Endothelial and platelet markers in diabetes mellitus type 2

The diagnostic value of platelet-to-neutrophil ratio in diabetic macular edema

PURPOSE

To evaluate the diagnostic value of platelet-to-neutrophil ratio (PNR) in the occurrence of diabetic macular edema (DME) in patients with diabetic retinopathy (DR).

METHODS

This cross-sectional study included 366 participants categorized into four groups: DME group (n = 96), DR group (n = 90, DR without DME), diabetes mellitus (DM) group (n = 90, without DR), and healthy control group (n = 90). PNR was calculated by dividing the platelet count by the neutrophil count. Each subject was classified as one of three DME types according to the optical coherence tomography (OCT) features: diffuse retinal thickening (DRT), cystoid macular edema (CME), serous retinal detachment (SRD). The correlations between the PNR and the occurrence of DME, as well as the DME subtypes based on OCT were investigated. Multivariate logistic regression analysis was employed to determine the risk factors for DME. Receiver operating characteristic (ROC) curve analysis was conducted to assess the predictive value of PNR for DME.

RESULTS

DME group exhibited significantly lower PNR level compared to the other three groups [50.73 (38.92, 65.20) in DME group, 95.63 (68.83, 120.19) in DR group, 92.39 (72.38, 130.61) in DM group, and 100.66 (75.26, 152.77) in healthy control group, respectively, p < 0.001], but did not differ across the DME subtypes based on OCT (p = 0.548). The ROC curve demonstrated that the PNR could better predict DME (area under the curve = 0.832, 95% confidence interval: 0.773 - 0.891, p < 0.001). When the cut-off value of the PNR was 68.51, the sensitivity was 80.2%, and the specificity was 75.6%. Multivariate regression analysis indicated that PNR ≤ 68.51 was an independent risk factor for DME occurrence in DR patients (Odds ratio = 12.05, 95% confidence interval: 5.93 - 24.47, p < 0.001).

CONCLUSION

PNR ≤ 68.51 was strongly associated with the development of DME in DR patients, while no significant differences in PNR levels were observed across the different OCT morphological groups. Hence, PNR may serve as a valuable diagnostic biomarker for identifying DME, thereby enhancing risk stratification and management strategies for patients with DR.

Endothelial Markers in Type 2 Diabetic Patients with Acute Decompensated Heart Failure: A Pilot Study

BACKGROUND

Impaired endothelial function has been associated with vascular complications in type 2 diabetes (T2D), but its role in T2D-related heart failure (HF) remains indeterminate. The aim of this study was to assess selected markers of endothelial function in T2D patients with acute decompensated HF.

METHODS

A pilot prospective study on patients with acute decompensated HF requiring in-hospital admission was carried out. The vascular endothelial growth factor (VEGF), intercellular adhesion molecule 1 (ICAM-1), and vascular cell adhesion molecule 1 (VCAM-1) were assessed at admission and after decongestion. Subsequently, differences in these markers between T2D and non-diabetic (ND) patients were studied.

RESULTS

In total, 39 patients (21 with T2D and 18 ND patients) were enrolled. Twenty-eight patients presented with preserved ejection fraction (EF), and 11 presented with reduced EF. Looking at the VEGF levels in T2D patients, on admission, a median of 233.0 pg/mL (1.7-598 pg/mL) was found compared to 106.0 pg/mL (1.7-888 pg/mL) in ND individuals; the differences reached statistical significance (p = 0.04). There were no significant differences in VEGF levels after decongestion, and in VCAM-1 (2237 ± 1195 vs. 2699 ± 1093 ng/mL, p = 0.37) and ICAM-1 (596 ± 268 vs. 638 ± 437 ng/mL, p = 0.79) levels between T2D and ND patients upon admission and after decongestion. The value of EF (preserved or reduced) affected the VEGF levels upon admission.

CONCLUSIONS

This study identified significantly higher VEGF levels upon admission due to acute decompensated HF in T2D patients.

Hyperactivity and Pro-inflammatory Functions of Platelets in Diabetes

Cardiovascular complications claim the lives of up to 70% of patients with diabetes mellitus (DM). The mechanisms increasing cardiovascular risk in DM remain to be fully understood and successfully addressed. Nonetheless, there is increasing evidence in the scientific literature of the participation of platelets in the cardiovascular complications of DM. Multiple reports describe the hyperactivity of platelets in DM and their participation in inflammatory responses. The understanding of the mechanisms underlying the contribution of platelets to cardiovascular pathologies in DM will help the development of targeted therapeutic strategies able to reduce cardiovascular risk in these patients. In this literature review, we summarise our current understanding of the molecular mechanisms leading to the contribution of platelets to cardiovascular risk in DM. Both platelet haemostatic activity leading to thrombus formation and their participation to inflammatory processes are stimulated by the biochemical conditions associated with DM. We also present evidence on how DM affect the efficacy of existing therapeutic treatments for thrombosis and, by converse, how antidiabetic drugs may affect platelet function and the haemostasis/thrombosis balance. Taken together, the growing evidence of the different and unexpected roles of platelets in the progression of DM provides a strong rationale for the design of cardiovascular drugs targeting specifically platelets, their pro-inflammatory activity and their activation mechanisms in this disease. Overall, this article provides an important up-to-date overview of the pathophysiological alterations of platelets in DM, which need to be taken into account for the effective management of cardiovascular health in this disease.

