from NDM (NDM-pD) expressed osteoblast-specific genes including ALPL, BGLAP, COL1A1, and RUNX2/PPAR while only 40% of PBMC-derived from diabetic patients (DM-pD) expressed those genes. By using age- and pentosidine-matched NDM-pD as a reference, AGER and BAX/BCL2 expression in PBMC isolated from diabetic patients showing impaired osteoblast-specific gene expression (DM-iD) were 6.6 and 5 folds higher than the reference while AGER and BAX/BCL2 expression in DM-pD were comparable to the reference. AGER expression showed a significant positive correlation with age (r=0.470, p=0.003). The multivariate analysis demonstrated that both age and AGER expression correlated with the potential for osteogenic differentiation in the PBMC isolated from patients with diabetes. In conclusion, this study showed osteogenic differentiation impairment in approximately half of PBMC derived from type 2 diabetic patients receiving metformin monotherapy. Both AGER and BAX/BCL2 overexpression were demonstrated only in PBMC-isolated from diabetic patients with poor osteogenic differentiation. Therefore, this study not only illustrated the existence of RAGE overexpression in PBMC derived from patients with early stages of T2DM but also strengthened the linkage between that RAGE overexpression and the retardation of osteogenic differentiation. Age was also shown to be a positive influencing factor for RAGE overexpression. Furthermore, both age and RAGE overexpression were demonstrated as independent risk factors for determining osteogenic differentiation potential of the PBMC-isolated from T2DM.

Electrophysiology as a prognostic indicator of visual recovery in diabetic patients undergoing cataract surgery

PurposeVisual outcomes after cataract surgery in diabetic patients with retinal or visual pathway disease are difficult to predict as the fundus may be obscured, and assessment of visual potential is challenging. This study assessed the value of visual electrophysiology as a prognostic indicator of visual recovery in diabetic patients with cataract, prior to cataract surgery.MethodsForty-one diabetic patients (aged 52–80; 74 eyes) and 13 age-matched non-diabetic control patients (21 eyes) were examined prior to cataract surgery. Pre-surgical examinations included best-corrected visual acuity (BCVA), slit-lamp bio-microscopy, ISCEV-standard full-field electroretinography (ffERG), and flash visual evoked potential (flash VEP) testing. Electrophysiological assessments included quantification of the DA and LA ERG, oscillatory potentials (OPs; OP1, OP2, OP3, OP4) and flash VEP P1, P2, and P3 components. Post-operative BCVA was measured in all cases and the diabetic patients grouped according to the severity of visual acuity loss: mild (logMAR ≤ 0.1), moderate (0.1 < logMAR < 0.5), or severe (logMAR ≥ 0.5). A fourth group included those without diabetes. The pre-surgical electrophysiological data was compared between the four groups by analysis of variance.ResultsThe severity of post-surgical visual acuity loss in the diabetic patients was classified as mild (N=22 eyes), moderate (N=31 eyes), or severe (N=21 eyes). In the group without diabetes, post-surgical visual impairment was classified as mild (N=21 eyes). The pre-operative DA 10.0 ERG a-wave amplitudes, DA 3.0 ERG OP2 amplitudes, and the LA 3.0 a- and b-wave amplitudes showed best significant differences among the four groups. The flash VEP did not show significant difference between groups.ConclusionElectrophysiological assessment of diabetic patients with cataract can provide a useful measure of retinal function. Full-field ERG components, including the DA 10.0 ERG a-wave, DA 3.0 ERG OP2 component, and the LA 3.0 a- and b-wave amplitudes, are of prognostic value in predicting post-surgical visual acuity, and may inform the surgical management of cataract patients with diabetes.

Indications of Liver and Kidney Functions in Non-Insulin Dependent Diabetic Patients

This study aimed at the investigation of abnormal liver and renal functions by biochemical manifestations of underlying metabolic abnormalities in relation to hyperglycemia in non-insulin-dependent diabetic patients. The study comprised 118 diabetic patients (56 males, 62 females) and 60 age-matched healthy non-diabetic controls (30 males, 30 females). All subjects were tested for serum levels of liver enzymatic indicators, which include aspartate transaminase (AST), alanine transaminase (ALT), and alkaline phosphatase (ALP), as well as non enzymatic parameters, including total bilirubin and total proteins.Also, serum levels of renal function markers, including microalbumin, creatinine, urea, and uric acid were measured.&#x0D; The findings of this study stated that serum ALT, AST, and ALP levels were significantly higher in diabetic males and females with both age ranges (40-59 &amp; 60-80 years). Serum total bilirubin level showed a significant decrease in diabetic males and females of both age groups. However, total proteins level showed a significant increase in diabetic males and females of both age groups. The results also showed that the level of microalbumin in urine as well as those of creatinine, urea, and uric acid in the serum were significantly higher in diabetic males and females. The present study concludes that there is a bidirectional relationship of enzymatic and non enzymatic liver and renal functions markers with the hyperglycemic status in Type 2 diabetes mellitus.

