Pharmacogenomic application of the haptoglobin genotype in the prevention of diabetic cardiovascular disease

Gut Microbiota Ecology and Inferred Functions in Children With ASD Compared to Neurotypical Subjects

Autism spectrum disorders (ASDs) is a multifactorial neurodevelopmental disorder. The communication between the gastrointestinal (GI) tract and the central nervous system seems driven by gut microbiota (GM). Herein, we provide GM profiling, considering GI functional symptoms, neurological impairment, and dietary habits. Forty-one and 35 fecal samples collected from ASD and neurotypical children (CTRLs), respectively, (age range, 3–15 years) were analyzed by 16S targeted-metagenomics (the V3–V4 region) and inflammation and permeability markers (i.e., sIgA, zonulin lysozyme), and then correlated with subjects’ metadata. Our ASD cohort was characterized as follows: 30/41 (73%) with GI functional symptoms; 24/41 (58%) picky eaters (PEs), with one or more dietary needs, including 10/41 (24%) with food selectivity (FS); 36/41 (88%) presenting high and medium autism severity symptoms (HMASSs). Among the cohort with GI symptoms, 28/30 (93%) showed HMASSs, 17/30 (57%) were picky eaters and only 8/30 (27%) with food selectivity. The remaining 11/41 (27%) ASDs without GI symptoms that were characterized by HMASS for 8/11 (72%) and 7/11 (63%) were picky eaters. GM ecology was investigated for the overall ASD cohort versus CTRLs; ASDs with GI and without GI, respectively, versus CTRLs; ASD with GI versus ASD without GI; ASDs with HMASS versus low ASSs; PEs versus no-PEs; and FS versus absence of FS. In particular, the GM of ASDs, compared to CTRLs, was characterized by the increase of Proteobacteria, Bacteroidetes, Rikenellaceae, Pasteurellaceae, Klebsiella, Bacteroides, Roseburia, Lactobacillus, Prevotella, Sutterella, Staphylococcus, and Haemophilus. Moreover, Sutterella, Roseburia and Fusobacterium were associated to ASD with GI symptoms compared to CTRLs. Interestingly, ASD with GI symptoms showed higher value of zonulin and lower levels of lysozyme, which were also characterized by differentially expressed predicted functional pathways. Multiple machine learning models classified correctly 80% overall ASDs, compared with CTRLs, based on Bacteroides, Lactobacillus, Prevotella, Staphylococcus, Sutterella, and Haemophilus features. In conclusion, in our patient cohort, regardless of the evaluation of many factors potentially modulating the GM profile, the major phenotypic determinant affecting the GM was represented by GI hallmarks and patients’ age.

Serum vitamin E as a significant prognostic factor in patients with dyslipidemia disorders

OBJECTIVES

Obesity and overweight are among the main causes of cardiovascular disease (CVD) mortality. Dyslipidemia, fatty liver index, is strongly related to CVD. Vitamin E as an antioxidant protects the hepatic cells against oxidative stress and prevents fatty liver disease. The aim of the current study is to evaluate the relationship between anthropometric parameters and fasted lipid profile with serum vitamin E levels.

STUDY DESIGN

A randomized trial was designed based on data from the Mashhad stroke and heart atherosclerotic disorders (MASHAD: 2010-2020).

METHODS

363 CVD subjects (173 males and 190 females) was selected at random, among 9704 subjects in three regions of Mashhad, northeast of Iran to investigate the specific correlations among their serum vitamin E, lipid profile (TG, HDL-C, LDL-C and TC), and anthropometric features (height, weight, BMI, hip and waist circumferences.

RESULT

The results indicated the significant relationships between vitamin E, and fasting serum lipid profile in subjects. Serum vitamin E was negatively correlated to TC, TG, and LDL-C and positively related to HDL-C. Also, statistically negative correlations were found between vitamin E and anthropometric parameters (weight, waist and hip circumference, middle Arm, and Systolic Blood Pressure). Moreover, vitamin E ratios such as vitamin E/(TC + TG) and vitamin E/TC values as standardized vitamin E, had significant negative correlation with BMI, the whole of anthropometric parameters, and dyslipidemia risk factors including TC, TG and LDL-C.

CONCLUSION

We found that vitamin E profile was significantly lower in the dyslipidemia subjects. It is generally suggested that vitamin E monitoring might be used as a useful prognostic and therapeutic agent in dyslipidemia disorder.

