Effect of vitamin E supplementation on HDL function by haptoglobin genotype in type 1 diabetes: results from the HapE randomized crossover pilot trial

Effects of dietary supplementation in treatment and control of progression and complications of insulin-dependent diabetes mellitus: a systematic review with meta-analyses of randomized clinical trials

There is no safe and effective prevention for insulin-dependent diabetes (IDDM) mellitus, which makes it highly dependent on its treatment. This systematic review with meta-analyses of randomized clinical trials investigated the overall effects of dietary supplements of vitamins, minerals, trace elements, and non-essential compounds with antioxidant properties, fatty acids, and amino acids in IDDM. Searches of MEDLINE, Embase, CENTRAL, LILACS, The Grey Literature Report, and ClinicaTrials.gov, and citations from previous reviews were used to identify reports published through July 2023. The Risk of Bias 2 (RoB2) tool was used to analyze the risk of bias and GRADE was used to assess the quality of the results. Fifty-eight studies (n=3,044) were included in qualitative analyses and seventeen (n=723) in meta-analyses. Qualitative analyses showed few positive effects on some metabolic function markers, such as endothelial and renal function and lipid profile. Meta-analyses showed a positive effect of omega-3 on glycated hemoglobin (HbA1c) (RMD=-0.33; 95%CI: -0.53, -0.12, P=0.002; I2=0%; GRADE: low quality; 4 studies) and of vitamin D on fasting C-peptide (FCP) (RMD=0.05; 95%CI: 0.01, 0.9, P=0.023; I2=0%; GRADE: very low quality; 4 studies). Most studies showed bias concern or high risk of bias. A recommendation for dietary supplementation in IDDM cannot be made because of the few positive results within different interventions and markers, the serious risk of bias in the included studies, and the low quality of evidence from meta-analyses. The positive result of vitamin D on FCP is preliminary, requiring further investigation.

Haptoglobin phenotype and intensive glycemic control for coronary artery disease risk reduction in people with type two diabetes: The Veterans Affairs Diabetes Trial

Background

Intensive glycemic control reduced the risk of coronary artery disease (CAD) events among White ACCORD study participants with the haptoglobin (Hp)2-2 phenotype, and not among participants without the Hp2-2 phenotype. It is unknown whether these results persist in a population with more severe diabetes.

Methods

Haptoglobin phenotype was measured in 1746 (97 %) samples from the Veterans Affairs Diabetes Trial (VADT) randomized controlled trial. Multivariable-adjusted Cox regression models assessed the effect of intensive therapy on CAD risk among participants with and without the Hp2-2 phenotype separately and when stratified within pre-specified race/ethnicity-based subgroups. Time-varying (achieved) HbA1c data (<7.0 % or ≥8.0 % compared to 7.0-7.9, updated every 3 months) were also analyzed in relation to CAD risk within each phenotype.

Results

567 (32.5 %) participants had the Hp2-2 phenotype. Compared to standard therapy, intensive glycemic control was not associated with risk of CAD among participants with the non-Hp2-2 or the Hp2-2 phenotype or for any race/ethnicity-based group. Compared to HbA1c of 7.0-7.9 %, having HbA1c <7.0 % was not associated with CAD risk for either phenotype or among any race/ethnicity-based group. Having HbA1c ≥8.0 % was associated with an increased risk of CAD among Hispanic participants without the Hp2-2 phenotype (HR= 3.61, 95 % CI: 1.54-8.41, p-interaction=0.53).

Conclusion

The effect of intensive glycemic therapy on CAD events was not dependent on Hp phenotype in the VADT study of veterans with severe diabetes who may represent a population where Hp phenotype information would not be useful for personalizing diabetes management. However, further research is needed to determine if these results are conclusive.

Intensive lifestyle intervention in type 2 diabetes and risk of incident coronary artery disease for the common haptoglobin phenotypes: the Look AHEAD study

BACKGROUND

Intensive glycemic control reduced coronary artery disease (CAD) events among the Action to Control Cardiovascular Disease Risk in Diabetes (ACCORD) participants with the haptoglobin (Hp) 2-2 phenotype only. It remains unknown whether Hp phenotype modifies the effect of an intensive lifestyle intervention (ILI) on CAD in type 2 diabetes.

METHODS

Haptoglobin phenotype was measured in 4542 samples from the Action for Health in Diabetes (Look AHEAD) study. Cox regression models assessed the effect of ILI (focused on weight loss from caloric restriction and physical activity) versus diabetes support and education (DSE) on CAD events in each phenotype group, and within pre-specified subgroups including race/ethnicity, sex, history of cardiovascular disease, diabetes medication use, and diabetes duration.