Dysregulated coagulation system links to inflammation in diabetic kidney disease

Diabetic kidney disease (DKD) is a significant contributor to end-stage renal disease worldwide. Despite extensive research, the exact mechanisms responsible for its development remain incompletely understood. Notably, patients with diabetes and impaired kidney function exhibit a hypercoagulable state characterized by elevated levels of coagulation molecules in their plasma. Recent studies propose that coagulation molecules such as thrombin, fibrinogen, and platelets are interconnected with the complement system, giving rise to an inflammatory response that potentially accelerates the progression of DKD. Remarkably, investigations have shown that inhibiting the coagulation system may protect the kidneys in various animal models and clinical trials, suggesting that these systems could serve as promising therapeutic targets for DKD. This review aims to shed light on the underlying connections between coagulation and complement systems and their involvement in the advancement of DKD.

The Role of Genetic Polymorphisms in Diabetic Retinopathy: Narrative Review

Diabetic retinopathy (DR) is renowned as a leading cause of visual loss in working-age populations with its etiopathology influenced by the disturbance of biochemical metabolic pathways and genetic factors, including gene polymorphism. Metabolic pathways considered to have an impact on the development of the disease, as well as genes and polymorphisms that can affect the gene expression, modify the quantity and quality of the encoded product (protein), and significantly alter the metabolic pathway and its control, and thus cause changes in the functioning of metabolic pathways. In this article, the screening of chromosomes and the most important genes involved in the etiology of diabetic retinopathy is presented. The common databases with manuscripts published from January 2000 to June 2023 have been taken into consideration and chosen. This article indicates the role of specific genes in the development of diabetic retinopathy, as well as polymorphic changes within the indicated genes that may have an impact on exacerbating the symptoms of the disease. The collected data will allow for a broader look at the disease and help to select candidate genes that can become markers of the disease.

Platelets in Renal Disease

Kidney disease is a major global health concern, affecting millions of people. Nephrologists have shown interest in platelets because of coagulation disorders caused by renal diseases. With a better understanding of platelets, it has been found that these anucleate and abundant blood cells not only play a role in hemostasis, but also have important functions in inflammation and immunity. Platelets are not only affected by kidney disease, but may also contribute to kidney disease progression by mediating inflammation and immune effects. This review summarizes the current evidence regarding platelet abnormalities in renal disease, and the multiple effects of platelets on kidney disease progression. The relationship between platelets and kidney disease is still being explored, and further research can provide mechanistic insights into the relationship between thrombosis, bleeding, and inflammation related to kidney disease, and elucidate targeted therapies for patients with kidney disease.

Alterations in factors associated with diabetic retinopathy combined with thrombosis: A review

Diabetic retinopathy (DR) is one of the most common and serious microvascular complications of diabetes mellitus, the incidence of which has been increasing annually, and it is the main cause of vision loss in diabetic patients and a common cause of blindness. It is now found that thrombosis plays a crucial role in the disease progression in DR patients, and the final vision loss in DR may be related to the occurrence of thrombosis in the retinal vessels, which is dominated by abnormal endothelial cell function, together with platelet dysfunction, imbalance of coagulation and fibrinolytic function, and related alterations of inflammatory factors leading to the main cause of thrombotic disease in DR patients. In this review, we examine the role between DR and thrombosis and the association of each factor, including endothelial dysfunction; platelet dysfunction; coagulation-fibrinolytic imbalance; and alterations in inflammatory factors.

Effects of Gold Nanoparticles Functionalized with Cornus mas L. Fruit Extract on the Aorta Wall in Rats with a High-Fat Diet and Experimental-Induced Diabetes Mellitus-An Imaging Study

Diabetes mellitus and high-fat diets trigger the mechanisms that alter the walls of blood vessels. Gold nanoparticles, as new pharmaceutical drug delivery systems, may be used in the treatment of different diseases. In our study, the aorta was investigated via imaging after the oral administration of gold nanoparticles functionalized with bioactive compounds derived from Cornus mas fruit extract (AuNPsCM) in rats with a high-fat diet and diabetes mellitus. Sprague Dawley female rats that received a high-fat diet (HFD) for 8 months were injected with streptozotocin to develop diabetes mellitus (DM). The rats were randomly allocated into five groups and were treated, for one additional month with HFD, with carboxymethylcellulose (CMC), insulin, pioglitazone, AuNPsCM solution or with Cornus mas L. extract solution. The aorta imaging investigation consisted of echography, magnetic resonance imaging and transmission electron microscopy (TEM). Compared to the rats that received only CMC, the oral administration of AuNPsCM produced significant increases in aorta volume and significant decreases in blood flow velocity, with ultrastructural disorganization of the aorta wall. The oral administration of AuNPsCM altered the aorta wall with effects on the blood flow.

