Bestrophin 1 – Phenotypes and Functional Aspects in Bestrophinopathies

This is to review the current state of knowledge on the functional and clinical aspects of bestrophin 1, a prominent member of a family of proteins involved in the control and properties of the light peak of the EOG. Initially human bestrophin 1 gene (BEST1) mutations were identified to underlie Best vitelliform macular dystrophy (VMD), a dominantly inherited, juvenile-onset form of macular degeneration. In the recent past the phenotypical spectrum of retinal disorders associated with BEST1 mutations has been extended and the term bestrophinopathies was coined. The physiological role of bestrophin 1 is still not completely understood but has been linked to the generation of a transepithelial chloride current by controlling voltage-dependent calcium channels (VDCC). Dysfunction of bestrophin 1 may result in abnormal ion and fluid transport by the retinal pigment epithelium (RPE) disturbing and even disrupting direct interactions between the RPE and the photoreceptors.     

Second malignancies after treatment of childhood non-Hodgkin lymphoma – a report of the Berlin-Frankfurt-Muenster study group

Second malignant neoplasms (SMN) pose a concern for survivors of childhood cancer. We evaluated incidence, type and risk factors for SMN in patients included in Berlin-Frankfurt-Muenster protocols for childhood non-Hodgkin lymphoma.3,590 patients <15 years of age at diagnosis, registered between 01/1981 and 06/2010, were analyzed. SMN were reported by the treating institutions and the German Childhood Cancer Registry. After a median follow-up of 9.4 years (quartile [Q] range, Q1 6.7 and Q3 12.1) 95 SMN were registered (26 carcinomas including nine basal cell carcinomas, 21 acute myeloid leukemias/myelodysplastic syndromes, 20 lymphoid malignancies, 12 central nervous system [CNS]-tumors, and 16 others). Cumulative incidence at 20 years was 5.7±0.7%, standard incidence ratio, excluding basal cell carcinomas, was 19.8 (95% Confidence Interval [CI]: 14.5-26.5). Median time from initial diagnosis to second malignancy was 8.7 years (range, 0.2-30.3 years). Acute-lymphoblasticleukemia- type therapy, cumulative anthracycline dose, and cranial radiotherapy for brain tumor-development were significant risk factors in univariate analysis only. In multivariate analysis including risk factors significant in univariate analysis, female sex (hazard ratio [HR] 1.87, 95% CI: 1.23-2.86, P=0.004), CNS-involvement (HR 2.24, 95% CI: 1.03-4.88, P=0.042), lymphoblastic lymphoma (HR 2.60, 95% CI: 1.69-3.97, P<0.001), and cancer-predisposing condition (HR 11.2, 95% CI: 5.52-22.75, P<0.001) retained an independent risk. Carcinomas were the most frequent SMN after non-Hodgkin lymphoma in childhood followed by acute myeloid leukemia and lymphoid malignancies. Female sex, lymphoblastic lymphoma, CNS-involvement, or/and known cancer-predisposing condition were risk factors for SMN-development. Our findings set the basis for individualized long-term follow-up and risk assessment of new therapies.     

