Does Haptoglobin Phenotype Influence Postnatal Morbidity in Preterm Neonates?

BACKGROUND: Haptoglobin (Hp) is an acute phase protein with antioxidant, bacteriostatic, and anti-inflammatory activities. Hp proteins associated with the three major phenotypes differ in their proinflammatory and anti-inflammatory action. Inflammation and oxidative stress are both involved in most pathophysiological processes in premature infants. The objective of this study was to determine whether Hp phenotype influences clinical manifestations and sepsis incidence in the premature infants. OBJECTIVE: Infants born before 35 weeks gestational age were prospectively evaluated for Hp phenotype and clinical events, including sepsis, necrotizing enterocolitis, bronchopulmonary dysplasia, intraventricular hemorrhage, and retinopathy of prematurity. The participants were observed until discharge. METHODS: A total of 122 preterm infants were enrolled in the study. Clinical events were not affected by the Hp phenotype. The expression of Hp protein was extremely low in the study population. More septic episodes were found in infants with a birth weight greater than 1,500 g, although, the difference was not statistically significant. RESULTS: Extremely low expression of Hp may explain the lack of a correlation between Hp phenotype and sepsis in preterm infants. Further research involving a larger neonatal population is required to better understand the role of the Hp phenotype in morbidity of premature infants.

An enzyme linked immunosorbent assay (ELISA) for the determination of the human haptoglobin phenotype.

BACKGROUND: Haptoglobin (Hp) is an abundant serum protein which binds extracorpuscular hemoglobin (Hb). Two alleles exist in humans for the Hp gene, denoted 1 and 2. Diabetic individuals with the Hp 2-2 genotype are at increased risk of developing vascular complications including heart attack, stroke, and kidney disease. Recent evidence shows that treatment with vitamin E can reduce the risk of diabetic vascular complications by as much as 50% in Hp 2-2 individuals. We sought to develop a rapid and accurate test for Hp phenotype (which is 100% concordant with the three major Hp genotypes) to facilitate widespread diagnostic testing as well as prospective clinical trials. METHODS: A monoclonal antibody raised against human Hp was shown to distinguish between the three Hp phenotypes in an enzyme linked immunosorbent assay (ELISA). Hp phenotypes obtained in over 8000 patient samples using this ELISA method were compared with those obtained by polyacrylamide gel electrophoresis or the TaqMan PCR method. RESULTS: Our analysis showed that the sensitivity and specificity of the ELISA test for Hp 2-2 phenotype is 99.0% and 98.1%, respectively. The positive predictive value and the negative predictive value for Hp 2-2 phenotype is 97.5% and 99.3%, respectively. Similar results were obtained for Hp 2-1 and Hp 1-1 phenotypes. In addition, the ELISA was determined to be more sensitive and specific than the TaqMan method. CONCLUSIONS: The Hp ELISA represents a user-friendly, rapid and highly accurate diagnostic tool for determining Hp phenotypes. This test will greatly facilitate the typing of thousands of samples in ongoing clinical studies.

Myasthenia gravis and return to flying status.

INTRODUCTION: Myasthenia gravis (MG) is a common primary disorder of neuromuscular transmission. Although MG was once a fatal disease, today treatment with immunomodulating agents and cholinomimetic medications with good supportive care have improved the prognosis and the ability of patients to adapt to their workplaces, including the flight environment. CASES: The diagnosis of MG in two aircrew members illustrates the range of severity for MG from isolated ocular symptoms to relentlessly progressive generalized disease, as well as the unpredictability of the disease and difficulty in treatment. Nevertheless, both patients were returned to limited flying status. DISCUSSION: MG presents the potential for subtle progression with resulting effects on flight performance. In addition to the disease itself, flight surgeons must also consider problems related to treatment and its side effects. Progression and exacerbations of MG can develop during the course of the disease, requiring careful adjustments to treatment regimens. Taking all these factors into consideration, including the unpredictability of this disease, pilots with apparently stabilized MG should nevertheless be assigned only to duties during which the patient would be able to maintain and use his flying capabilities without risking the mission, himself, and other crewmembers.

Haptoglobin genotype is a determinant of survival and cardiac remodeling after myocardial infarction in diabetic mice.