Novel Biotherapeutics Targeting Biomolecular and Cellular Approaches in Diabetic Wound Healing

Wound healing responses play a major role in chronic inflammation, which affects millions of people around the world. One of the daunting tasks of creating a wound-healing drug is finding equilibrium in the inflammatory cascade. In this study, the molecular and cellular mechanisms to regulate wound healing are explained, and recent research is addressed that demonstrates the molecular and cellular events during diabetic wound healing. Moreover, a range of factors or agents that facilitate wound healing have also been investigated as possible targets for successful treatment. It also summarises the various advances in research findings that have revealed promising molecular targets in the fields of therapy and diagnosis of cellular physiology and pathology of wound healing, such as neuropeptides, substance P, T cell immune response cDNA 7, miRNA, and treprostinil growth factors such as fibroblast growth factor, including thymosin beta 4, and immunomodulators as major therapeutic targets.

The Role of Platelets in Diabetic Kidney Disease

Diabetic kidney disease (DKD) is among the most common microvascular complications in patients with diabetes, and it currently accounts for the majority of end-stage kidney disease cases worldwide. The pathogenesis of DKD is complex and multifactorial, including systemic and intra-renal inflammatory and coagulation processes. Activated platelets play a pivotal role in inflammation, coagulation, and fibrosis. Mounting evidence shows that platelets play a role in the pathogenesis and progression of DKD. The potentially beneficial effects of antiplatelet agents in preventing progression of DKD has been studied in animal models and clinical trials. This review summarizes the current knowledge on the role of platelets in DKD, including the potential therapeutic effects of antiplatelet therapies.

Understanding the Activation of Platelets in Diabetes and Its Modulation by Allyl Methyl Sulfide, an Active Metabolite of Garlic

BACKGROUND

Diabetes mellitus (DM) is a chronic metabolic disorder associated with higher risk of having cardiovascular disease. Platelets play a promising role in the pathogenesis of cardiovascular complications in diabetes. Since last several decades, garlic and its bioactive components are extensively studied in diabetes and its complications. Our aim was to explore the antiplatelet property of allyl methyl sulfide (AMS) focusing on ameliorating platelet activation in diabetes.

METHOD

We used streptozotocin- (STZ-) induced diabetic rats as model for type 1 diabetes. We have evaluated the effect of allyl methyl sulfide on platelet activation by administrating AMS to diabetic rats for 10 weeks. Flow cytometry-based analysis was used to evaluate the platelet activation, platelet aggregation, platelet macrophage interaction, and endogenous ROS generation in the platelets obtained from control, diabetes, and AMS- and aspirin-treated diabetic rats.

RESULTS

AMS treatment for 10 weeks effectively reduced the blood glucose levels in diabetic rats. Three weeks of AMS (50 mg/kg/day) treatment did not reduce the activation of platelets but a significant (p < 0.05) decrease was observed after 10 weeks of treatment. Oral administration of AMS significantly (p < 0.05) reduced the baseline and also reduced ADP-induced aggregation of platelets after 3 and 10 weeks of treatment. Furthermore, 10 weeks of AMS treatment in diabetic rats attenuated the endogenous ROS content (p < 0.05) of platelets and platelet macrophage interactions. The inhibition of platelet activation in diabetic rats after AMS treatment was comparable with aspirin treatment (30 mg/kg/day).

CONCLUSION

We observed an inhibitory effect of allyl methyl sulfide on platelet aggregation, platelet activation, platelet macrophage interaction, and increased ROS levels in type 1 diabetes. Our data suggests that AMS can be useful to control cardiovascular complication in diabetes via inhibition of platelet activation.

Repurposing metformin for covid-19 complications in patients with type 2 diabetes and insulin resistance

Understanding the exact role of current drugs in Covid-19 disease is essential in the era of global pandemics. Metformin which prescribed as the first-line treatment of type 2 diabetes has beneficial effects on Sars-cov2 infection. These effects are including regulation of immune system, Renin-Angiotensin System and Dipeptidyl Peptidase 4 function in Covid-19 infection. It also activates ACE2, the main receptor of Sars-cov2, in the epithelial cells of respiratory tissue through AMPK signaling and subsequently decreases the rate of viral adhesion. Metformin also declines the adherence of Sars-cov2 to DPP4 (the other receptor of the virus) on T cells. Hence, regulatory effects of metformin on membranous ACE2, and DPP4 can modulate immune reaction against Sars-cov2. Also, immunometabolic effects of metformin on inflammatory cells impair hyper-reactive immune response against the virus through reduction of glycolysis and propagation of mitochondrial oxidation. Metformin also decreases platelet aggravation and risk of thrombosis. In this article, we argue that metformin has beneficial effects on Covid-19 infection in patients with type 2 diabetes and insulin resistance. This opinion should be investigated in future clinical trials.

