Hypoglycemia affects the changes in endothelial progenitor cell levels during insulin therapy in type 2 diabetic patients

The Impact of Modern Anti-Diabetic Treatment on Endothelial Progenitor Cells

Diabetes is one of the leading chronic diseases globally with a significant impact on mortality. This condition is associated with chronic microvascular and macrovascular complications caused by vascular damage. Recently, endothelial progenitor cells (EPCs) raised interest due to their regenerative properties. EPCs are mononuclear cells that are derived from different tissues. Circulating EPCs contribute to regenerating the vessel's intima and restoring vascular function. The ability of EPCs to repair vascular damage depends on their number and functionality. Diabetic patients have a decreased circulating EPC count and impaired EPC function. This may at least partially explain the increased risk of diabetic complications, including the increased cardiovascular risk in these patients. Recent studies have confirmed that many currently available drugs with proven cardiovascular benefits have beneficial effects on EPC count and function. Among these drugs are also medications used to treat different types of diabetes. This manuscript aims to critically review currently available evidence about the ways anti-diabetic treatment affects EPC biology and to provide a broader context considering cardiovascular complications. The therapies that will be discussed include lifestyle adjustments, metformin, sulphonylureas, gut glucosidase inhibitors, thiazolidinediones, dipeptidyl peptidase 4 inhibitors, glucagon-like peptide 1 receptor analogs, sodium-glucose transporter 2 inhibitors, and insulin.

Risk Factors for Albuminuria in Normotensive Older Adults with Type 2 Diabetes Mellitus and Normal Renal Function: A Cross-Sectional Study

INTRODUCTION

Diabetes mellitus (DM) is prevalent in developed and developing countries, including China. However, few studies have examined the potential risk factors for albuminuria in normotensive older adults with type 2 DM and normal renal function.

METHODS

We recruited normotensive older adults (≥ 65 years) with type 2 DM and normal renal function from the First Affiliated Hospital of Soochow University from January to December 2019. We stratified participants according to their urine albumin to creatinine ratio (ACR) into the following groups: normal ACR (ACR1), microalbuminuria (ACR2), and macroalbuminuria (ACR3). Demographic characteristics, anthropometric parameters, and metabolic profiles were recorded. Creatinine clearance (Ccr) and homeostasis model assessment-insulin resistance (HOMA-IR) were calculated. Logistic regression was used to examine risk factors for albuminuria.

RESULTS

A total of 250 older adults were enrolled during the study period, including 124, 82, and 44 with normal albuminuria, microalbuminuria, and macroalbuminuria, respectively. We found that an extended duration of DM (odds ratio [OR] 1.085, 95% confidence interval [CI] 1.012-1.164, P = 0.022), elevated systolic blood pressure (OR 1.049, 95%CI 1.018-1.081, P < 0.01), elevated glycated hemoglobin (OR 1.734, 95% CI 1.332-2.258, P < 0.01), low insulin (OR 0.871, 95% CI 0.804-0.944, P < 0.01), and low C-peptide (OR 0.365, 95% CI 0.239-0.588, P < 0.01) were independent risk factors for albuminuria.

CONCLUSION

Elevated blood pressure, low insulin, low C-peptide, and poor glycemic control were significant risk factors for albuminuria. These parameters may serve as early indicators for intervention.

Effects of glucose variability on hematopoietic stem/progenitor cells in patients with type 1 diabetes

BACKGROUND AND PURPOSE

Diabetes reduces the levels of hematopoietic stem/progenitor cells (HSPCs), which can contribute to organ and tissue homeostasis. Among patients with diabetes, lower HSPC levels predict the development or worsening of micro- and macro-angiopathy. High glucose variability is also associated with diabetic complications and we have previously shown that acute hypoglycaemia can stimulate stem/progenitor cells. Thus, we evaluated the relationship between glucose variability or time in hypoglycaemia and HSPCs in patients with type 1 diabetes (T1D).

METHODS

Patients with T1D were compared to healthy subjects. HSPCs (CD34⁺, CD133⁺, CD34⁺CD133⁺, CD34 + CD45^dim) were quantified by flow cytometry. Using flash glucose monitoring system for 90 days, we calculated several measures of glucose variability and time in hypoglycaemia.