BACKGROUND: We have recently demonstrated in man that a functional allelic polymorphism in the Haptoglobin (Hp) gene plays a major role in determining survival and congestive heart failure after myocardial infarction (MI). We sought to recapitulate the effect of Hp type on outcomes and cardiac remodeling after MI in transgenic mice. METHODS: The Hp 2 allele exists only in man. Wild type C57Bl/6 mice carry the Hp 1 allele with high homology to the human Hp 1 allele. We genetically engineered a murine Hp 2 allele and targeted its insertion by homologous recombination to the murine Hp locus to create Hp 2 mice. Diabetes Mellitus (DM) was induced with streptozotocin. MI was produced by occlusion of the left anterior descending artery in DM C57Bl/6 mice carrying the Hp 1 or Hp 2 allele. MI size was determined with TTC staining. Left ventricular (LV) function and dimensions were assessed by 2-dimensional echocardiography. RESULTS: In the absence of DM, Hp 1-1 and Hp 2-2 mice had similar LV dimensions and LV function. MI size was similar in DM Hp 1-1 and 2-2 mice 24 hours after MI (50.2 +/- 2.1%and 46.9 +/- 5.5%, respectively, p = 0.6). However, DM Hp 1-1 mice had a significantly lower mortality rate than DM Hp 2-2 mice 30 days after MI (HR 0.41, 95% CI (0.19-0.95), p = 0.037 by log rank). LV chamber dimensions were significantly increased in DM Hp 2-2 mice compared to DM Hp 1-1 mice 30 days after MI (0.196 +/- 0.01 cm2 vs. 0.163 +/- 0.01 cm2, respectively; p = 0.029). CONCLUSION: In DM mice the Hp 2-2 genotype is associated with increased mortality and more severe cardiac remodeling 30 days after MI.

Vitamin E supplementation reduces cardiovascular events in a subgroup of middle-aged individuals with both type 2 diabetes mellitus and the haptoglobin 2-2 genotype: a prospective double-blinded clinical trial.

OBJECTIVE: Clinical trials of vitamin E have failed to demonstrate a decrease in cardiovascular events. However, these studies did not address possible benefit to subgroups with increased oxidative stress. Haptoglobin (Hp), a major antioxidant protein, is a determinant of cardiovascular events in patients with Type 2 diabetes mellitus (DM). The Hp gene is polymorphic with 2 common alleles, 1 and 2. The Hp 2 allelic protein product provides inferior antioxidant protection compared with the Hp 1 allelic product. We sought to test the hypothesis that vitamin E could reduce cardiovascular events in DM individuals with the Hp 2-2 genotype, a subgroup that comprises 2% to 3% of the general population. METHODS AND RESULTS: 1434 DM individuals > or = 55 years of age with the Hp 2-2 genotype were randomized to vitamin E (400 U/d) or placebo. The primary composite outcome was myocardial infarction, stroke, and cardiovascular death. At the first evaluation of events, 18 months after initiating the study, the primary outcome was significantly reduced in individuals receiving vitamin E (2.2%) compared with placebo (4.7%; P=0.01) and led to early termination of the study. CONCLUSIONS: Vitamin E supplementation appears to reduce cardiovascular events in individuals with DM and the Hp 2-2 genotype (ClinicalTrials.gov NCT00220831).

Haptoglobin genotype and endothelial function in diabetes mellitus: a pilot study.

Endothelial function (EnF) is impaired in patients with diabetes mellitus (DM) due in large part to an increase in oxidative stress. Haptoglobin (Hp) is a potent antioxidant protein which is encoded by two different alleles (1 and 2) with the Hp 1 protein being a superior antioxidant to the Hp 2 protein. We hypothesized that DM individuals with the Hp 2-2 genotype would have greater endothelial dysfunction as compared to DM individuals with the Hp 1-1 genotype. We studied EnF in 16 Hp 2-2, 14 Hp 1-1 DM individuals and 14 healthy subjects. DM patients' groups were matched in terms of age, cardiovascular risk factors and metabolic characteristics. EnF was assessed using post-ischemic reactive hyperemia and strain gauge plethysmography and expressed either as the maximal flow after the ischemic period or as the area under the flow-time curve (AUC). We showed that EnF indices, AUC and maximal flow, were also higher in the healthy and Hp 1-1 groups compared with Hp 2-2 genotype group (615 +/- 60 and 600 +/- 40 vs. 450 +/- 50 ml dl(-1), 29 +/- 2.6 and 25 +/- 3 vs. 14 +/- 1.8 ml min(-1) dl(-1), P < 0.003 and P < 0.05, for AUC and maximal flow, one-way ANOVA, respectively). We concluded that Hp 2-2 diabetic patients had a worse EnF than controls and Hp 1-1 diabetic subjects.

