Endogenous hyperinsulinaemia and exogenous insulin: A common theme between atherosclerosis, increased cancer risk and other morbidities

Association between Triglyceride-Glucose Index and Early Neurological Outcomes after Thrombolysis in Patients with Acute Ischemic Stroke

BACKGROUND

The triglyceride-glucose (TyG) index is a novel biomarker of insulin resistance which might plausibly influence endogenous fibrinolysis and thus early neurological outcomes in patients with acute ischemic stroke (AIS) treated with intravenous thrombolysis using recombinant tissue-plasminogen activator.

METHODS

We included consecutive AIS patients within 4.5 h of symptom onset undergoing intravenous thrombolysis between January 2015 and June 2022 in this multi-center retrospective observational study. Our primary outcome was early neurological deterioration (END), defined as ≥2 (END₂) or ≥ 4 (END₄) National Institutes of Health Stroke Scale (NIHSS) score worsening compared to the initial NIHSS score within 24 h of intravenous thrombolysis. Our secondary outcome was early neurological improvement (ENI), defined as a lower NIHSS score at discharge. TyG index was calculated using the log scale of fasting triglyceride (mg/dL) × fasting glucose (mg/dL)/2. We evaluated the association of END and ENI with TyG index using a logistic regression model.

RESULTS

A total of 676 patients with AIS were evaluated. The median age was 68 (Interquartile range, IQR (60-76) years old), and 432 (63.9%) were males. A total of 89 (13.2%) patients developed END₂, 61 (9.0%) patients developed END₄, and 492 (72.7%) experienced ENI. In multivariable logistic regression analysis, after adjustment for confounding factors, TyG index was significantly associated with increased risks of END₂ (categorical variable, vs. lowest tertile, medium tertile odds ratio [OR] 1.05, 95% confidence interval, CI 0.54-2.02, highest tertile OR 2.94, 95%CI 1.64-5.27, overall p < 0.001) and END₄ (categorical variable, vs. lowest tertile, medium tertile OR 1.21, 95%CI 0.54-2.74, highest tertile OR 3.80, 95%CI 1.85-7.79, overall p < 0.001), and a lower probability of ENI (categorical variable, vs. lowest tertile, medium tertile OR 1.00, 95%CI 0.63-1.58, highest tertile OR 0.59, 95%CI 0.38-0.93, overall p = 0.022).

CONCLUSIONS

Increasing TyG index was associated with a higher risk of END and a lower probability of ENI in patients with acute ischemic stroke treated with intravenous thrombolysis.

Relationship among Insulin Therapy, Insulin Resistance, and Severe Coronary Artery Disease in Type 2 Diabetes Mellitus

Objectives

The effect of insulin therapy on coronary artery disease (CAD) remains controversial. This study aimed to analyze the association between insulin resistance and the morbidity of severe CAD in type 2 diabetes mellitus (T2DM).

Methods

A total of 2044 T2DM patients aged ≥40 years were included in this cross-sectional observational study. Clinical information and laboratory results were collected from the medical records. Those who underwent percutaneous coronary intervention (PCI) were classified as severe CAD, while those who did not have a history of and were not suffering from CAD were classified as patients without CAD.

Results

T2DM patients with severe CAD and without CAD had no significant differences in glycosylated hemoglobin A1c (8.55% ± 2.10% vs. 8.39% ± 1.77%, P=0.234). The proportion of insulin treatment was also similar between the two groups (56.85% vs. 53.65%, odds ratio = 1.138, P=0.310). In the patients without insulin treatment, the levels of fasting C peptide (FCP) correlated with severe CAD prevalence. FCP was categorized into 3 tertiles (<1.5 ng/mL, 1.5 ng/mL- 3 ng/mL, and ≥3 ng/mL), and the prevalence rates of severe CAD were 7.88%, 14.31%, and 18.28%, respectively (P < 0.05). In the patients with insulin treatment, the body mass index (BMI) was the significant risk factor of severe CAD. The prevalence of severe CAD according to BMI tertiles (<24 kg/m², 24 kg/m²–28 kg/m², and ≥28 kg/m²) was 11.22%, 14.61%, and 24.62%, respectively (P < 0.01).

Conclusions

Our results showed that insulin resistance, rather than insulin therapy, increases the risk of severe CAD in T2DM patients with inadequate glycemic control. Non-insulin treated patients with high FCP and insulin-treated patients with high BMI are at higher risk of severe CAD.

Association between insulin resistance and post-ischaemic stroke outcome in patients without diabetes: protocol for a systematic review and meta-analysis

INTRODUCTION

Insulin resistance is an independent risk factor for atherosclerosis, coronary artery disease and ischaemic stroke. Currently, insulin resistance is not usually included in post-stroke risk stratification. This systematic review and meta-analysis intends to determine if available scientific knowledge supports an association between insulin resistance and post-stroke outcomes in patients without diabetes.

