Metabolic syndrome in subjects at high risk for type 2 diabetes: the genetic, physiopathology and evolution of type 2 diabetes (GENFIEV) study

Current Insights into the Effects of Dietary α-Linolenic Acid Focusing on Alterations of Polyunsaturated Fatty Acid Profiles in Metabolic Syndrome

The plant-derived α-linolenic acid (ALA) is an essential n-3 acid highly susceptible to oxidation, present in oils of flaxseeds, walnuts, canola, perilla, soy, and chia. After ingestion, it can be incorporated in to body lipid pools (particularly triglycerides and phospholipid membranes), and then endogenously metabolized through desaturation, elongation, and peroxisome oxidation to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), with a very limited efficiency (particularly for DHA), beta-oxidized as an energy source, or directly metabolized to C18-oxilipins. At this moment, data in the literature about the effects of ALA supplementation on metabolic syndrome (MetS) in humans are inconsistent, indicating no effects or some positive effects on all MetS components (abdominal obesity, dyslipidemia, impaired insulin sensitivity and glucoregulation, blood pressure, and liver steatosis). The major effects of ALA on MetS seem to be through its conversion to more potent EPA and DHA, the impact on the n-3/n-6 ratio, and the consecutive effects on the formation of oxylipins and endocannabinoids, inflammation, insulin sensitivity, and insulin secretion, as well as adipocyte and hepatocytes function. It is important to distinguish the direct effects of ALA from the effects of EPA and DHA metabolites. This review summarizes the most recent findings on this topic and discusses the possible mechanisms.

MG53 marks poor beta cell performance and predicts onset of type 2 diabetes in subjects with different degrees of glucose tolerance

AIM

- MG53 is a myokine modulating insulin signalling in several tissues; its relationship to glucose tolerance or risk of developing type 2 diabetes mellitus (T2DM) is unknown. This observational, prospective study aimed at evaluating the relationship between MG53 and glucose tolerance, testing whether its circulating levels may be associated with disease progression in a cohort at high risk of T2DM.

METHODS

- Five hundred and fifteen subjects who underwent a deep characterization of their glucose tolerance in the years 2003-2005 participated in this study. MG53 levels were measured at baseline. Glucose tolerance status was available over a follow-up of 15±2 years for 283 of them; their vital status as of December 2020 was also retrieved.

RESULTS

- MG53 levels were significantly lower in subjects with normal glucose tolerance than in subjects with impaired glucose regulation (IGR) or T2DM. Individuals in the highest MG53 levels quartile had more frequently 1h-post load glucose ≥155 mg/dL (54% vs 39%; p=0.015), worse proportional control of β-cell function (p<0.05-0.01), as determined by mathematical modelling, and worse Disposition Index (DI) (0.0155±0.0081 vs 0.0277±0.0030; p<0.0001). At follow-up, baseline MG53 levels were higher in progressors than in non-progressors (120.1±76.7 vs 72.7±63.2 pg/ml; p=0.001; ROC curve area for incident diabetes of 0.704). In a multivariable regression with classic risk factors for T2DM and DI, MG53 remained independently associated with progression with T2DM.

CONCLUSION

- MG53 may be a novel biomarker of glucose dysregulation associated with β-cell dysfunction, likely improving our ability to identify, among high-risk subjects, those more likely to develop T2DM.

Increasing glycaemia is associated with a significant decline in HDL cholesterol in women with prediabetes in two national populations

Internationally, studies have shown associations between lipids and glycemia; however, whether the link varies by gender and population has been rarely examined. We investigated relationships between glycemia and HDL- and Non-HDL-cholesterol and their modification by gender. We undertook a cross-sectional analysis from the National Health Examination Survey for Thailand (NHES-Thailand) and the Health Survey for England (HS-England) in adults aged 18-75 year. Glycaemia was assessed by FPG in Thailand and by HbA1c in the UK. In population- and gender-stratified analyses, the relationships between glycemia and lipids were explored. A total of 15,145 Thai and 3484 UK adults with blood measurement were included. The prevalences of prediabetes were: in NHES-Thailand, 16% (SE = 0.004), based on FPG (5.6 to < 7.0 mmol/L) and in HS-England, 19% (0.007) based on HbA1c (39 to < 48 mmol/mol). Increasingly abnormal glucose homeostasis was associated with increasing age, adiposity, SBP, proportion of antihypertensive and lipid-lowering agent use and with decreasing HDL-cholesterol. Independent of age, adiposity, smoking, alcohol, physical activity, and lipid and BP lowering drug use, increasing glycemia was associated with decreasing HDL-cholesterol specifically in women with prediabetes (NHES-Thailand, beta-coefficient - 0.07 (95% CI - 0.15, - 0.001) p = 0.04 and HS-England, - 0.03 (- 0.04, - 0.006) p = 0.01). In both populations, among those with prediabetes, increasing glycaemia is associated with an adverse, significant decline in HDL cholesterol, specifically in women. These adverse effects are apparent in widely-differing international populations.