RESULTS

Forty-four patients with T1D and 44 healthy subjects were enrolled. Compared to healthy controls, T1D patients had significantly lower levels of HSPCs and duration of diabetes was inversely correlated with HSPC levels. Significant direct correlations were found between HSPC levels and the coefficient of variation of glucose levels or time in hypoglycaemia, which were stronger in patients with short-term than in those with long-standing diabetes.

CONCLUSION

This study confirms the pauperization of HSPCs in T1D patients and demonstrates a potential HSPC-stimulatory effect of hypoglycaemia, which mitigates with long-lasting diabetes. These data are consistent with a model whereby disease chronicity progressively blunts the release of HSPCs in response to adrenergic triggers, like hypoglycaemic events.

Chaperone-Based Therapeutic Target Innovation: Heat Shock Protein 70 (HSP70) for Type 2 Diabetes Mellitus

Type 2 diabetes mellitus (T2DM) is still a global health problem. Current T2DM treatments are limited to curing the symptoms and have not been able to restore insulin sensitivity in insulin-sensitive tissues that have become resistant. In the past decade, some studies have shown the significant role of a chaperone family, heat shock protein 70 (HSP70), in insulin resistance pathogenesis that leads to T2DM. HSP70 is a cytoprotective molecular chaperone that functions in protein folding and degradation. In general, studies have shown that decreased concentration of HSP70 is able to induce inflammation process through JNK activation, inhibit fatty acid oxidation by mitochondria through mitophagy decrease and mitochondrial biogenesis, as well as activate SREBP-1c, one of the lipogenic gene transcription factors in ER stress. The overall molecular pathways are potentially leading to insulin resistance and T2DM. Increased expression of HSP70 in brain tissues is able to improve insulin sensitivity and glycemic control specifically. HSP70 modulation-targeting strategies (including long-term physical exercise, hot tub therapy (HTT), and administration of alfalfa-derived HSP70 (aHSP70)) in subjects with insulin resistance are proven to have therapeutic and preventive potency that are promising in T2DM management.

All-cause mortality in patients on sulphonylurea monotherapy compared to metformin monotherapy in a nation-wide cohort

BACKGROUND

Type 2 diabetes is associated with increased mortality. There is some data that sulphonylurea therapy may contribute to this.

AIMS

To compare all-cause 3-year mortality of patients on sulphonylurea monotherapy to that of patients on metformin monotherapy after adjusting for potential confounders.

METHODS

We searched the Maltese national electronic database for diabetes treatment in April 2014. This is an electronic database of all treatment that patients are prescribed through the local National Health Service. We identified patients on metformin or sulphonylurea monotherapy and linked this to the national mortality database and the laboratory information system.

RESULTS

There were 25,792 persons who were on treatment for diabetes in April 2014. Of these, 9977 were on metformin monotherapy and 1717 on sulphonylurea monotherapy. This cohort was followed up until April 2017. There were 2518 deaths (9.76%) during this period, giving an average of 32.5 deaths per 1000 persons with diabetes. Logistic regression showed that persons on sulphonylurea monotherapy were 2.03 (95% CI 1.68-2.44, p < .001) times more likely to die within 3 years than persons on metformin monotherapy, after adjusting for age, eGFR and HbA1c. The logistic regression model was statistically significant, p < .001. Additional adjustment for LDL-cholesterol, HDL-cholesterol and urinary albumin-creatinine ratio did not alter the results.

CONCLUSION

Our data shows that sulphonylurea monotherapy is associated with higher all-cause mortality when compared to metformin monotherapy after adjusting for potential confounders.

Effects of Hypoglycemia on Circulating Stem and Progenitor Cells in Diabetic Patients

CONTEXT

Iatrogenic hypoglycemia is the most common acute diabetic complication, and it significantly increases morbidity. In people with diabetes, reduction in the levels of circulating stem and progenitor cells predicts adverse outcomes.

OBJECTIVE

To evaluate whether hypoglycemia in diabetes affects circulating stem cells and endothelial progenitor cells (EPCs).

DESIGN

We performed an experimental hypoglycemia study (Study 1) and a case-control study (Study 2).

SETTING

Tertiary referral inpatient clinic.

PATIENTS AND OTHER PARTICIPANTS

Type 1 diabetic patients (Study 1, n = 19); diabetic patients hospitalized for severe iatrogenic hypoglycemia, matched inpatient and outpatient controls (Study 2, n = 22/group).

INTERVENTIONS

Type 1 diabetic patients underwent two in-hospital sessions of glucose monitoring during a breakfast meal with or without induction of hypoglycemia in random order. In Study 2, patients hospitalized for hypoglycemia and matched controls were compared.