Paeoniflorin ameliorates glycemic variability-induced oxidative stress and platelet activation in HUVECs and DM rats

Glycemic variability (GV) plays an important role in the pathogenesis of vascular complications associated with diabetes mellitus (DM). Paeoniflorin is an effective Chinese traditional medicine with anti-inflammatory and immune-regulatory effects. Previous studies implicated the beneficial effects of paeoniflorin in treatment for diabetic complications, such as type 2 diabetic nephropathy and diabetes with myocardial ischemic injury. Current evidence suggests that oxidative stress and platelet activation, as well as their interaction, are potentially associated with GV and involved in the pathogenesis of diabetes-associated vascular complications. This study aimed to explore the effects of paeoniflorin on oxidative stress and platelet activation, using human umbilical vein endothelial cells (HUVECs) cultured with different glucose concentrations, and streptozotocin-induced diabetic rats fed different glycemic index diets. Paeoniflorin treatment effectively improved the morphology and cell viability of HUVECs under glucose fluctuation. Moreover, the platelet aggregation rate, CD62p expression, and reactive oxygen species (ROS) concentration decreased, while glutathione peroxidase (GSH-px) levels increased in paeoniflorin-treated groups. In conclusion, our study found that paeoniflorin ameliorates oxidative stress and platelet activation induced by glycemic variability both in vivo and in vitro, suggesting a novel potential strategy for treatment of diabetic complications.

Glycemic variability (GV) plays an important role in the pathogenesis of vascular complications associated with diabetes mellitus (DM).

Prealbumin to fibrinogen ratio is closely associated with diabetic peripheral neuropathy

The aim of our study was to explore the diagnostic value of prealbumin to fibrinogen ratio (PFR) for predicting prognosis with the optimal cut-off value in diabetic peripheral neuropathy (DPN) patients. A total of 568 type 2 diabetes mellitus (T2DM) patients were enrolled in this study. The values including Toronto clinical neuropathy score (TCNS), nerve conduction velocity (NCV), vibration perception threshold (VPT), blood cells count, biochemical parameters, fibrinogen and PFR were recorded. The patients were divided into tertiles based on admission PFR value. First, clinical parameters were compared among the groups. Secondly, a logistic regression and ROC analysis were performed as the statistical model. The percentage of DPN, TCNS and VPT were significantly higher in the lowest PFR tertile than in the middle PFR tertile and the highest PFR tertile (P < 0.01-0.001). NCV was significantly lower in lowest PFR tertile than in the middle PFR tertile and the highest PFR tertile (P < 0.01-0.001). The Spearman correlation analysis showed that PFR was negatively correlated with TCNS and VPT (P < 0.001), while PFR was positively correlated with median motor NCV (P < 0.001), peroneal motor NCV (P < 0.001), median sensory NCV (P < 0.001), and peroneal sensory NCV (P < 0.001). After adjusting these potentially related factors, PFR was independently related to DPN (P = 0.007). The area under ROC curve was 0.627. This study finds the first evidence to suggest PFR may be the key component associated with DPN in T2DM, while PFR might underlie the pathophysiologic features of DPN.

Effect of dietary inclusion of almond fruit on sexual behavior, arginase activity, pro-inflammatory, and oxidative stress markers in diabetic male rats

This study was designed to examine the effect of almond-included diets on sexual behavior, arginase activity, and pro-inflammatory markers in diabetic male rats. Forty-two male rats were divided into seven groups (n = 6). Diabetes was triggered via a single dose intraperitoneal injection of streptozotocin (50 mg/kg). Diabetes was confirmed 72 hr after STZ induction, and animals with blood glucose ≥ 250 mg/dl were considered diabetic and used for the experiment. The effects of almond-supplemented diets on glucose level, sexual function, NF-κB and TNF-α levels, arginase and purinergic enzyme activities, and levels of oxidative stress markers were assessed. A significant decrease in sexual activities with a simultaneous increase in pro-inflammatory markers, arginase and purinergic enzyme activities as well as TBARS and ROS levels was observed in diabetic rats. Interestingly, treatment with supplemented diets ameliorated the effects. Conclusively, intake of almonds could prevent the risk of erectile dysfunction in diabetic subjects. PRACTICAL APPLICATIONS: Intake of diets rich in fruits, nuts, and vegetables has been reported to reduce the risk of metabolic syndrome. Here, we investigate the effect of dietary inclusion of almond fruit on sexual behavior, arginase activity, oxidative stress, and pro-inflammatory markers in diabetic male rats. Interestingly, data generated from this work reveal that the supplemented diets enhanced sexual activities, and reduced oxidative stress and pro-inflammatory markers in diabetic male rats. Thus, consumption of almond (drupe and seed) could prevent/reduce the erectile dysfunction in individual with diabetes.

