Hepatic rather than cardiac steatosis relates to glucose intolerance in women with prior gestational diabetes

Assessment of fetal hepatic lipid content by magnetic resonance imaging and association of results with clinical maternal and fetal parameters

PURPOSE

To quantify hepatocellular lipids in the fetal liver, we tested the feasibility of the multiecho mDixon Quant sequence (chemical shift encoded magnetic resonance imaging (MRI)) during clinically routine fetal whole-body MRI and investigated the correlation of hepatocellular lipids with different clinical maternal and fetal parameters.

METHODS

The livers of 155 fetuses were prospectively investigated with multiecho CSE-MRI sequences during clinically indicated whole-body MRI, performed between gestational weeks 19 and 38 on a 1.5 Tesla scanner. The hepatocellular lipids were quantified by measuring the proton density fat fraction in the left and right liver lobe. Results of the right liver lobe were correlated with the maternal body mass index, maternal age, presence of maternal diabetes, gestational age at assessment, estimated fetal weight, fetal sex, and birth weight.

RESULTS

Quantification of fetal hepatocellular lipids was feasible in 151/155 (97.4 %) fetuses. Four examinations were excluded due to strong motion artifacts and poor image quality. The proton density fat fraction values ranged from 0 % to 5.7 % (mean 2.26; SD 1.37). Hepatocellular lipids were associated with the presence of maternal diabetes (p = 0.027). No association was found between hepatocellular lipids and maternal body mass index (p = 0.306), maternal age (p = 0.582), gestational age (p = 0.456), estimated fetal weight (p = 0.176), fetal sex (p = 0.181), or birth weight (p = 0.957).

CONCLUSION

Quantification of fetal hepatocellular lipids is feasible and may routinely be performed during whole-body MRI to detect early liver fat accumulation, particularly in the presence of maternal diabetes.

Sex differences in ectopic lipid deposits and cardiac function across a wide range of glycemic control: a secondary analysis

OBJECTIVE

The objective of this study was to identify sex differences in ntrahepatocellular (HCL) and intramyocardial lipids (MYCL) and cardiac function in participants with different grades of glucometabolic impairment and different BMI strata.

METHODS

Data from 503 individuals from 17 clinical experimental studies were analyzed. HCL and MYCL were assessed with 3T and 7T scanners by magnetic resonance spectroscopy. Cardiac function was measured with a 3T scanner using electrocardiogram-gated TrueFISP sequences. Participants were classified as having normoglycemia, prediabetes, or type 2 diabetes. Three-way ANCOVA with post hoc simple effects analyses was used for statistical assessment.

RESULTS

Consistent increases of HCL with BMI and deterioration of glucose metabolism, especially in female individuals, were detected. MYCL increased with BMI and glucose impairment in female individuals, but not in male individuals. Sex differences were found in cardiac function loss, with significant effects found among male individuals with worsening glucose metabolism. Myocardial mass and volume of the ventricle were higher in male individuals in all groups. This sex difference narrowed with increasing BMI and with progressing dysglycemia.

CONCLUSIONS

Sex differences in HCL and MYCL may be associated with a higher cardiovascular disease risk observed in female individuals progressing to diabetes. Further studies are needed to elucidate possible sex differences with advancing glucometabolic impairment and obesity and their potential impact on cardiovascular outcomes.

Myocardial steatosis across the spectrum of human health and disease

Preclinical data strongly suggest that myocardial steatosis leads to adverse cardiac remodelling and left ventricular dysfunction. Using 1 H cardiac magnetic resonance spectroscopy, similar observations have been made across the spectrum of health and disease. The purpose of this brief review is to summarize these recent observations. We provide a brief overview of the determinants of myocardial triglyceride accumulation, summarize the current evidence that myocardial steatosis contributes to cardiac dysfunction, and identify opportunities for further research.