Diminished posttetanic potentiation in failing human myocardium

In heart failure a decreased function of SERCA2 has been demonstrated. The present study aimed at investigating the relation between sarcoplasmic reticulum-Ca²⁺-load (SR-Ca²⁺-load) and the activity of the SERCA2. SR-Ca²⁺ load was evaluated by measuring posttetanic potentiation (PTP) in human nonfailing (NF, n=10) and endstage failing myocardium (DCM, n=11). In addition, the effect of cyclopiazonic acid (CPA), a specific inhibitor of SERCA2, on PTP was studied in both NF and DCM. In crude membrane preparations from the same hearts the maximal SERCA2 activity was determined and correlated with the PTP. In failing myocardium the PTP was significantly reduced compared to nonfailing myocardium (13.7±0.75 mN/mm² vs. 17.1±1.55 mN/mm², p<0.05, ±SEM). When PTP was studied in the presence of increased extracellular Ca²⁺-concentrations, the difference between NF and DCM was further pronounced. CPA decreased PTP in both nonfailing and failing human tissue. The maximal SERCA2 activity was significantly reduced in failing myocardium (NF 267±18.5 nmol ATP/mg protein · min⁻¹ vs. DCM 191±13.4 nmol ATP/mg protein · min⁻¹, p<0.05, ± SEM). Correlation of the PTP and maximal SERCA2 activity revealed a close correlation between both parameters in NF and DCM. In summary, the presented results suggest that reduced SERCA2 activity in DCM influences posttetanic force potentiation probably through a reduced SR-Ca²⁺-load. Received: 30 July 1999 Returned for 1. revision: 9 September 1999 1. Revision received: 24 November 1999 Returned for 2. revision: 26 January 2000 2. Revision received: 26 April 2000 Accepted: 9 May 2000     

Impact of Obesity on Outcomes of Pregnancy in Women With Heart Disease

BackgroundWomen with heart disease are at risk for complications during pregnancy. This study sought to examine the effect of maternal obesity on pregnancy complications in women with heart disease.ObjectivesThe objective was to determine the incidence of adverse cardiac events (CE) in pregnant women with heart disease and obesity.MethodsAdverse CE during pregnancy were examined in a prospective cohort of women with heart disease. CE were a composite of the following: cardiac death/arrest, arrhythmias, heart failure, myocardial infarction, stroke, aortic dissection, and thromboembolic events. Pre-eclampsia and post-partum hemorrhage were also studied. Outcomes were examined according to body mass index (BMI). To identify additional predictors of CE, a baseline risk score (CARPREG [Canadian Cardiac Disease in Pregnancy Study] II score) for predicting cardiac complications was calculated for all pregnancies and included in a multivariable logistic regression model.ResultsOf 790 pregnancies, 19% occurred in women with BMI ≥30 kg/m² (obesity), 25% in women with BMI 25 to 29.9 kg/m² (overweight), 53% in women with BMI 18.5 to 24.9 kg/m² (normal weight), and 3% in women with BMI <18.5 kg/m² (underweight). Women with obesity were at higher risk of CE when compared with women with normal weight (23% vs. 14%; p = 0.006). In a multivariable model, obesity (odds ratio: 1.7; 95% confidence interval: 1.0 to 2.7) and higher CARPREG II risk scores (odds ratio: 1.7; 95% confidence interval: 1.5 to 1.9) predicted CE. Pre-eclampsia was more frequent in women with obesity compared with those with normal weight (8% vs. 2%; p = 0.001).ConclusionsObesity increases the risk of maternal cardiovascular complications in pregnant women with heart disease. This modifiable risk factor should be addressed at the time of preconception counseling.     

Regulation of myocardial connexins during hypertrophic remodelling.

Cardiac hypertrophic remodelling, initiated by signalling cascades in response to increased workload, injury or intrinsic disease, is initially adaptive. However, prolonged hypertrophy as a consequence of pathological stress leads to maladaptive changes that increase the risk for fatal ventricular arrhythmias. One of these changes is the remodelling of myocardial gap junctions, which provide for electrical coupling of adjacent cardiomyocytes. Myocardial gap junctions are composed of three connexin isotypes, connexin40 (Cx40), -43 (Cx43), and -45 (Cx45) and each display a characteristic developmental and regional expression pattern. Alterations in the distribution and expression of Cx43, the predominant isoform in the adult ventricles, has been the main focus of examination in humans, experimental animal models and cultured cardiomyocytes in response to hypertrophy. The molecular mechanisms and signalling pathways underlying these changes have been studied less thoroughly. In this review we summarize what is known about the remodelling of myocardial gap junctions during hypertrophy, the putative underlying mechanisms and functional consequences thereof.     

