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.

Intensified glycemic control by HbA1c for patients with coronary heart disease and Type 2 diabetes: a review of findings and conclusions

The occurrence and development of coronary heart disease (CHD) are closely linked to fluctuations in blood glucose levels. While the efficacy of intensified treatment guided by HbA1c levels remains uncertain for individuals with diabetes and CHD, this review summarizes the findings and conclusions regarding HbA1c in the context of CHD. Our review showed a curvilinear correlation between regulated level of HbA1c and therapeutic effectiveness of intensified glycemic control among patients with type 2 diabetes and coronary heart disease. It is necessary to optimize the dynamic monitoring indicators of HbA1c, combine genetic profiles, haptoglobin phenotypes for example and select more suitable hypoglycemic drugs to establish more appropriate glucose-controlling guideline for patients with CHD at different stage of diabetes.

Polymorphisms of haptoglobin modify the relationship between dietary iron and the risk of gestational iron-deficiency anemia

PURPOSE

To assess whether polymorphisms of haptoglobin (Hp) modify the relationship between dietary iron and the risk of gestational iron-deficiency anemia (IDA).

METHODS

This study analyzed 1430 singleton pregnant women aged 20 ~ ≤ 48 years from the 2017-2019 National Nutrition and Health Survey of Pregnant Women in Taiwan. Sociodemographic, blood biochemical, Hp phenotype, and 24-h dietary recall data were collected. Erythropoiesis-related total prenatal supplementation was defined as the reported use of multivitamins and minerals, vitamin B complex, folate, and iron.

RESULTS

Distributions of the Hp 1-1, Hp 2-1, and Hp 2-2 phenotypes were 13.6, 39.8, and 46.5%, respectively. Women with the Hp 1-1 phenotype had the lowest mean levels of serum ferritin (p-trend = 0.017), the highest prevalence of gestational ID (p-trend = 0.033) as well as the highest prevalence of gestational IDA (did not reach statistical differences, p-trend = 0.086). A gene-diet interaction on serum ferritin was observed between the Hp 1 and Hp 2 (2-1/2-2) alleles (p < 0.001). An adjusted multivariate logistic regression showed that compared to those with a normal blood iron status and who reported using erythropoiesis-related total prenatal supplements, those who did not had a 4.05-fold [odds ratio (OR) = 4.05 (95% confidence interval (CI) 2.63-6.24), p < 0.001] increased risk of gestational IDA. The corresponding ORs for carriers of the Hp 1 and Hp 2 alleles were 4.78 (95% CI 1.43-15.99) and 3.79 (95% CI 2.37-6.06), respectively.

CONCLUSION

Pregnant women who are Hp 1 carriers are at increased risk for developing IDA if they do not meet the recommended dietary allowance for iron or use erythropoiesis-related prenatal supplements.

Identification of the epitope of 10-7G glycan antibody to recognize cancer-associated haptoglobin

We previously identified fucosylated haptoglobin (Fuc-Hpt) as a clinical serum biomarker of pancreatic cancer and established the novel glycan monoclonal antibody (mAb) 10-7G. This antibody recognizes cancer-associated haptoglobin including Fuc-Hpt and the precursor of haptoglobin. Interestingly, Western blot analysis showed that the 10-7G mAb reacts with the haptoglobin α chain, which has no N-glycan potential sites; haptoglobin β chain has four N-glycan sites. In this study, we identified the epitope for the 10-7G mAb using haptoglobin deletion mutants, as well as inhibition ELISA with recombinant peptides. We illustrated molecular graphics to show a relationship between the epitope and the β chain. Furthermore, we hypothesized that the 10-7G mAb minimally recognizes normal haptoglobin, but aberrant glycosylation on the β chain causes conformational changes, enabling the 10-7G mAb to easily access the epitope within the α chain. Because 10-7G values, an enzyme-linked immunosorbent assay-immobilized 10-7G mAb, in patients with pancreatic cancer varied by haptoglobin phenotype, the amount of aberrant glycosylation needed to affect haptoglobin conformation probably depends on haptoglobin phenotype. Taken together, the 10-7G mAb recognized characteristic peptides on the haptoglobin α chain as a result of conformational changes and is a promising tool for diagnosing pancreatic cancer by haptoglobin phenotype.