Plasma Glycated Hemoglobin and Sleep Patterns in Local Patients with Type 2 Diabetes Mellitus

Objective: To ascertain glycemic control and sleep quality in patients with Type 2 Diabetes Mellitus and compare them with age-matched non-diabetic control subjects.Methodology: In this cross-sectional study, plasma glycated hemoglobin (HbA1c) levels and sleep patterns in diabetic subjects were compared with non-diabetic control subjects. Ethical approval was granted by the institutional ethical review board of Central Park Medical College vide number CPMC/IRB/1728. After taking written informed consent, a total of fifty participants between the ages of 40-60 years were recruited by convenience sampling from the medical outpatient clinic at Central Park Teaching Hospital in 2018. Based on the fasting blood glucose levels, participants were categorized as Group I (diabetic subjects) and Group II (non-diabetic control subjects). Sleep quality was assessed using two validated scales, namely Insomnia Severity Index (ISI) and Epworth Sleepiness Scale (ESS). HbA1c levels were evaluated using standardized blood assays. Independent samples t-test was employed to determine mean differences between the two groups. A p-value of ? 0.05 was considered significant.Results: Mean age of the study participants (n=50) was 49.28±2.34 years. The diabetic subjects had significantly higher HbA1c levels (10.15±2.50 vs. 6.26±1.04; p-value 0.001) and ISI scores (12.64±7.91 vs. 4.68±4.88; p-value 0.000) as compared to non-diabetic control subjects, indicating poorer glycemic control and greater degree of insomnia.Conclusion: Poorly controlled diabetes mellitus as reflected by higher HbA1c levels is associated with increased insomnia.

A study of serum growth differentiation factor 15 in Indian women with and without gestational diabetes mellitus in the third trimester of pregnancy and its association with pro-inflammatory markers and glucose metabolism

The pathogenesis of gestational diabetes mellitus (GDM) is multifactorial and it shares many features with type 2 diabetes mellitus. Growth differentiation factor 15 (GDF-15), a member of transforming growth factor-β superfamily, is expressed in a high amount in the placenta in addition to other organs. This cross-sectional study was performed to assess the difference of GDF-15 and pro-inflammatory cytokines between pregnant women with or without GDM, and to explore the possible association of GDF-15 with the parameters of dysglycemia (Serum insulin, HOMA-IR, fasting, 60min, and 120min post-75 gm oral glucose plasma glucose levels) and inflammation (IL-6 and TNF-α) in women with GDM at 24-28weeks of gestation. Thirty-five women with GDM and 30 age-matched non-diabetic pregnant control (NDPC) subjects were recruited for the study. Mean serum GDF-15, IL-6, and TNF-α levels were significantly higher in GDM in comparison to the NDPC population. These differences persisted even after adjusting for the possible confounders like maternal age and BMI. GDF-15 level showed a positive correlation with parameters of dysglycemia (Serum insulin, HOMA-IR, fasting, 60min, and 120min post-75 gm oral glucose plasma glucose levels) but a variable correlation with the markers of inflammation. In conclusion, our study provides evidence that, in Indian women, serum GDF-15 level is higher in GDM in comparison to age-matched pregnant subjects without GDM in the early third trimester pregnancy. Moreover, in third trimester, GDF-15 level increases with increase in plasma glucose and insulin resistance.

Diabetic Cardiomiopathy Progression is Triggered by miR122-5p and Involves Extracellular Matrix: A 5-Year Prospective Study