METHODS AND ANALYSIS

The authors will conduct a literature search in Medline, Embase, Web of Science and Cochrane Central. The review will include studies that assess the association between elevated insulin homeostasis model of insulin resistance (HOMA-IR) and post-stroke outcome (functional outcome and recurrent stroke). The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting guidelines will be used. The primary outcome will be post-stroke functional outcome (Modified Rankin Scale), and the secondary outcome will be recurrent ischaemic stroke. Comparison of outcome will be made between highest and lowest HOMA-IR range (as defined in each article included in this systematic review). Risk of bias will be assessed qualitatively. Meta-analysis will be performed if sufficient homogeneity exists between studies. Heterogeneity of outcomes will be assessed by I².

ETHICS AND DISSEMINATION

No human or animal subjects or samples were/will be used. The results will be published in a peer-reviewed journal, and will be disseminated at local and international neurology conferences.

PROSPERO REGISTRATION NUMBER

CRD42020173608.

Comparison of the effect of insulin glargine and regular insulin on perioperative glycemic control in patients with type 2 diabetes mellitus under insulin treatment during vitrectomy surgery under general anesthesia: A randomized clinical trial study

Background: Perioperative glycemic control is an important factor in the clinical management of a patient with diabetes mellitus under surgery. Poorly controlled long-term hyperglycemia not only predisposes individuals to systemic complications of diabetes mellitus and cardiovascular morbidity but also increases the risk of anesthesia and weakens the outcome of the surgery. Given the importance of the issue and the limited studies on glucose control using insulin glargine during surgery, we aimed to investigate the effects of glargine on glucose control in patients with diabetes mellitus during vitrectomy surgery.

Methods: This randomized, double-blind trial was conducted in two groups of 35 patients with diabetes mellitus under treatment with insulin. In the control group, the patients received regular insulin based on the blood glucose and the sliding scale, and in the intervention group, they received insulin glargine (0.3 unit/kg) before surgery. From the start of the operation up to 3 hours of the surgery blood glucose of the patients was measured every 45 minutes and once 6 hours after the operation, and if needed, the regular insulin was injected. Data were analyzed using SPSS 16. Frequency, percentage, mean, and standard deviation (SD) were used to describe the data. To compare the quantitative variables, the independent t-test or U-Mann-Whitney test was used. For comparison of the qualitative variables, Chi-square test or Fischer's exact test and repeated measure ANOVA was employed. The significance level (P-value) was considered as p<0.05.

Results: Use of insulin glargine was associated with significantly lower blood glucose levels compared to regular insulin at 90-minutes (p=0.004), 135 minutes (p=0.001), and 6 hours after the operation (p=0.005).

Conclusion: Glycemic control using glargine compared to regular insulin has a better performance with less need for surplus insulin dose administration during surgery.

Atherosclerosis is a vascular stem cell disease caused by insulin

The present article proposes the hypothesis that when multipotent vascular stem cells are exposed to excessive insulin in a rhythmic pattern of sharply rising and falling concentrations, their differentiation is misdirected toward adipogenic and osteogenic cell lineages. This results in plaque-like accumulation of adipocytes with fat and cholesterol deposition from adipocyte debris, and osteogenic (progenitor) cells with a calcified matrix in advanced lesions. The ingrowth of capillaries and infiltration with macrophages, which upon uptake of lipids turn into foam cells, are unspecific pro-resolving reactions. Epidemiological, histopathological, pharmacological, and experimental evidence in favour of this hypothesis is summarised.

Randomized Trial of the Effects of Insulin and Metformin on Myocardial Injury and Stress in Diabetes Mellitus: A Post Hoc Exploratory Analysis

Background

Subclinical myocardial injury, as measured by high‐sensitivity cardiac troponin T (hsTnT), and myocardial stress, as measured by N‐terminal pro‐B‐type natriuretic peptide (NT‐proBNP), are related to glycemic control in patients with type 2 diabetes mellitus, and are strong predictors of adverse cardiovascular outcomes. We sought to determine whether antihyperglycemic therapy improves measures of myocardial injury and myocardial stress in patients with type 2 diabetes mellitus.

