The Vasculature in Prediabetes

Integrin β5 subunit regulates hyperglycemia-induced vascular endothelial cell apoptosis through FoxO1-mediated macroautophagy

BACKGROUND

Hyperglycemia frequently induces apoptosis in endothelial cells and ultimately contributes to microvascular dysfunction in patients with diabetes mellitus (DM). Previous research reported that the expression of integrins as well as their ligands was elevated in the diseased vessels of DM patients. However, the association between integrins and hyperglycemia-induced cell death is still unclear. This research was designed to investigate the role played by integrin subunit β5 (ITGB5) in hyperglycemia-induced endothelial cell apoptosis.

METHODS

We used leptin receptor knockout (Lepr-KO) ( db / db ) mice as spontaneous diabetes animal model. Selective deletion of ITGB5 in endothelial cell was achieved by injecting vascular targeted adeno-associated virus via tail vein. Besides, we also applied small interfering RNA in vitro to study the mechanism of ITGB5 in regulating high glucose-induced cell apoptosis.

RESULTS

ITGB5 and its ligand, fibronectin, were both upregulated after exposure to high glucose in vivo and in vitro . ITGB5 knockdown alleviated hyperglycemia-induced vascular endothelial cell apoptosis and microvascular rarefaction in vivo.In vitro analysis revealed that knockdown of either ITGB5 or fibronectin ameliorated high glucose-induced apoptosis in human umbilical vascular endothelial cells (HUVECs). In addition, knockdown of ITGB5 inhibited fibronectin-induced HUVEC apoptosis, which indicated that the fibronectin-ITGB5 interaction participated in high glucose-induced endothelial cell apoptosis. By using RNA-sequencing technology and bioinformatic analysis, we identified Forkhead Box Protein O1 (FoxO1) as an important downstream target regulated by ITGB5. Moreover, we demonstrated that the excessive macroautophagy induced by high glucose can contribute to HUVEC apoptosis, which was regulated by the ITGB5-FoxO1 axis.

CONCLUSION

The study revealed that high glucose-induced endothelial cell apoptosis was positively regulated by ITGB5, which suggested that ITGB5 could potentially be used to predict and treat DM-related vascular complications.

The Association between Functional Dyspepsia and Metabolic Syndrome-The State of the Art

Functional dyspepsia is a common functional disorder of the gastrointestinal tract that is responsible for many primary care visits. No organic changes have been found to explain its symptoms. We hypothesize that modern lifestyles and environmental factors, especially psychological stress, play a crucial role in the high prevalence of functional dyspepsia and metabolic syndrome. While gastrointestinal tract diseases are rarely linked to metabolic disorders, chronic stress, obesity-related metabolic syndrome, chronic inflammation, intestinal dysbiosis, and functional dyspepsia have significant pathophysiological associations. Functional dyspepsia, often associated with anxiety and chronic psychological stress, can activate the neuroendocrine stress axis and immune system, leading to unhealthy habits that contribute to obesity. Additionally, intestinal dysbiosis, which is commonly present in functional dyspepsia, can exacerbate systemic inflammation and obesity, further promoting metabolic syndrome-related disorders. It is worth noting that the reverse is also true: obesity-related metabolic syndrome can worsen functional dyspepsia and its associated symptoms by triggering systemic inflammation and intestinal dysbiosis, as well as negative emotions (depression) through the brain-gut axis. To understand the pathophysiology and deliver an effective treatment strategy for these two difficult-to-cure disorders, which are challenging for both caregivers and patients, a psychosocial paradigm is essential.

Microvascular insulin resistance associates with enhanced muscle glucose disposal in CD36 deficiency

Dysfunction of endothelial insulin delivery to muscle associates with insulin resistance. CD36, a fatty acid transporter and modulator of insulin signaling is abundant in endothelial cells, especially in capillaries. Humans with inherited 50% reduction in CD36 expression have endothelial dysfunction but whether it is associated with insulin resistance is unclear. Using hyperinsulinemic/euglycemic clamps in Cd36-/- and wildtype mice, and in 50% CD36 deficient humans and matched controls we found that Cd36-/- mice have enhanced systemic glucose disposal despite unaltered transendothelial insulin transfer and reductions in microvascular perfusion and blood vessel compliance. Partially CD36 deficient humans also have better glucose disposal than controls with no capillary recruitment by insulin. CD36 knockdown in primary human-derived microvascular cells impairs insulin action on AKT, endothelial nitric oxide synthase, and nitric oxide release. Thus, insulin resistance of microvascular function in CD36 deficiency paradoxically associates with increased glucose utilization, likely through a remodeling of muscle gene expression.

Association of serum uric acid levels with blood pressure and the incidence of hypertension in the middle-aged and elderly populations

OBJECTIVE

This study aimed to investigate the relationship between serum uric acid (SUA) levels and hypertension in the middle-aged and elderly populations.

METHODS

The cross-sectional analysis included 13 349 middle-aged and elderly general health checkup examinees without cardiovascular disease. The retrospective cohort analysis included 6659 normotensive participants (mean age: 64.6 years). Participants were divided into three groups based on their SBP/DBP levels: normal (<120/<80 mmHg), high normal (120-129/<80 mmHg), and elevated (130-139/80-89 mmHg), and were classified into three groups based on the results of 75 g oral glucose tolerance test: normoglycemia, prediabetes, and diabetes.

RESULTS

SUA levels were significantly associated with SBP and DBP in this cross-sectional study. Over a mean 6.5-year follow-up period, 2038 participants developed hypertension. According to the SUA quartiles, the incidence of hypertension increased [26.1% in quartile (Q1) (≤4.1 mg/dl), 28.6% in Q2 (4.2-4.9 mg/dl), 32.6% in Q3 (5.0-5.8 mg/dl), 34.9% in Q4 (≥5.9 mg/dl); P for trend <0.001]. In multivariable analyses, SUA levels were positively associated with hypertension incidence only in the normal BP group [Q4 vs. Q1 odds ratio (OR): 1.64, 95% confidence intervals (CIs): 1.11-2.44; Q3 vs. Q1 OR: 1.69, 95% CI: 1.19-2.42] and in the normoglycemic group (Q4 vs. Q1 OR: 1.34, 95% CI: 1.02-1.76; Q3 vs. Q1 OR: 1.36, 95% CI: 1.07-1.74).

CONCLUSION

In the middle-aged and elderly populations, normotensive or normoglycemic individuals with SUA levels at least 5 mg/dl may be potential targets for SUA management to prevent hypertension.

Prediabetes-Associated Changes in Skeletal Muscle Function and Their Possible Links with Diabetes: A Literature Review

The skeletal muscle plays a critical role in regulating systemic blood glucose homeostasis. Impaired skeletal muscle glucose homeostasis associated with type 2 diabetes mellitus (T2DM) has been observed to significantly affect the whole-body glucose homeostasis, thereby resulting in other diabetic complications. T2DM does not only affect skeletal muscle glucose homeostasis, but it also affects skeletal muscle structure and functional capacity. Given that T2DM is a global health burden, there is an urgent need to develop therapeutic medical therapies that will aid in the management of T2DM. Prediabetes (PreDM) is a prominent risk factor of T2DM that usually goes unnoticed in many individuals as it is an asymptomatic condition. Hence, research on PreDM is essential because establishing diabetic biomarkers during the prediabetic state would aid in preventing the development of T2DM, as PreDM is a reversible condition if it is detected in the early stages. The literature predominantly documents the changes in skeletal muscle during T2DM, but the changes in skeletal muscle during prediabetes are not well elucidated. In this review, we seek to review the existing literature on PreDM- and T2DM-associated changes in skeletal muscle function.

The role of fibrinolysis in the development of prediabetes-associated coronary heart disease: a focus on the plasminogen activator inhibitor -1 and its potential use as a predictive marker in diet-induced prediabetes

Introduction

Type 2 diabetes mellitus (T2DM) is associated with an increased risk of cardiovascular diseases (CVD). However, the onset of T2DM is preceded by prediabetes, which is associated with sedentary lifestyles and consumption of high-calorie diets. Studies have shown that impaired glucose homeostasis creates an environment for developing T2DM-related complications. Using a high-fat-high-carbohydrate diet-induced prediabetes animal model, this study sought to assess the risk factors of coronary heart disease (CHD) in diet-induced prediabetes and identify biomarkers that can be used for early detection of prediabetes-associated CHD.

Methods

Male Sprague Dawley rats were randomly grouped into two groups and were kept on different diets for 20 weeks (n = 6 in each group). One group was fed standard rat chow to serve as a non-prediabetes (NPD) control, while the other group consumed a high-fat-high-carbohydrate diet to induce prediabetes (PD). Post induction, the homeostasis model assessment- insulin resistance (HOMA-IR) and glycated haemoglobin (HbA1c) was used to test for insulin resistance. Body weight, mean arterial pressure (MAP), resting heart rate (HR), inflammatory cytokines (C-reactive protein (CRP), tumor necrosis factor (TNF-α), interleukin-6 (IL-6)), lipids (total cholesterol (TC), triglyceride (TG), lipoproteins (HDL, LDL, VLDL)), endothelial function (endothelial nitric oxide (eNOS), endothelin -1 (ET-1)), fibrinolysis (plasminogen activator inhibitor-1 (PAI-1)) were all measured to assess the risk of CHD. All data were expressed as means ± S.E.M. Statistical comparisons were performed with Graph Pad. Instat Software using Student's two-sided t-test. The Pearson correlation coefficient and linear regression were calculated to assess the association. The value of p < 0.05 was considered statistically significant.