Coagulatory Defects in Type-1 and Type-2 Diabetes

Diabetes (both type-1 and type-2) affects millions of individuals worldwide. A major cause of death for individuals with diabetes is cardiovascular diseases, in part since both types of diabetes lead to physiological changes that affect haemostasis. Those changes include altered concentrations of coagulatory proteins, hyper-activation of platelets, changes in metal ion homeostasis, alterations in lipid metabolism (leading to lipotoxicity in the heart and atherosclerosis), the presence of pro-coagulatory microparticles and endothelial dysfunction. In this review, we explore the different mechanisms by which diabetes leads to an increased risk of developing coagulatory disorders and how this differs between type-1 and type-2 diabetes.

The relationship between mean platelet volume and albuminuria in patients with type 2 diabetes mellitus

BACKGROUND&AIM

Mean platelet volume (MPV) is suggested as a marker of platelet reactivity and tendency for thrombosis and microvascular complications like albuminuria in patients with type 2 DM. We aimed to measure the MPV in patients with type 2 DM and its correlation with albuminuria, body mass index (BMI), duration of DM, hypertension (HTN), stroke, ischemic heart disease (IHD), and HbA1c level.

METHODS

A cross sectional study included 100 patients with type 2 DM ≥ 18 y of both genders who were randomly selected from the medical units of Baghdad Teaching Hospital. After taking verbal consents; MPV was measured&correlated with aimed variables. Diabetics with HbA1c ≤ 7% were considered as having adequate control while those with (HbA1c) > 7% as having poor control. Albumin creatinine ratio (ACR) in urine was measured and classified into normal, moderately and severely increased. Odds ratios with 95% CI were calculated and P ≤ 0.05 was considered as statistically significant.

RESULTS

The mean MPV was 7.7 fl ± 1.2. Regarding ACR, 42% had normal level, 37% with moderately increased and 21% had severely increased level. Regarding HbA1c, 68% were having poorly controlled DM. Mean platelets' count and MPV were higher in the uncontrolled group with a statistically significant association. There was a statistically significant positive correlation between MPV and albuminuria, duration of DM, HTN, IHD, Stroke, BMI, HbA1c, and platelets count.

CONCLUSIONS

The mean MPV was statistically significantly higher in the uncontrolled DM group and there was a statistically significant positive correlation between MPV and albuminuria.

Comprehensive Quality Control of the Regenerative Therapy Using Platelet Concentrates: The Current Situation and Prospects in Japan

Platelet concentrates (PCs), represented by platelet-rich plasma (PRP), have been widely applied in the fields of regenerative and aesthetic therapies. PCs' mechanisms of action, however, are too complicated, and it is not easy to present the whole picture; besides, clinical outcomes are hardly reproducible in many cases. Therefore, several medically advanced countries seemingly intend to regulate PC therapies weakly or strictly because of the increasing popularity. Japan established laws and regulations for PC therapy in the "Act on the Safety of Regenerative Medicine" along with the "Pharmaceuticals, Medical Devices and Other Therapeutic Products Act" in 2014, which, to our knowledge, represent the strictest regulatory framework for production and therapeutic use of PCs in the world. According to these laws and regulations, PCs produced for topical use should be prepared as cell-based medicinal products, essentially as should stem cells, in accordance with their registered ("licensed" under actual conditions) standard operating procedures. Nonetheless, criteria for their quality are not standardized. In this review, we discuss the quality of PC preparations by focusing on the basic concept and regulatory framework of regenerative medicine in Japan. Within the new framework, PC therapy is regulated by a specific notification and registration system, as is stem cell therapy. In comparison with the latter, however, risk factors that hamper successful PC therapy are much fewer. Via appropriate evaluation of patients' conditions and whole-blood samples by simple and sensitive but not yet fully standardized assays, it is theoretically possible that PC quality will be controlled nearly completely. In addition to or instead of standardization of preparation protocols, standardization of preoperative examination of individual PC preparations is an urgent task for improving and guaranteeing the safety and efficacy of PC therapy.

