Statin treatment is associated with insulin sensitivity decrease in type 1 diabetes mellitus: A prospective, observational 56-month follow-up study

Impact of statin treatment on cardiovascular risk in patients with type 1 diabetes: a population-based cohort study

BACKGROUND

Cardiovascular disease (CVD) is a major complication in type 1 diabetes mellitus (T1D) patients. Previous studies have suggested that statins may be helpful for prevention of CVD in T1D, but there are limited data on the role of statins in T1D. We investigated the relationship between statin treatment and cardiovascular risk in T1D patients using a population-based cohort.

METHODS

We conducted a retrospective cohort study using the Korean nationwide health insurance database from January 2007 to December 2017. This study included 11,009 T1D patients aged ≥ 20 years without a prior history of CVD. The primary outcome was a composite development of stroke or myocardial infarction. Statin use during follow-up was treated as a time-varying variable. We performed a multivariable time-dependent Cox regression analysis adjusting for sex, age, type of insurance, hypertension, renal disease, and use of antiplatelets and renin-angiotensin-aldosterone system inhibitors.

RESULTS

During the mean follow-up of 9.9 ± 3.7 years of follow-up, 931 T1D patients (8.5%) suffered primary outcome. Statin treatment was associated with a reduced risk of the primary outcome (adjusted hazard ratio, 0.76; 95% confidence interval 0.66-0.88; p < 0.001). Statin use led to decreased risks of ischemic stroke and myocardial infarction, but was not related to hemorrhagic stroke. We also found that the risk of cardiovascular events decreased as the cumulative exposure duration of statins increased.

CONCLUSIONS

Statin use was associated with a lower risk of cardiovascular events in T1D patients. Further prospective studies are needed to confirm the potential role of statins in prevention of CVD in patients with T1D.

Impaired glucagon suppression and reduced insulin sensitivity in subjects with prediabetes undergoing atorvastatin therapy

OBJECTIVE

Statin therapy has been linked to an increased risk of type 2 diabetes in high-risk populations; however, the pathophysiology of this association remains to be clarified. We investigated glucagon suppression and its relationship with insulin resistance in prediabetic subjects undergoing atorvastatin therapy; in addition, we studied molecular insulin signaling in pancreatic α-cells exposed to atorvastatin in vitro.

DESIGN AND METHODS

Fifty subjects with prediabetes were divided into two groups based on atorvastatin therapy. All subjects underwent an oral glucose tolerance test. Early (0-30 min), late (30-120 min) and overall (0-120 min) glucagon suppression were evaluated. Insulin sensitivity was estimated by the insulin sensitivity index (ISI0-120). Insulin signaling pathway and insulin-mediated glucagon suppression were investigated in pancreatic αTC1-6 cells chronically exposed (24 or 48 h) to atorvastatin (100 ng/mL).

RESULTS

Individuals on statin therapy (n = 26) showed a significantly reduced early (0-30 min) (P = 0.003) and overall (0-120 min) (P = 0.01) glucagon suppression compared with controls (n = 24). In multivariate regression analysis, early glucagon suppression (0-30 min) exhibited a significant correlation with statin therapy. Regression analysis showed a significant association between ISI 0-120 and early0-30 (r = 0.33, P < 0.05) and overall0-120 (r = 0.38, P < 0.05) glucagon suppression. Moreover, in αTC1-6 cells atorvastatin treatment affected insulin-mediated glucagon suppression, insulin receptor phosphorylation and IRS-1-AKT pathway signaling.

CONCLUSIONS

Prediabetic patients undergoing statin therapy exhibit impaired glucagon suppression associated with lower insulin sensitivity. Our data revealed a new molecular aspect behind the deregulation of insulin sensitivity secondary to statin exposure.

Ambivalence about the selection of cardiovascular risk stratification tools: Evidence in a type 1 diabetes population

BACKGROUND

Cardiovascular disease (CVD) is one of the leading causes of death among people with diabetes, however, despite the increasing incidence of CVD, there are few tools for evaluating Cardiovascular Risk (CVR) in the population of patients with Type 1 Diabetes (T1D), with the existing ones diverging in the stratification of risk and in the suggestions for therapeutic conduct.