Results

There was significant insulin resistance accompanied by significantly increased HbA1c and body weight in PD compared to NPD. Simultaneously, there was a significant increase in inflammatory cytokines in PD compared to NPD. This was accompanied by significantly increased TG and VLDL and endothelial dysfunction in PD. The association between HOMA-IR and PAI-1 was insignificantly positive in NPD, whereas a significantly strong positive association was observed in PD.

Conclusion

There is a positive correlation between insulin resistance and PAI-1 during prediabetes; therefore, suggesting that prediabetes increases the risk of developing vascular thrombosis. The current therefore study warrants further investigation on PAI-1 and other markers of fibrinolysis for the early detection of thrombosis and risk of CHD in prediabetes.

The Emerging Role of Prediabetes and Its Management: Focus on L-Arginine and a Survey in Clinical Practice

The worldwide impressive growth of metabolic disorders observed in the last decades, especially type 2 diabetes mellitus and obesity, has generated great interest in the potential benefits of early identification and management of patients at risk. In this view, prediabetes represents a high-risk condition for the development of type 2 diabetes mellitus and cardiovascular diseases, and an ideal target to intercept patients before they develop type 2 diabetes gaining a prominent role even in international guidelines. For prediabetic individuals, lifestyle modification is the cornerstone of diabetes prevention, with evidence of about 50% relative risk reduction. Accumulating data also show potential benefits from pharmacotherapy. In this context, the only available data pertain to metformin as a pharmaceutical drug and vitamin D and L-arginine as nutraceuticals. L-arginine appears to be a very interesting tool in the clinical management of patients with pre-diabetes. In this review we summarize the current knowledge on the role of L-arginine in prediabetes as a potentially useful preventive strategy against the progression to type 2 diabetes, with a particular focus on the underlying molecular mechanisms and the past and ongoing trials. In this article we also report the interesting data about the perception of the prediabetic condition and its therapeutic management in the clinical practice in Italy. An early identification and a prompt management of people with prediabetes appears to be of paramount importance to prevent the progression to diabetes and avoid its cardiovascular consequences.

Predictive performance of established cardiovascular risk scores in the prediabetic population: external validation using the UK Biobank data set

AIMS

Prediabetes is a highly heterogenous metabolic state with increased risk of cardiovascular disease (CVD). Current guidelines raised the necessity of CVD risk scoring for prediabetes without clear recommendations. Thus, this study aimed to systematically assess the performance of 11 models, including five general population-based and six diabetes-specific CVD risk scores, in prediabetes.

METHODS AND RESULTS

A cohort of individuals aged 40-69 years with prediabetes (HbA1c ≥ 5.7 and <6.5%) and without baseline CVD or known diabetes was identified from the UK Biobank, which was used to validate 11 prediction models for estimating 10- or 5-year risk of CVD. Model discrimination and calibration were evaluated by Harrell's C-statistic and calibration plots, respectively. We further performed decision curve analyses to assess the clinical usefulness.Overall, 56 831 prediabetic individuals were included, of which 4303 incident CVD events occurred within a median follow-up of 8.9 years. All the 11 risk scores assessed had modest C-statistics for discrimination ranging from 0.647 to 0.680 in prediabetes. Scores developed in the general population did not outperform those diabetes-specific models (C-statistics, 0.647-0.675 vs. 0.647-0.680), while the PREDICT-1° Diabetes equation developed for Type 2 diabetes performed best [0.680 (95% confidence interval, 0.672-0.689)]. The calibration plots suggested overall poor calibration except that the PREDICT-1° Diabetes equation calibrated well after recalibration. The decision curves generally indicated moderate clinical usefulness of each model, especially worse within high threshold probabilities.

CONCLUSION

Neither risk stratification schemes for the general population nor those specific for Type 2 diabetes performed well in the prediabetic population. The PREDICT-1° Diabetes equation could be a substitute in the absence of better alternatives, rather than the general population-based scores. More precise and targeted risk assessment tools for this population remain to be established.

The association between prediabetes and bone mineral density: A meta-analysis

BACKGROUND

Prediabetes is an intermediate metabolic state between euglycaemia and diabetes, including three different definitions: impaired fasting glucose, impaired glucose tolerance, and mildly elevated glycated haemoglobin (HbA1c) (range 5.7%-6.4%). The effect of prediabetes on bone mineral density (BMD) has not been established. Therefore, we performed a meta-analysis to evaluate the association between prediabetes and BMD.

METHODS

We retrieved studies related to prediabetes and BMD from PubMed, Web of Science, and Embase databases from January 1990 to December 2022. All data were analysed using the random effects model. Statistical heterogeneity was tested by I2 . Subgroup analysis was performed after each study-level variable was pre-defined by meta-regression.

RESULTS

A total of 17 studies were included involving 45,788 patients. We detected a significant overall association of prediabetes with increased spine BMD (weighted mean difference [WMD] = 0.01, 95% CI [0.00, 0.02], p = 0.005; I2  = 62%), femur neck (FN) BMD (WMD = 0.01, 95% CI [0.00, 0.01], p < 0.001; I2  = 19%), and femur total (FT) BMD (WMD = 0.02, 95% CI [0.01, 0.03], p < 0.001; I2  = 51%). Several variables leading to heterogeneity were defined by meta-regression, including age, sex, region, study type, dual-energy X-ray absorptiometry scanner manufacturer, and prediabetes definition. Subgroup analyses indicated that the association of prediabetes with increased BMD was stronger in men, Asians, and older adults over 60 years of age.

CONCLUSIONS

Current evidence shows that prediabetes is strongly associated with increased BMD of the spine, FN, and FT. The association was stronger among males, Asians, and older adults over 60 years of age.

Effects of GLP-1 receptor agonists on mitochondrial function, inflammatory markers and leukocyte-endothelium interactions in type 2 diabetes

OBJECTIVE

Type 2 diabetes (T2D) is linked to metabolic, mitochondrial and inflammatory alterations, atherosclerosis development and cardiovascular diseases (CVDs). The aim was to investigate the potential therapeutic benefits of GLP-1 receptor agonists (GLP-1 RA) on oxidative stress, mitochondrial respiration, leukocyte-endothelial interactions, inflammation and carotid intima-media thickness (CIMT) in T2D patients.

RESEARCH DESIGN AND METHODS

Type 2 diabetic patients (255) and control subjects (175) were recruited, paired by age and sex, and separated into two groups: without GLP-1 RA treatment (196) and treated with GLP-1 RA (59). Peripheral blood polymorphonuclear leukocytes (PMNs) were isolated to measure reactive oxygen species (ROS) production by flow cytometry and oxygen consumption with a Clark electrode. PMNs were also used to assess leukocyte-endothelial interactions. Circulating levels of adhesion molecules and inflammatory markers were quantified by Luminex's technology, and CIMT was measured as surrogate marker of atherosclerosis.

RESULTS

Treatment with GLP-1 RA reduced ROS production and recovered mitochondrial membrane potential, oxygen consumption and MPO levels. The velocity of leukocytes rolling over endothelial cells increased in PMNs from GLP-1 RA-treated patients, whereas rolling and adhesion were diminished. ICAM-1, VCAM-1, IL-6, TNFα and IL-12 protein levels also decreased in the GLP-1 RA-treated group, while IL-10 increased. CIMT was lower in GLP-1 RA-treated T2D patients than in T2D patients without GLP-1 RA treatment.

CONCLUSIONS

GLP-1 RA treatment improves the redox state and mitochondrial respiration, and reduces leukocyte-endothelial interactions, inflammation and CIMT in T2D patients, thereby potentially diminishing the risk of atherosclerosis and CVDs.

CXCR7 Agonist TC14012 Improves Angiogenic Function of Endothelial Progenitor Cells via Activating Akt/eNOS Pathway and Promotes Ischemic Angiogenesis in Diabetic Limb Ischemia

PURPOSE

Endothelial progenitor cells (EPCs) play a critical role in repairing damaged vessels and triggering ischemic angiogenesis, but their number is reduced and function is impaired under diabetic conditions. Improving EPC function has been considered a promising strategy to ameliorate diabetic vascular complications. In the present study, we aim to investigate whether and how CXCR7 agonist TC14012 promotes the angiogenic function of diabetic EPCs.

METHODS

High glucose (HG) treatment was used to mimic the hyperglycemia in diabetes. Tube formation, cell scratch recovery and transwell assay, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, and cleaved-caspase3 expression were used to evaluate the angiogenic capability, cell migration, and apoptosis of EPCs, respectively. Hind limb ischemia (HLI) model was used to appraise the ability of TC14012 in promoting diabetic ischemic angiogenesis in vivo.

RESULTS

HG treatment impaired EPC tube formation and migration, and induced EPC apoptosis and oxidative damage, while TC14012 rescued tube formation and migration, and prevented HG-induced apoptosis and oxidative damage of EPCs. Furthermore, these beneficial effects of TC14012 on EPCs were attenuated by specific siRNAs against CXCR7, validating that CXCR7 is a functional target of TC14012 in EPCs. Mechanistic studies demonstrated that HG treatment reduced CXCR7 expression in EPCs, and impaired Akt and endothelial nitric oxide synthase (eNOS) phosphorylation and nitric oxide (NO) production; similarly, these signal impairments in HG-exposed EPCs could be rescued by TC14012. However, the protective effects of TC14012 on tube formation and migration, Akt and eNOS phosphorylation, and NO production in HG-treated EPCs were almost completely abolished by siRNAs against CXCR7 or Akt specific inhibitor wortmannin. More importantly, in vivo study showed that TC14012 administration enhanced blood perfusion recovery and angiogenesis in the ischemic hind limb and increased the EPC number in peripheral circulation of db/db mice, demonstrating the capability of TC14012 in promoting EPC mobilization and ischemia angiogenic function.

