Cardiovascular disease morbidity and mortality in patients with type 1 diabetes mellitus : management strategies

Sex-Related Differences in Platelet Aggregation: A Literature Review Supplemented with Local Data from a Group of Generally Healthy Individuals

The process of platelet aggregation is often influenced by several factors including sex and age. A literature review confirmed the existence of sex-related differences in platelet aggregation. Although 68 out of 78 papers found such differences, there are still some controversies regarding these differences, which can be due to multiple factors (age, trigger, concomitant disease, sample handling, etc.). These outcomes are discussed in line with novel results obtained from a local study, in which blood samples from a total of 53 overall healthy women and men with ages ranging from 20 to 66 years were collected. Aggregation was induced with seven different triggers (ristocetin, thrombin receptor activating peptide 6 [TRAP-6], arachidonic acid [AA], platelet-activating factor 16 [PAF-16], ADP, collagen, or thromboxane A₂ analog U-46619) ex vivo. In addition, three FDA-approved antiplatelet drugs (vorapaxar, ticagrelor, or acetylsalicylic acid [ASA]) were also tested. In general, women had higher aggregation responses to some agonists (ADP, TRAP), as well as lower benefit from inhibitors (ASA, vorapaxar). The aggregatory responses to AA and TRAP decreased with age in both sexes, while responses to ADP, U-46619, and PAF were affected by age only in women. In conclusion, more studies are needed to decipher the biological importance of sex-related differences in platelet aggregation in part to enable personalized antiplatelet treatment.

Long-term prognosis in patients continuing taking antithrombotics after peptic ulcer bleeding

AIM

To investigate the long-term prognosis in peptic ulcer patients continuing taking antithrombotics after ulcer bleeding, and to determine the risk factors that influence the prognosis.

METHODS

All clinical data of peptic ulcer patients treated from January 1, 2009 to January 1, 2014 were retrospectively collected and analyzed. Patients were divided into either a continuing group to continue taking antithrombotic drugs after ulcer bleeding or a discontinuing group to discontinue antithrombotic drugs. The primary outcome of follow-up in peptic ulcer bleeding patients was recurrent bleeding, and secondary outcome was death or acute cardiovascular disease occurrence. The final date of follow-up was December 31, 2014. Basic demographic data, complications, and disease classifications were analyzed and compared by t- or χ²-test. The number of patients that achieved various outcomes was counted and analyzed statistically. A survival curve was drawn using the Kaplan-Meier method, and the difference was compared using the log-rank test. COX regression multivariate analysis was applied to analyze risk factors for the prognosis of peptic ulcer patients.

RESULTS

A total of 167 patients were enrolled into this study. As for the baseline information, differences in age, smoking, alcohol abuse, and acute cardiovascular diseases were statistically significant between the continuing and discontinuing groups (70.8 ± 11.4 vs 62.4 ± 12.0, P < 0.001; 8 (8.2%) vs 15 (21.7%), P < 0.05; 65 (66.3%) vs 13 (18.8%), P < 0.001). At the end of the study, 18 patients had recurrent bleeding and three patients died or had acute cardiovascular disease in the continuing group, while four patients had recurrent bleeding and 15 patients died or had acute cardiovascular disease in the discontinuing group. The differences in these results were statistically significant (P = 0.022, P = 0.000). The Kaplan-Meier survival curve indicated that the incidence of recurrent bleeding was higher in patients in the continuing group, and the risk of death and developing acute cardiovascular disease was higher in patients in the discontinuing group (log-rank test, P = 0.000 for both). Furthermore, COX regression multivariate analysis revealed that the hazard ratio (HR) for recurrent bleeding was 2.986 (95%CI: 067-8.356, P = 0.015) in the continuing group, while HR for death or acute cardiovascular disease was 5.216 (95%CI: 1.035-26.278, P = 0.028).

CONCLUSION

After the occurrence of peptic ulcer bleeding, continuing antithrombotics increases the risk of recurrent bleeding events, while discontinuing antithrombotics would increase the risk of death and developing cardiovascular disease. This suggests that clinicians should comprehensively consider the use of antithrombotics after peptic ulcer bleeding.