Generation of highly effective and stable murine alloreactive Treg cells by combined anti‐CD4 mAb,TGF‐β, and RA treatment

The transfer of alloreactive regulatory T (aTreg) cells into transplant recipients represents an attractive treatment option to improve long‐term graft acceptance. We recently described a protocol for the generation of aTreg cells in mice using a nondepleting anti‐CD4 antibody (aCD4). Here, we investigated whether adding TGF‐β and retinoic acid (RA) or rapamycin (Rapa) can further improve aTreg‐cell generation and function. Murine CD4⁺ T cells were cultured with allogeneic B cells in the presence of aCD4 alone, aCD4+TGF‐β+RA or aCD4+Rapa. Addition of TGF‐β+RA or Rapa resulted in an increase of CD25⁺Foxp3⁺‐expressing T cells. Expression of CD40L and production of IFN‐γ and IL‐17 was abolished in aCD4+TGF‐β+RA aTreg cells. Additionally, aCD4+TGF‐β+RA aTreg cells showed the highest level of Helios and Neuropilin‐1 co‐expression. Although CD25⁺Foxp3⁺ cells from all culture conditions displayed complete demethylation of the Treg‐specific demethylated region, aCD4+TGF‐β+RA Treg cells showed the most stable Foxp3 expression upon restimulation. Consequently, aCD4+TGF‐β+RA aTreg cells suppressed effector T‐cell differentiation more effectively in comparison to aTreg cells harvested from all other cultures, and furthermore inhibited acute graft versus host disease and especially skin transplant rejection. Thus, addition of TGF‐β+RA seems to be superior over Rapa in stabilising the phenotype and functional capacity of aTreg cells.     

Separating stimulus‐driven and response‐related LRP components with Residue Iteration Decomposition (RIDE)

When the lateralized readiness potential (LRP) is recorded in stimulus–response compatibility (SRC) tasks, two processes may overlap in the LRP, stimulus‐driven response priming and activation based on response selection rules. These overlapping processes are hard to disentangle with standard analytical tools. Here, we show that Residue Iteration Decomposition (RIDE), based on latency variability, separates the overlapping LRP components from a Simon task into stimulus‐driven and response‐related components. SRC affected LRP amplitudes only in the stimulus‐driven component, whereas LRP onsets were affected only in the response‐locked component. Importantly, the compatibility effect in reaction times was more similar to the effect in the onsets of the RIDE‐derived response‐locked LRP component than in the unseparated LRP. Thus, RIDE‐separated LRP components are devoid of distortions inherent to standard LRPs.     

Retinoid X receptor beta polymorphisms do not explain functional differences in vitamins D and A response in Antineutrophil cytoplasmic antibody associated vasculitis patients

It has been suggested that the retinoid X receptor beta (RXRB) gene is a risk factor for Wegener's granulomatosis. We addressed if there is a functional difference in the response to retinoic acid (RA) and vitamin D in Antineutrophil cytoplasmic antibody (ANCA) associated systemic vasculitis (AASV) patients and if this was associated with RXRB genotypes. TNFα and IL-10 production were measured in whole blood assay from AASV patients (n = 51) and healthy controls (HC, n = 67). One micromolar of 1,25-(OH)₂ D3, 9-cis RA (9c-RA) or all-trans RA (ATRA) was added to the assay. Genotyping was performed for exons 7 and 2 of the RXRB gene and for a microsatellite in vicinity of the RXRB gene. Lipopolysaccharide (LPS) mediated TNFα production and IL-10 were significantly lower in patients. Addition of 1,25-(OH)₂ D3, ATRA or 9c-RA, blunted TNFα production, more pronounced in patients. Although all three compounds inhibited IL-10 production significantly in HC, only 1,25-(OH)₂ D3 was found to be effective in patients. Allele distribution of the RXRB microsatellite differed significantly between patients and HC. This was not found for the SNP in exons 2 and 7. Genotype of the latter correlated with the ability of 1,25-(OH)₂ D3 and ATRA to inhibit IL-10 production. We provide immunological evidence for a functional difference in vitamins D and A responsiveness in AASV patients. Since the inhibition of TNFα was more effective in patients, vitamin D supplementation might be an additional therapeutical approach.