CONCLUSION

TC14012 can prevent EPCs from HG-induced dysfunction and apoptosis, improve eNOS activity and NO production via CXCR7/Akt signal pathway, and promote EPC mobilization and diabetic ischemia angiogenesis.

Association between blood glucose levels and arterial stiffness marker: comparing the second derivative of photoplethysmogram and cardio-ankle vascular index scores

Objective

This study aimed to compare the association between fasting plasma glucose (FPG) and glycosylated hemoglobin A1c (HbA1c) levels using the second derivative of photoplethysmogram (SDPTG) index and the cardio-ankle vascular index (CAVI).

Methods

Electronic medical records of 276 participants (160 men, 116 women) who visited the health promotion center of a university hospital were examined. Age, sex, body mass index (BMI), blood pressure, and lipid profile were considered as risk factors for arterial stiffness, together with the FPG, HbA1c, CAVI, and SDPTG indices. Hierarchical regression models were constructed, and all participants were divided into low-normal, high-normal, prediabetic, and diabetic groups to examine the group-based differences in CAVI and SDPTG indices.

Results

FPG and HbA1c were independently predictive of increased CAVI, and their predictive powers for CAVI were equivalent (β = 0.214 and 0.200, respectively). Risk factors, including age, BMI, and male sex, were also predictive of CAVI (β= 0.593-0.630, -0.256 - -0.280, and 0.142-0.178, respectively). None of the FPG and HbA1c values were predictive of the SDPTG indices. The CAVI was higher in the diabetes group than in the other three groups according to HbA1c level, while the d/a index of the SDPTG decreased in the prediabetes group and increased in the diabetes group.

Conclusions

CAVI may not be substituted for SDPTG indices when evaluating arterial stiffness based on the glucose level. Moreover, the progression rate of arterial stiffness may differ between the diabetic and nondiabetic stages.

Deficiency of endothelial sirtuin1 in mice stimulates skeletal muscle insulin sensitivity by modifying the secretome

Downregulation of endothelial Sirtuin1 (Sirt1) in insulin resistant states contributes to vascular dysfunction. Furthermore, Sirt1 deficiency in skeletal myocytes promotes insulin resistance. Here, we show that deletion of endothelial Sirt1, while impairing endothelial function, paradoxically improves skeletal muscle insulin sensitivity. Compared to wild-type mice, male mice lacking endothelial Sirt1 (E-Sirt1-KO) preferentially utilize glucose over fat, and have higher insulin sensitivity, glucose uptake, and Akt signaling in fast-twitch skeletal muscle. Enhanced insulin sensitivity of E-Sirt1-KO mice is transferrable to wild-type mice via the systemic circulation. Endothelial Sirt1 deficiency, by inhibiting autophagy and activating nuclear factor-kappa B signaling, augments expression and secretion of thymosin beta-4 (Tβ4) that promotes insulin signaling in skeletal myotubes. Thus, unlike in skeletal myocytes, Sirt1 deficiency in the endothelium promotes glucose homeostasis by stimulating skeletal muscle insulin sensitivity through a blood-borne mechanism, and augmented secretion of Tβ4 by Sirt1-deficient endothelial cells boosts insulin signaling in skeletal muscle cells.

Sex differences in cardiometabolic biomarkers during the pre-diabetes stage

Using two large prospective epidemiological studies in the U.S., we examined biomarkers that reflect sex-specific pathophysiological pathways to cardiovascular complications among people with pre-diabetes. Women with pre-diabetes exhibited higher levels of adipokines, while men had lower eGFR. Sex differences in lipoproteins and vascular inflammatory markers during pre-diabetes indicate sex-specific lipoprotein and inflammatory mechanisms to cardiovascular complications.

Coronary microvascular dysfunction and cardiovascular disease: Pathogenesis, associations and treatment strategies

Coronary microvascular dysfunction (CMD) is a high-risk factor for a variety of cardiovascular events. Due to its complex aetiology and concealability, knowledge of the pathophysiological mechanism of CMD is still limited at present, which greatly restricts its clinical diagnosis and treatment. Studies have shown that CMD is closely related to a variety of cardiovascular diseases, can aggravate the occurrence and development of cardiovascular diseases, and is closely related to a poor prognosis in patients with cardiovascular diseases. Improving coronary microvascular remodelling and increasing myocardial perfusion might be promising strategies for the treatment of cardiovascular diseases. In this paper, the pathogenesis and functional assessment of CMD are reviewed first, along with the relationship of CMD with cardiovascular diseases. Then, the latest strategies for the treatment of CMD and cardiovascular diseases are summarized. Finally, urgent scientific problems in CMD and cardiovascular diseases are highlighted and future research directions are proposed to provide prospective insights for the prevention and treatment of CMD and cardiovascular diseases in the future.

Down-regulation of WWP2 aggravates Type 2 diabetes mellitus-induced vascular endothelial injury through modulating ubiquitination and degradation of DDX3X

BACKGROUND

Endothelial injury caused by Type 2 diabetes mellitus (T2DM) is considered as a mainstay in the pathophysiology of diabetic vascular complications (DVCs). However, the molecular mechanism of T2DM-induced endothelial injury remains largely unknown. Here, we found that endothelial WW domain-containing E3 ubiquitin protein ligase 2 (WWP2) act as a novel regulator for T2DM-induced vascular endothelial injury through modulating ubiquitination and degradation of DEAD-box helicase 3 X-linked (DDX3X).

METHODS

Single-cell transcriptome analysis was used to evaluate WWP2 expression in vascular endothelial cells of T2DM patients and healthy controls. Endothelial-specific Wwp2 knockout mice were used to investigate the effect of WWP2 on T2DM-induced vascular endothelial injury. In vitro loss- and gain-of-function studies were performed to assess the function of WWP2 on cell proliferation and apoptosis of human umbilical vein endothelial cells. The substrate protein of WWP2 was verified using mass spectrometry, coimmunoprecipitation assays and immunofluorescence assays. The mechanism of WWP2 regulation on substrate protein was investigated by pulse-chase assay and ubiquitination assay.

RESULTS

The expression of WWP2 was significantly down-regulated in vascular endothelial cells during T2DM. Endothelial-specific Wwp2 knockout in mice significantly aggravated T2DM-induced vascular endothelial injury and vascular remodeling after endothelial injury. Our in vitro experiments showed that WWP2 protected against endothelial injury by promoting cell proliferation and inhibiting apoptosis in ECs. Mechanically, we found that WWP2 is down-regulated in high glucose and palmitic acid (HG/PA)-induced ECs due to c-Jun N-terminal kinase (JNK) activation, and uncovered that WWP2 suppresses HG/PA-induced endothelial injury by catalyzing K63-linked polyubiquitination of DDX3X and targeting it for proteasomal degradation.

CONCLUSION

Our studies revealed the key role of endothelial WWP2 and the fundamental importance of the JNK-WWP2-DDX3X regulatory axis in T2DM-induced vascular endothelial injury, suggesting that WWP2 may serve as a new therapeutic target for DVCs.

The Importance of Prediabetes Screening in the Prevention of Cardiovascular Disease

Background

Prediabetes is a disordered state of glucose metabolism defined by an elevated blood glucose level that is below the level required for the diagnosis of diabetes. Prediabetes is associated with an increased risk of cardiovascular disease. The onset and progression of macrovascular disease occur during the prediabetes phase. Early diagnosis and screening of prediabetes are essential steps to prevent diabetes and its associated complications.

Objective

To assess the prevalence of prediabetes and undiagnosed diabetes in patients with cardiovascular disease according to the ADA criteria.

Methods

This cross-sectional study included 2968 a high cardiovascular risk patients aged 40 to 75 years admitted to the Department of Internal Medicine. Sociodemographic variables and other relevant medical history information were collected by the researchers during the clinical interview. A fasting blood sample was obtained to determine HbA1c levels and other relevant laboratory findings.

Results

Of the total number of participants, 1496 participants were not diagnosed with diabetes, 485 (32.4%) of them had HbA1c values indicating prediabetes and 158 (10.6%) of them had HbA1c values indicating new diagnosed diabetes. Up to one-third of those with undiagnosed prediabetes had already been diagnosed with cardiovascular complications.

Conclusion

Routine screening of glycemic metabolism could be valuable in identifying high-risk individuals before a cardiovascular event occurs.

Long noncoding RNA LEENE promotes angiogenesis and ischemic recovery in diabetes models

Impaired angiogenesis in diabetes is a key process contributing to ischemic diseases such as peripheral arterial disease. Epigenetic mechanisms, including those mediated by long noncoding RNAs (lncRNAs), are crucial links connecting diabetes and the related chronic tissue ischemia. Here we identify the lncRNA that enhances endothelial nitric oxide synthase (eNOS) expression (LEENE) as a regulator of angiogenesis and ischemic response. LEENE expression was decreased in diabetic conditions in cultured endothelial cells (ECs), mouse hind limb muscles, and human arteries. Inhibition of LEENE in human microvascular ECs reduced their angiogenic capacity with a dysregulated angiogenic gene program. Diabetic mice deficient in Leene demonstrated impaired angiogenesis and perfusion following hind limb ischemia. Importantly, overexpression of human LEENE rescued the impaired ischemic response in Leene-knockout mice at tissue functional and single-cell transcriptomic levels. Mechanistically, LEENE RNA promoted transcription of proangiogenic genes in ECs, such as KDR (encoding VEGFR2) and NOS3 (encoding eNOS), potentially by interacting with LEO1, a key component of the RNA polymerase II-associated factor complex and MYC, a crucial transcription factor for angiogenesis. Taken together, our findings demonstrate an essential role for LEENE in the regulation of angiogenesis and tissue perfusion. Functional enhancement of LEENE to restore angiogenesis for tissue repair and regeneration may represent a potential strategy to tackle ischemic vascular diseases.