RESULTS

1590 (35%) participants had the Hp2-2 phenotype. The ILI did not lower glycated hemoglobin (%HbA1c) to < 6.5% in either phenotype, with a peak significant difference between treatment arms of 0.5% [non-Hp2-2] and 0.6% [Hp2-2]. The cumulative CAD incidence was 13.4% and 13.8% in the DSE arm and 12.2% and 13.6% in the ILI arm for non-Hp2-2 and Hp2-2 groups, respectively. Compared to DSE, the ILI was not associated with CAD among participants without (HR = 0.95, 95% CI 0.78-1.17) or with (0.89, 0.68-1.19) the Hp2-2 phenotype (p-interaction between Hp phenotype and ILI = 0.58). After Bonferroni correction, there were no significant results among any subgroups.

CONCLUSIONS

Hp phenotype did not modify the effect of the weight loss ILI on risk of CAD in Look AHEAD, potentially because it did not substantially impact glycemic control among participants with or without the Hp2-2 phenotype. Further research is needed to determine if these results are conclusive.

Relationship Between Time-Varying Achieved High-Density Lipoprotein Cholesterol and Risk of Coronary Events Depends on Haptoglobin Phenotype Within the ACCORD Lipid Study

Background The Hp (haptoglobin)2-2 phenotype (~40% of people) is associated with dysfunctional high-density lipoprotein (HDL) that is heavily oxidized in hyperglycemia, which may explain why raising HDL-cholesterol (HDL-C) does not reliably prevent coronary artery disease (CAD) in diabetes. Methods and Results In this observational study using longitudinal data from the ACCORD (Action to Control Cardiovascular Risk in Diabetes) lipid trial, time-varying (achieved) HDL-C updated at 4, 8, and 12 months, and annually thereafter over a mean of 4.7 years, was analyzed in relation to risk of CAD and secondary outcomes using Cox proportional hazards regression with time-varying covariables among participants with (n=1781) and without (n=3191) the Hp2-2 phenotype. HDL-C did not differ between the phenotypes throughout the study. Having low HDL-C (<40 mg/dL for male participants and <50 mg/dL for female participants) was associated with a greater risk of CAD compared with non-low HDL-C among participants with the non-Hp2-2 phenotype (hazard ratio [HR], 1.48 [95% CI, 1.18-1.87]) but not among the Hp2-2 phenotype (HR, 0.97 [95% CI, 0.70-1.35]; P interaction=0.03). Similarly, an inverse relationship was observed between HDL-C quintiles and CAD risk among participants without the Hp2-2 phenotype, whereas no significant inverse relationship was observed among participants with the Hp2-2 phenotype (P interaction=0.38). Among the Hp2-2 phenotype group, having low HDL-C was associated with higher risk of CVD mortality (HR, 2.09 [95% CI, 1.05-4.13]), and compared with the lowest HDL-C quintile, higher quintiles were associated with lower risk of CVD mortality and congestive heart failure. Conclusions Hp phenotype modified the association between HDL-C and risk of CAD in the ACCORD lipid study, suggesting that HDL dysfunction in the Hp2-2 phenotype may hinder CAD-protective properties of HDL-C.

Nutrient Patterns and Its Association and Metabolic Syndrome among Chinese Children and Adolescents Aged 7-17

This study was designed to explore the associations between nutrient patterns (NPs) and metabolic syndrome (MetS) and its five components among Chinese children and adolescents aged 7-17. The required data of participants were collected from the China National Nutrition and Health Surveillance of Children and Lactating Mothers in 2016-2017. Ultimately, 13,071 participants were included. Nutrient patterns were obtained by means of factor analysis. Multivariate logistic regression analysis was conducted to evaluate the association between nutrient patterns with MetS and its components. After adjusting covariates, the results of logistic regression models revealed that high-carbohydrate patterns were associated with the presence of abdominal obesity. The high-animal protein pattern was negatively associated with high triglyceride (TG) and low high-density lipoprotein cholesterol (HDL-C). The high-sodium-and-fat pattern had a negative relationship with elevated blood pressure (BP) and was positively associated with low HDL-C. The high-Vitamin D-and-Vitamin B₁₂ pattern had protective effects on MetS, high TG, and low HDL-C. Further large-scale longitudinal investigations are necessary in the future.