Utility of metabolic syndrome as a risk enhancing factor in decision of statin use

BACKGROUND

Statins effectively reduce risk for atherosclerotic cardiovascular disease (ASCVD) when 10-year risk is ≥ 7.5%. In many patients at intermediate risk (7.5-<20% risk), there is uncertainty about reliability of risk assessment by current pooled cohort equations (PCE). A decision to initiate statin therapy is favored by several risk enhancing factors not employed in PCEs.

OBJECTIVE

This study examines the scope of the metabolic syndrome, a risk enhancing factor, and its principal sequala, diabetes, in 26,796 US adults age 40-75 years from the NHANES survey data, 1999-2016.

METHODS

The prevalence of metabolic syndrome without diabetes (MetS+) and of diabetes (DM+) were determined for 10-year risk categories estimated to be low (<7.5%), intermediate (7.5% -< 20%) and high (≥20%). Data were weighted to account for complex study design.

RESULTS

90.4% of the population was free of ASCVD. In subjects projected to be at low risk by PCEs, MetS+ was present in 15.0% and 17.6% of women and men, respectively. MetS + increased to 30.6% of women and 29.6% of men at intermediate risk, and to 21.5% of women and 32.2% of men at high risk. In addition, DM+ was present in 6.1%/5.3% (F/M) of low risk individuals, 20.1%/14.8% (F/M) of intermediate risk subjects, and 44.3%/39.4% (F/M) of high-risk persons. Prevalence of both MetS+ and DM + rose progressively with age in women and men.

CONCLUSIONS

MetS+ and DM + are common multiplex risk factors that predispose to higher lifetime risk and support statin therapy in patients at intermediate and high risk.

Assessment of Cardiovascular Risk Factors in Patients with Type 2 Diabetes in Upper Egypt Villages

BACKGROUND

A large percentage of diabetic patients also have other components of metabolic syndrome, which is a group of cardiovascular (CV) hazard factors related to both diabetes mellitus (DM) and cardiovascular diseases (CVD). We do not know about the prevalence of CV risk factors in diabetic patients in Upper Egypt. We aimed to assess the CV risk factors in type 2 diabetic patients in Upper Egypt villages.

METHODS

We conducted a cross-sectional study that included 800 patients with type 2 DM. We classified the participants into three groups according to the hemoglobin A1c (HbA1c) levels. We assessed the prevalence of other cardiovascular risk factors and their association with HbA1c levels through a detailed history, full clinical examination, and laboratory tests.

RESULTS

We found that 75% of the participants were males, 25.5% elderly, 60.25% had hypertension, 60.75% had dyslipidemia, 33.25% were overweight or obese, 19.75% had a family history of coronary artery disease (CAD), 55.75% had established CVD, 42.5% were smokers, and only 12.25% were physically inactive. We found that 84% of the participants had ≥ two cardiovascular risk factors other than DM. HbA1c level was ≥ 7% in 77% of patients. After multivariate regression analysis, we found a significant association of higher systolic blood pressure (BP), more elevated diastolic BP, higher body mass index (BMI), increased waist circumference, old age, long duration of DM, and an increase in the number of clustered CV risk factors with a higher HbA1c level. At the same time, insulin therapy was significantly associated with a lower HbA1c level.

CONCLUSION

All type 2 diabetic patients in Upper Egypt villages have other associated CV risk factors. The clustering of cardiovascular risk factors showed a significant association with higher HbA1c levels. These findings require the thought of associated CV risk factors in choosing medical treatments to optimize glycemic control and multifactorial intervention to improve CV risk.

