Cardiac Involvement in Diabetes

Sex-specific pattern of left ventricular hypertrophy and diastolic function in patients with type 2 diabetes mellitus

AIMS

Few prospective studies have evaluated sex-specific pattern, natural progression of left ventricular (LV) remodelling, and diastolic dysfunction in patients with type 2 diabetes (T2DM). The aim of this study was to study the sex-specific prevalence, longitudinal changes of LV remodelling, and diastolic dysfunction in patients with T2DM. Further, the prognostic value of diastolic function in women and men was also evaluated.

METHODS AND RESULTS

A total of 350 patients with T2DM (mean age 61 ± 11 years; women, 48.3%) was recruited. Detailed echocardiography was performed at baseline and after 25 months. A major adverse cardiovascular event (MACE) was defined as cardiovascular death, heart failure hospitalization, or myocardial infarction. Despite a similar age, prevalence of hypertension and body mass index, women had a higher prevalence of LV hypertrophy and diastolic dysfunction at baseline and follow-up compared with men. A total of 21 patients developed MACE (5 cardiovascular death, 9 hospitalization for heart failure, and 7 myocardial infarction) during a median follow-up of 56 months. Women with diastolic dysfunction had a higher incidence of MACE than those with normal diastolic function but this association was neutral in men. Multivariable Cox-regression analysis indicated that diastolic dysfunction was associated with MACE in women [hazard ratio = 6.30; 95% confidence interval (CI) = 1.06-37.54; P < 0.05] but not men (hazard ratio = 2.29, 95% CI = 0.67-7.89; P = 0.19).

CONCLUSION

LV hypertrophy and diastolic dysfunction, both at baseline and follow-up, were more common in women than men. Pre-clinical diastolic dysfunction was independently associated with MACE only in women with T2DM but was neutral in men.

Myeloid differentiation protein 1 protected myocardial function against high-fat stimulation induced pathological remodelling

Myeloid differentiation 1 (MD‐1) is a secreted protein that regulates the immune response of B cell through interacting with radioprotective 105 (RP105). Disrupted immune response may contribute to the development of cardiac diseases, while the roles of MD‐1 remain elusive. Our studies aimed to explore the functions and molecular mechanisms of MD‐1 in obesity‐induced cardiomyopathy. H9C2 myocardial cells were treated with free fatty acid (FFA) containing palmitic acid and oleic acid to challenge high‐fat stimulation and adenoviruses harbouring human MD‐1 coding sequences or shRNA for MD‐1 overexpression or knockdown in vitro. MD‐1 overexpression or knockdown transgenic mice were generated to assess the effects of MD‐1 on high‐fat diet (HD) induced cardiomyopathy in vivo. Our results showed that MD‐1 was down‐regulated in H9C2 cells exposed to FFA stimulation for 48 hours and in obesity mice induced by HD for 20 weeks. Both in vivo and in vitro, silencing of MD‐1 accelerated myocardial function injury induced by HD stimulation through increased cardiac hypertrophy and fibrosis, while overexpression of MD‐1 alleviated the effects of HD by inhibiting the process of cardiac remodelling. Moreover, the MAPK and NF‐κB pathways were overactivated in MD‐1 deficient mice and H9C2 cells after high‐fat treatment. Inhibition of MAPK and NF‐κB pathways played a cardioprotective role against the adverse effects of MD‐1 silencing on high‐fat stimulation induced pathological remodelling. In conclusion, MD‐1 protected myocardial function against high‐fat stimulation induced cardiac pathological remodelling through negative regulation for MAPK/NF‐κB signalling pathways, providing feasible strategies for obesity cardiomyopathy.

Left ventricular chamber dilation and filling pressure may help to categorise patients with type 2 diabetes

BACKGROUND

Type 2 diabetes may alter cardiac structure and function. Many patients with type 2 diabetes have diastolic dysfunction with preserved ejection fraction (EF). Recently, this latter measure was criticised. Thus, this research looked at the impact of left ventricular end-diastolic volume and E/e' ratio variations in patients with type 2 diabetes and preserved EF with the aim to recognise different clinical phenotypes.

METHODS

In this cross-sectional study, we evaluated 176 men affected by type 2 diabetes with transthoracic echocardiography. All subjects have preserved EF (>50%). Patients were stratified into four groups based on the median value of both left ventricular end-diastolic volume and E/e' ratio, and the clinical variables were registered. The independent predictors associated with the groups were analysed by a multinomial logistic regression model.

RESULTS

Diabetes duration, age, estimated glomerular filtration rate and antihypertensive treatments were significantly different among the groups as were EF, left atrial volume index (LAVI), E/A, septum thickness and s' mean wave. Multinomial regression analysis showed that the groups significantly differed for age, diabetes duration, EF, LAVI, septum thickness and s' mean wave. The main result of this study was that patients with higher left ventricular volume and higher E/e' ratio (group 2) showed the worse clinical profile.

CONCLUSIONS

Our study might suggest that variations of left ventricular end-diastolic volume along with E/e' ratio variations, even in the normal range, may allow to recognise phenotypes of patients with type 2 diabetes with worse clinical characteristics. This finding should be tested in prospective studies to assess the predictive roles of these phenotypes.