Cardiovascular risk factors in women with previous gestational diabetes mellitus: A systematic review and meta-analysis

This systematic review and meta-analysis aimed to synthesize evidence on conventional cardiovascular disease (CVD) risk factors among women with previous Gestational Diabetes Mellitus (GDM). The review protocol is registered with PROSPERO (CRD42019118149). PubMed, CINAHL, SCOPUS, and EMBASE databases were searched. Studies reporting on CVD risk factors in women with previous GDM compared to women without previous GDM were selected. A total of 139 studies were eligible, of which 93 were included in the meta-analysis. Women with previous GDM have significantly higher systolic blood pressure (2.47 mmHg 95% CI 1.74 to 3.40, n = 48, 50,118 participants) diastolic blood pressure (1.89 mmHg 95% CI 1.32 to 2.46, n = 48, 49,495 participants), BMI (1.54 kg/m2 95% CI 1.32 to 2.46, n = 78, 255,308 participants), total cholesterol (0.26 SMD 95% CI 0.15 to 0.37, n = 48, 38,561 participants), LDL cholesterol (0.19 SMD 95% CI 0.08 to 0.30, n = 44, 16,980 participants), triglycerides (0.56 SMD 95% CI 0.42 to 0.70, n = 46, 13,175 participants), glucose (0.69 SMD 95% CI 0.56 to 0.81, n = 55, 127,900 participants), insulin (0.41 SMD 95% CI 0.23 to 0.59, n = 32, 8881 participants) and significantly lower HDL cholesterol (-0.28 SMD 95% CI -0.39 to -0.16, n = 56, 35,882 participants), compared to women without previous GDM. The increased blood pressure, total cholesterol, triglycerides and glucose are seen as early as <1 year post-partum.Women with previous GDM have a higher risk of CVD based on significant increases in conventional risk factors. Some risk factors are seen as early as <1 year post-partum. Women with GDM may benefit from early screening to identify modifiable CVD risk factors.

Hepatic fat and glucose tolerance in women with recent gestational diabetes

OBJECTIVE

Women with a history of gestational diabetes mellitus (GDM) have an elevated risk of ultimately developing pre-diabetes and diabetes later in life. They also have an increased prevalence of fatty liver, but recent studies have reported conflicting findings on whether hepatic fat affects their risk of pre-diabetes/diabetes. Thus, we sought to evaluate the associations of liver fat with glucose homeostasis and determinants thereof in women with and without recent gestational dysglycemia.

METHODS

Two hundred and fifty-seven women underwent an antepartum oral glucose tolerance test (OGTT), which diagnosed 97 with GDM, 40 with gestational impaired glucose tolerance (GIGT), and 120 with normal glucose tolerance (NGT). At a mean of 4.8 years post partum, they underwent an OGTT (which revealed that 52 had progressed to pre-diabetes/diabetes) and hepatic ultrasound, on which liver fat was graded as none (n=164), mild (n=66), or moderate (n=27).

RESULTS

Liver fat was more prevalent in women with previous GDM than in those with GIGT or NGT (p=0.009) and in women with current pre-diabetes/diabetes than in those without (p=0.0003). As the severity of liver fat increased, there was a progressive worsening of insulin sensitivity and beta-cell function, coupled with rising fasting and 2-hour glucose (all p<0.0001). On multiple linear regression analyses, moderate liver fat was independently associated with lower insulin sensitivity (p=0.0002) and higher 2-hour glucose (p=0.009). Moreover, moderate liver fat emerged as an independent predictor of pre-diabetes/diabetes (OR=3.66, 95% CI 1.1 to 12.5).

CONCLUSION

The higher prevalence of liver fat in women with previous GDM is associated with their increased risk of pre-diabetes/diabetes.

Gliptin therapy reduces hepatic and myocardial fat in type 2 diabetic patients

BACKGROUND

Increased hepatic fat and cardiac fat are common in patients with type 2 diabetes mellitus (T2DM) and are associated with a greater risk of liver fibrosis and cardiovascular (CV) events. Sex-specific differences of dipeptidyl peptidase-four (DPP-4) inhibitor effects on hepatic (HCL) and myocardial fat content (MYCL) have not yet been evaluated.

METHOD

Forty-one T2DM patients (20 male, 21 female) received a gliptin add-on therapy if HbA1c goals were not reached under metformin monotherapy. They underwent cardiac and liver magnetic resonance tomography and spectroscopy before and 6 months after therapy initiation. Plasma samples were analysed for the growth differentiation factor 15 (GDF-15), a novel marker for cardiovascular risk.