Omics as a Tool to Help Determine the Effectiveness of Supplements

There has been considerable interest in dietary supplements in the last two decades. Companies are releasing new specifics at an alarming pace, while dietary supplements are one of the less-studied substances released for public consumption. However, access to state-of-the-art and high-throughput techniques, such as the ones used in omics, make it possible to check the impact of a substance on human transcriptome or proteome and provide answers to whether its use is reasonable and beneficial. In this review, the main domains of omics are briefly introduced. The review focuses on the three most widely used omics techniques: NGS, LC-MS, NMR, and their usefulness in studying dietary supplements. Examples of studies are described for some of the most commonly supplemented substances, such as vitamins: D, E, A, and plant extracts: resveratrol, green tea, ginseng, and curcumin extract. Techniques used in omics have proven to be useful in studying dietary supplements. NGS techniques are helpful in identifying pathways that change upon supplementation and determining polymorphisms or conditions that qualify for the necessity of a given supplementation. LC-MS techniques are used to establish the serum content of supplemented a compound and its effects on metabolites. Both LC-MS and NMR help establish the actual composition of a compound, its primary and secondary metabolites, and its potential toxicity. Moreover, NMR techniques determine what conditions affect the effectiveness of supplementation.

Cardiovascular Disease in Adults with Type 1 Diabetes: Looking Beyond Glycemic Control

PURPOSE OF REVIEW

Despite improvements in treatment, people with type 1 diabetes continue to have increased cardiovascular disease (CVD) risk. Glycemic control does not fully explain this excess CVD risk, so a greater understanding of other risk factors is needed.

RECENT FINDINGS

The authors review the relationship between glycemia and CVD risk in adults with type 1 diabetes and summarize evidence regarding other factors that may explain risk beyond glycemia. Insulin resistance, weight gain, sex differences, genetics, inflammation, emerging markers of risk, including lipid subclasses and epigenetic modifications, and future directions are discussed. As glycemic control improves, an increased focus on other CVD risk factors is warranted in type 1 diabetes. Novel markers and precision medicine approaches may improve CVD prediction, but a lack of type 1 diabetes-specific guidelines for lipids, blood pressure, and physical activity are likely impediments to optimal CVD prevention in this high-risk population.

Haptoglobin Phenotype Modifies the Effect of Fenofibrate on Risk of Coronary Event: ACCORD Lipid Trial

OBJECTIVE

The haptoglobin (Hp)2-2 phenotype (∼35-40% of people) is associated with increased oxidation and dysfunctional HDL in hyperglycemia and may explain why drugs designed to pharmacologically raise HDL cholesterol and lower triglycerides have not reliably prevented cardiovascular disease in diabetes. We aimed to determine whether the effect of adding fenofibrate versus placebo to simvastatin on the risk of coronary artery disease (CAD) events depends on Hp phenotype in the Action to Control Cardiovascular Risk in Diabetes (ACCORD) lipid trial.

RESEARCH DESIGN AND METHODS

Cox proportional hazards regression models quantified the relationship between fenofibrate therapy and CAD events in the ACCORD lipid trial in participants with the Hp2-2 phenotype (n = 1,795) separately from those without (n = 3,201).

RESULTS

Fenofibrate therapy successfully lowered the risk of CAD events in participants without the Hp2-2 phenotype (multivariable adjusted hazard ratio 0.74 [95% CI 0.60-0.90] compared with no fenofibrate therapy) but not in participants with the Hp2-2 phenotype (1.16 [0.87-1.56]; P interaction = 0.009). Subgroup analyses revealed that this protective effect of fenofibrate against CAD events among the non-Hp2-2 phenotype group was pronounced in participants with severe dyslipidemia (P interaction = 0.01) and in males (P interaction = 0.02) with an increased CAD risk from fenofibrate treatment observed in females with the Hp2-2 phenotype (P interaction = 0.002).

CONCLUSIONS

The effect of fenofibrate added to simvastatin on risk of CAD events depends on Hp phenotype in the ACCORD lipid trial.

Effects of Dietary Education Program for the Japan Diet on Cholesterol Efflux Capacity: A Randomized Controlled Trial

Aim: Improving cholesterol efflux capacity (CEC) of high-density lipoprotein (HDL) has been regarded as a novel target for preventing cardiovascular disease. HDL reportedly has antioxidant properties which may contribute to its functions. We investigated changes in CEC with intake of the Japan Diet (JD) recommended by the Japan Atherosclerosis Society and the relationship of these changes to serum antioxidant concentrations.