Differential immune responses and microbiota profiles in children with autism spectrum disorders and co-morbid gastrointestinal symptoms

OBJECTIVES

Many studies have reported the increased presence of gastrointestinal (GI) symptoms in children with autism spectrum disorders (ASD). Altered microbiome profiles, pro-inflammatory responses and impaired intestinal permeability have been observed in children with ASD and co-morbid GI symptoms, yet few studies have compared these findings to ASD children without GI issues or similarly aged typical developing children. The aim of this study was to determine whether there are biological signatures in terms of immune dysfunction and microbiota composition in children with ASD with GI symptoms.

METHODS

Children were enrolled in one of four groups: ASD and GI symptoms of irregular bowel habits (ASD^GI), children with ASD but without current or previous GI symptoms (ASD^NoGI), typically developing children with GI symptoms (TD^GI) and typically developing children without current or previous GI symptoms (TD^NoGI). Peripheral blood mononuclear cells (PBMC) were isolated from the blood, stimulated and assessed for cytokine production, while stool samples were analyzed for microbial composition.

RESULTS

Following Toll-Like receptor (TLR)-4 stimulation, the ASD^GI group produced increased levels of mucosa-relevant cytokines including IL-5, IL-15 and IL-17 compared to ASD^NoGI. The production of the regulatory cytokine TGFβ1 was decreased in the ASD^GI group compared with both the ASD^NoGI and TD^NoGI groups. Analysis of the microbiome at the family level revealed differences in microbiome composition between ASD and TD children with GI symptoms; furthermore, a predictive metagenome functional content analysis revealed that pathways were differentially represented between ASD and TD subjects, independently of the presence of GI symptoms. The ASD^GI also showed an over-representation of the gene encoding zonulin, a molecule regulating gut permeability, compared to the other groups.

CONCLUSIONS

Overall our findings suggest that children with ASD who experience GI symptoms have an imbalance in their immune response, possibly influenced by or influencing metagenomic changes, and may have a propensity to impaired gut barrier function which may contribute to their symptoms and clinical outcome.

Vitamin E in the prevention of cardiovascular disease: the importance of proper patient selection

Vitamin E is a naturally occurring fat-soluble antioxidant which has been proposed as a treatment for both primary and secondary protection against cardiovascular (CV) events. Promising data from observational epidemiological studies associating higher vitamin E dietary intake with lower risk of CV events have not been validated in randomized controlled clinical trials assessing the effect of vitamin E on CV outcomes. While the pendulum of medical opinion has swung to suggest that high dose vitamin E supplements have no place in the treatment and prevention of CV disease, new data is emerging that allows identification of a specific target population for this treatment, namely patients with diabetes mellitus and the haptoglobin genotype 2-2. This review details the scientific basis and clinical evidence related to the effect of vitamin E on CV outcomes, and the importance of proper patient selection in gaining therapeutic benefit from this intervention.

Is the Hp 2-2 diabetic mouse model a good model to study diabetic nephropathy?

Diabetic nephropathy (DN) is the leading cause of end stage renal disease and dialysis worldwide. Despite aggressive treatment, the number of patients on hemodialysis due to type 1 and type 2 diabetes mellitus is increasing annually. The lack of reliable animal models that mimic human disease has delayed the identification of specific factors that cause or predict DN. Different investigators around the world are testing different murine models. Validation criteria for early and advanced DN, phenotypic methods, background strain have recently been developed. Establishment of an authentic mouse model of DN will undoubtedly facilitate the understanding of the underlying genetic mechanisms that contribute to the development of DN and to study new treatments. Here we describe the characteristics of our new mouse model with type 1 diabetes mellitus and different haptoglobin genotypes that can mimic human DN.

Zonulin, regulation of tight junctions, and autoimmune diseases

Recent studies indicate that besides digestion and absorption of nutrients and water and electrolytes homeostasis, another key function of the intestine is to regulate the trafficking of environmental antigens across the host mucosal barrier. Intestinal tight junctions (TJs) create gradients for the optimal absorption and transport of nutrients and control the balance between tolerance and immunity to nonself antigens. To meet diverse physiological challenges, intestinal epithelial TJs must be modified rapidly and in a coordinated fashion by regulatory systems that orchestrate the state of assembly of the TJ multiprotein network. While considerable knowledge exists about TJ ultrastructure, relatively little is known about their physiological and pathophysiological regulation. Our discovery of zonulin, the only known physiologic modulator of intercellular TJs described so far, has increased our understanding of the intricate mechanisms that regulate the intestinal epithelial paracellular pathway and has led us to appreciate that its upregulation in genetically susceptible individuals leads to autoimmune diseases.