Tuberous sclerosis in a military pilot.

Tuberous sclerosis (TS) is a multisystem disorder characterized by hamartomas in various organs. It usually manifests itself during infancy or childhood with neurological features, including mental retardation and seizures. We present the case of a military pilot who was diagnosed with TS at 22 yr. of age after he had completed flight training. Suspicion of TS arose from evaluation of a chronic rash around the pilot's nose, and diagnosis was confirmed based on the presence of multiple calcified nodules on CT imaging of the brain. No neurological abnormalities were found. The primary aeromedical concerns were the risk of seizures or development of tumors at sites that might lead to sudden incapacitation. Hamartomas can be reliably detected at an early stage by means of annual history, physical examination, and imaging of tumor-prone organs. After review of the literature and consultation with medical specialists, we assessed the risk of adult-onset seizures in a TS patient without preexisting neurological findings as scarce. The pilot was therefore granted a waiver limited to flying a two-pilot helicopter with a program of tight medical follow-up.

Haptoglobin genotype is a regulator of reverse cholesterol transport in diabetes in vitro and in vivo.

Two common alleles exist at the haptoglobin (Hp) locus, and the Hp2 allele is associated with an increased incidence of cardiovascular disease, specifically in diabetes mellitus (DM). Oxidative stress is increased in Hp2 mice and humans with DM. Oxidative modification of the apolipoprotein A-I inhibits reverse cholesterol transport. We sought to test the hypothesis that reverse cholesterol transport is impaired in Hp2 DM mice and humans. In vitro, using serum from non-DM and DM individuals, we measured cholesterol efflux from (3)H-cholesterol-labeled macrophages. In vivo, we injected (3)H-cholesterol-loaded macrophages intraperitoneally into non-DM and DM mice with the Hp1-1 or Hp2-2 genotype and monitored (3)H-tracer levels in plasma, liver, and feces. In vitro, in DM individuals only, we observed significantly decreased cholesterol efflux from macrophages incubated with serum from Hp2-1 or Hp2-2 as compared with Hp1-1 individuals (P<0.01). The interaction between Hp type and DM was recapitulated using purified Hp and glycated Hb. In vivo, DM mice loaded with (3)H-cholesterol-labeled macrophages had a 40% reduction in (3)H-cholesterol in plasma, liver, and feces as compared with non-DM mice (P<0.01). The reduction in reverse cholesterol transport associated with DM was significantly greater in Hp2-2 mice as compared with Hp1-1 mice (54% versus 25% in plasma; 52% versus 27% in liver; 57% versus 32% in feces; P<0.03). reverse cholesterol transport is decreased in Hp2-2 DM. This may explain in part the increased atherosclerotic burden found in Hp2-2 DM individuals.

Renal slit diaphragm--the open zipper and the failing heart.

Inherited forms of proteinuria constitute a rare and heterogeneous group of diseases, the most prominent of which is glomerular dysfunction, which leads to proteinuria. Investigation of the genetic background underlying these diseases has provided significant data on the normal operation of the glomerular filter. Among the different components of the glomerulus, the podocyte slit diaphragm is considered the main source for genetically derived protein alteration, which leads in turn to proteinuria. Investigation of the different proteins revealed that the lack of nephrin and podocin is the leading cause of several inherited forms of proteinuria. It was also proposed that the lack of podocin is linked to cardiac anomalies. This review suggests that the absence of slit diaphragm proteins and the open zipper phenomenon are associated with cardiac anomalies.

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.

Preclinical and Preliminary Clinical Evaluation of Genetically Transduced Dermal Tissue Implants for the Sustained Secretion of Erythropoietin and Interferon α.