Association between arterial stiffness/remodeling and new-onset type 2 diabetes mellitus in general population

OBJECTIVE

We studied if large artery stiffness is involved in type 2 diabetes pathogenesis. We also investigated the effect of genetic risk for type 2 diabetes in these associations and the causality.

RESEARCH DESIGN AND METHODS

In the prospective population-based Rotterdam Study (n = 3,055; mean age, 67.2 years), markers of aortic and carotid stiffnesses and measures of arterial remodeling were assessed. Cox proportional hazard regression analysis estimated the associations between arterial stiffness measures with incident type 2 diabetes. We used 403 single nucleotide polymorphisms to calculate the genetic risk score (GRS) for type 2 diabetes. We adopted Mendelian randomization (MR) analysis to evaluate the causal associations.

RESULTS

Over a median follow-up of 14.0 years, higher carotid-femoral pulse wave velocity (hazard ratio,1.18; 95 %CI: 1.04-1.35), carotid distensibility coefficient (1.17; 1.04-1.32), and carotid intima-media thickness (1.15; 1.01-1.32) were independently associated with incident diabetes. The associations were stronger among individuals with a higher GRS for type 2 diabetes. MR analysis did not support the causality of the observed associations.

CONCLUSIONS

Elevated arterial stiffness is independently associated with incident type 2 diabetes. For most arterial stiffness markers, the associations with incident type 2 diabetes were more robust in individuals with a higher GRS for diabetes.

Endothelial cell-specific mineralocorticoid receptor activation promotes diastolic dysfunction in diet-induced obese male mice

Widespread consumption of diets high in fat and fructose (Western diet, WD) has led to increased prevalence of obesity and diastolic dysfunction (DD). DD is a prominent feature of heart failure with preserved ejection fraction (HFpEF). However, the underlying mechanisms of DD are poorly understood, and treatment options are still limited. We have previously shown that deletion of the cell-specific mineralocorticoid receptor in endothelial cells (ECMR) abrogates DD induced by WD feeding in female mice. However, the specific role of ECMR activation in the pathogenesis of DD in male mice has not been clarified. Therefore, we fed 4-wk-old ECMR knockout (ECMRKO) male mice and littermates (LM) with either a WD or chow diet (CD) for 16 wk. WD feeding resulted in DD characterized by increased left ventricle (LV) filling pressure (E/e') and diastolic stiffness [E/e'/LV inner diameter at end diastole (LVIDd)]. Compared with CD, WD in LM resulted in increased myocardial macrophage infiltration, oxidative stress, and increased myocardial phosphorylation of Akt, in concert with decreased phospholamban phosphorylation. WD also resulted in focal cardiomyocyte remodeling, characterized by areas of sarcomeric disorganization, loss of mitochondrial electron density, and mitochondrial fragmentation. Conversely, WD-induced DD and associated biochemical and structural abnormalities were prevented by ECMR deletion. In contrast with our previously reported observations in females, WD-fed male mice exhibited enhanced Akt signaling and a lower magnitude of cardiac injury. Collectively, our data support a critical role for ECMR in obesity-induced DD and suggest critical mechanistic differences in the genesis of DD between males and females.

Macro- and microhemodynamic disorders as cardiovascular risk factors in overweight young people

Obesity is associated with a high risk of cardiovascular diseases. Therefore, an urgent task of preventive medicine is to search for markers indicating the early development of cardiovascular pathology in young people in order to develop preventive measures.The aim of the study. To study macro- and microhemodynamics in young people with normal and elevated body mass index (BMI).Methods. After receiving informed consent, we evaluated microhemodynamics using Doppler ultrasound (Angiodin-PC (BIOSS, Russia); 16 MHz sensor) and macrohemodynamics by daily blood pressure monitoring (MnSDP-3 (BPLab, Peter Telegin LLC, Russia)) in students (20.05 ± 1.46 years old) who did not play sports in the period from 2019 to 2021. The subjects were divided into 2 groups according to their BMI: group 1 (control) – BMI ≤ 25 (average age 20.5 ± 0.7 years; average weight 59.47 ± 8.26 kg); group 2 – BMI ≥ 25 (average age 20.12 ± 1.73 years; average weight 83.8 ± 9.59 kg).Results. It has been proven that already at a young age, an increased BMI adversely affects the elasticity of the vascular wall. We registered a statistically significant increase in the peripheral resistance index (RI; Purcello index) (p = 0.022,) and the Stewart index (SD) (p = 0.0034) which are reflecting vascular wall remodeling. There is also a statistically significant increase in average blood pressure per day, day/night against the background of increased BMI. An insufficient degree of nocturnal decrease in systolic blood pressure is revealed, as well as an increase in pressure load and blood pressure variability.Conclusion. Since changes in the structure and function of the vessels of the microcirculatory bed are a precursor to preclinical disorders of systemic blood flow, the introduction of high-frequency Doppler ultrasound into the protocol of examination of people having metabolic syndrome will allow us to assess the functional status of large and small arteries and to identify early vascular disorders.

Early Retinal Microvasculopathy in Prediabetic Patients and Correlated Factors

INTRODUCTION

We aimed to detect early retinal microcirculation changes in prediabetic patients and investigate their correlation with clinical examinations.

METHODS

Forty-seven prediabetic individuals, 29 controls, and 81 type 2 diabetic mellitus (T2DM) patients were enrolled in this study. A review of clinical data and spectral-domain optical coherence tomography angiography (SD-OCTA) parameters of macular vessel diameter (VD), foveal avascular zone (FAZ), and macular vessel area density (VAD) was performed.

RESULTS

Levels of low-density lipoprotein cholesterol and triglycerides in prediabetes and T2DM groups were significantly higher than those in the control group. The urine microalbumin-to-creatinine ratio (ACR) was mildly and moderately increased in the prediabetes and T2DM groups, respectively. The estimated glomerular filtration rate of the three groups was within the normal range. SD-OCTA showed that VAD in the superficial macular area was decreased in the prediabetes group compared to the control group (p = 0.01). The FAZ size, particularly in the deep layer, was expanded in the prediabetes group. In the deep retinal layer of the macular area, VD and FAZ size in the prediabetes group were larger than those in the control group. In the prediabetes group, the axial length was significantly correlated with macular VD and FAZ size (p < 0.05), and ACR was correlated with FAZ size (p < 0.05). Age had a negative correlation with VAD (p < 0.01). ACR had a positive correlation with FAZ size (p < 0.05).

CONCLUSIONS

Enlargement and irregularity of the FAZ area, deep capillary dilation, and a decrease in VAD occur in the retina of prediabetic patients with mild kidney function impairment.

Coronary Microvascular Dysfunction in Diabetes Mellitus: Pathogenetic Mechanisms and Potential Therapeutic Options

Diabetic patients are frequently affected by coronary microvascular dysfunction (CMD), a condition consisting of a combination of altered vasomotion and long-term structural change to coronary arterioles leading to impaired regulation of blood flow in response to changing cardiomyocyte oxygen requirements. The pathogenesis of this microvascular complication is complex and not completely known, involving several alterations among which hyperglycemia and insulin resistance play particularly central roles leading to oxidative stress, inflammatory activation and altered barrier function of endothelium. CMD significantly contributes to cardiac events such as angina or infarction without obstructive coronary artery disease, as well as heart failure, especially the phenotype associated with preserved ejection fraction, which greatly impact cardiovascular (CV) prognosis. To date, no treatments specifically target this vascular damage, but recent experimental studies and some clinical investigations have produced data in favor of potential beneficial effects on coronary micro vessels caused by two classes of glucose-lowering drugs: glucagon-like peptide 1 (GLP-1)-based therapy and inhibitors of sodium-glucose cotransporter-2 (SGLT2). The purpose of this review is to describe pathophysiological mechanisms, clinical manifestations of CMD with particular reference to diabetes, and to summarize the protective effects of antidiabetic drugs on the myocardial microvascular compartment.

Therapeutic Applications of Nanomedicine in Metabolic Diseases by Targeting the Endothelium

The endothelial cells not only constitute the barrier between the blood and interstitial space, but also actively regulate vascular tone, blood flow, and the function of adjacent parenchymal cells. The close anatomical relationship between endothelial cells and highly vascularized metabolic organs suggests that the crosstalk between these units is vital for systemic metabolic homeostasis. Here, we review recent studies about the pivotal role of endothelial cells in metabolic diseases. Specifically, we discuss how the dysfunction of endothelial cells directly contributes to the development of insulin resistance (IR), type 2 diabetes mellitus (T2DM), atherosclerosis, and non-alcoholic fatty liver disease (NAFLD) via communication with parenchymal cells. Furthermore, although many biological macromolecules have been shown to ameliorate the progression of metabolic diseases by improving endothelial function, the low solubility, poor bioavailability, or lack of specificity of these molecules limit their clinical application. Given the advantages in drug delivery of nanomedicine, we focus on summarizing the reports that improving endothelial dysfunction through nanomedicine-based therapies provides an opportunity for preventing metabolic diseases.

Cardiovascular Risk Among Saudi Adults with Prediabetes: A Sub-Cohort Analysis from the Heart Health Promotion (HHP) Study

Background

This study aimed to estimate the prevalence of prediabetes among Saudi adults and to evaluate their risk of developing cardiovascular diseases.