RESULTS

Thirty-eight patients on gliptin therapy completed the study. We observed a positive correlation between MYCL and HCL before therapy (R = 0·41, P = 0·05). After 6 months of therapy, we noticed a significant weight reduction in women only (P = 0·02) whereas waist circumference decreased similarly in both sexes. HbA1c sunk significantly in both sexes (P = 0·002). HCL decreased significantly (P = 0·0004), with women featuring higher basal HCL (P < 0·05). MYCL decreased in women only (P = 0·01) and GDF-15 comparably in both sexes (P < 0·05).

CONCLUSIONS

6 months of DPP-4-therapy led to a significant overall decrease in HCL and body weight such as a reduction of MYCL only in women. This preliminary data set could implicate that gliptin may be a feasible therapy option in fatty liver patients with diabetes potentially including positive effects on cardiovascular function particularly in women.

Sex and Gender Differences in Risk, Pathophysiology and Complications of Type 2 Diabetes Mellitus

The steep rise of type 2 diabetes mellitus (T2DM) and associated complications go along with mounting evidence of clinically important sex and gender differences. T2DM is more frequently diagnosed at lower age and body mass index in men; however, the most prominent risk factor, which is obesity, is more common in women. Generally, large sex-ratio differences across countries are observed. Diversities in biology, culture, lifestyle, environment, and socioeconomic status impact differences between males and females in predisposition, development, and clinical presentation. Genetic effects and epigenetic mechanisms, nutritional factors and sedentary lifestyle affect risk and complications differently in both sexes. Furthermore, sex hormones have a great impact on energy metabolism, body composition, vascular function, and inflammatory responses. Thus, endocrine imbalances relate to unfavorable cardiometabolic traits, observable in women with androgen excess or men with hypogonadism. Both biological and psychosocial factors are responsible for sex and gender differences in diabetes risk and outcome. Overall, psychosocial stress appears to have greater impact on women rather than on men. In addition, women have greater increases of cardiovascular risk, myocardial infarction, and stroke mortality than men, compared with nondiabetic subjects. However, when dialysis therapy is initiated, mortality is comparable in both males and females. Diabetes appears to attenuate the protective effect of the female sex in the development of cardiac diseases and nephropathy. Endocrine and behavioral factors are involved in gender inequalities and affect the outcome. More research regarding sex-dimorphic pathophysiological mechanisms of T2DM and its complications could contribute to more personalized diabetes care in the future and would thus promote more awareness in terms of sex- and gender-specific risk factors.

Myocardial Fat Accumulation Is Independent of Measures of Insulin Sensitivity

BACKGROUND

Myocardial steatosis, an independent predictor of diastolic dysfunction, is frequently present in type 2 diabetes mellitus. High free fatty acid flux, hyperglycemia, and hyperinsulinemia may play a role in myocardial steatosis. There are no prior studies examining the relationship between insulin sensitivity (antilipolytic and glucose disposal actions of insulin) and cardiac steatosis.

OBJECTIVE

Using a cross-sectional study design of individuals with and without metabolic syndrome (MetSyn), we examined the relationships between cardiac steatosis and the sensitivity of the antilipolytic and glucose disposal actions of insulin.

METHODS

Pericardial fat (PF) volume, intramyocardial and hepatic fat (MF and HF) content, visceral fat (VF) and sc fat content were assessed by magnetic resonance imaging in 77 subjects (49 without MetSyn and 28 with MetSyn). In a subset of the larger cohort (n = 52), peripheral insulin sensitivity index (SI) and adipocyte insulin sensitivity (Adipo-SI) were determined from an insulin-modified frequently sampled iv glucose tolerance test. The Quantitative Insulin Sensitivity Check Index was used as a surrogate for hepatic insulin sensitivity.

RESULTS

Individuals with the MetSyn had significantly higher body mass index, total body fat, and MF, PF, HF, and VF content. HF and VF, but not MF, were negatively correlated with the Quantitative Insulin Sensitivity Check Index, Adipo-SI, and SI. Stepwise regression revealed that waist circumference and serum triglyceride levels independently predicted MF and PF, respectively. Adipo-SI and serum triglyceride levels independently predict HF.

CONCLUSION

Myocardial steatosis is unrelated to hepatic, adipocyte, or peripheral insulin sensitivity. Although it is frequently observed in insulin-resistant subjects, further studies are necessary to identify and delineate pathogenic mechanisms that differentially affect cardiac and hepatic steatosis.