The relationship of systemic markers of haemostasis with retinal blood vessel responses in cardiovascular disease and/or diabetes

Background Hypercoagulability is a leading factor in diabetes and cardiovascular disease. Retinal vessel responses to flickering light are an important tool for assessing ocular function. We hypothesised a significant relationship between systemic markers of haemostasis and retinal vessel function. Methods Intra-ocular pressure and retinal microcirculation function were measured in 116 patients with diabetes and/or cardiovascular disease using unstimulated and stimulated arterial and venous retinal vessel responses to flickering light. Haemostasis was evaluated by platelet microparticles, soluble P selectin, and five functional markers of fibrin clot formation and lysis, hyperglycaemia by HbA1c. Results Intra-ocular pressure was linked to the rates of clot formation (p = 0.006) and clot dissolution (p = 0.013) whilst central retinal vein equivalent was linked to HbA1c (p = 0.017). In the first of three flickering light cycles only, arterial baseline diameter fluctuation was linked to the lag time to clot formation (p = 0.017), whilst maximum venous dilatation was linked to HbA1c (p = 0.001) and clot density (p = 0.011). HbA1c was linked to venous dilatation amplitude (p = 0.003). There were no significant links between any ocular index and any platelet index. Conclusions In addition to glycaemia, several haemostasis measures, but no measures of platelet activity, are linked to ocular and retinal blood vessel indices in patients with diabetes and/or cardiovascular disease. These associations may have pathophysiological significance.

Vitamin D diminishes the high platelet aggregation of type 2 diabetes mellitus patients

Platelet activation is found in inflammatory conditions and implicated in the pathogenesis of chronic medical conditions, such as atherosclerosis, coronary vascular disease, cerebrovascular disease, and diabetes mellitus (DM). HbA1c is inversely related to vitamin D25 levels in individuals with and without DM. This study aimed to determine the relation between platelet aggregation, vitamin D and HbA1c among healthy individuals and those with Type 2 DM (T2DM). The direct effect of vitamin D1, 25 (calcitriol) on platelet aggregation was also investigated. The study included four groups: A. normoglycemic Control group: HbA1c<5.7%; B. Pre-diabetes (DM): 5.7% ≥ HbA1c ≤ 6.4%; C. DM on aspirin therapy: HbA1c>6.4%(+)Asp.; and D. DM not on aspirin therapy: HbA1c > 6.4%(-)Asp. Platelet aggregation was tested with and without calcitriol or saline pre-treatment, using collagen or adenosine diphosphate (ADP) as agonists. Platelet aggregation was higher in DM(-)Asp group compared to normoglycemic and DM(+)Asp, and higher, but not significant compared to pre-DM. The entire study population exhibited negative correlation between HbA1c and serum concentration of vitamin D25. Excluding DM(+)Asp, aggregation induced by collagen was significantly higher in patients with insufficient (<76 nmol/L) vitamin D25 compared to sufficient (≥76 nmol/L) vitamin D25. In this cohort, a negative correlation was found between serum concentrations of vitamin D25 and collagen-induced percent maximum (%max) aggregation and area under curve (AUC) aggregation. In the DM(-)Asp group, collagen-induced aggregation was reduced by approximately 25% after calcitriol treatment. Calcitriol decreased ADP-induced aggregation of control and DM(+)Asp groups to approximately 85% of saline treatment. We conclude that glycemic control is inversely associated with high platelet aggregation and low vitamin D25 levels. This elevated aggregation could be regulated by a novel, direct effect of calcitriol, indicating a beneficial effect of vitamin D on vascular complications related to diabetes. We offer a possible non-genomic mechanism for the vitamin D/Vitamin D receptor (VDR) pathway.

Does type 2 diabetes affect the on-treatment levels of direct oral anticoagulants in patients with atrial fibrillation?

AIMS

Type 2 diabetes (T2D) is connected with several abnormalities in haemostasis; and with higher risk of stroke and systemic embolism in patients with non-valvular atrial fibrillation (NV-AF). However, it is recently unknown whether T2D affects the activity of direct oral anticoagulants (DOACs). The aim of this study was to determine the impact of T2D on DOACs activity in patients with NV-AF.

METHODS

This pilot prospective study enrolled totally 65 patients with NV-AF (20 dabigatran-treated, 110 mg/twice daily; 28 rivaroxaban-treated, 15 mg/daily; 17 apixaban-treated, 5 mg/twice daily). 25 patients had T2D (8 dabigatran-treated, 11 rivaroxaban-treated, and 6 apixaban-treated). DOAC activity was tested with Hemoclot® Thrombin Inhibitor assay in dabigatran-treated patients, and with factor Xa-calibrated anti-Xa chromogenic analysis in rivaroxaban- and apixaban-treated patients prior and two hours after drug administration.

RESULTS

There were no significant differences in dabigatran baseline (62.1 ± 8.0 vs. 51.8 ± 38.9 ng/ml, p = .76) and 2-h-post-drug-administration (91.7 ± 57.2 vs. 72.2 ± 33.2 ng/ml, p = .48) activity comparing T2D and non-diabetic patients. Similarly, no significant differences were found in rivaroxaban baseline (35.9 ± 22.5 vs. 55.3 ± 45.1 ng/ml, p = .19) and 2-h-post-drug-administration (145.7 ± 74.1 vs. 202.6 ± 135.0 ng/ml, p = .22) anti-Xa activity. In addition, no significant differences were present in apixaban baseline (96.0 ± 54.5 vs. 63.9 ± 36.8 ng/ml, p = .24) and 2-h-post-drug-administration (151.0 ± 78.3 vs. 151.7 ± 59.1 ng/ml, p = .98) anti-Xa activity between T2D and non-diabetic patients.