Protein drugs are currently delivered by bolus injection and although treatment frequently is successful, these methods also have major drawbacks, which call for the development of alternative technologies allowing prolonged delivery of these drugs. We developed a new ex vivo gene therapy platform called Transduced Autologous Restorative Gene Therapy (TARGT) for sustained long term production and secretion of autologous therapeutic proteins. A biopsy of dermal tissue taken from the patient is transduced ex vivo with a viral vector encoding the required gene under a constitutive promoter. Following measurement of protein secretion ex vivo, the transduced dermal tissue is implanted back into the patient, where it secretes the therapeutic protein into the circulation for several months or longer. A major hurdle to this approach is potential immunogenicity of the transduced tissue following implantation. In this paper we describe the preclinical and early clinical development of this technology, which allowed for overcoming these hurdles. To that end, we have used the helper dependent (HD) adenoviral vector with newly designed expression cassette containing genetic elements to optimize transgene expression. Moreover, we have developed procedures for TARGT tissue implantation, with measures to improve engraftment and reduce inflammation and rejection. Implantation of human TARGT to severe combined immune deficient (SCID) mice indicated long-term production of active proteins in the blood. Preliminary results of a clinical trial from two anemic end-stage renal disease patients, implanted with TARGTs expressing the human erythropoietin (EPO) gene, demonstrated prolonged secretion with physiologic blood level of the hormone and hemoglobin maintenance in the desired range, for a period of at least 5 months without exogenous EPO administration. We believe that the TARGT technology has the potential to become a platform for the sustained delivery of therapeutic proteins in various clinical indications.

Haptoglobin genotype is a consistent marker of coronary heart disease risk among individuals with elevated glycosylated hemoglobin.

OBJECTIVES: This study sought to investigate into the biologically plausible interaction between the common haptoglobin (Hp) polymorphism rs#72294371 and glycosylated hemoglobin (HbA(1c)) on risk of coronary heart disease (CHD). BACKGROUND: Studies of the association between the Hp polymorphism and CHD report inconsistent results. Individuals with the Hp2-2 genotype produce Hp proteins with an impaired ability to prevent oxidative injury caused by elevated HbA(1c). METHODS: HbA(1c) concentration and Hp genotype were determined for 407 CHD cases matched 1:1 to controls (from the NHS [Nurses' Health Study]) and in a replication cohort of 2,070 individuals who served as the nontreatment group in the ICARE (Prevention of Cardiovascular Complications in Diabetic Patients With Vitamin E Treatment) study, with 29 CHD events during follow-up. Multivariate models were adjusted for lifestyle and CHD risk factors as appropriate. A pooled analysis was conducted of NHS, ICARE, and the 1 previously published analysis (a cardiovascular disease case-control sample from the Strong Heart Study). RESULTS: In the NHS, Hp2-2 genotype (39% frequency) was strongly related to CHD risk only among individuals with elevated HbA(1c) (≥ 6.5%), an association that was similar in the ICARE trial and the Strong Heart Study. In a pooled analysis, participants with both the Hp2-2 genotype and elevated HbA(1c) had a relative risk of 7.90 (95% confidence interval: 4.43 to 14.10) for CHD compared with participants with both an Hp1 allele and HbA(1c) <6.5% (p for interaction = 0.004), whereas the Hp2-2 genotype with HbA(1c) <6.5% was not associated with risk (relative risk: 1.34 [95% confidence interval: 0.73 to 2.46]). CONCLUSIONS: Hp genotype was a significant predictor of CHD among individuals with elevated HbA(1c).

Haptoglobin genotype and cardiovascular outcomes in diabetes mellitus - natural history of the disease and the effect of vitamin E treatment. Meta-analysis of the medical literature.

BACKGROUND: Diabetes mellitus carries a high risk for vascular events. Diabetics with different haptoglobin (Hp) types may carry different risk profiles, and may respond differently to vitamin E treatment. We aim to summarize the evidence about cardiovascular risk in diabetic patients, according to their Hp type, and the effect of vitamin E treatment on these sub-groups. METHODS: We searched MEDLINE and on-going trials' databases until February 2011; gray literature; reference lists of identified articles; and experts. Two investigators screened and selected studies that prospectively followed cardiovascular outcomes in diabetic patients with different Hp types (natural history analysis), and randomized controlled trials reporting the effect of vitamin E on cardiovascular outcomes in diabetics, in which Hp typing was performed (interventional analysis). RESULTS: Five and three studies, comprising 1829 and 2110 patients, were eligible for the natural history and the interventional analyses, respectively. The percentage of diabetic patients experiencing non-fatal MI, stroke, or cardiovascular death was significantly higher in the Hp 2-2 population (odds ratio (OR) 2.03 (95% confidence interval (CI) 1.46 to 2.81)). In patients with Hp 2-2 genotype, the OR for a combined endpoint was 0.66 in favor of the vitamin E treated group (95% CI 0.48 to 0.9). This effect was not shown in other Hp types. CONCLUSION: Hp type 2-2 carries a high risk of cardiovascular events in diabetic patients. A pharmacogenomic approach towards treatment of diabetic patients with vitamin E may be warranted.