ObjectivesThe purpose of this study was to follow the long-term progression of diabetic cardiomyopathy by combining cardiac magnetic resonance (CMR) and molecular analysis. BackgroundThe evolution of diabetic cardiomyopathy to heart failure affects patients’morbidity and mortality. CMR is the gold standard to assess cardiac remodeling, but there is a lack of markers linked to the mechanism of diabetic cardiomyopathy progression. MethodsFive-year longitudinal study on patients with type 2 diabetes mellitus (T2DM) enrolled in the CECSID (Cardiovascular Effects of Chronic Sildenafil in Men With Type 2 Diabetes) trial compared with nondiabetic age-matched controls. CMR with tagging together with metabolic and molecular assessments were performed at baseline and 5-year follow-up. ResultsA total of 79 men (age 64 ± 8 years) enrolled, comprising 59 men with T2DM compared with 20 nondiabetic age-matched controls. Longitudinal CMR with tagging showed an increase in ventricular mass (ΔLVMi = 13.47 ± 29.66 g/m2; p = 0.014) and a borderline increase in end-diastolic volume (ΔEDVi = 5.16 ± 14.71 ml/m2; p = 0.056) in men with T2DM. Cardiac strain worsened (Δσ = 1.52 ± 3.85%; p = 0.033) whereas torsion was unchanged (Δθ = 0.24 ± 4.04°; p = 0.737), revealing a loss of the adaptive equilibrium between strain and torsion. Contraction dynamics showed a decrease in the systolic time-to-peak (ΔTtP = −35.18 ± 28.81 ms; p < 0.001) and diastolic early recoil-rate (ΔRR = −20.01 ± 19.07 s-1; p < 0.001). The ejection fraction and metabolic parameters were unchanged. Circulating miR microarray revealed an up-regulation of miR122-5p. Network analysis predicted the matrix metalloproteinases (MMPs) MMP-16 and MMP-2 and their regulator (tissue inhibitors of metalloproteinases) as targets. In db/db mice we demonstrated that miR122-5p expression is associated with diabetic cardiomyopathy, that in the diabetic heart is overexpressed, and that, in vitro, it regulates MMP-2. Finally, we demonstrated that miR122-5p overexpression affects the extracellular matrix through MMP-2 modulation. ConclusionsWithin 5 years of diabetic cardiomyopathy onset, increasing cardiac hypertrophy is associated with progressive impairment in strain, depletion of the compensatory role of torsion, and changes in viscoelastic contraction dynamics. These changes are independent of glycemic control and paralleled by the up-regulation of specific microRNAs targeting the extracellular matrix. (Cardiovascular Effects of Chronic Sildenafil in Men With Type 2 Diabetes [CECSID]; NCT00692237)

A chromatin signature by the methyltransferase SETD7 regulates semaphorin-3G transcription and angiogenic response in diabetes: insights for personalized epigenetic therapies

Abstract Background Despite advances in revascularization strategies, type 2 diabetic (T2D) patients with peripheral artery disease (PAD) continue to have a high risk of limb amputation. Modulation of blood vessel growth holds great promise for the treatment of PAD patients. Epigenetic modifications, namely histone post-translational modifications, have shown to regulate transcriptional programs implicated in the pathogenesis of cardiovascular disease. Aim To investigate the role of chromatin changes in regulating post-ischemic vascularization in experimental diabetes as well as in patients with T2D. Methods Experiments were performed in primary human aortic endothelial cells (HAECs), double-mutant leptin deficient mice (Lepdb/db) carrying a genetic deletion of the methyltransferase SETD7 (Setd7−/−Lepdb/db) as well as in gastrocnemius muscle samples from T2D patients with PAD and age-matched non-diabetic controls. Unbiased gene expression profiling was performed by RNA sequencing (RNA-seq) followed by Ingenuity Pathway Analysis (IPA). Pharmacological blockade of SETD7 was performed by using the selective inhibitor (R)-PFI-2. Scratch and tube formation assays were performed to investigate the impact of SETD7 on angiogenic response. Results RNA-seq in high glucose-treated HAECs revealed a profound upregulation of the methyltransferase SETD7 (fold change 2.8, p&amp;lt;0.001), an enzyme involved in mono-methylation of lysine 4 at histone 3 (H3K4me1). Both SETD7 gene silencing and pharmacological inhibition by (R)PFI-2 rescued hyperglycemia-induced impairment of HAECs migration and tube formation, while SETD7 overexpression blunted the angiogenic response. RNA-seq and Chromatin Immunoprecipitation (ChIP) assays showed that SETD7-dependent H3K4me1 regulates the transcription of the angiogenesis inhibitor semaphorin-3G (SEMA-3G). Increased SEMA-3G transcript was associated with enhanced secretion from HAECs. Co-immunofluorescence experiments showed that SEMA-3G blunts the angiogenic response by competing with VEGF receptors VEGFR/Neuropillin2. Moreover, SEMA-3G overexpression blunted migration and tube formation in SETD7-depleted HAECs. SETD7 and SEMA-3G were significantly upregulated in endothelial cells from Lepdb/db mice, whereas SEMA-3G transcription was blunted in Setd7−/−Lepdb/db animals. Consistently, endothelial sprouting was defective in aortas from Lepdb/db as compared to WT mice, whereas Setd7−/−Lepdb/db mice displayed a preserved angiogenic response. Of clinical relevance, SETD7/SEMA-3G axis was upregulated in gastrocnemius muscle specimens from T2D patients with PAD as compared with non-diabetic controls. Conclusion In HAECs, genetically modified mice and T2D patients we show that SETD7-dependent chromatin changes regulate SEMA-3G transcription and angiogenic response. Pharmacological inhibition of SETD7 may represent a novel epigenetic therapy to boost neovascularization in T2D patients with PAD. Funding Acknowledgement Type of funding source: Public Institution(s). Main funding source(s): University of Zurich/Universitätsspital Zürich