MAIN OUTCOME MEASURE

Circulating stem cells and EPCs were measured by flow cytometry based on the expression of CD34 and kinase insert domain receptor (KDR).

RESULTS

In Study 1, the physiologic decline of CD34+KDR+ EPCs from 8 am to 2 pm was abolished by insulin-induced hypoglycemia in type 1 diabetic patients. In Study 2, diabetic patients hospitalized for severe iatrogenic hypoglycemia had significantly lower levels of CD34+ stem cells and CD34+KDR+ EPCs compared with diabetic inpatients or outpatient controls.

CONCLUSIONS

In diabetic patients, a single mild hypoglycemic episode can compromise the physiologic EPC fluctuation, whereas severe hypoglycemia is associated with a marked reduction in stem cells and EPCs. These data provide a possible link between hypoglycemia and adverse outcomes of diabetes.

Relationship of Hyperglycaemia, Hypoglycaemia, and Glucose Variability to Atherosclerotic Disease in Type 2 Diabetes

OBJECTIVE

Type 2 diabetes mellitus (T2DM) is known to be associated with increased cardiovascular risk. The aim of this study was therefore to investigate the independent effects of hyperglycaemia, hypoglycaemia, and glucose variability on microvascular and macrovascular disease in T2DM.

METHODS

Subjects with T2DM of <10 years duration and on stable antiglycaemic treatment underwent carotid intima-media thickness (CIMT), ankle-brachial index (ABI), albumin-creatinine ratio (ACR), and HbA_1c measurement, as well as 72-hour continuous glucose monitoring. Macrovascular disease was defined as one or more of the following: history of ischaemic heart disease (IHD), cerebrovascular accident (CVA), ABI < 0.9, or abnormal CIMT.

RESULTS

The study population comprised 121 subjects with T2DM (89 males : 32 females). The mean age was 62.6 years, and the mean DM duration was 3.7 years. Macrovascular disease was present in 71 patients (58.7%). In multivariate logistic regression analysis, body surface area (BSA) (OR 18.88 (95% CI 2.20-156.69), p = 0.006) and duration of blood glucose (BG) < 3.9 mmol/L (OR 1.12 (95% CI 1.014-1.228), p = 0.024) were independent predictors of macrovascular disease. BSA (OR 12.6 (95% CI 1.70-93.54), p = 0.013) and duration of BG < 3.9 mmol/L (OR 1.09 (95% CI 1.003-1.187), p = 0.041) were independent predictors of abnormal CIMT. Area under the curve for BG > 7.8 mmol/L (β = 15.83, p = 0.005) was the sole independent predictor of albuminuria in generalised linear regression.

CONCLUSIONS

This study demonstrates that hypoglycaemia is associated with the occurrence of atherosclerotic disease while hyperglycaemia is associated with microvascular disease in a Caucasian population with T2DM of recent duration.

Impact of Insulin Detemir Administration Time on Hypoglycemia Rates in Hospitalized Patients

STUDY OBJECTIVE

To determine if insulin detemir administration time affects the frequency of hypoglycemia (blood glucose level <70 mg/dl) in hospitalized patients.

DESIGN

Retrospective cohort study.

PATIENTS

A total of 357 adults (aged 18-89 yrs) who received insulin detemir for at least 48 hours while hospitalized between January 1, 2014, and December 31, 2015, were included. Patients were categorized into one of three groups according to insulin detemir administration time: detemir given once/day between 7 a.m. and 10 a.m. (AM group [71 patients]), detemir given once/day between 6 p.m. and 10 p.m. (PM group [158 patients]), and detemir given twice/day (BID group [128 patients]).

SETTING

Community hospital.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was the percentage of patient days with any occurrence of hypoglycemia. The key secondary outcomes included the percentages of patients who experienced any hypoglycemic event, severe hypoglycemia, hypoglycemia requiring treatment, and refractory hypoglycemia; time of hypoglycemia; and percentage of patients experiencing one or more episodes of hyperglycemia. The AM group had a lower proportion of days with hypoglycemia compared with the PM group (7.9% vs 11.9%, p=0.008). There was a nonsignificant trend toward a lower proportion of days with hypoglycemia in the BID group compared with the PM group (9.1% vs 11.9%, p=0.0302). No significant differences in percentage of patient days with hyperglycemia and rates of severe hypoglycemia, hypoglycemia requiring treatment, or refractory hypoglycemia were noted among the three groups.