CONCLUSIONS

This pilot study did not detect differences in DOACs activity according to T2D status in patients with NV-AF.

Influencing factors in quantitative measurement using activated platelet levels and platelet-activating capacity for the assessment of thrombosis in pre-metabolic syndrome and type 2 diabetes mellitus

Activated platelet levels and platelet-activating capacity are well recognized as useful index parameters for the physiological and pharmacological prediction of thrombotic events. Recently, quantitative measurements for platelet functions using a flow cytometer have been increasing gradually. However, the relation of physiological factors, such as sex, aging, and laboratory tests, to platelet functions has not been well documented. We conducted a blood analysis of people with normal/pre-metabolic syndrome and patients with type 2 diabetes mellitus to clarify the pathological factors. The levels of basal (non-stimulated)-activated, platelet-expressed P-selectin and activated platelet stimulated by agonists were measured by a flow cytometer, and ratios of platelet-activating capacity were also calculated. Statistical analyses indicated significantly high basal-activated platelet in pre-metabolic syndrome, and basal-activated platelet was positively associated with hyperlipidemia and hepatic damage. Platelet-activating capacity was significantly low in aging and hyperlipidemia, but high in hyperglycemia, and was negatively associated with hyperlipidemia and hepatic damage. Aging and high nutrient condition impaired platelet functions. Quantitative measurements of basal-activated platelet and platelet-activating capacity are precise parameters for the prediction of thrombotic events.

Tissue plasminogen activator (t-PA) and plasminogen activator inhibitor type 1 (PAI-1) in diabetic foot syndrome

PURPOSE

The aim was to evaluate tissue plasminogen activator (tPA) and plasminogen activator inhibitor type 1 (PAI-1) concentration using enzyme linked immunosorbent assay method (ELISA) in diabetic foot syndrome (DFS) as compared to a group of healthy people and patients with diabetes mellitus without symptomatic vascular complications (DM2T).

MATERIAL/METHODS

Venous blood samples were collected from 90 patients with type 2 diabetes mellitus (30 - DM2T; 60 - DFS). Age-matched controls were also included (n=30). tPA and PAI-1 plasma levels were measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

We found a significantly lower concentration of tPA:Ag in patients with DFS in comparison to the DM2T group; tPA concentrations were significantly higher in DM2T as compared to the control group. We observed significantly lower concentration of PAI-1:Ag in DF patients treated for hypertension as compared to patients without hypertension. The tPA:Ag and PAI-1:Ag concentration analysis in DFS depending on age, gender and BMI did not show any significant differences.

CONCLUSIONS

A lower concentration of tPA in patients with DFS may be associated with damage to the endothelial cells, especially in the microvasculature, and the sympathetic nervous system.

The relationship of systemic markers of renal function and vascular function with retinal blood vessel responses

PURPOSE

To test the hypothesis of a significant relationship between systemic markers of renal and vascular function (processes linked to cardiovascular disease and its development) and retinal microvascular function in diabetes and/or cardiovascular disease.

METHODS

Ocular microcirculatory function was measured in 116 patients with diabetes and/or cardiovascular disease using static and continuous retinal vessel responses to three cycles of flickering light. Endothelial function was evaluated by von Willebrand factor (vWf), endothelial microparticles and soluble E selectin, renal function by serum creatinine, creatinine clearance and estimated glomerular filtration rate (eGFR). HbA1c was used as a control index.

RESULTS

Central retinal vein equivalence and venous maximum dilation to flicker were linked to HbA1c (both p < 0.05). Arterial reaction time was linked to serum creatinine (p = 0.036) and eGFR (p = 0.039); venous reaction time was linked to creatinine clearance (p = 0.018). Creatinine clearance and eGFR were linked to arterial maximum dilatation (p < 0.001 and p = 0.003, respectively) and the dilatation amplitude (p = 0.038 and p = 0.048, respectively) responses in the third flicker cycle. Of venous responses to the first flicker cycle, HbA1c was linked to the maximum dilation response (p = 0.004) and dilatation amplitude (p = 0.017), vWf was linked to the maximum constriction response (p = 0.016), and creatinine clearance to the baseline diameter fluctuation (p = 0.029). In the second flicker cycle, dilatation amplitude was linked to serum creatinine (p = 0.022).

CONCLUSIONS

Several retinal blood vessel responses to flickering light are linked to glycaemia and renal function, but only one index is linked to endothelial function. Renal function must be considered when interpreting retinal vessel responses.