Methods: A randomized parallel controlled clinical trial on JD intake was performed in Japanese patients with dyslipidemia. Ninety-eight participants were randomly divided into the JD (n=49) or the partial JD (PJD) (n=49) group. Nutrition education, based on each diet at baseline and at 3 months, was provided and the participants were followed up for 6 months.

Results: Mean CEC was 1.05 in total and correlated positively with HDL-cholesterol (p＜0.001) at baseline. CEC did not change while oxygen radical absorbance capacity (ORAC) was decreased in both groups (p＜0.001). Although serum total carotenoid increased in both groups, serum α-tocopherol decreased in the JD group as compared to the PJD group (p＜0.05). CEC correlated positively with HDL ORAC at baseline (p=0.021) and with serum total carotenoid at 3 and 6 months (p=0.005, 0.035). Changes in CEC correlated positively with changes in HDL ORAC at 3 months and serum total tocopherol at 3 and 6 months (p＜0.001).

Conclusion: CEC was not changed by JD education in Japanese patients with dyslipidemia who already had normal CEC at baseline. CEC was suggested to be positively associated with serum α- and γ-tocopherol and HDL ORAC.

Diet-derived nutrient patterns and components of metabolic syndrome: a cross-sectional community- based study

BACKGROUND

Metabolic syndrome (MetS) is one of the main public health problems worldwide. Although some relations between dietary intakes and MetS have been found, few studies have focused on association between dietary nutrients interactions and the risk of the MetS and its components. The aim of the present study was to examine the association between nutrient patterns and MetS and its components among Iranian adult population.

METHODS

A total of 588 subjects (aged 18-64 years, 271 males and 317 females) enrolled in the cross sectional study. Dietary consumption was evaluated using an 80-item food frequency questionnaire (FFQ). Biochemical assessments including fasting blood sugar (FBS), aspartate aminotransferase (AST), alanine amino transferase (ALT) and serum lipids were performed by enzymatic methods. Nutrient patterns were obtained by factor analysis procedure using principal component method. Multinational logistic regression analysis was used to evaluate the association between nutrient patterns and MetS and its components.

RESULTS

Three nutrient patterns explaining 53.66% of the variance in dietary nutrients intake, were recognized in the current study. Animal-sourced nutrient pattern was significantly associated with the higher odds of MetS and high triglyceride (TG) levels. Plant-sourced nutrient pattern (high intake of fiber, carbohydrate, vitamins B₆, B₃, C, B₁, E, D, magnesium, potassium, and linoleic acid) was significantly associated with lower risk of MetS and lower blood pressure (p < 0.05). Third nutrient pattern (mixed-source) was significantly related to higher risk of MetS, high waist circumference (WC) and high systolic blood pressure (SBP).

CONCLUSION

This present study confirms the important effect of nutrients and their patterns on MetS risk. Our results suggest that adherence to the nutrient pattern rich in fiber, carbohydrate, vitamins D, B₆, B₃, C, B₁, E, magnesium, potassium, linoleic acid, and docosahexaenoic acid (DHA) is associated with a lower risk of MetS, while animal- and mixed-sourced nutrient patterns are positively associated with greater odds of MetS; However, further longitudinal and interventional studies are required to make a clear conclusion.

Impact of Vitamin E supplementation on vascular function in haptoglobin genotype stratified diabetes patients (EVAS Trial): a randomised controlled trial

AIMS

Vitamin E (Vit-E) may preferentially improve cardiovascular risk in haptoglobin 2-2 (Hp2-2) genotype diabetes individuals. We studied the impact of Vit-E supplementation on vascular function in diabetes individuals stratified by haptoglobin genotype in Singapore.

METHODS

In this 24-week, double blind, placebo-controlled RCT, we recruited 187 subjects (101 Hp2-2, 86 non-Hp2-2).

INTERVENTION

alpha-tocopherol-400 IU.

PRIMARY OUTCOME

Change in EndoPAT-derived reactive-hyperaemia index (RHI) and augmentation index (AIx); Secondary Outcomes: Pulse-Wave velocity (Sphygmocor-PWV), carotid intima media thickness (CIMT), inflammation (hsCRP), derivatives of reactive-oxygen metabolites (dROMs), biological antioxidant-potential (BAPs), HbA1c, LDL-C, HDL-C and oxidised LDL-C (ox-LDL).