METHODS

A cross-sectional study was carried out with 104 participants diagnosed with T1D, aged 18-40, attending specialized services. The Steno Type 1 Risk Engine and the Cardiovascular Risk Stratification Calculator (CRSC) were used to assess the risk of a cardiovascular event over a 10-year period.

FINDINGS

Of the total sample selected, 62% were female, with a median age of 32 years (IQ 24; 43). There was a large difference between the stratification of CVR between the calculators, and 65.82% of the patients classified as low risk for CVD according to the Steno were identified as intermediate (30, 38.00%) and high risk (35.44%) by the CRSC. The analysis also highlighted a great difference in eligibility for statin use according to the risk stratification of the tools.

CONCLUSION

The CRSC and Steno tools evaluated and stratified the CVR of the same population with T1D, with there being divergence of the results. It was found that the CRSC tool classified the majority of the sample as high risk. Due to this result, the eligibility to use statins, which is one of the applications of these tools, showed great differences, with the Steno tool presenting less aggressive provisions regarding the prescription of statins in patients with type 1 DM.

Statin Therapy Negatively Impacts Skeletal Muscle Regeneration and Cutaneous Wound Repair in Type 1 Diabetic Mice

Those with diabetes invariably develop complications including cardiovascular disease (CVD). To reduce their CVD risk, diabetics are generally prescribed cholesterol-lowering 3-hydroxy-methylglutaryl coenzyme A reductase inhibitors (i.e., statins). Statins inhibit cholesterol biosynthesis, but also reduce the synthesis of a number of mevalonate pathway intermediates, leading to several cholesterol-independent effects. One of the pleiotropic effects of statins is the reduction of the anti-fibrinolytic hormone plasminogen activator inhibitor-1 (PAI-1). We have previously demonstrated that a PAI-1 specific inhibitor alleviated diabetes-induced delays in skin and muscle repair. Here we tested if statin administration, through its pleiotropic effects on PAI-1, could improve skin and muscle repair in a diabetic rodent model. Six weeks after diabetes onset, adult male streptozotocin-induced diabetic (STZ), and WT mice were assigned to receive control chow or a diet enriched with 600 mg/kg Fluvastatin. Tibialis anterior muscles were injured via Cardiotoxin injection to induce skeletal muscle injury. Punch biopsies were administered on the dorsal scapular region to induce injury of skin. Twenty-four days after the onset of statin therapy (10 days post-injury), tissues were harvested and analyzed. PAI-1 levels were attenuated in statin-treated diabetic tissue when compared to control-treated tissue, however no differences were observed in non-diabetic tissue as a result of treatment. Muscle and skin repair were significantly attenuated in Fluvastatin-treated STZ-diabetic mice as demonstrated by larger wound areas, less mature granulation tissue, and an increased presence of smaller regenerating muscle fibers. Despite attenuating PAI-1 levels in diabetic tissue, Fluvastatin treatment impaired cutaneous healing and skeletal muscle repair in STZ-diabetic mice.

Lessons from basic pancreatic beta cell research in type-2 diabetes and vascular complications

The changes in life-style with increased access of food and reduced physical activity have resulted in the global epidemic of obesity. Consequently, individuals with type 2 diabetes and cardiovascular disease have also escalated. A central organ in the development of diabetes is the pancreas, and more specifically the pancreatic beta cells within the islets of Langerhans. Beta cells have been assigned the important task of secreting insulin when blood glucose is increased to lower the glucose level. An early sign of diabetes pathogenesis is lack of first phase insulin response and reduced second phase secretion. In this review, which is based on the foreign investigator award lecture given at the JSDC meeting in Sendai in October 2016, we discuss a possible cellular explanation for the reduced first phase insulin response and how this can be influenced by lipids. Moreover, since patients with cardiovascular disease and high levels of cholesterol are often treated with statins, we summarize recent data regarding effects on statins on glucose homeostasis and insulin secretion. Finally, we suggest microRNAs (miRNAs) as central players in the adjustment of beta cell function during the development of diabetes. We specifically discuss miRNAs regarding their involvement in insulin secretion regulation, differential expression in type 2 diabetes, and potential as biomarkers for prediction of diabetes and cardiovascular complications.