Study of endothelial function response to exercise training in hypertensive individuals (SEFRET): study protocol for a randomized controlled trial

Background

Endothelial dysfunction is a hallmark of diabetes mellitus and systemic arterial hypertension (SAH) and an early maker for atherosclerosis. Aerobic exercise training is known to enhance endothelial function, but little is understood about the effects of resistance or combined exercise training on endothelial function. The aim of this study is to investigate the effect of a 12-week aerobic (AT), resistance (RT), or combined (aerobic and resistance, CT) training program on endothelial function and assess associated effects on blood pressure in individuals with SAH.

Methods/design

Eighty-one subjects with SAH aged 18 to 70 years will be selected and randomly assigned to three types of exercise training: AT, RT or CT. The study will involve the following procedures and tests: anamnesis, anthropometric assessment, echocardiography, blood pressure measurements through ambulatory blood pressure monitoring, flow-mediated dilation, ergospirometry, one repetition maximum test (1-RM), and blood collection (number of circulating endothelial progenitor cells, number of circulating endothelial microparticles, lipid profile, glucose, glycated hemoglobin, and creatinine). The AT intervention will consist of a 40-min exercise session with progressive intensities ranging from 50 to 75 % of heart rate reserve. The RT intervention will consist of a 40-minute session with four sets of six to 12 repetitions with a rest period of 60 to 90 seconds between each set and each type of exercise. Weight loads will be adjusted to 60 to 80 % of 1-RM for six types of exercise. The CT intervention will consist of a 20-min aerobic exercise session, followed by an additional 20-min resistance exercise session; each resistance exercise will have two sets less to match the total training volume.

Discussion

The study results are expected evidence of cardiovascular protective effects of different types of exercise training through the modulation of endothelial function in hypertensive individuals. Knowing the magnitude of improvement of endothelium-dependent vasodilation for the different types of exercise training can provide scientific evidence for the prescription of exercise programs for vascular protection targeting hypertensive individuals.

Trial registration

The Brazilian Clinical Trials Registry (http://www.ensaiosclinicos.gov.br/) under RBR-9ygmdn and dated 1 March 2015.

Higher mitochondrial potential and elevated mitochondrial respiration are associated with excessive activation of blood platelets in diabetic rats

AIMS

The high glucose concentration observed in diabetic patients is a recognized factor of mitochondrial damage in various cell types. Its impact on mitochondrial bioenergetics in blood platelets remains largely vague. The aim of the study was to determine how the metabolism of carbohydrates, which has been impaired by streptozotocin-induced diabetes may affect the functioning of platelet mitochondria.

MATERIALS AND METHODS

Diabetes was induced in Sprague Dawley rats by intraperitoneal injection of streptozotocin. Platelet mitochondrial respiratory capacity was monitored as oxygen consumption (high-resolution respirometry). Mitochondrial membrane potential was assessed using a fluorescent probe, JC-1. Activation of circulating platelets was monitored by flow cytometry measuring of the expressions of CD61 and CD62P on a blood platelet surface. To determine mitochondrial protein density in platelets, Western Blot technique was used.

KEY FINDINGS

The results indicate significantly elevated mitochondria mass, increased mitochondrial membrane potential (ΔΨm) and enhanced respiration in STZ-diabetic animals, although the respiration control ratios appear to remain unchanged. Higher ΔΨm and elevated mitochondrial respiration were closely related to the excessive activation of circulating platelets in diabetic animals.

SIGNIFICANCE

Long-term diabetes can result in increased mitochondrial mass and may lead to hyperpolarization of blood platelet mitochondrial membrane. These alterations may be a potential underlying cause of abnormal platelet functioning in diabetes mellitus and hence, a potential target for antiplatelet therapies in diabetes.

Urinary Biomarkers in the Assessment of Early Diabetic Nephropathy

Diabetic nephropathy (DN) is a frequent and severe complication of diabetes mellitus (DM). Its diagnosis in incipient stages may allow prompt interventions and an improved prognosis. Towards this aim, biomarkers for detecting early DN can be used. Microalbuminuria has been proven a remarkably useful biomarker, being used for diagnosis of DN, for assessing its associated condition-mainly cardiovascular ones-and for monitoring its progression. New researches are pointing that some of these biomarkers (i.e., glomerular, tubular, inflammation markers, and biomarkers of oxidative stress) precede albuminuria in some patients. However, their usefulness is widely debated in the literature and has not yet led to the validation of a new "gold standard" biomarker for the early diagnosis of DN. Currently, microalbuminuria is an important biomarker for both glomerular and tubular injury. Other glomerular biomarkers (transferrin and ceruloplasmin) are under evaluation. Tubular biomarkers in DN seem to be of a paramount importance in the early diagnosis of DN since tubular lesions occur early. Additionally, biomarkers of inflammation, oxidative stress, podocyte biomarkers, and vascular biomarkers have been employed for assessing early DN. The purpose of this review is to provide an overview of the current biomarkers used for the diagnosis of early DN.