RESULTS

Overall, with Vit-E supplementation no significant change in RHI, PWV, CIMT, hsCRP, dROMS, BAPs, HDL-C and HbA1c was observed (p > 0.05); an increase in LDL-C with concomitant decrease in ox-LDL, and incidentally increase in eGFR was observed (p < 0.05). No interaction effect with haptoglobin genotype was seen for all outcomes (p > 0.05). Subgroup analysis: In the non-Hp-2-2 group, Vit-E supplementation led to a higher EndoPAT-derived AIx, accompanied by higher LDL and ox-LDL concentrations (p < 0.05); Hp2-2 group: Vit-E supplementation led to higher eGFR when compared to the non-Hp2-2 group (exploratory) (p < 0.05). We observed an interaction effect for baseline haptoglobin concentration (threshold > 119 mg/dl) with intervention in terms of increased EndoPAT-derived AIx in the Hp > 119 mg/dl group whereas no change in the group with Hp ≤ 119 mg/dl.

CONCLUSION

Vit-E supplementation did not show any preferential benefit or deleterious effect on vascular function in Hp2-2 diabetes subjects in Singapore. A possible deleterious effect of an increase in arterial stiffness in individuals with Hp > 119 mg/dl was observed. Future studies should consider personalisation based on baseline Hp concentrations in patients with T2DM rather than just Hp2-2 genotype to evaluate impact on the detailed lipid pathways, cardiac and renal physiology. The impact of ethnic differences needs to be explored in greater details.

Advanced Glycation End Products: Potential Mechanism and Therapeutic Target in Cardiovascular Complications under Diabetes

The occurrence and development of cardiovascular complications are predominantly responsible for the increased morbidity and mortality observed in patients with diabetes. Oxidative stress under hyperglycemia is currently considered the initial link to diabetic cardiovascular complications and a key node for the prevention and treatment of diabetes-related fatal cardiovascular events. Numerous studies have indicated that the common upstream pathway in the context of oxidative stress in the cardiovascular system under diabetic conditions is the interaction of advanced glycation end products (AGEs) with their receptors (RAGEs). Therefore, a further understanding of the relationship between oxidative stress and AGEs is of great significance for the prevention and treatment of cardiovascular complications in patients with diabetes. In this review, we will briefly summarize the recent research advances in diabetes with an emphasis on oxidative stress and its association with AGEs in diabetic cardiovascular complications.

Is Magnetic Resonance Imaging Detection of Kidney Iron Deposition Increased in Haptoglobin 2-2 Genotype Carriers with Type 1 Diabetes?

Haptoglobin's (Hp) main role is to bind free hemoglobin (Hb), reducing its oxidative potential. The Hp-Hb complex formed is cleared from the circulation by macrophage receptor CD163. In diabetes, impaired Hp 2-2-Hb CD163 clearance and abnormal glomerular permeability allow the large Hp 2-2-Hb complex to cross the barrier, where its redox active iron leads to cellular toxicity. Although Hp 2-2 predicts renal function decline, whether renal iron deposition differs by Hp is unknown. We used renal quantitative T2* magnetic resonance imaging to estimate iron level in the cortex and medullar of type 1 diabetes (T1D) adults [15 Hp 1-1 and 15 Hp 2-2 carriers of similar age (53 years), duration (45 years), and gender]. Total kidney iron level was estimated as the sum of the cortex and medullar iron. Albuminuria was defined as urinary albumin to creatinine ratio >30 mg/g in two of three samples. Total kidney iron did not differ by gender or Hp but was higher in those with albuminuria (p = 0.05), an association confined to Hp 2-2 carriers (p = 0.04 vs. p = 0.51 in Hp 1-1). These data lead to the hypothesis that kidney iron deposition is increased among Hp 2-2 carriers with albuminuria in T1D. Antioxid. Redox Signal. 29, 735-741.