Determinants of Bone Material Strength and Cortical Porosity in Patients with Type 2 Diabetes Mellitus.

Reduced bone material strength index (BMSi) and increased cortical porosity (CtPo) have emerged as potentially contributing to fracture risk in type 2 diabetes mellitus (T2DM) patients. To determine whether BMSi or CtPo are related to other diabetic complications. Cross-sectional observational study. Subjects recruited from a random sample of southeast Minnesota residents. A total of 171 T2DM patients (mean age, 68.8 years) and 108 age-matched nondiabetic controls (mean age, 67.3 years). Bone material strength index was measured using microindentation, skin advanced glycation end-products (AGEs) measured using autofluorescence, high-resolution peripheral quantitative computed tomography at the distal radius and tibia, assessment of diabetic microvascular complications including urine microalbuminuria, retinopathy, neuropathy, and vascular disease (ankle brachial index and transcutaneous oxygen tension [TcPO2]). All analyses were adjusted for age, sex, and body mass index. Skin AGEs were negatively correlated with the BMSi in both T2DM (r = -0.30, P < 0.001) and control (r = -0.23, P = 0.020) subjects. In relating diabetic complications to CtPo, we found that T2DM patients with clinically significant peripheral vascular disease (TcPO2 ≤ 40 mm Hg) had higher (+21.0%, P = 0.031) CtPo at the distal tibia as compared to controls; in these subjects, CtPo was negatively correlated with TcPO2 at both the distal tibia (r = -0.39, P = 0.041) and radius (r = -0.41, P = 0.029). Our findings demonstrate that bone material properties are related to AGE accumulation regardless of diabetes status, while CtPo in T2DM patients is linked to TcPO2, a measure of microvascular blood flow.

Microvascular Changes in the Choriocapillaris of Diabetic Patients Without Retinopathy Investigated by Swept-Source OCT Angiography.

PurposeTo investigate the microvascular changes in macular retina and choriocapillaris (CC) in diabetic eyes without retinopathy using swept-source optical coherence tomography angiography (SS-OCTA).MethodsA commercial SS-OCTA system was used to collect 6 × 6-mm macular scans from patients. Three depth-resolved retinal slabs and a CC slab were segmented by a validated semiautomated algorithm. Retinal vessel area density, vessel skeleton density, and nonperfusion area were calculated on segmented retinal slabs. Foveal avascular zone was automatically measured based on en face image of the whole retinal layer. For CC quantification, the percentage of flow deficits (FD%) and the flow deficit (FD) sizes were measured. ResultsSixteen eyes from 16 diabetic patients without clinically detectable retinopathy and 16 eyes from 16 age-matched nondiabetic controls were included. There was no significant difference between the two groups in all retinal vessel quantitative parameters (all P > 0.05). However, the mean FD% and mean FD sizes were significantly increased in CC in the central 1.0-mm disk (P = 0.011 and P = 0.017, respectively), the central 1.5-mm rim (P = 0.003 and P = 0.009, respectively), the central 2.5-mm rim (P = 0.018 and P = 0.020, respectively), and the entire 5.0-mm disk (P = 0.009 and P = 0.008, respectively) in diabetic eyes compared with controls.ConclusionsCC perfusion in the macula is decreased in diabetic patients without retinopathy as compared to age-matched normal controls. Decreased CC perfusion in the macula may be an early indicator of otherwise clinically undetectable diabetic vasculopathy.