Phenotype of haptoglobin and presence of subclinical vascular disease: Population study

INTRODUCTION AND OBJECTIVES

Haptoglobin is a protein involved in the protection against oxidative damage caused by iron in haemoglobin. This protein is polymorphic, with 3 isomorphs prevalent in the population. The carriers of the Hp2-2 isoform have a lower antioxidant capacity and, in the population with diabetes, an increased risk of subclinical vascular disease and cardiovascular complications. The objective of this study was to evaluate whether this isomorphy is associated with an increased risk of carotid arteriosclerosis in subjects with and without diabetes, and free of cardiovascular disease.

PATIENTS AND METHODS

A study was conducted in a population between 45 and 74years of age, randomly selected from the northwest area of Madrid. The participants were characterised in terms of their glycaemic status by oral glucose overload and the determination of the concentration of Hb1Ac. The haptoglobin phenotypes in all of them were determined by means of an immunoenzymatic assay, and the presence of carotid arteriosclerosis by ultrasound.

RESULTS

Of the 1,256 participants included in the present analysis (mean age 61.6±6years, 41.8% males), the distribution of the isoforms of haptoglobin was as follows: Hp1-1: 13.3%, Hp1-2: 48.5%, and Hp2-2: 38.2%. In comparison with subjects Hp1-1 and Hp1-2, those with the Hp2-2 phenotype had a higher prevalence of dyslipidaemia (53.3% vs 43%; P<.0001) and arterial hypertension (39.2% vs. 32.2%, P=.012), and they more frequently received treatment with statins (31.5% vs 21.6%, P<.0001), and with antihypertensive agents (38.4% vs 30.8%, P=.006). The carriers of the Hp2-2 isoform had a higher prevalence of carotid plaques (OR: 1.35, 95%CI: 1.07-1.69, P=.011), with no differences in that prevalence as regards the glycaemic status. There were no differences in the intima-media thickness between the different phenotypes. The relationship of the Hp2-2 phenotype with the presence of plaques in the carotid was independent of age, gender, presence of risk factors (dyslipidaemia, hypertension and diabetes), the concentration of LDL-cholesterol, C-reactive protein and uric acid, blood pressure, and treatment with statins, and hypertensive drugs (OR: 1.31, 95%CI 1.01-1.70, P=.044).

CONCLUSION

Subjects with the Hp2-2 phenotype of haptoglobin have a higher prevalence of carotid arteriosclerosis, which is independent of the presence of other cardiovascular risk factors and their glycaemic status.

Haptoglobin phenotype influences the effectiveness of diet-induced weight loss in middle-age abdominally obese women with metabolic abnormalities

BACKGROUND & AIMS

Haptoglobin (Hp) is associated with risks of obesity and cardiometabolic dysfunction; however, the role of the Hp phenotype in diet-induced weight loss remains to be elucidated. This study investigated whether the Hp phenotype contributes to inter-individual variations in body weight reduction as well as changes in the metabolic profile.

METHODS

Secondary data analysis from a randomized controlled trial. In total, 151 abdominally obese Taiwanese women with ≥2 metabolic components were randomized to each of four dietary programs [calorie restriction (CR), calorie restriction plus fish oil supplementation (CRF), calorie restricted meal replacement (CRMR), and calorie restricted meal replacement with fish oil supplementation (CRMRF)] for 12 weeks. Abdominal obesity was defined as a waist circumference (WC) ≥ 80 cm in women. Hp phenotyping was performed by plasma gel electrophoresis.

RESULTS

The prevalence of the Hp 1-1, 2-1, and 2-2 phenotypes were 12.58%, 41.06% and 46.35%, respectively. The mean age was 50.59 ± 12.22 years, and mean reduction in the percent body weight was 4.7% ± 3.8%. The Hp 1-1 phenotype exhibited significant decreases in the WC, body fat mass, plasma insulin levels, free hemoglobin and homeostatic model assessment of insulin resistance (HOMA-IR) compared to the Hp 2-1 or Hp 2-2 phenotypes after adjusting for the baseline age, WC, metabolic syndrome (MetS), and dietary programs (all adjusted p < 0.05). A greater improvement in the prevalence of central obesity and, to a lesser extent, MetS was also found in women with the Hp 1-1 phenotype.