The protean role of haptoglobin and haptoglobin genotypes on vascular complications in diabetes mellitus

Introduction and background Haptoglobin (Hp) is considered to be an antioxidant and protective against cardiovascular complications. Polymorphisms in the Hp gene interact with diabetes mellitus to affect the risk of vascular complications. Methods We review the updated literature about the protean role of Hp and Hp genotypes spanning genomics, molecular, translational and clinical studies. We searched Pubmed, SCOPUS and Google Scholar for all articles using the keywords: haptoglobin and/or haptoglobin polymorphism and diabetes. We review the diverse Hp genotypes, phenotypes and the impact on diabetes complications, including lessons from animal models and in vitro models. We describe the clinical studies on the associations of Hp genotypes with vascular complications in type 1 and type 2 diabetes comprehensively. We review the studies looking at vitamin E supplementation in a personalized manner in Hp2-2 diabetes individuals. Results and conclusion Hp genotypes have evolved as a result of deletions in the traditional Hp genes. The Hp genotypes have been associated with microvascular and macrovascular complications in type 1 diabetes mellitus but the association in type 2 diabetes is more consistent with cardiovascular complications. A preferential benefit of vitamin E and other antioxidants in the Hp2-2 genotype for cardiovascular complications in type 2 diabetes has been seen presumably secondary to interaction with high-density lipoprotein function. Hence, the Hp genotype can be used to personalize antioxidant therapeutics in diabetes patients. These results need to be corroborated in large, global, pragmatic, prospective, cardiovascular outcome trials in type 2 diabetes patients.

Haptoglobin Genotype Is a Determinant of Hemoglobin Adducts and Vitamin E Content in HDL

Haptoglobin (Hp) is an abundant hemoglobin- (Hb-) binding serum protein and a constituent of the HDL proteome. In man, there exists a common polymorphism at the Hp locus with two common alleles defined by the presence (Hp 2 allele) or absence (Hp 1 allele) of a 1.7 kb in-frame partial duplication of exons 3 and 4 of the Hp gene. Numerous studies have demonstrated that the Hp 2-2 genotype is associated with a 3-5-fold increase in vascular disease among individuals with diabetes mellitus (DM). Increased Hp-Hb complex has been shown to be associated with the HDL of Hp 2-2 DM individuals. Hb-associated HDL has been proposed to result in the oxidation of HDL and the consumption of antioxidants in HDL, such as vitamin E, rendering the HDL further susceptible to oxidation. In this study, we set out to identify proteins which become cross-linked to Hb in HDL and to measure vitamin E in HDL as a function of the Hp genotype. We report on the identification of a novel 72 kd Hb reactive species which is cross-linked to HDL and demonstrate that vitamin E in HDL is decreased in Hp 2-2 DM individuals.

HDL functionality in type 1 diabetes

Type 1 diabetes (T1D) is a chronic autoimmune disease characterized by absence of insulin secretion due to destruction of the pancreatic beta-cells. Patients with T1D exhibit an increased risk for cardiovascular disease (CVD) compared with non-diabetic subjects. It has been established that low concentration of high-density lipoprotein cholesterol (HDL-C), an independent risk marker of CVD, coincides with a reduced protective capacity against oxidative stress. However, conflicting results have been reported on the prevalence of low HDL-C levels in T1D. Interestingly, changes in composition and function of HDL particles (abnormal ratio of cholesteryl ester-to-triglyceride, reduction in the phospholipid content, reduced capacity to promote cholesterol efflux from macrophages, impaired anti-inflammatory and anti-oxidant activities) have been described in patients with T1D. Hence, exploring HDL function, even in the presence of normal HDL-C levels, might provide additional insight into the underlying pathophysiology associated with increased CV risk in T1D. In the current review, we will provide a detailed overview of the current evidence for a role of HDL function as independent risk factor for the development of CVD in T1D.

Anti-oxidative treatment with vitamin E improves peripheral vascular function in patients with diabetes mellitus and Haptoglobin 2-2 genotype: A double-blinded cross-over study

Vascular dysfunction in both conduit arteries and small vessels is a major contributor to the development of cardiovascular disease (CVD) in diabetes mellitus (DM). In diabetes there is a process of systemic chronic inflammation accompanied by high oxidative stress causing a subsequent decrease in vascular reactivity and negatively affect the metabolic processes responsible for functioning of the microvasculature. Vitamin E is classified as an antioxidant due to its ability to scavenge lipid radicals and terminate oxidative chain reactions. We conducted a double-blinded cross-over study with vitamin E versus placebo in individuals with type 2DM and the Hp2-2 genotype and assessed different aspects of peripheral vascular function in these patients. Twenty patients completed the study with 10 individuals in each study cohort. We were able to show significant improvement of indirect indices of vascular function following 8weeks of treatment with vitamin E. This improvement was consistent for weeks even after stopping the vitamin E treatment. We concluded that a pharmacogenomic rationale utilizing the Hp genotype might potentially provide cardiovascular benefit with vitamin E.