Methods

This is a cohort of 2470 Saudi adults attending employee clinics in the university hospital. WHO-STEPs approach was used to collect sociodemographic (age, gender, and education), clinical (body mass index and blood pressure) and laboratory data (HbA1c, lipid profile and vitamin D concentration). Prediabetes was defined according to HbA1c level of 5.7–6.4%. Cardiovascular risk (CVR) scores were evaluated using the Framingham Risk Score. SPSS was used for data analysis to investigate the relation between different CVR and prediabetes.

Results

Prediabetes affected 25.1% of the study population. Males had higher rates of prediabetes than females (27.5% versus 23.5%). The prevalence of prediabetes increased from 11.6% among young individuals (18–29 years) to 56.0% among participants 60 years and older. Prediabetes patients exhibited considerably higher levels of all cardiovascular risk factors and nearly half of them (49.3%) had at least two risk factors. The prevalence of intermediate CVR among prediabetics was 13.2% compared to just 2.9% among the normal group, and high CVR was defined in 3.7% among prediabetics compared to only 1.7% in the normal group. Having prediabetes increased the odds to develop higher CVR of 2.64 times compared to those without prediabetes (OR = 2.64, 95% CI = 1.51–4.64) and the level of vitamin D did not affect the odds of CVR.

Conclusion

Prediabetes is quite prevalent among Saudi adults, and they are at a higher risk of cardiovascular diseases. Patients with prediabetes have higher cardiac risk scores when compared to normal participants across the whole spectrum of (25(OH)D) concentrations. Additionally, no significant correlation was observed between HbA1c and (25(OH)D) levels in prediabetics or normoglycemic subjects.

Predictive Capacity of Beat-to-Beat Blood Pressure Variability for Cardioautonomic and Vascular Dysfunction in Early Metabolic Challenge

Diabetic patients present established cardiovascular disease at the onset of diagnostic metabolic symptoms. While premature autonomic and vascular deterioration considered risk factors for major cardiovascular complications of diabetes, present in initial stages of metabolic impairment, their early detection remains a significant challenge impeding timely intervention. In the present study, we examine the utility of beat-to-beat blood pressure variability (BPV) parameters in capturing subtle changes in cardiac autonomic and vascular control distinguishing between various risk categories, independent of the average BP. A rat model of mild hypercaloric (HC) intake was used to represent the insidious cardiovascular changes associated with early metabolic impairment. Invasive hemodynamics were used to collect beat-to-beat BP time series in rats of either sex with different durations of exposure to the HC diet. Linear (standard deviation and coefficient of variation) and nonlinear (approximate entropy, ApEn, and self-correlation of detrended fluctuation analysis, α) BPV parameters were calculated to assess the impact of early metabolic impairment across sexes and feeding durations. HC-fed male, but not female, rats developed increased fat:lean ratio as well as hyperinsulinemia. Unlike linear parameters, multivariate analysis showed that HC-fed rats possessed lower ApEn and higher α, consistent with early changes in heart rate variability and blunting of parasympathetic baroreceptor sensitivity, particularly in males. Moreover, logistic regression demonstrated the superiority of nonlinear parameters of diastolic BPV in predicting a prediabetic disease state. Our findings support the use of nonlinear beat-to-beat BPV for early detection of cardiovascular derangements in the initial stages of metabolic impairment.

Retinoic acid inhibits the angiogenesis of human embryonic stem cell-derived endothelial cells by activating FBP1-mediated gluconeogenesis

BACKGROUND

Endothelial cells are located in the inner lumen of blood and lymphatic vessels and exhibit the capacity to form new vessel branches from existing vessels through a process called angiogenesis. This process is energy intensive and tightly regulated. Glycolysis is the main energy source for angiogenesis. Retinoic acid (RA) is an active metabolite of vitamin A and exerts biological effects through its receptor retinoic acid receptor (RAR). In the clinic, RA is used to treat acne vulgaris and acute promyelocytic leukemia. Emerging evidence suggests that RA is involved in the formation of the vasculature; however, its effect on endothelial cell angiogenesis and metabolism is unclear.

METHODS

Our study was designed to clarify the abovementioned effect with human embryonic stem cell-derived endothelial cells (hESC-ECs) employed as a cell model.

RESULTS

We found that RA inhibits angiogenesis, as manifested by decreased proliferation, migration and sprouting activity. RNA sequencing revealed general suppression of glycometabolism in hESC-ECs in response to RA, consistent with the decreased glycolytic activity and glucose uptake. After screening glycometabolism-related genes, we found that fructose-1,6-bisphosphatase 1 (FBP1), a key rate-limiting enzyme in gluconeogenesis, was significantly upregulated after RA treatment. After silencing or pharmacological inhibition of FBP1 in hESC-ECs, the capacity for angiogenesis was enhanced, and the inhibitory effect of RA was reversed. ChIP-PCR demonstrated that FBP1 is a target gene of RAR. When hESC-ECs were treated with the RAR inhibitor BMS493, FBP1 expression was decreased and the effect of RA on angiogenesis was partially blocked.

CONCLUSIONS

The inhibitory role of RA in glycometabolism and angiogenesis is RAR/FBP1 dependent, and FBP1 may be a novel therapeutic target for pathological angiogenesis.

Long-term risks for cardiovascular disease and mortality across the glycaemic spectrum in a male-predominant Chinese cohort aged 75 years or older: the Kailuan study

BACKGROUND

Ageing and diabetes are growing global health burdens. The current understanding of cardiovascular disease (CVD) and mortality risk across the glycaemic spectrum in older populations is limited.

OBJECTIVES

This study sought to characterise CVD and all-cause mortality risk across the glycaemic spectrum among Chinese adults aged 75 years or older in a community-based setting over10 years.

METHODS

The 3,989 adults in the Kailuan Study were aged over 75 years (median age was 79 years [interquartile range: 76-82]; 2,785 normoglycaemic, 691 prediabetic and 513 diabetic, determined by fasting blood glucose levels) at baseline, predominantly male (92.9% male) and followed until December 2019. Time-varying Cox regression and competing-risk models were used to examine the hazard ratio (HR) of incident CVD and mortality across the glycaemic exposures.

RESULTS

During median follow-up of 11.3 years, 433 first CVD and 2,222 deaths were recorded. Compared with normoglycaemia, multivariable-adjusted models revealed the following: (i) prediabetes was not associated with future risks for CVD (HR: 1.17; 95% CI 0.82-1.69) and all-cause mortality (HR 1.06; 95% CI 0.70-1.60); (ii) diabetes-associated enhanced risks for CVD and all-cause mortality were mainly confined to those exhibiting low-grade inflammation (high-sensitivity C-reactive protein ≥2.0 mg/L) levels. The results were consistent after multiple sensitivity analyses.

CONCLUSIONS

Among a male-predominant Chinese population aged 75 years or older, compared with normoglycaemic participants, prediabetes was not associated with an enhanced 10-year CVD and all-cause mortality risk, and diabetes-associated enhanced 10-year risk was mainly confined to individuals exhibiting low-grade inflammation.

The Significance of Systemic Immune-Inflammatory Index for Mortality Prediction in Diabetic Patients Treated with Off-Pump Coronary Artery Bypass Surgery

Diabetes mellitus (DM) represents a complex carbohydrate metabolism disorder characterized by inflammatory over-reactivity. The study aimed to investigate the potential influence of postoperative inflammatory activation on mortality risk after off-pump coronary artery bypass grafting in diabetic patients. There were 510 patients treated with off-pump coronary artery bypass grafting due to stable complex coronary artery disease, including 175 patients with type-2 DM (T2DM.) The mean follow-up time was 3.7 +/− 1.5 years with a 9% all-cause mortality rate in the diabetic group. In multivariable analysis, preoperative comorbidities (stroke, peripheral artery disease, postoperative systemic inflammatory index >952, and postoperative left ventricle ejection fraction (LVEF) < 45%) were revealed as prognostic factors. The receiver operator characteristics curve analysis for postoperative calculations of systemic immune-inflammatory index (SII) appeared significant (AUC = 0.698, p = 0.008), yielding sensitivity of 68.75% and specificity of 71.07%. Systemic immune-inflammatory index (SII) can be regarded as a predictive marker for long-term prognosis in diabetic patients after off-pump coronary artery bypass grafting. The role of perioperative inflammatory activation may play a crucial role in mortality prediction.

Old and Novel Therapeutic Approaches in the Management of Hyperglycemia, an Important Risk Factor for Atherosclerosis

Hyperglycemia is considered one of the main risk factors for atherosclerosis, since high glucose levels trigger multiple pathological processes, such as oxidative stress and hyperproduction of pro-inflammatory mediators, leading to endothelial dysfunction. In this context, recently approved drugs, such as glucagon-like-peptide-1 receptor agonists (GLP-1RAs) and sodium-glucose cotransporter-2 inhibitors (SGLT2i), could be considered a powerful tool for to reduce glucose concentration and cardiovascular risk. Interestingly, many patients with type 2 diabetes mellitus (T2DM) and insulin resistance have been found to be deficient in vitamin D. Recent studies pointed out the unfavorable prognostic values of T2DM and vitamin D deficiency in patients with cardiac dysfunction, either when considered individually or together, which shed light on the role of vitamin D in general health status. New evidence suggests that SGLT2i could adversely affect the production of vitamin D, thereby increasing the risk of fractures, which are common in patients with T2DM. Therefore, given the biological effects of vitamin D as an anti-inflammatory mediator and a regulator of endothelial function and calcium equilibrium, these new findings should be taken into consideration as well. The aim of this review is to gather the latest advancements regarding the use of antidiabetic and antiplatelet drugs coupled with vitamin D supplementation to control glucose levels, therefore reducing the risk of coronary artery disease (CAD).