CONCLUSIONS

Obese women with the Hp 1-1 phenotype might obtain greater benefits in terms of reducing abdominal fat and improving insulin sensitivity in response to hypocaloric diet-induced weight reduction. The findings from this study support potential gene-diet interactions affecting weight loss. This trial was registered at ClinicalTrials.gov as NCT01768169.

CLINICAL TRIAL REGISTRY

This trial was registered at ClinicalTrials.gov as NCT01768169.

Smoking and haptoglobin phenotype modulate serum ferritin and haptoglobin levels in Parkinson disease

The phenotype Hp 2-1 of haptoglobin has been previously associated with increased risk of Parkinson disease (PD) and with serum iron abnormalities in PD patients. Tobacco smoking has been consistently observed in epidemiology studies to be inversely related to PD risk, with mechanisms that remain uncertain. We recently observed that the protective effect of smoking on PD risk is stronger among subjects of haptoglobin Hp 2-2 and Hp 1-1 phenotypes, and weaker among subjects of haptoglobin Hp 2-1 phenotype. In this PD case-control study, we investigated whether tobacco smoking was associated with changes in serum haptoglobin and ferritin concentration that depended on haptoglobin phenotype among 106 PD patients and 238 controls without PD or other neurodegenerative disorders. Serum ferritin concentration, serum haptoglobin concentration, haptoglobin phenotype, and smoking data information of cases and controls were obtained. Differences in haptoglobin and ferritin concentration by smoking status and pack-years of smoking were calculated as well as regression between pack-years and haptoglobin and ferritin concentration, and the effect of haptoglobin phenotype on these parameters. Tobacco smoking was associated with an elevation in serum haptoglobin concentration, especially among healthy controls of haptoglobin Hp 2-2 phenotype, and with an elevation in ferritin concentration especially among PD patients of haptoglobin Hp 2-1 phenotype. These findings suggest that an elevation in haptoglobin concentration, preferentially among subjects of haptoglobin Hp 2-2 phenotype, could be a contributing factor to the protective effect of smoking on PD risk.

Haptoglobin phenotype modifies serum iron levels and the effect of smoking on Parkinson disease risk

INTRODUCTION

Haptoglobin is a hemoglobin-binding protein that exists in three functionally different phenotypes, and haptoglobin phenotype 2-1 has previously been associated with Parkinson disease (PD) risk, with mechanisms not elucidated. Some evidence is emerging that low levels of serum iron may increase PD risk. In this study we investigated whether PD patients have lower serum iron and ferritin than controls, and whether this is dependent on haptoglobin phenotype. We also investigated the effect of Hp phenotype as a modifier of the effect of smoking on PD risk.

METHODS

The study population consisted of 128 PD patients and 226 controls. Serum iron, ferritin, and haptoglobin phenotype were determined, and compared between PD cases and controls. Stratified analysis by haptoglobin phenotype was performed to determine effect of haptoglobin phenotype on serum iron parameter differences between PD cases and controls and to investigate its role in the protective effect of smoking on PD risk.

RESULTS

PD cases had lower serum iron than controls (83.28 ug/100 ml vs 94.00 ug/100 ml, p 0.006), and in particular among subjects with phenotype 2-1. The protective effect of smoking on PD risk resulted stronger in subjects with phenotype 1-1 and 2-2, and weakest among subjects with phenotype 2-1. Ferritin levels were higher in PD cases than controls among subjects of White ethnicity.

CONCLUSIONS

Our results report for the first time that the haptoglobin phenotype may be a contributor of iron levels abnormalities in PD patients. The mechanisms for these haptoglobin-phenotype specific effects will have to be further elucidated.

Presence of haptoglobin-2 allele is associated with worse functional outcomes after spontaneous intracerebral hemorrhage

OBJECTIVE

To determine if the haptoglobin (Hp) phenotype, which has been shown to be a predictor of clinical outcomes in cerebrovascular disorders, particularly subarachnoid hemorrhage, was predictive of functional outcomes after spontaneous intracerebral hemorrhage (ICH).

METHODS

Patients admitted with a diagnosis of ICH were prospectively included and divided into 3 groups based on their genetically determined Hp phenotype: 1-1, 2-1, and 2-2. Outcome measures included mortality and 30-day modified Rankin Scale scores. Demographics and outcomes were compared for each phenotype using multivariate linear regression analysis.