The cardioprotective efficacy of TVP1022 in a rat model of ischaemia/reperfusion.

BACKGROUND AND PURPOSE: Because myocardial infarction is a major cause of morbidity and mortality worldwide, protecting the heart from the ischaemia and reperfusion (I/R) damage is the focus of intense research. Based on our in vitro findings showing that TVP1022 (the S-enantiomer of rasagiline, an anti-Parkinsonian drug) possesses cardioprotective effects, in the present study we investigated the hypothesis that TVP1022 can attenuate myocardial damage in an I/R model in rats. EXPERIMENTAL APPROACH: The model consisted of 30-min occlusion of the left anterior descending artery followed by 4 or 24 h reperfusion. In addition, we investigated the possible mechanisms of cardioprotection in H9c2 cells and neonatal rat ventricular myocytes (NRVM) exposed to oxidative stress induced by H(2) O(2) . KEY RESULTS: TVP1022 (20 and 40 mg·kg(-1) ) administered 5 min before reperfusion followed by an additional dose 4 h after reperfusion reduced the infarct size and attenuated the decline in ventricular function. TVP1022 also attenuated I/R-induced deterioration in cardiac mitochondrial integrity evaluated by mitochondrial swelling capacity. In vitro, using H9c2 cells and NRVM, TVP1022 attenuated both serum free- and H(2) O(2) -induced damage, preserved mitochondrial membrane potential and Bcl-2 levels, inhibited mitochondrial cytochrome c release and the increase in cleaved caspase 9 and 3 levels, and enhanced the phosphorylation of protein kinase C and glycogen synthase kinase-3ß. CONCLUSIONS AND IMPLICATIONS: TVP1022 provided cardioprotection in a model of myocardial infarction, and therefore should be considered as a novel adjunctive therapy for attenuating myocardial damage resulting from I/R injuries.

Vitamin E therapy results in a reduction in HDL function in individuals with diabetes and the haptoglobin 2-1 genotype.

OBJECTIVE: Vitamin E provides cardiovascular protection to individuals with diabetes and the haptoglobin 2-2 genotype but appears to increase cardiovascular risk in individuals with diabetes and the haptoglobin 2-1 genotype. We have previously demonstrated that the haptoglobin protein is associated with HDL and that HDL function and its oxidative modification are haptoglobin genotype dependent. We set out to test the hypothesis that the pharmacogenetic interaction between the haptoglobin genotype on cardiovascular risk might be secondary to a parallel interaction between the haptoglobin genotype and vitamin E on HDL function. RESEARCH DESIGN AND METHODS: Fifty-nine individuals with diabetes and the haptoglobin 2-1 or 2-2 genotypes were studied in a double-blind placebo controlled crossover design. Participants were treated with either vitamin E (400IU) or placebo for 3 months and crossed over for an equivalent duration. Serum was collected at baseline and after the completion of each treatment. HDL functionality as well as HDL associated markers of oxidation and inflammation were measured after each interval in HDL purified from the cohort. RESULTS: Compared to placebo, vitamin E significantly increased HDL function in haptoglobin 2-2 but significantly decreased HDL function in haptoglobin 2-1. This pharmacogenetic interaction was paralleled by similar non-significant trends in HDL associated lipid peroxides, glutathione peroxidase, and inflammatory cargo. CONCLUSION: There exists a pharmacogenetic interaction between the haptoglobin genotype and vitamin E on HDL function (clinicaltrials.gov NCT01113671).

Vasospasm after subarachnoid hemorrhage in haptoglobin 2-2 mice can be prevented with a glutathione peroxidase mimetic.

Vasospasm after subarachnoid hemorrhage (SAH) is attributable to inflammation and oxidative stress associated with extracellular hemoglobin (Hb). Haptoglobin (Hp) binds free Hb and the Hp-Hb complex is cleared by macrophages, and the Hp-2 isoform of Hp is associated with more oxidative stress and more severe vasospasm. We hypothesized that treatment with an anti-oxidant, the glutathione peroxidase mimetic SYI-2074, would reduce vasospasm after SAH in Hp-2 mice. We found that SAH induced significant vasospasm in Hp-2 mice (lumen patency reduced to 65.9%), but no vasospasm was seen in mice that received SYI-2074 after SAH (lumen patency of 98.7%). We conclude that vasospasm after SAH in Hp-2 mice can be prevented with SYI-2074, suggesting that oxidative stress contributes significantly to vasospasm.