Haptoglobin Hp2 Variant Promotes Premature Cardiovascular Death in Stroke Survivors

BACKGROUND AND PURPOSE

Haptoglobin (Hp) is an acute phase plasma protein protecting tissues from oxidative damage. It exists in 2 variant alleles (hp1/hp2) giving rise to 3 protein isoforms with different biochemical properties and efficiency to limit oxidative stress. We previously found that hp2 variant is associated with stroke risk in the patients with carotid stenosis and the risk of ischemic cardiovascular events in a general population cohort. This study examined the hypothesis that Hp genotype is associated with general cardiovascular risk in patients with stroke.

METHODS

Hp was genotyped in SAM study (Helsinki Stroke Aging Memory, n=378). A total of 1426 individuals ascertained from a nationally representative cross-sectional health survey served as population controls.

RESULTS

Hp genotype frequencies were 15.6% (hp1-1), 44.2% (hp1-2), and 40.2% (hp2-2) in patients with stroke. During a mean of 7.5-year follow-up after first-ever stroke, hp2 carriers had a substantially higher rate of cardiac deaths (24.5% versus 8.5%; P=0.006) and a trend toward more fatal strokes (23.5% versus 13.6%; P=0.122). The combined risk of ischemic cardiovascular deaths was 2.4-fold higher among hp2 carriers (95% confidence interval, 1.28-4.43) after adjustment for major cardiovascular risk factors.

CONCLUSIONS

Hp2 allele is associated with premature ischemic cardiovascular deaths after first-ever ischemic stroke.

Cardiovascular complications of type 1 diabetes: update on the renal link

AIMS

Despite recent findings of increased life expectancy among individuals with type 1 diabetes, mortality remains greatly increased compared to the general population. As this is largely the result of cardiovascular and renal complications, we aimed to review recent findings surrounding these diseases in type 1 diabetes.

METHODS

We reviewed published findings concerning the cardiovascular complications of type 1 diabetes, with a particular focus on links with renal disease.

RESULTS

The cardiovascular and renal complications of type 1 diabetes share many features including insulin resistance, oxidative damage, and genetic associations with the Haptoglobin genotype, and both are strongly affected by glycemic control.

CONCLUSIONS

Although current knowledge on predictors of type 1 diabetes cardiovascular and renal complications has increased, further investigation is required to understand the mechanisms leading to cardio-renal complications in this population.

Link of dietary patterns with metabolic syndrome: analysis of the National Health and Nutrition Examination Survey

BACKGROUND

Population-based interventions aimed at halting the increasing prevalence of metabolic syndrome (MetS) require thorough understanding of dietary interplays. Objective is to identify the independent dietary nutrients associated with MetS and its components using dietary pattern identification and the single-nutrient approaches in The United States.

METHODS

This is a cross-sectional observation. Participants are selected from the National Health and Nutrition Examination Survey (NHANES) with available dietary intake, biochemical and anthropometrical data from 2001 to 2012. Exposure is diet obtained from 24-h dietary recall. Main outcome measure is MetS and its components.

RESULTS

Overall, 23 157 eligible individuals including 6561 with MetS were included in the final analysis. Using principle component analysis, we identified three food patterns that explained 50.8% of the variance of the dietary nutrient consumption. The highest quartile of the factor score representative of saturated/monounsaturated fatty acids or the first dietary pattern was associated with 1.27-fold (95% confidence interval (CI): 1.10-1.46, P=0.001) higher odds of association with MetS when compared with the first quartile. The second pattern representative of vitamins and trace elements had an odds ratio of 0.79 (95% CI: 0.70-0.89, P<0.001) for association with MetS, and the third pattern representative of polyunsaturated fatty acids did not have any association with MetS. The nutrient-by-nutrient approach showed that mild alcohol intake and lower consumption of total saturated fatty acids and sodium were associated with lower risk of MetS.

CONCLUSIONS

Application of multiple complementary analytic approaches reveals more comprehensive dietary determinants of MetS and its components as potential intervening targets.

Glycaemic control modifies the haptoglobin 2 allele-conferred susceptibility to coronary artery disease in Type 1 diabetes

AIMS

We aimed to assess whether the association of the haptoglobin 2 allele with coronary artery disease is modified by glycaemic control in a prospective cohort study of individuals with childhood-onset Type 1 diabetes.