Role of Inflammation in Retinal Microcirculation in Diabetic Eyes: Correlation between Aqueous Flare and Microvascular Findings

Purpose: To investigate the correlation between aqueous flare and macular microvascular status assessed by optic coherence tomography angiography (OCTA) in diabetes mellitus. Methods: A cross-sectional study was conducted on 52 diabetic patients with nonproliferative retinopathy, 44 diabetic patients without retinopathy, and 20 nondiabetic age-matched controls. Spectral domain OCT, OCTA, and laser flare-cell meter were performed. Results: Compared to eyes without retinopathy, eyes with retinopathy had higher flare intensity (p = 0.024), enlarged capillary nonperfusion area (p < 0.001), and enlarged foveal avascular zone (p < 0.001). There was a significant correlation between flare intensity and capillary nonperfusion areas (p < 0.001, r = 0.511) and superficial capillary density (p = 0.005, r = –0.388) in diabetic eyes with retinopathy. Conclusion: The results demonstrated a positive correlation between aqueous flare levels, an indicator of intraocular inflammation, and microvascular damage demonstrated by OCTA in the early stages of diabetic retinopathy (DR). This finding supports the role of inflammation in the pathogenesis of DR.

Faulty homocysteine recycling in diabetic retinopathy

BackgroundAlthough hyperglycemia is the main instigator in the development of diabetic retinopathy, elevated circulating levels of a non-protein amino acid, homocysteine, are also associated with an increased risk of retinopathy. Homocysteine is recycled back to methionine by methylenetetrahydrofolate reductase (MTHFR) and/or transsulfurated by cystathionine β-synthase (CBS) to form cysteine. CBS and other transsulfuration enzyme cystathionine-γ-lyase (CSE), through desulfuration, generates H2S. Methionine cycle also regulates DNA methylation, an epigenetic modification associated with the gene suppression. The aim of this study was to investigate homocysteine and its metabolism in diabetic retinopathy.MethodsHomocysteine and H2S levels were analyzed in the retina, and CBS, CSE and MTHFR in the retinal microvasculature from human donors with established diabetic retinopathy. Mitochondrial damage was evaluated in retinal microvessels by quantifying enzymes responsible for maintaining mitochondrial dynamics (fission-fusion-mitophagy). DNA methylation status of CBS and MTHFR promoters was examined using methylated DNA immunoprecipitation technique. The direct effect of homocysteine on mitochondrial damage was confirmed in human retinal endothelial cells (HRECs) incubated with 100 μM L-homocysteine.ResultsCompared to age-matched nondiabetic control human donors, retina from donors with established diabetic retinopathy had ~ 3-fold higher homocysteine levels and ~ 50% lower H2S levels. The enzymes important for both transsulfuration and remethylation of homocysteine including CBS, CSE and MTHFR, were 40–60% lower in the retinal microvasculature from diabetic retinopathy donors. While the mitochondrial fission protein, dynamin related protein 1, and mitophagy markers optineurin and microtubule-associated protein 1A/1B-light chain 3 (LC3), were upregulated, the fusion protein mitofusin 2 was downregulated. In the same retinal microvessel preparations from donors with diabetic retinopathy, DNA at the promoters of CBS and MTHFR were hypermethylated. Incubation of HRECs with homocysteine increased reactive oxygen species and decreased transcripts of mtDNA-encoded CYTB.ConclusionsCompromised transsulfuration and remethylation processes play an important role in the poor removal of retinal homocysteine in diabetic patients. Thus, regulation of their homocysteine levels should ameliorate retinal mitochondrial damage, and by regulating DNA methylation status of the enzymes responsible for homocysteine transsulfuration and remethylation, should prevent excess accumulation of homocysteine.

Effects of Diabetes on Bone Material Properties.

Individuals with type 1 and type 2 diabetes mellitus (T1DM, T2DM) have an increased risk of bone fracture compared to non-diabetic controls that is not explained by differences in BMD, BMI, or falls. Thus, bone tissue fracture resistance may be reduced in individuals with DM. The purpose of this review is to summarize work that analyzes the effects of T1DM and T2DM on bone tissue compositional and mechanical properties. Studies of clinical T2DM specimens revealed increased mineralization and advanced glycation endproduct (AGE) concentrations and significant relationships between mechanical performance and composition of cancellous bone. Specifically, in femoral cancellous tissue, compressive stiffness and strength increased with mineral content; and post-yield properties decreased with AGE concentration. In addition, cortical resistance to in vivo indentation (bone material strength index) was lower in patients with T2DM vs. age-matched non-diabetic controls, and this resistance decreased with worsening glycemic control. Recent studies on patients with T1DM and history of a prior fragility fracture found greater mineral content and concentrations of AGEs in iliac trabecular bone and correspondingly stiffer, harder bone at the nanosacle. Recent observational data showed greater AGE and mineral content in surgically retrieved bone from patients with T2DM vs. non-DM controls, consistent with reduced bone remodeling. Limited data on human T1DM bone tissue also showed higher mineral and AGE content in patients with prior fragility fractures compared to non-DM and non-fracture controls.