The Triglyceride Glucose Index Is a Risk Factor for Enlarged Perivascular Space

The triglyceride glucose (TyG) index is considered a simple surrogate marker for insulin resistance and has been associated with cerebrovascular diseases. However, limited information is available regarding its association with the subclinical cerebral small vessel disease (CSVD). Here, we investigated the association of TyG index with the burden and distribution of enlarged perivascular space (EPVS) in the non-diabetic population. The data of 531 non-diabetic patients from 2017 to 2020 were assessed. Participants were grouped according to the burden of EPVS. TyG index was calculated using the log scale of fasting triglycerides (mg/dl) × fasting glucose (mg/dl)/2. The association of TyG index with EPVS burden and distribution was evaluated. In the multivariable logistic regression analysis, the TyG index was associated with moderate to severe EPVS [odds ratio (OR): 2.077; 95% CI = 1.268–3.403]. The TyG index was significantly associated with an increased risk of moderate to severe EPVS in subgroups of age <65 years, male, diastolic blood pressure (DBP) <90 mmHg, low-density lipoprotein cholesterol (LDL-C) ≥2.85 mmol/L, serum homocysteine <10 μmol/L, and estimated glomerular filtration rate (eGFR) <90 ml/min/1.73 m², as well as those without smoking. Further analysis of EPVS distribution, the TyG index was found to be associated with moderate to severe EPVS in the centrum semiovale (CSO), not in the basal ganglia (BG). Conclusively, the TyG index was independently and positively associated with moderate to severe CSO EPVS. TyG index may serve as an independent risk factor for CSVD in clinical practice.

Glucose Uptake by Skeletal Muscle within the Contexts of Type 2 Diabetes and Exercise: An Integrated Approach

Type 2 diabetes continues to negatively impact the health of millions. The inability to respond to insulin to clear blood glucose (insulin resistance) is a key pathogenic driver of the disease. Skeletal muscle is the primary tissue for maintaining glucose homeostasis through glucose uptake via insulin-dependent and -independent mechanisms. Skeletal muscle is also responsive to exercise-meditated glucose transport, and as such, exercise is a cornerstone for glucose management in people with type 2 diabetes. Skeletal muscle glucose uptake requires a concert of events. First, the glucose-rich blood must be transported to the skeletal muscle. Next, the glucose must traverse the endothelium, extracellular matrix, and skeletal muscle membrane. Lastly, intracellular metabolic processes must be activated to maintain the diffusion gradient to facilitate glucose transport into the cell. This review aims to examine the physiology at each of these steps in healthy individuals, analyze the dysregulation affecting these pathways associated with type 2 diabetes, and describe the mechanisms by which exercise acts to increase glucose uptake.

Skeletal Muscle Microvascular Dysfunction in Obesity-Related Insulin Resistance: Pathophysiological Mechanisms and Therapeutic Perspectives

Obesity is a worrisomely escalating public health problem globally and one of the leading causes of morbidity and mortality from noncommunicable disease. The epidemiological link between obesity and a broad spectrum of cardiometabolic disorders has been well documented; however, the underlying pathophysiological mechanisms are only partially understood, and effective treatment options remain scarce. Given its critical role in glucose metabolism, skeletal muscle has increasingly become a focus of attention in understanding the mechanisms of impaired insulin function in obesity and the associated metabolic sequelae. We examined the current evidence on the relationship between microvascular dysfunction and insulin resistance in obesity. A growing body of evidence suggest an intimate and reciprocal relationship between skeletal muscle microvascular and glucometabolic physiology. The obesity phenotype is characterized by structural and functional changes in the skeletal muscle microcirculation which contribute to insulin dysfunction and disturbed glucose homeostasis. Several interconnected etiologic molecular mechanisms have been suggested, including endothelial dysfunction by several factors, extracellular matrix remodelling, and induction of oxidative stress and the immunoinflammatory phenotype. We further correlated currently available pharmacological agents that have deductive therapeutic relevance to the explored pathophysiological mechanisms, highlighting a potential clinical perspective in obesity treatment.

Lycopene ameliorates skin aging by regulating the insulin resistance pathway and activating SIRT1

Lycopene could reverse insulin resistance through SIRT1 during skin aging and promotes microcirculation via the improvement of microvascular neovascularization to protect aging skin.

Association of Impaired Fasting Blood Glucose With Triple Coronary Artery Stenosis and Myocardial Infarction Among Patients With Coronary Artery Stenosis

Background: The association between impaired fasting glucose level (IFG) and coronary heart disease (CAD) remain controversial. In the present study, we sought to ascertain a relationship of IFG with the number of diseased coronary artery and occurrence of myocardial infarction, among CAD cases. Methods: We studied 1,451 consecutive no-diabetic patients who underwent coronary angiography at the First Affiliated Hospital of Shantou University Medical College in Southern China. Demographic, biochemical, clinical and angiographic data were collected. Results: The prevalence of IFG was higher in patients with angiographically confirmed CAD than in subjects without angiographic evidence of CAD (33.4 versus 28.2%, p = 0.034). Compared with CAD cases without IFG, CAD cases with IFG had a higher odds ratio (OR) of having triple-vessel disease as opposed to having single- or double-vessel disease [OR = 1.53, 95% confidence interval (CI) = 1.13-2.07]. Furthermore, the occurrence of MI was higher in CAD cases with IFG than in CAD cases without IFG (OR = 1.73, 95% CI = 1.27-2.36). Conclusions: There is an association between IFG and a predisposition to severe CAD indicated by triple vessel disease or myocardial infarction.

Community intervention study of viscera massage in overweight/obese type 2 diabetes high-risk population

BACKGROUND

Prediabetes is an intermediate metabolic state between normoglycemia and diabetes. Without intervention, prediabetes often progresses to diabetes and prediabetes is associated with increased risk of cardiovascular disease, cancer, renal disease, and dementia. Lifestyle modification play a major role in controlling prediabetes. But lifestyle interventions are often with poor compliance and side effects of drugs are often be dislike by people. As a non-invasive therapy with no side effects, abdominal massage (AM), also called viscera massage in China, has been used to treat prediabetes and obesity-associated diseases. The gut microbiota has been recognized as an important factor in the development of metabolic diseases. Individuals with prediabetes have aberrant intestinal microbiota character. Colonic transport time and stool consistency are strongly associated with gut microbiota. Viscera massage can ease constipation by reducing colonic transport time and promoting intestinal motility. We can infer that viscera massage can modulate composition of gut microbiota affects human metabolism. So, in this trial, we will explore the mechanism of viscera massage on prediabetes from the perspective of intestinal microbiota.

METHODS AND DESIGN

Eighty prediabetes individuals will be recruited for this study. Eighty prediabetes individuals will be divided into lifestyle intervention group and viscera massage + lifestyle intervention group by a simple random method. Each group will have 40 individuals. The manipulation of the viscera massage + lifestyle intervention group will be mainly carried out through rubbing the abdomen, kneading abdomen, vibrating abdomen, and pressing the abdomen, 30 minutes per time, once a day, with 2 days off every 5 days. Lifestyle interventions will be performed by combining pushing healthy lifestyle guidance information through Wechat application and giving face-to-face advice together daily. The lifestyle intervention group will receive healthy lifestyle intervention only. All the intervention will be conducted for 4 weeks. Weight, body mass index (BMI), waist circumference, waist-to-hip ratio, and waist-to-height ratio will be measured at the last day of every week. Triglycerides, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, fasting blood-glucose, 2-hour post-meal blood glucose (2hPG) and glycosylated hemoglobin, fasting insulin and insulin resistance index will be tested at the first day and last day of the intervention course. The fecal samples of subjects will be gathered at the first day and last day of the intervention course and will be performed 16S rRNA gene sequencing and metagenomic detection. Finally, the effect and potential mechanism of viscera massage on prediabetes will be discussed in combination with all the results.

DISCUSSION

The results of this study will be used to verify the effect of AM on prediabetes and explore the mechanism of AM on prediabetes from the perspective of gut microbiota.

Rivaroxaban compared with low-dose aspirin in individuals with type 2 diabetes and high cardiovascular risk: a randomised trial to assess effects on endothelial function, platelet activation and vascular biomarkers

AIMS/HYPOTHESIS

Individuals with type 2 diabetes mellitus and subclinical inflammation have stimulated coagulation, activated platelets and endothelial dysfunction. Recent studies with the direct factor Xa inhibitor rivaroxaban in combination with low-dose aspirin demonstrated a significant reduction of major cardiovascular events, especially in individuals with type 2 diabetes and proven cardiovascular disease. Therefore, we asked the question of whether treatment with rivaroxaban could influence endothelial function, arterial stiffness and platelet activation.

METHODS

We conducted a multi-centre, prospective, randomised, open-label trial in 179 participants with type 2 diabetes (duration 2-20 years), subclinical inflammation (high-sensitivity C-reactive protein 2-10 mg/l) and at least two traits of the metabolic syndrome to compare the effects of the direct factor Xa inhibitor rivaroxaban (5 mg twice daily) vs aspirin (100 mg every day) on endothelial function (assessed by forearm occlusion plethysmography), skin blood flow (assessed by laser-Doppler fluxmetry), arterial stiffness (assessed by pulse wave velocity) and serum biomarkers of endothelial function and inflammation. Furthermore, we investigated phosphorylation of vasodilator-stimulated phosphoprotein (VASP) in platelets, the concentration of platelet-derived microparticles (PMPs) and the effects of isolated PMPs on HUVEC proliferation in vitro.