Study of coronary artery calcification risk in Egyptian adolescents with type-1 diabetes

The objective of the study is to assess coronary artery calcification (CAC) among adolescents with type-1 diabetes and to determine its relation with high-sensitivity C-reactive protein (hs-CRP), dyslipidaemia, glycaemic control and microvascular complications. The study included sixty patients with type-1 diabetes. Their ages ranged from 12 to 18 years and their diabetes duration ranged between 10 and 15 years. Patients were compared with 60 healthy subjects who served as controls. Clinical examination and laboratory investigations were done for evaluation of glycaemic control and presence of microvascular complications. Lipid profile, hs-CRP and multislice spiral computed tomography were done. Hs-CRP, total cholesterol, triglycerides and low-density lipoproteins levels were significantly higher in patients with diabetes compared to controls (P < 0.001). Twelve patients with diabetes (20%) had positive CAC. The mean calcium score was significantly higher in patients with diabetes compared to controls (P < 0.05). Smoking significantly affects CAC as 50% of smokers with diabetes had evidence of CAC compared to 9.1% of non-smokers with diabetes (P < 0.001). Fifty percent of patients with diabetes on angiotensin-converting enzyme inhibitor (ACEI) had evidence of CAC compared to 0% of patients without history of ACEI therapy (P < 0.001). Diabetics with CAC had significantly elder age, longer disease duration and higher mean glycosylated hemoglobin compared to diabetics without CAC (P < 0.05). Blood pressure percentiles, albumin creatinine ratio and serum lipids were significantly higher in patients with CAC compared to those without CAC (P < 0.001). All diabetics with severe retinopathy had positive CAC compared to 0% with normal Fundus (P < 0.001). All diabetics with overt nephropathy had positive CAC compared to 13.3% and 0% in micro- and normo-albuminuric patients (P < 0.001). Young patients with diabetes have evidence of CAC. Smoking, microvascular complications and dyslipidaemia might contribute to this risk.

Intracellular Ca2+ regulating proteins in vascular smooth muscle cells are altered with type 1 diabetes due to the direct effects of hyperglycemia

Background

Diminished calcium (Ca²⁺) transients in response to physiological agonists have been reported in vascular smooth muscle cells (VSMCs) from diabetic animals. However, the mechanism responsible was unclear.

Methodology/Principal Findings

VSMCs from autoimmune type 1 Diabetes Resistant Bio-Breeding (DR-BB) rats and streptozotocin-induced rats were examined for levels and distribution of inositol trisphosphate receptors (IP₃R) and the SR Ca²⁺ pumps (SERCA 2 and 3). Generally, a decrease in IP₃R levels and dramatic increase in ryanodine receptor (RyR) levels were noted in the aortic samples from diabetic animals. Redistribution of the specific IP₃R subtypes was dependent on the rat model. SERCA 2 was redistributed to a peri-nuclear pattern that was more prominent in the DR-BB diabetic rat aorta than the STZ diabetic rat. The free intracellular Ca²⁺ in freshly dispersed VSMCs from control and diabetic animals was monitored using ratiometric Ca²⁺ sensitive fluorophores viewed by confocal microscopy. In control VSMCs, basal fluorescence levels were significantly higher in the nucleus relative to the cytoplasm, while in diabetic VSMCs they were essentially the same. Vasopressin induced a predictable increase in free intracellular Ca²⁺ in the VSMCs from control rats with a prolonged and significantly blunted response in the diabetic VSMCs. A slow rise in free intracellular Ca²⁺ in response to thapsigargin, a specific blocker of SERCA was seen in the control VSMCs but was significantly delayed and prolonged in cells from diabetic rats. To determine whether the changes were due to the direct effects of hyperglycemica, experiments were repeated using cultured rat aortic smooth muscle cells (A7r5) grown in hyperglycemic and control conditions. In general, they demonstrated the same changes in protein levels and distribution as well as the blunted Ca²⁺ responses to vasopressin and thapsigargin as noted in the cells from diabetic animals.

Conclusions/Significance

This work demonstrates that the previously-reported reduced Ca²⁺ signaling in VSMCs from diabetic animals is related to decreases and/or redistribution in the IP₃R Ca²⁺ channels and SERCA proteins. These changes can be duplicated in culture with high glucose levels.

Improvements in glycaemic control and cardiovascular risk factors in a cohort of patients with type 1 diabetes over a 5-year period

BACKGROUND

Management of patients with type 1 diabetes in the UK has changed over the past 20 years. The targets for glycaemic control, blood pressure and cholesterol are lower. We examined a cohort of patients with type 1 diabetes who have been through these changes to assess their effects.

DESIGN AND METHODS

A cohort of patients with type 1 diabetes who attended a secondary care outpatient diabetes clinic between 1991 and 1996 were reviewed in 2001 and 2006. Comparison is made between current biophysical markers and those obtained in 2001.

