Asymmetric segregation and self-renewal of hematopoietic stem and progenitor cells with endocytic Ap2a2

The stem cell-intrinsic model of self-renewal via asymmetric cell division (ACD) posits that fate determinants be partitioned unequally between daughter cells to either activate or suppress the stemness state. ACD is a purported mechanism by which hematopoietic stem cells (HSCs) self-renew, but definitive evidence for this cellular process remains open to conjecture. To address this issue, we chose 73 candidate genes that function within the cell polarity network to identify potential determinants that may concomitantly alter HSC fate while also exhibiting asymmetric segregation at cell division. Initial gene-expression profiles of polarity candidates showed high and differential expression in both HSCs and leukemia stem cells. Altered HSC fate was assessed by our established in vitro to in vivo screen on a subcohort of candidate polarity genes, which revealed 6 novel positive regulators of HSC function: Ap2a2, Gpsm2, Tmod1, Kif3a, Racgap1, and Ccnb1. Interestingly, live-cell videomicroscopy of the endocytic protein AP2A2 shows instances of asymmetric segregation during HSC/progenitor cell cytokinesis. These results contribute further evidence that ACD is functional in HSC self-renewal, suggest a role for Ap2a2 in HSC activity, and provide a unique opportunity to prospectively analyze progeny from HSC asymmetric divisions.     

European Society of Hypertension scientific newsletter: hypertension and aortic diseases

Hypertension, one of the major cardiovascular risk factors, promotes the formation of atheromatous lesions in the large arteries, including the aorta. It also favors aortic aneurysm and acute aortic syndrome such as aortic dissection or hematoma. In patients with aortic disease, beta-blockers and/or renin-angiotensin-aldosterone system inhibitors should be preferentially used to decrease blood pressure and improve arterial wall properties.     

Hemoglobin sickle cell disease complications: a clinical study of 179 cases

Background

Hemoglobin sickle cell disease is one of the most frequent hemoglobinopathies. Surprisingly, few studies have been dedicated to this disease, currently considered to be a mild variant of homozygous sickle cell disease. The aim of this study was to update our knowledge about hemoglobin sickle cell disease.

Design and Methods

The study involved a single center series of 179 patients. Clinical and biological data were collected with special attention to the assessment of pulmonary arterial hypertension and nephropathy.

Results

Hemoglobin sickle cell diagnosis was delayed and performed in adulthood in 29% of cases. Prevalence of hospitalized painful vasoocclusive crisis, acute chest syndrome and priapism was 36%, 20% and 20%, respectively. The most common chronic organ complications were retinopathy and sensorineural otological disorders in 70% and 29% of cases. Indeed, prevalence of complications reported in homozygous sickle cell disease, such as nephropathy, suspicion of pulmonary hypertension, strokes and leg ulcers was rather low (13%, 4% and 1%, respectively). Phlebotomy performed in 36% of this population (baseline hemoglobin 11.5 g/dL) prevented recurrence of acute events in 71% of cases.

Conclusions

Our data suggest that hemoglobin sickle cell disease should not be considered as a mild form of sickle cell anemia but as a separate disease with a special emphasis on viscosity-associated otological and ophthalmological disorders, and with a low prevalence of vasculopathy (strokes, pulmonary hypertension, ulcers and nephropathy). Phlebotomy was useful in reducing acute events and a wider use of this procedure should be further investigated.     

Genetic Variants in Toll-Like Receptor 2 (TLR2), TLR4, TLR9, and FCγ Receptor II Are Associated with Antibody Response to Quadrivalent Meningococcal Conjugate Vaccine in HIV-Infected Youth

This study examined the association of host genetic variants with the antibody response to the quadrivalent meningococcal conjugate vaccine (MCV4) in HIV-infected youth. Genetic variants associated with severity of meningococcal disease, including the IgG Fc receptor (FCγRII)-A484T, interleukin-10 (IL-10)-A1082G, -C819T, and -C627A, IL-4-C589T, mannose binding lectin-2 (MBL2)-A/O, -H/L, -P/Q, and -X/Y, toll-like receptor 2 (TLR2)-G2408A, TLR4-A12874G and -C13174T, and TLR9-T1237C and -T1486C were determined by real-time PCR (RT-PCR) for 271 HIV-infected subjects (median, 17 years). Response was defined as a ≥4-fold increase from entry in bactericidal antibody titers to each serogroup. Generalized estimating equation (GEE) models were used to evaluate the association of allelic variants with the immunologic response to all serogroups within each subject with and without adjusting for CD4 percentage and HIV viral load. At week 4, but not after, subjects with TLR2-2408-G/A versus -G/G genotypes and the TLR4-12874-A/A genotype were more likely to achieve a ≥4-fold increase overall in the four serogroups (unadjusted P of 0.006 and adjusted P of 0.008 and unadjusted P of 0.008 and adjusted P of 0.019, respectively). At week 28, the TLR9-1237 T allele was associated with enhanced antibody response (T allele versus C/C, unadjusted P of 0.014 and adjusted P of 0.009), which was maintained at week 72 (unadjusted and adjusted P of 0.008). At week 72, the FcγRII-131Arg allotype was associated with a ≥4-fold increase in antibody titer versus those with His/His (unadjusted P of 0.009; adjusted P of <0.001). These findings suggest that for HIV-infected youth, the initial antibody response to MCV4 is associated with variants in TLR2 and TLR4 while the long-term response is associated with genetic polymorphisms in TLR9 and FcγRIIa.     

A randomised comparison of single-incision versus traditional transobturator midurethral sling in women with stress urinary incontinence: results of a 24-month follow-up

Introduction and hypothesis

Midurethral sling procedures have become the principal surgical treatment for women with stress urinary incontinence (SUI). The 1-year results of this international trial comparing the efficacy and morbidity of a single-incision midurethral sling (SIMS; MiniArc) and a transobturator standard midurethral sling (SMUS; Monarc) showed that MiniArc is non-inferior regarding subjective cure and superior with regard to postoperative pain and recovery. The objective was to compare subjective and objective cure, morbidity and surgery-related discomfort following SIMS and transobturator SMUS up to a 24-month follow-up.

Methods

We carried out a non-blinded, randomised, controlled trial. Women with symptomatic SUI were eligible. Primary outcome was subjective cure, defined as an improvement on the Patient Global Impression of Improvement (PGI-I), at 12, 24 and 36 months. Secondary outcomes were objective cure based on the cough stress test, disease-specific quality of life questionnaires, surgical parameters and physical performance during recovery. Analysis was by intent to treat. Differences between the two groups regarding dichotomous variables were Chi-squared tested and presented as relative risks (RR) with corresponding 95 % confidence intervals.

Results

We randomised 97 women to MiniArc and 96 to Monarc. At the 24-month follow-up, subjective cure was 84 % following MiniArc and 89 % following Monarc (RR ?5; 95% CI ?0.17 to 0.06). Objective cure was 93 % following MiniArc and 94 % following Monarc (RR ?1; 95% CI ?0.10 to 0.07). Both procedures have low complication rates.

Conclusions

At the 2-year follow-up, the non-prespecified analysis of this randomised trial showed that the MiniArc, a single-incision sling, had similar subjective and similar objective cure rates, although non-inferiority to Monarc for subjective cure could not be demonstrated.