Hypertensive disorders during pregnancy and 3 years after delivery in women with gestational hyperglycemia

AIMS

Women with gestational hyperglycemia commonly experience hypertensive disorders during pregnancy. More information is needed about how hypertension develops in these patients over time. We investigated the prevalence of hypertension during and 3 years after pregnancy in Caucasian women with gestational hyperglycemia. We also investigated metabolic syndrome presence, glucose tolerance status, insulin sensitivity and insulin secretion levels in the follow-up period.

METHODS

In a prospective longitudinal study with a 3-year follow-up, we assessed hypertension status and clinical-related characteristics of 103 consecutive women with gestational hyperglycemia sub-grouped according to their hypertensive status during and after pregnancy.

RESULTS

Overall, 29 (28.1%) women had hypertension during pregnancy (24 gestational hypertension; 4 chronic hypertension; 1 preeclampsia). At follow-up 16 (15.5%) women were diagnosed as having hypertension (11 with hypertension in pregnancy; 5 with a normotensive pregnancy). Women with hypertension after pregnancy had higher BMI, metabolic syndrome rate and worse insulin resistance indexes than normotensive women. Weight increase at follow-up (OR 1.17, 95% CI 1.00-1.35) and hypertension in pregnancy (OR 6.72, 95% CI 1.17-38.64) were associated with hypertension after pregnancy.

CONCLUSIONS

Women with gestational hyperglycemia should undergo regular monitoring during and after pregnancy to detect metabolic and clinical impairments and to prevent cardiovascular harm.

Prediabetes: A Worldwide Epidemic

Prediabetes, defined by blood glucose levels between normal and diabetic levels, is increasing rapidly worldwide. This abnormal physiologic state reflects the rapidly changing access to high-calorie food and decreasing levels of physical activity occurring worldwide, with resultant obesity and metabolic consequences. This is particularly marked in developing countries. Prediabetes poses several threats; there is increased risk of developing type 2 diabetes mellitus (T2DM), and there are risks inherent to the prediabetes state, including microvascular and macrovascular disease. Studies have helped to elucidate the underlying pathophysiology of prediabetes and to establish the potential for treating prediabetes and preventing T2DM.

Cardiometabolic Risk Profiles in Patients With Impaired Fasting Glucose and/or Hemoglobin A1c 5.7% to 6.4%: Evidence for a Gradient According to Diagnostic Criteria: The PREDAPS Study

It has been suggested that the early detection of individuals with prediabetes can help prevent cardiovascular diseases. The purpose of the current study was to examine the cardiometabolic risk profile in patients with prediabetes according to fasting plasma glucose (FPG) and/or hemoglobin A1c (HbA1c) criteria.Cross-sectional analysis from the 2022 patients in the Cohort study in Primary Health Care on the Evolution of Patients with Prediabetes (PREDAPS Study) was developed. Four glycemic status groups were defined based on American Diabetes Association criteria. Information about cardiovascular risk factors-body mass index, waist circumference, blood pressure, cholesterol, triglycerides, uric acid, gamma-glutamyltransferase, glomerular filtration-and metabolic syndrome components were analyzed. Mean values of clinical and biochemical characteristics and frequencies of metabolic syndrome were estimated adjusting by age, sex, educational level, and family history of diabetes.A linear trend (P < 0.001) was observed in most of the cardiovascular risk factors and in all components of metabolic syndrome. Normoglycemic individuals had the best values, individuals with both criteria of prediabetes had the worst, and individuals with only one-HbA1c or FPG-criterion had an intermediate position. Metabolic syndrome was present in 15.0% (95% confidence interval: 12.6-17.4), 59.5% (54.0-64.9), 62.0% (56.0-68.0), and 76.2% (72.8-79.6) of individuals classified in normoglycemia, isolated HbA1c, isolated FPG, and both criteria groups, respectively.In conclusion, individuals with prediabetes, especially those with both criteria, have worse cardiometabolic risk profile than normoglycemic individuals. These results suggest the need to use both criteria in the clinical practice to identify those individuals with the highest cardiovascular risk, in order to offer them special attention with intensive lifestyle intervention programs.