RESULTS

The study included 94 patients. The distribution of Hp phenotype was Hp 1-1, 12 (13%); Hp 2-1, 46 (49%); and Hp 2-2, 36 (38%). The 3 Hp subgroups did not differ in terms of demographic variables, comorbidities, or ICH characteristics. There was a nonsignificant trend toward increased mortality in Hp 2-1 and Hp 2-2 compared with Hp 1-1, with mortality of 8% in Hp 1-1, 17% in Hp 2-1, and 25% in Hp 2-2 (P = 0.408). In the regression model adjusted for confounders, Hp 2-1 (odds ratio = 0.05, 95% confidence interval = 0.01-0.47, P < 0.001) and Hp 2-2 phenotypes (odds ratio = 0.14, 95% confidence interval = 0.02-0.86, P = 0.045) had significantly lower odds of modified Rankin Scale scores 0-2 compared with Hp 1-1.

CONCLUSIONS

After ICH, individuals with the Hp-2 allele (2-1 and 2-2) had worse functional outcomes than individuals with the Hp-1 allele (Hp 1-1). There was a nonsignificant association between Hp phenotype and mortality. Larger prospective studies with better surrogates of ICH outcomes are warranted.

Haptoglobin phenotype, pre-eclampsia, and response to supplementation with vitamins C and E in pregnant women with type-1 diabetes

OBJECTIVE

The phenotype of the antioxidant and pro-angiogenic protein haptoglobin (Hp) predicts cardiovascular disease risk and treatment response to antioxidant vitamins in individuals with diabetes. Our objective was to determine whether Hp phenotype influences pre-eclampsia risk, or the efficacy of vitamins C and E in preventing pre-eclampsia, in women with type-1 diabetes.

DESIGN

This is a secondary analysis of a randomised controlled trial in which women with diabetes received daily vitamins C and E, or placebo, from 8 to 22 weeks of gestation until delivery.

SETTING

Twenty-five antenatal metabolic clinics across the UK (in north-west England, Scotland, and Northern Ireland).

POPULATION

Pregnant women with type-1 diabetes.

METHODS

Hp phenotype was determined in white women who completed the study and had plasma samples available (n = 685).

MAIN OUTCOME MEASURE

Pre-eclampsia.

RESULTS

Compared with Hp 2-1, Hp 1-1 (OR 0.59, 95% CI 0.30-1.16) and Hp 2-2 (OR 0.93, 95% CI 0.60-1.45) were not associated with significantly decreased pre-eclampsia risk after adjusting for treatment group and HbA1c at randomisation. Our study was not powered to detect an interaction between Hp phenotype and treatment response; however, our preliminary analysis suggests that vitamins C and E did not prevent pre-eclampsia in women of any Hp phenotype (Hp 1-1, OR 0.77, 95% CI 0.22-2.71; Hp 2-1, OR 0.81, 95% CI 0.46-1.43; Hp 2-2, 0.67, 95% CI 0.34-1.33), after adjusting for HbA1c at randomisation.

CONCLUSIONS

The Hp phenotype did not significantly affect pre-eclampsia risk in women with type-1 diabetes.

Haptoglobin polymorphism and association with complications in ghanaian type 2 diabetic patients

There is scanty information on the role of genetic factors, especially those relating to haptoglobin (Hp) phenotypes in the expression of complications among diabetes mellitus patients in Ghana. In this study, we investigated whether there is any association between Hp phenotypes and diabetic complications and to determine if association of the Hp phenotypes with diabetic complications in Ghanaian diabetics differ from those in Caucasians. A total of 398 participants were randomly recruited into the study. These comprised diabetic patients numbering 290 attending a diabetes Clinic in Ghana and 108 non-diabetic controls from the same community. Analyses of the results indicate that most of the diabetics with complications were of the Hp 2-2 (35%) and Hp 2-1 (23.9%) phenotypes. Fewer diabetics were found to be of the Hp 2-1 M phenotype. The controls were mostly of Hp 1-1 and Hp 2-1 M phenotypes. The odds ratio of having complications in a diabetic with an Hp 2-2 phenotype was 18.27 times greater than that for Hp 0-0. Hp 2-2 phenotype with its poor antioxidant activity may therefore be a useful predictor for the propensity of an individual to develop diabetes complications.