RESULTS

Only 81.9% (n = 214) of the original cohort attended in 2006. These patients had an average duration of diabetes of 23.46 (SD +/- 8.06) years. There were 134 male patients (62.62%). In these patients HbA1c had reduced by 0.4% (absolute reduction); a relative reduction of 4.41% (P = 0.0001). Statistically significant reductions in diastolic blood pressure (74-68 mmHg) and total cholesterol (5.37-4.62 mmol/l) occurred. However, weight (75.04-82.31 kg) and BMI (25.32-27.72 kg/m(2)) significantly increased. There was no statistically significant change in insulin dose (units/kg), serum creatinine, urinary ACR or systolic blood pressure.

CONCLUSION

An urban setting, mobile population and patient non-attendance can complicate modern diabetes care. Despite these difficulties, input by the diabetes team working with the patients can achieve small improvements in Hba1c and cardiovascular risk factors by increased use of long acting insulins, metformin, statins and blood pressure medication.

Similarity of the impact of type 1 and type 2 diabetes on cardiovascular mortality in middle-aged subjects

OBJECTIVE

To compare the risk of cardiovascular disease (CVD) death and the impact of hyperglycemia on the risk of CVD mortality associated with type 1 diabetes to that associated with type 2 diabetes.

RESEARCH DESIGN AND METHODS

The study comprised 173 participants with type 1 diabetes, 834 participants with type 2 diabetes, and 1,294 nondiabetic participants, aged 45-64 years at baseline and free of CVD. The age of onset of diabetes was >30 years in both diabetic groups.

RESULTS

During an 18-year follow-up, 86 participants with type 1 diabetes, 567 participants with type 2 diabetes, and 252 nondiabetic participants died. CVD mortality rates per 1,000 person-years were 23.1 (95% CI 16.9-31.9) in type 1 diabetic, 35.3 (30.8-40.4) in type 2 diabetic, and 4.6 (3.8-5.7) in nondiabetic participants. Adjusted hazard ratios for CVD mortality in participants with type 1 diabetes versus no diabetes was 3.6 (95% CI 2.2-5.7) in men and 13.3 (6.9-22.5) in women and in participants with type 2 diabetes versus no diabetes 3.3 (2.5-4.5) in men and 10.1 (6.7-17.4) in women. An increment of 1 unit (%) of GHb increased CVD mortality by 52.5% (95% CI 28.4-81.3) in type 1 diabetic subjects and by 7.5% (4.3-10.8) in type 2 diabetic participants.

CONCLUSIONS

The impact of type 1 and type 2 diabetes on CVD mortality was similar. The effect of increasing hyperglycemia on the risk of CVD mortality was more profound in type 1 than in type 2 diabetic subjects.

Peripheral artery tonometry demonstrates altered endothelial function in children with type 1 diabetes

OBJECTIVES

To assess the ability of reactive hyperemia-peripheral artery tonometry (RH-PAT) to serve as a surrogate marker of endothelial dysfunction in children with type 1 diabetes (T1D).

RESEARCH DESIGN AND METHODS

Forty-four children with T1D [age 14.6 +/- 2.7 yr; duration of diabetes 6.01 +/- 4 yr; range of diabetes duration 1-16 yr; and hemoglobin A1c (HbA1c) 8.34 +/- 1.2%] and 20 children without diabetes (age 14.1 +/- 1.5 yr) underwent RH-PAT endothelial function testing after an overnight fast. Height, weight, body mass index (BMI), blood pressure (BP), fasting lipid profile, and glucose level were determined in each child. Children with T1D underwent a second RH-PAT study 4 wk after their initial study to determine the intrapatient variability of the technique.

RESULTS

Children with T1D had endothelial dysfunction as evidenced by lower mean RH-PAT scores (1.63 +/- 0.5) when compared with children without diabetes (mean RH-PAT score 1.95 +/- 0.3) (p = 0.01). Repeat RH-PAT scores were predicted by initial RH-PAT scores (p = 0.0025). Mean intrapatient standard deviation of RH-PAT score was 0.261 and mean coefficient of variation was 14.8. Variations in RH-PAT score were not explained by differences in glucose, HbA1c, BMI, systolic BP, diastolic BP, or lipids.

CONCLUSIONS

Although larger validation studies are required, RH-PAT is a promising non-invasive technique to assess endothelial function in children with T1D. Non-invasive measures of endothelial dysfunction may provide the additional risk stratification data needed to justify more aggressive primary prevention of cardiovascular disease in children with T1D.