RESULTS

Rivaroxaban treatment for 20 weeks (n = 89) resulted in a significant improvement of post-ischaemic forearm blood flow (3.6 ± 4.7 vs 1.0 ± 5.2 ml/100 ml, p = 0.004), a numerically increased skin blood flow and reduced soluble P-Selectin plasma level vs aspirin. We did not find significant differences of arterial stiffness or further biomarkers. Neither rivaroxaban nor aspirin influenced VASP phosphorylation of platelets. The number of PMPs increased significantly with both rivaroxaban (365.2 ± 372.1 vs 237.4 ± 157.1 μl^-1, p = 0.005) and aspirin (266.0 ± 212.7 vs 201.7 ± 162.7 μl^-1, p = 0.021). PMPs of rivaroxaban-treated participants stimulated HUVEC proliferation in vitro compared with aspirin. Rivaroxaban was associated with a higher number of bleeding events.

CONCLUSIONS/INTERPRETATION

Our findings indicate that the direct factor Xa inhibitor rivaroxaban improved endothelial function in participants with type 2 diabetes and subclinical inflammation but also increased the risk of bleeding.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02164578.

FUNDING

The study was supported by a research grant from Bayer Vital AG, Germany.

Association between diabetes status and subsequent onset of glaucoma in postmenopausal women

The purpose of this study was to analyze the risk of glaucoma based on diabetes status using a large nationwide longitudinal cohort of postmenopausal women. This study included 1,372,240 postmenopausal women aged ≥ 40 years who underwent National Health Screening Program in 2009. Subjects were classified into the following 5 categories based on diabetes status: no diabetes, impaired fasting glucose (IFG), new onset diabetes, diabetes treated with oral hypoglycemic medication, and diabetes treated with insulin. Subjects were followed from 2005 through 2018, and hazard ratios of glaucoma onset were calculated for each group. Subgroup analyses of subjects stratified by age, smoking, drinking, hypertension, and dyslipidemia were performed. During the follow up period, 42,058 subjects developed glaucoma. The adjusted hazard ratio was 1.061 (95% CI, 1.036–1.086) in the IFG group, 1.151 (95% CI, 1.086–1.220) in the new onset diabetes group, 1.449 (95% CI, 1.406–1.493) in the diabetes treated with oral hypoglycemic medication group, and 1.884(95% CI, 1.777–1.999) in the diabetes treated with insulin group compared to the no diabetes group. The results were consistent in subgroup analyses after stratifying by age, lifestyle factors (smoking and drinking), and comorbidities (hypertension and dyslipidemia). Diabetes status is associated with increased risk of glaucoma development in postmenopausal women.

Male and Female Rats Have Different Physiological Response to High-Fat High-Sucrose Diet but Similar Myocardial Sensitivity to Ischemia-Reperfusion Injury

Prediabetes is a strong predictor of type 2 diabetes and its associated cardiovascular complications, but few studies explore sexual dimorphism in this context. Here, we aim to determine whether sex influences physiological response to high-fat high-sucrose diet (HFS) and myocardial tolerance to ischemia-reperfusion injury. Male and female Wistar rats were subjected to standard (CTRL) or HFS diet for 5 months. Then, ex-vivo experiments on isolated perfused heart model were performed to evaluate tolerance to ischemia-reperfusion injury. HFS diet induced fasting hyperglycemia and increased body fat percent to a similar level in both sexes. However, glucose intolerance was more pronounced in female HFS. Cholesterol was increased only in female while male displayed higher level of plasmatic leptin. We observed increased heart weight to tibia length ratio only in males, but we showed a similar decrease in tolerance to ischemia-reperfusion injury in female and male HFS compared with respective controls, characterized by impaired cardiac function, energy metabolism and coronary flow during reperfusion. In conclusion, as soon as glucose intolerance and hyperglycemia develop, we observe higher sensitivity of hearts to ischemia-reperfusion injury without difference between males and females.

LDL-Cholesterol versus Glucose in Microvascular and Macrovascular Disease

BACKGROUND

The causal relationships between increased concentrations of low density lipoprotein (LDL)-cholesterol and glucose and risk of ischemic heart disease are well established. The causal contributions of LDL-cholesterol and glucose to risk of peripheral micro- and macrovascular diseases are less studied, especially in prediabetic stages and in a general population setting.

CONTENT

This review summarizes the current evidence for a causal contribution of LDL-cholesterol and glucose to risk of a spectrum of peripheral micro- and macrovascular diseases and reviews possible underlying disease mechanisms, including differences between vascular compartments, and finally discusses the clinical implications of these findings, including strategies for prevention and treatment.

SUMMARY

Combined lines of evidence suggest that LDL-cholesterol has a causal effect on risk of peripheral arterial disease and chronic kidney disease, both of which represent manifestations of macrovascular disease due to atherosclerosis and accumulation of LDL particles in the arterial wall. In contrast, there is limited evidence for a causal effect on risk of microvascular disease. Glucose has a causal effect on risk of both micro- and macrovascular disease. However, most evidence is derived from studies of individuals with diabetes. Further studies in normoglycemic and prediabetic individuals are warranted. Overall, LDL-cholesterol-lowering reduces risk of macrovascular disease, while evidence for a reduction in risk of microvascular disease is inconsistent. Glucose-lowering has a beneficial effect on risk of microvascular diseases and on risk of chronic kidney disease and estimated glomerular filtration rate (eGFR) in some studies, while results on risk of peripheral arterial disease are conflicting.

Dynorphins in Development and Disease: Implications for Cardiovascular Disease

It is well-established that cardiovascular disease continues to represent a growing health problem and significant effort has been made to elucidate the underlying mechanisms. In this review, we report on past and recent high impact publications in the field of intracrine network signaling, focusing specifically on opioids and their interrelation with key modulators of the cardiovascular system and the onset of related disease. We present an overview of studies outlining the scope of cardiovascular and cerebrovascular processes that are affected by opioids, including heart function, ischemia, reperfusion, and blood flow. Specific emphasis is placed on the importance of dynorphin molecules in cerebrovascular and cardiovascular regulation. Evidence suggests that excessive or insufficient dynorphin could make an important contribution to cardiovascular physiology, yet numerous paradoxical observations frequently impede a clear understanding of the role of dynorphin. Thus, we argue that dynorphin-mediated signaling events for which an immediate regulatory effect is disputed should not be dismissed as unimportant, as they may play a role in cross-talk with other signaling networks. Finally, we consider the most recent evidence on the role of dynorphin during cardiovascular-related inflammation and on the potential value of endogenous and exogenous inhibitors of kappa-opioid receptor, a major dynorphin A receptor, to limit or prevent cardiovascular disease and its related sequelae.

PM2.5 promotes β cell damage by increasing inflammatory factors in mice with streptozotocin

Emerging evidence indicates that exposure to fine particulate matter contributes to the onset of diabetes. The present study aimed to investigate the mechanism of particulate matters (PM)_2.5 affecting glucose homeostasis in mice with type 1 diabetes mellitus. Male C57BL/6 mice were housed under filtered air (FA) or PM_2.5 for 12 weeks and then received intraperitoneal injection of streptozotocin (STZ; 40 mg/kg) or acetic buffer daily for 5 days. At 4 weeks after the last injection, fasting glucose was tested. In the plasma and liver, cholesterol levels were determined by cholesterol oxidase-peroxidase and triglyceride levels were determined by triglycerophosphate oxidase-peroxidase. Homeostasis model assessment of β cell function (Homa-β) was computed based on fasting insulin and glucose levels. Interleukin-1β (IL-1β) and tumor necrosis factor-α (TNFα) levels in plasma, visceral adipose tissues, RAW264.7 macrophages and MIN6 pancreatic β cells treated with PM_2.5 (0-50 µg/ml) were quantified via ELISA. Before STZ injection, fasting blood glucose (FBG) levels were similar between FA and PM_2.5 groups. After STZ injection, FBG levels were higher in mice pre-exposed to PM_2.5 compared with those pre-exposed to FA. When taking FBG levels ≥7 mmol/l as the criteria for impaired glucose level, its incidence was 53.3% and 77.8% in FA and PM_2.5 groups, respectively. Independent of STZ injection, IL-1β levels in the adipose tissue were upregulated in mice pre-exposed to PM_2.5 compared with FA. The addition of PM_2.5 stimulated IL-1β and TNFα production in macrophages and pancreatic β cells, and inhibited the secretion of insulin from MIN6 cells in a dose-dependent manner. In conclusion, pre-exposure of PM_2.5 impaired pancreatic β cells in mice upon STZ injection, partially via enhanced inflammation, and suppressed the secretion of insulin.

Effect of short duration moderate intensity physical activity on glycemic control and antioxidant status of prediabetic population

OBJECTIVES

To determine the effect of moderate-intensity physical activity on glycemic control and antioxidant status in the prediabetic population.

METHODS

This experimental study was carried out in the Physiology Department, Institute of Basic Medical Sciences, Khyber Medical University, Peshawar, Pakistan. A total of 50 adult prediabetic subjects having 22 females and 28 males with the age range of 18 to 35 years were included. Diagnosis of prediabetes was made by glycated hemoglobin falling in the range of 5.7-6.4%, and impaired fasting glucose (100-125 mg/dL). Anthropometric measurements and biochemical assays were carried out at pre and post-exercise intervention. The participants performed moderate exercise of 30 min with heart rate max 7% ± 5% for 5 days a week for 8 weeks, monitored with pedometer. Enzyme-linked immunosorbent assay was carried out for individual and total antioxidants.

RESULTS

Anthropometric parameters showed a significant decrease at post-exercise analysis. Similar changes were observed for fasting glucose (p<0.001) and glycated hemoglobin (p<0.001). Slight increase in uric acid (p<0.005) and total antioxidant concentration (p<0.001) were found. However, superoxide dismutase, glutathione peroxidase, vitamin C, and nitric oxide decreased (p<0.001).