Is it time to screen for the haptoglobin genotype to assess the cardiovascular risk profile and vitamin E therapy responsiveness in patients with diabetes?

Diabetes mellitus (DM) carries an increased risk for cardiovascular complications. Haptoglobin (Hp) is an abundant plasma protein with an antioxidant function by virtue of its ability to block the oxidative activity of extracorpuscular hemoglobin. There exist two common functional alleles at the Hp genetic locus, denoted 1 and 2, with three Hp genotypes (Hp 1-1, 2-1, and 2-2). The Hp protein expressed in Hp 2-2 individuals is markedly inferior in protecting against hemoglobin-induced oxidative stress. Hp 2-2 DM individuals have been shown to be at increased risk for the development of diabetes complications, particularly diabetic cardiovascular disease (CVD). We review the biological mechanisms underlying the interaction between the Hp genotype and DM on CVD and the accumulating evidence in favor of Hp genotyping all individuals with DM and providing antioxidant vitamin E supplementation specifically to Hp 2-2 DM individuals to reduce their CVD morbidity and mortality.

Haptoglobin: basic and clinical aspects

Haptoglobin is an abundant hemoglobin-binding protein present in the plasma. The function of haptoglobin is primarily to determine the fate of hemoglobin released from red blood cells after either intravascular or extravascular hemolysis. There are two common alleles at the Hp genetic locus denoted 1 and 2. There are functional differences between the Hp 1 and Hp 2 protein products in protecting against hemoglobin-driven oxidative stress that appear to have important clinical significance. In particular, individuals with the Hp 2-2 genotype and diabetes mellitus appear to be at significantly higher risk of microvascular and macrovascular complications. A pharmacogenomic strategy of administering high dose antioxidants specifically to Hp 2-2 DM individuals may be clinically effective.

Divergent effects of alpha-tocopherol and vitamin C on the generation of dysfunctional HDL associated with diabetes and the Hp 2-2 genotype

The haptoglobin (Hp) 2-2 genotype is associated with increased risk of cardiovascular disease (CVD) in diabetes (DM). We recently proposed this increased risk arises from the tethering of redox active hemoglobin (Hb) to high density lipoprotein (HDL), thereby resulting in oxidative modification of HDL. Clinical trials have demonstrated that vitamin E (alpha-tocopherol) decreases while vitamin C increases CVD in Hp 2-2 DM individuals. We sought to test the hypothesis that the interaction of alpha-tocopherol or vitamin C on CVD in Hp 2-2 DM was due to their divergent effects on HDL oxidation and function. Vitamin C significantly increased while alpha-tocopherol completely blocked oxidation mediated by glycosylated Hb-Hp 2-2. Vitamin C had no benefit while alpha-tocopherol completely restored HDL function in Hp 2-2 DM mice. Co-administration of vitamin C mitigated the protective effects of alpha-tocopherol on HDL. There exists a pharmacogenomic interaction between vitamin C and alpha-tocopherol and the Hp 2-2 genotype on HDL function and structure. Choosing the correct antioxidant in the correct subset of patients may be critical in order to demonstrate benefit from antioxidant therapy.

Pharmacogenomic application of the haptoglobin genotype in the treatment of HDL dysfunction

An emerging paradigm of research has suggested that in the setting of diabetes mellitus (DM) the quality or function of high-density lipoprotein (HDL) may be a determinant of cardiovascular disease risk. Specific structural modifications of HDL protein and lipid components, resulting from oxidative modification, have been proposed to mediate HDL’s loss of the ability to promote cholesterol efflux (reverse cholesterol transport), serve as an antioxidant and anti-inflammatory agent. Therefore, inhibiting HDL oxidative modification would be expected to improve its function and provide cardioprotection. Nevertheless, antioxidant strategies to reduce cardiovascular events from atherosclerosis in DM have failed. It has been proposed that this failure may have been due to the inadequate nature of patient selection. High dose antioxidant therapy may only provide benefit to a subset of DM individuals with oxidatively modified HDL. We will review evidence that haptoglobin (Hp) identifies such individuals who can be successfully treated with vitamin E. These data will suggest that a pharmacogenomic approach utilizing the Hp genotype may be useful in identifying individuals who will benefit from antioxidant therapy.