Methods and Results

We randomized, in a 2×2 factorial fashion, 438 patients with type 2 diabetes mellitus to insulin glargine, metformin, the combination, or placebo and measured changes in NT‐proBNP and hsTnT after 12 weeks of therapy. At baseline, the median (Q1–Q3) plasma concentration was 35.4 (15.7–86.3) ng/L for NT‐proBNP and 6.7 (4.6–10.1) ng/L for hsTnT. The adjusted (95% confidence interval) change in NT‐proBNP concentration was 20.7% (7.9–35.0) in the insulin arm compared with 0.13% (−10.8 to 12.5) in the no‐insulin arm (P=0.03 for comparison). These changes were not related to changes in fasting or postprandial glucose, glycated hemoglobin, weight, blood pressure, or inflammation. In the metformin arm, the adjusted change in NT‐proBNP was 7.8% (−3.7 to 20.7) compared with 13.0% (0.72–26.8) in the no‐metformin arm (P=0.58). No significant changes in hsTnT concentrations were observed for any of the treatment arms.

Conclusions

Insulin glargine was associated with a significant 20.7% increase in NT‐proBNP, a marker of myocardial stress, after 12 weeks of therapy. No change in hsTnT, a marker of myocardial injury, was observed. The changes were independent of substantial improvements in glucose control.

Clinical Trial Registration

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00366301.

Insulin Therapy Increases Cardiovascular Risk in Type 2 Diabetes

Insulin therapy increased cardiovascular (CV) risk and mortality among type 2 diabetes (T2D) patients in several recently reported clinical outcomes trials. To assess whether this association is causative or coincidental, PubMed searches were used to query the effects of insulin therapy for T2D on CV health and longevity from large-scale outcomes trials, meta-analyses, and patient registry studies, as well as basic research on insulin's direct and pleiotropic actions. Although several old studies provided conflicting results, the majority of large observational studies show strong dose-dependent associations for injected insulin with increased CV risk and worsened mortality. Insulin clearly causes weight gain, recurrent hypoglycemia, and, other potential adverse effects, including iatrogenic hyperinsulinemia. This over-insulinization with use of injected insulin predisposes to inflammation, atherosclerosis, hypertension, dyslipidemia, heart failure (HF), and arrhythmias. These associations support the findings of large-scale evaluations that strongly suggest that insulin therapy has a poorer short- and long-term safety profile than that found to many other anti-T2D therapies. The potential adverse effects of insulin therapy should be weighed against proven CV benefits noted for select other therapies for T2D as reported in recent large randomized controlled trials.

Meal-induced platelet activation in diabetes mellitus type 1 or type 2 is related to postprandial insulin rather than glucose levels

AIM

Postprandial platelet activation was related to postprandial insulin rather than glucose levels in a previous meal insulin study in type 2 diabetes mellitus (T2DM). We therefore compared postprandial platelet activation in type 1 (T1DM) patients without insulin secretion and T2DM patients with high postprandial insulin levels.

MATERIAL AND METHODS

Patients with T1DM (n=11) and T2DM (n=12) were studied before and 90min after a standardized meal without premeal insulin. Five T1DM patients volunteered for a restudy with their regular premeal insulin. Platelet activation was assessed by flow cytometry, with and without the thromboxane analogue U46619 or ADP, and by whole blood aggregometry (Multiplate®). Effects of insulin (100μU/mL) in vitro were also studied.

RESULTS

Before the meal, glucose, insulin and platelet activation markers other than platelet-leukocyte aggregates (PLAs) were similar in T1DM and T2DM; PLAs were higher in T1DM. Postprandial glucose levels increased more markedly in T1DM (to 22.1±1.4 vs. 11.2±0.6mmol/L) while insulin levels increased only in T2DM (from 24.4±4.4 to 68.8±12.3μU/mL). Platelet P-selectin expression, fibrinogen binding and PLA formation stimulated by U46619 were markedly enhanced (approximately doubled) and whole blood aggregation stimulated by U46619 was increased (p<0.05 for all) after the meal in T2DM patients but not in T1DM patients. The pilot study with premeal insulin in T1DM patients showed postprandial platelet activation when postprandial insulin levels increased. In vitro insulin mildly activated platelets in both groups.

CONCLUSION

Postprandial platelet activation via the thromboxane pathway is related to postprandial hyperinsulinemia and not to postprandial hyperglycaemia in patients with diabetes.

Transdermal delivery of insulin by amidated pectin hydrogel matrix patch in streptozotocin-induced diabetic rats: effects on some selected metabolic parameters

PURPOSE

Studies in our laboratory are concerned with developing optional insulin delivery routes based on amidated pectin hydrogel matrix gel. We therefore investigated whether the application of pectin insulin (PI)-containing dermal patches of different insulin concentrations sustain controlled release of insulin into the bloodstream of streptozotocin (STZ)-induced diabetic rats with concomitant alleviation of diabetic symptoms in target tissues, most importantly, muscle and liver.