CONCLUSION

Administration of detemir in the morning may reduce the occurrence of hypoglycemia in hospitalized patients. Institutions that include detemir on their formularies may consider evaluating the incidence of hypoglycemia and modifying administration schedules as part of their medication safety program.

Circulating Endothelial Progenitor Cells in Type 1 Diabetic Patients: Relation with Patients' Age and Disease Duration

OBJECTIVES

Circulating endothelial progenitor cells (cEPCs) have been reported to be dysfunctional in diabetes mellitus (DM) patients, accounting for the vascular damage and the ensuing high risk for cardiovascular disease (CVD) characteristic of this disease. The aim of the present study was to evaluate the number of circulating cEPCs in type 1 DM (T1DM) patients, without clinical vascular damage, of different ages and with different disease duration.

METHODS

An observational, clinical-based prospective study was performed on T1DM patients enrolled in two clinical centers. cEPCs were determined by flow cytometry, determining the number of CD34/CD133/VEGFR2-positive cells within peripheral blood mononuclear cells (PBMCs).

RESULTS

The number of cEPCs was lower in adult T1DM patients, whilst higher in childhood/young patients, compared to controls of the same age range. When patients were grouped into two age groups (≥ or <20 years) (and categorized on the basis of the duration of the disease), the number of cEPCs in young (<20 years) patients was higher compared with older subjects, regardless of disease duration. A subset of patients with very high cEPCs was identified in the <20 years group.

CONCLUSION

There is an association between the number of cEPCs and patients' age: childhood/young T1DM patients have significantly higher levels of cEPCs, respect to adult T1DM patients. Such difference is maintained also when the disease lasts for more than 10 years. The very high levels of cEPCs, identified in a subset of childhood/young patients, might protect vessels against endothelial dysfunction and damage. Such protection would be less operative in older subjects, endowed with lower cEPC numbers, in which complications are known to develop more easily.

Modulating putative endothelial progenitor cells for the treatment of endothelial dysfunction and cardiovascular complications in diabetes

Diabetes induces a decrease in the number and function of different pro-angiogenic cell types generically designated as putative endothelial progenitor cells (EPC), which encompasses cells from myeloid origin that act in a paracrine fashion to promote angiogenesis and putative "true" EPC that contribute to endothelial replacement. This not only compromises neovasculogenesis in ischemic tissues but also impairs, at an early stage, the reendotheliziation process at sites of injury, contributing to the development of endothelial dysfunction and cardiovascular complications. Hyperglycemia, insulin resistance and dyslipidemia promote putative EPC dysregulation by affecting the SDF-1/CXCR-4 and NO pathways and the p53/SIRT1/p66Shc axis that contribute to their mobilization, migration, homing and vasculogenic properties. To optimize the clinical management of patients with hypoglycemic agents, statins and renin-angiotensin system inhibitors, which display pleiotropic effects on putative EPC, is a first step to improve their number and angiogenic potential but specific strategies are needed. Among them, mobilizing therapies based on G-CSF, erythropoietin or CXCR-4 antagonism have been developed to increase putative EPC number to treat ischemic diseases with or without prior cell isolation and transplantation. Growth factors, genetic and pharmacological strategies are also evaluated to improve ex vivo cultured EPC function before transplantation. Moreover, pharmacological agents increasing in vivo the bioavailability of NO and other endothelial factors demonstrated beneficial effects on neovascularization in diabetic ischemic models but their effects on endothelial dysfunction remain poorly evaluated. More experiments are warranted to develop orally available drugs and specific agents targeting p66Shc to reverse putative EPC dysfunction in the expected goal of preventing endothelial dysfunction and diabetic cardiovascular complications.

Vascular repair strategies in type 2 diabetes: novel insights

Impaired functions of vascular cells are responsible for the majority of complications in patients with type 2 diabetes (T2D). Recently a better understanding of mechanisms contributing to development of vascular dysfunction and the role of systemic inflammatory activation and functional alterations of several secretory organs, of which adipose tissue has more recently been investigated, has been achieved. Notably, the progression of vascular disease within the context of T2D appears to be driven by a multitude of incremental signaling shifts. Hence, successful therapies need to target several mechanisms in parallel, and over a long time period. This review will summarize the latest molecular strategies and translational developments of cardiovascular therapy in patients with T2D.