CONCLUSION

Moderate physical activity for 8 weeks significantly reduced the individual antioxidant levels, nominal increase in total antioxidant capacity and uric acid, and there was an explicit decline in the anthropometric and diabetic profile of prediabetic population.

Metformin has no impact on nitric oxide production in patients with pre-diabetes

AIMS/INTRODUCTION

The authors evaluated the impact of different dose of metformin on NO (nitric oxide) production in subjects with pre-diabetes.

MATERIALS AND METHODS

The metformin-naïve patients from one Diabetic Center with newly diagnosed pre-diabetes, without cardio-vascular diseases, were randomized (based on the identification number, individual for each inhabitant in the country) for treatment with different doses of metformin (group A 3 × 500 mg, group B 3 × 1000 mg) for 12 weeks. Then, the subjects from group B were switched to dose 3 × 500 for the last 3 weeks. The wide panel of L-arginine/NO pathway metabolites concentrations was assessed using the liquid chromatography-mass spectrometry technique.

RESULTS

Between October 2017 and December 2018, 36 individuals were initially randomized to intervention groups. The study was completed with 25 subjects: 14 patients in group A, 11 in group B; also 11 healthy volunteers were recruited. There was no difference between participants with pre-diabetes and healthy volunteers as regards the baseline characteristics except for fasting glucose and fatty liver. The decrease of L-citrulline concentration only was reported for treatment groups during the intervention period, with no change for the other NO-production related substances.

CONCLUSION

It was the first study on the in vivo release of NO in humans with different metformin doses in patients with pre-diabetes. Metformin did not seem to increase NO production measured by the citrulline plasma levels, irrespective of the dose. The citrulline concentration change might indicate the drug impact on the condition of the enterocytes.

Association of Flow Parameters and Diameter in the Common Carotid Artery with Impaired Glucose Metabolism

AIM

Diameter, intima-media thickness (IMT), and flow parameters, including resistance index (RI) and pulsatility index (PI), in the common carotid artery (CCA) are markers of arterial remodeling, atherosclerosis, and vascular resistance, respectively. We investigated the differences among these markers in association with plasma glucose level, serum insulin level, and insulin resistance in participants without cardiovascular disease.

METHODS

CCA parameters (including the CCA interadventitial diameter and mean IMT at the time of 75-g oral glucose tolerance testing) were assessed in 4218 participants. RI and PI were assessed in 3380 of these participants. To assess plasma glucose and serum immunoreactive insulin profiles during oral glucose tolerance testing, we used the total areas under the curves (AUCglu and AUCins, respectively). We used the homeostasis model assessment of insulin resistance (HOMA-IR) and the Matsuda index to assess insulin resistance. Insulin secretion was assessed with the HOMA-β.

RESULTS

AUCglu was significantly associated with CCA interadventitial diameter (β=0.048, P＜0.001), RI (β=0.144, P＜0.001), and PI (β=0.103, P＜0.001) but not with mean IMT. AUCins (β=-0.064, P＜0.001) and HOMA-β (β=-0.054, P＜0.001) were significantly and negatively associated with CCA interadventitial diameter, but not with mean IMT. Both HOMA-IR and Matsuda index were significantly associated with RI and PI.

CONCLUSIONS

These findings indicate that all CCA parameters except IMT are associated with impaired glucose metabolism in patients without cardiovascular disease.

Heterogeneity in insulin-stimulated glucose uptake among different muscle groups in healthy lean people and people with obesity

AIMS/HYPOTHESIS

It has been proposed that muscle fibre type composition and perfusion are key determinants of insulin-stimulated muscle glucose uptake, and alterations in muscle fibre type composition and perfusion contribute to muscle, and consequently whole-body, insulin resistance in people with obesity. The goal of the study was to evaluate the relationships among muscle fibre type composition, perfusion and insulin-stimulated glucose uptake rates in healthy, lean people and people with obesity.

METHODS

We measured insulin-stimulated whole-body glucose disposal and glucose uptake and perfusion rates in five major muscle groups (erector spinae, obliques, rectus abdominis, hamstrings, quadriceps) in 15 healthy lean people and 37 people with obesity by using the hyperinsulinaemic-euglycaemic clamp procedure in conjunction with [²H]glucose tracer infusion (to assess whole-body glucose disposal) and positron emission tomography after injections of [¹⁵O]H₂O (to assess muscle perfusion) and [¹⁸F]fluorodeoxyglucose (to assess muscle glucose uptake). A biopsy from the vastus lateralis was obtained to assess fibre type composition.

RESULTS

We found: (1) a twofold difference in glucose uptake rates among muscles in both the lean and obese groups (rectus abdominis: 67 [51, 78] and 32 [21, 55] μmol kg^-1 min^-1 in the lean and obese groups, respectively; erector spinae: 134 [103, 160] and 66 [24, 129] μmol kg^-1 min^-1, respectively; median [IQR]) that was unrelated to perfusion or fibre type composition (assessed in the vastus only); (2) the impairment in insulin action in the obese compared with the lean group was not different among muscle groups; and (3) insulin-stimulated whole-body glucose disposal expressed per kg fat-free mass was linearly related with muscle glucose uptake rate (r² = 0.65, p < 0.05).

CONCLUSIONS/INTERPRETATION

Obesity-associated insulin resistance is generalised across all major muscles, and is not caused by alterations in muscle fibre type composition or perfusion. In addition, insulin-stimulated whole-body glucose disposal relative to fat-free mass provides a reliable index of muscle glucose uptake rate.

Peri-renal adipose inflammation contributes to renal dysfunction in a non-obese prediabetic rat model: Role of anti-diabetic drugs

Diabetic nephropathy is a major health challenge with considerable economic burden and significant impact on patients' quality of life. Despite recent advances in diabetic patient care, current clinical practice guidelines fall short of halting the progression of diabetic nephropathy to end-stage renal disease. Moreover, prior literature reported manifestations of renal dysfunction in early stages of metabolic impairment prior to the development of hyperglycemia indicating the involvement of alternative pathological mechanisms apart from those typically triggered by high blood glucose. Here, we extend our prior research work implicating localized inflammation in specific adipose depots in initiating cardiovascular dysfunction in early stages of metabolic impairment. Non-obese prediabetic rats showed elevated glomerular filtration rates and mild proteinuria in absence of hyperglycemia, hypertension, and signs of systemic inflammation. Isolated perfused kidneys from these rats showed impaired renovascular endothelial feedback in response to vasopressors and increased flow. While endothelium dependent dilation remained functional, renovascular relaxation in prediabetic rats was not mediated by nitric oxide and prostaglandins as in control tissues, but rather an upregulation of the function of epoxy eicosatrienoic acids was observed. This was coupled with signs of peri-renal adipose tissue (PRAT) inflammation and renal structural damage. A two-week treatment with non-hypoglycemic doses of metformin or pioglitazone, shown previously to ameliorate adipose inflammation, not only reversed PRAT inflammation in prediabetic rats, but also reversed the observed functional, renovascular, and structural renal abnormalities. The present results suggest that peri-renal adipose inflammation triggers renal dysfunction early in the course of metabolic disease.

Thrombospondin 1 in Metabolic Diseases

The thrombospondin family comprises of five multifunctional glycoproteins, whose best-studied member is thrombospondin 1 (TSP1). This matricellular protein is a potent antiangiogenic agent that inhibits endothelial migration and proliferation, and induces endothelial apoptosis. Studies have demonstrated a regulatory role of TSP1 in cell migration and in activation of the latent transforming growth factor beta 1 (TGFβ1). These functions of TSP1 translate into its broad modulation of immune processes. Further, imbalances in immune regulation have been increasingly linked to pathological conditions such as obesity and diabetes mellitus. While most studies in the past have focused on the role of TSP1 in cancer and inflammation, recently published data have revealed new insights about the role of TSP1 in physiological and metabolic disorders. Here, we highlight recent findings that associate TSP1 and its receptors to obesity, diabetes, and cardiovascular diseases. TSP1 regulates nitric oxide, activates latent TGFβ1, and interacts with receptors CD36 and CD47, to play an important role in cell metabolism. Thus, TSP1 and its major receptors may be considered a potential therapeutic target for metabolic diseases.

Integrated pancreatic microcirculatory profiles of streptozotocin-induced and insulin-administrated type 1 diabetes mellitus

OBJECTIVE

As an integrated system, pancreatic microcirculatory disturbance plays a vital role in the pathogenesis of type 1 diabetes mellitus (T1DM), which involves changes in microcirculatory oxygen and microhemodynamics. Therefore, we aimed to release type 1 diabetic and insulin-administrated microcirculatory profiles of the pancreas.

METHODS

BALB/c mice were assigned to control, T1DM, and insulin-administrated groups randomly. T1DM was induced by intraperitoneal injection of streptozotocin (STZ). 1.5 IU insulin was administrated subcutaneously to keep the blood glucose within the normal range. After anesthetizing by isoflurane, the raw data set of pancreatic microcirculation was collected by the multimodal device- and computer algorithm-based microcirculatory evaluating system. After adjusting outliers and normalization, pancreatic microcirculatory oxygen and microhemodynamic data sets were imported into the three-dimensional module and compared.

RESULTS

Microcirculatory profiles of the pancreas in T1DM exhibited a loss of microhemodynamic coherence (significantly decreased microvascular blood perfusion) accompanied by an impaired oxygen balance (significantly decreased PO₂ , SO₂ , and rHb). More importantly, with insulin administration, the pathological microcirculatory profiles were partially restored. Meanwhile, there were correlations between pancreatic microcirculatory blood perfusion and PO₂ levels.

CONCLUSIONS

Our findings establish the first integrated three-dimensional pancreatic microcirculatory profiles of STZ-induced and insulin-administrated T1DM.