METHODS

Oral glucose test (OGT) responses to PI dermal matrix patches (2.47, 3.99, 9.57, 16.80 µg/kg) prepared by dissolving pectin/insulin in deionised water and solidified with CaCl2 were monitored in diabetic rats given a glucose load after an 18-h fast. Short-term (5 weeks) metabolic effects were assessed in animals treated thrice daily with PI patches 8 hours apart. Animals treated with drug-free pectin and insulin (175 µg/kg, s.c.) acted as untreated and treated positive controls, respectively. Blood, muscle and liver samples were collected for measurements of selected biochemical parameters.

RESULTS

After 5 weeks, untreated diabetic rats exhibited hyperglycaemia and depleted hepatic and muscle glycogen concentrations. Compared to untreated STZ-induced diabetic animals, OGT responses of diabetic rats transdermally applied PI patches exhibited lower blood glucose levels whilst short-term treatments restored hepatic and muscle glycogen concentrations. Plasma insulin concentrations of untreated diabetic rats were low compared with control non-diabetic rats. All PI treatments elevated plasma insulin concentrations of diabetic rats although the levels induced by high doses (9.57 and 16.80 µg/kg) were greater than those caused by low doses (2.47 and 3.99 µg/kg) but comparable to those in sc insulin treated animals.

CONCLUSIONS

The data suggest that the PI hydrogel matrix patch can deliver physiologically relevant amounts of pharmacologically active insulin.

NOVELTY OF THE WORK

A new method to administer insulin into the bloodstream via a skin patch which could have potential future applications in diabetes management is reported.

Adding glimepiride to current insulin therapy increases high-molecular weight adiponectin levels to improve glycemic control in poorly controlled type 2 diabetes

BACKGROUND

To observe the efficacy and safety of adding glimepiride to established insulin therapy in poorly controlled type 2 diabetes (T2D) and to assess the relationship of changes in the serum high-molecular weight (HMW) adiponectin levels and glycemic control after glimepiride treatment.

METHODS

Fifty-six subjects with poorly controlled insulin-treated T2D were randomly assigned to either the glimepiride-added group (the group A, n = 29) or the insulin-increasing group (the group B, n = 27) while continuing current insulin-based therapy. Glycosylated hemoglobin (HbA1c) value, daily insulin dose, body weight, waist circumference, plasma lipid concentration, serum HMW adiponectin level and the number of hypoglycemic events were evaluated before and after treatment.

RESULTS

At the end of study, insulin doses were significantly reduced, and the mean HbA1c, fasting blood glucose (FBG) and 2-hour postprandial blood glucose (P2BG) were improved greater in the group A compared with the group B. The serum HMW adiponectin levels were significantly increased in the group A compared with the group B. Most importantly, we found that changes in HbA1c were inversely correlated with changes in serum HMW adiponectin in the group A (r = -0.452, p = 0.02).

CONCLUSIONS

Adding glimepiride to current insulin treatment led to better improvement in glycemic control with a significant smaller daily insulin dose, and the increases in the serum HMW adiponectin levels may directly contribute to improvement glycemic control.

What next after metformin? A retrospective evaluation of the outcome of second-line, glucose-lowering therapies in people with type 2 diabetes

CONTEXT

After failure of metformin monotherapy, many second-line, glucose-lowering therapies are available to treat people with type 2 diabetes.

OBJECTIVE

The objective of the study was to compare clinical outcomes using common alternative regimens.

DESIGN AND SETTING

This was a retrospective cohort study using data from the U.K.-based General Practice Research Database.

PATIENTS

These were primary care patients with type 2 diabetes who had metformin monotherapy as their first treatment and who then initiated on relevant second-line, glucose-lowering regimens during the study period 2000-2010. A total of 27,457 patients were prescribed a second-line therapy, of whom 26,278 (95.7%) were prescribed a regimen with 1,000 or more observations.

MAIN OUTCOME MEASURES

All-cause mortality, major adverse cardiovascular events (MACE), cancer, and a combined end point of any of these were measured. Secondary end points were change in glycosylated hemoglobin between baseline and 12 months. Time to clinical end points was compared using Cox proportional hazards models.

RESULTS

Sulfonylurea monotherapy had significantly higher hazard ratios (HRs) for all-cause mortality (HR 1.459, 1.207-1.763); MACE (HR 1.578, 1.187-2.099); stroke (HR 1.444, 1.050-1.987); and the combined end point (HR 1.381, 1.194-1.597). Metformin plus pioglitazone had significantly lower adjusted HRs for all-cause mortality (HR 0.707, 0.515-0.970) and the combined end point (HR 0.747, 0.612-0.911). Mean glycosylated hemoglobin improved between baseline and 12 months for all regimens other than sulfonylurea monotherapy.

CONCLUSION

The combination of metformin plus pioglitazone appears to provide superior clinical outcomes compared with the most commonly used regimen, metformin plus sulfonylurea. Sulfonylurea monotherapy resulted in worse outcome.