METHODS

Coronary artery disease events (death from coronary artery disease, confirmed myocardial infarction, stenosis ≥50%, revascularization) were assessed between 1986 and 2013 among 480 individuals with Type 1 diabetes (baseline age 28 years; diabetes duration 19 years). Better glycaemic control was defined as an updated mean HbA_1c during follow-up of <8% (64 mmol/mol).

RESULTS

In crude models, the incidence of coronary artery disease increased with the number of haptoglobin 2 alleles (hazard ratio 1.34, 95% CI 1.05-1.71). This association was more pronounced in those with better than in those with worse glycaemic control (P interaction = 0.05) and remained essentially unaltered after multivariable adjustments (hazard ratio 2.65, 95% CI 1.30-5.41 in those with better glycaemic control and hazard ratio 1.20, 95% CI 0.93-1.56 in those with worse glycaemic control).

CONCLUSIONS

These results suggest that, although better control may reduce the incidence of coronary artery disease in Type 1 diabetes, a residual risk related to the haptoglobin 2 allele remains.

The Haptoglobin genotype predicts cardio-renal mortality in type 1 diabetes

AIMS

The Haptoglobin (HP) 2-2 genotype increases cardiovascular diabetes complication incidence. In type 1 diabetes, HP 2-2 also predicts declining kidney function and end-stage renal disease. We investigated whether HP 2-2 predisposes to cardio-renal mortality, while considering other causes of death as competing risks.

METHODS

Individuals with type 1 diabetes and HP data available (n=486; mean baseline age, 27 and duration, 19 years) were selected for study. Vital status was assessed as of 8/31/2014. The underlying cause of death was determined and classified based on standardized procedures.

RESULTS

During 25 years of follow-up, 79 (16.3%) cardio-renal deaths and 43 (8.8%) deaths related to other causes occurred. Although total mortality did not differ by HP (25.4% with HP 1 versus 24.6% with HP 2-2, p=0.84), a greater proportion of HP 2-2 carriers exhibited a cardio-renal death (19.0 versus 14.2, p=0.05). In time-to-event analyses, HP 2-2 was associated with a statistically significant increase of the sub-distribution hazard ratio for cardio-renal mortality (HR=1.64, p=0.03), although this effect was somewhat attenuated after multivariable adjustment (HR=1.58, p=0.05).

CONCLUSIONS

Our results suggest that in addition to predicting the incidence of cardio-renal complications, HP 2-2 also increases susceptibility for cardio-renal mortality in type 1 diabetes. These findings require validation in other cohorts.

The Risk of Coronary Heart Disease Associated With Glycosylated Hemoglobin of 6.5% or Greater Is Pronounced in the Haptoglobin 2-2 Genotype

BACKGROUND

Research targeting glycosylated hemoglobin A1c (HbA1c) to <6.5% to prevent coronary heart disease (CHD) events has conflicting results. We previously observed the haptoglobin (Hp) Hp2-2 genotype is associated with a ∼10-fold increased CHD risk among individuals with HbA1c ≥6.5%, and thus might be useful in identifying those at high risk of CHD who would benefit from maintaining HbA1c <6.5%.

OBJECTIVES

This study sought to model whether HbA1c ≥ 6.5% in the Hp2-2 genotype is associated with CHD in a prospective case-control study nested within the Health Professionals Follow-Up Study (HPFS).

METHODS

HbA1c concentration and Hp genotype were determined for 695 incident cases of CHD from 1994 to 2010 and matched control participants. Logistic regression models calculated relative risk (RR) and 95% CI, for the first and second halves of follow-up, adjusting for confounding variables. A dataset from the Nurses' Health Study served as a replication cohort.

RESULTS

The prevalence of the Hp2-2 genotype in HPFS was 39%. Compared with HbA1c <6.5%, the RR of CHD for HbA1c ≥6.5% for the Hp2-2 genotype over full follow-up was 3.07 (95% CI: 1.37 to 6.86) to 3.88 (95% CI: 1.31 to 11.52) during the first half of follow-up and 2.16 (95% CI: 0.61 to 7.61) in the second half. The corresponding RRs for the Hp1-1 + Hp2-1 genotypes were: full follow-up, 2.19 (95% CI: 1.14 to 4.24); first half, 1.60 (95% CI: 0.73 to 3.53); and second half, 4.72 (95% CI: 1.26 to 17.65).

CONCLUSIONS

In 2 independent cohorts, the risk of CHD associated with HbA1c ≥6.5% is pronounced in the Hp2-2 genotype, particularly in early cases. The Hp2-2 genotype may identify individuals at greatest CHD risk from hyperglycemia.