PPARG2 Pro12Ala and ADAMTS9 rs4607103 as "insulin resistance loci" and "insulin secretion loci" in Italian individuals. The GENFIEV study and the Verona Newly Diagnosed Type 2 Diabetes Study (VNDS) 4

We investigated cross-sectionally whether the type 2 diabetes (T2DM) risk alleles of rs1801282 (PPARG2) and rs4607103 (ADAMTS9) were associated with T2DM and/or insulin sensitivity (IS) and beta cell function (βF) in Italians without and with newly diagnosed T2DM. In 676 nondiabetic subjects (336 NGR and 340 IGR) from the GENFIEV study and in 597 patients from the Verona Newly Diagnosed Type 2 Diabetes Study (VNDS), we (1) genotyped rs1801282 and rs4607103, (2) assessed βF by C-peptide/glucose modeling after OGTT, and (3) assessed IS by HOMA-IR in both studies and by euglycemic insulin clamp in VNDS only. Logistic, linear, and two-stage least squares regression analyses were used to test (a) genetic associations with T2DM and with pathophysiological phenotypes, (b) causal relationships of the latter ones with T2DM by a Mendelian randomization design. Both SNPs were associated with T2DM. The rs4607103 risk allele was associated to impaired βF (p < 0.01) in the GENFIEV study and in both cohorts combined. The rs1801282 genotype was associated with IS both in the GENFIEV study (p < 0.03) and in the VNDS (p < 0.03), whereas rs4607103 did so in the VNDS only (p = 0.01). In a Mendelian randomization design, both HOMA-IR (instrumental variables: rs1801282, rs4607103) and βF (instrumental variable: rs4607103) were related to T2DM (p < 0.03-0.01 and p < 0.03, respectively). PPARG2 and ADAMTS9 variants are both associated with T2DM and with insulin resistance, whereas only ADAMTS9 may be related to βF. Thus, at least in Italians, they may be considered bona fide "insulin resistance genes".

Pre-diabetes, metabolic syndrome, and cardiovascular risk

Pre-diabetes represents an elevation of plasma glucose above the normal range but below that of clinical diabetes. Pre-diabetes can be identified as either impaired fasting glucose (IFG) or impaired glucose tolerance (IGT). The latter is detected by oral glucose tolerance testing. Both IFG and IGT are risk factors for type 2 diabetes, and risk is even greater when IFG and IGT occur together. Pre-diabetes commonly associates with the metabolic syndrome. Both in turn are closely associated with obesity. The mechanisms whereby obesity predisposes to pre-diabetes and metabolic syndrome are incompletely understood but likely have a common metabolic soil. Insulin resistance is a common factor; systemic inflammation engendered by obesity may be another. Pre-diabetes has only a minor impact on microvascular disease; glucose-lowering drugs can delay conversion to diabetes, but whether in the long run the drug approach will delay development of microvascular disease is in dispute. To date, the drug approach to prevention of microvascular disease starting with pre-diabetes has not been evaluated. Pre-diabetes carries some predictive power for macrovascular disease, but most of this association appears to be mediated through the metabolic syndrome. The preferred clinical approach to cardiovascular prevention is to treat all the metabolic risk factors. For both pre-diabetes and metabolic syndrome, the desirable approach is lifestyle intervention, especially weight reduction and physical activity. When drug therapy is contemplated and when the metabolic syndrome is present, the primary consideration is prevention of cardiovascular disease. The major targets are elevations of cholesterol and blood pressure.

Blood glucose control and coronary heart disease

Epidemiologic data support the hypothesis of a direct and independent relationship between hyperglycemia and cardiovascular disease. The lack of a clear-cut threshold value in diabetic patients, and the persistence of the relationship in nondiabetic population as well, suggest that glycemia is a continuous variable, similarly to other cardiovascular risk factors. Moreover, increased plasma glucose levels contribute to cardiovascular risk by activating multiple atherogenic mechanisms. In spite of evident plausibility for hyperglycemia as a cardiovascular risk factor per se, intervention data remain controversial. Results of recent large-scale intervention trials, such as ACCORD, ADVANCE, and VADT, seem to undermine the concept that tight glycemic control confers some protection against cardiovascular disease in patients with type 2 diabetes, while maintenance of near-normal glycemic control from earlier stage of the disease and during acute coronary events seems to be more beneficial. However, individualized therapies remain the cornerstone of strategies aimed to reduce cardiovascular risk associated to hyperglycemia.