Activation of microglia and astrocytes in the nucleus tractus solitarius during ventilatory acclimatization to 10% hypoxia in unanesthetized mice

Nucleus tractus solitarius (NTS) is the integrative sensory relay of autonomic functions in the brainstem. To explore the nonneuronal cellular basis of central chemosensitivity during the first 24 hr of ventilatory acclimatization to hypoxia (VHA), we have investigated glial activation markers in the NTS. Conscious mice (C57/BL6) were placed in a hermetic hypoxia chamber containing a plethysmograph to record ventilation. After 4 days of habituation to the normoxic environment, mice were subjected to physiological hypoxia (10% O₂) for 1, 6, or 24 hr. To dissociate interactions between microglia and astrocytes, another group received daily minocycline, a microglia activation blocker. By immunochemical localization of astrocytes (GFAP), activated microglia (Cd11b), and total microglia (Iba‐1), we identified an oxygen‐sensing glial layer in the NTS, in which astrocytes are first activated after 1–6 hr of hypoxia, followed by microglia after 6–24 hr of hypoxia. Minocycline administration suppressed microglial activation and decreased astrocyte activation at 6 hr and VHA at 24 hr of hypoxia. These results suggest that astrocytes contribute to the neuronal response during the first hour of hypoxia, whereas microglial cells, via cross‐talk with astrocytes, are involved in the VHA during the first 24 hr of acclimatization. © 2014 Wiley Periodicals, Inc.     

C3 nephritic factor associated with C3 glomerulopathy in children

Background

C3 glomerulopathy (C3G) is characterized by predominant C3 deposits in glomeruli and dysregulation of the alternative pathway of complement. Half of C3G patients have a C3 nephritic factor (C3NeF). C3G incorporated entities with a range of features on microscopy including dense deposit diseases (DDD) and C3 glomerulonephritis (C3GN). The aim of this work was to study children cases of C3G associated with C3NeF.

Methods

We reviewed 18 cases of C3G with a childhood onset associated with C3NeF without identified mutations in CFH, CFI, and MCP genes.

Results

Clinical histories started with recurrent hematuria for seven patients, nephrotic syndrome for four, acute post-infectious glomerulonephritis for three and acute renal failure for four. Twelve patients had a low C3 at first investigation. Kidney biopsy showed ten C3GN and eight DDD. Twenty-three percent of the patients tested presented elevated sC5b9. Seven patients relapsed 3 to 6 years after the onset. At the end of follow-up, two patients were under dialysis, 11 had a persistent proteinuria, five had none; four patients did not follow any treatment. Steroids were first used in 80 % of cases.

Conclusions

C3NeF associated C3G has a heterogeneous presentation and outcome. Anti-proteinuric agents may control the disease during follow-up, even after nephrotic syndrome at the onset. The efficiency of immunosuppressive therapy remains questionable.     

Does diabetes modify the effect of FRAX risk factors for predicting major osteoporotic and hip fracture?

Summary

In an observational study population of 62,413 individuals (6,455 [10 %] with diabetes), diabetes was independently associated with major osteoporotic fractures (MOFs) but did not significantly modify the effect of FRAX^TM risk factors or prior fracture site. However, the presence of diabetes exerted a much stronger effect on hip fracture risk in younger versus older individuals.

Introduction

Diabetes mellitus increases fracture risk independent of risk factors that comprise the WHO FRAX^TM tool. We explored whether diabetes modifies the effect of FRAX clinical risk factors on MOF and hip fracture risk.

Methods

Using a registry of clinical dual-energy X-ray absorptiometry (DXA) results for Manitoba, Canada, we identified women and men aged 40 years and older undergoing baseline DXA in 1996–2011. Health services data were used to identify diabetes diagnosis, FRAX risk factors and incident fractures using previously validated algorithms. Prior fracture was stratified as clinical vertebral, hip, humerus, forearm, pelvis and ‘other’. Cox proportional hazards models were used to test for statistical interactions of diabetes with FRAX clinical risk factors and prior fracture site.

Results

During a mean follow-up of 6 years, there were 4,218 MOF and 1,108 hip fractures. Diabetes was a significant independent risk factor for MOF adjusted for FRAX risk factors including bone mineral density (BMD) (adjusted hazard ratio [aHR] 1.32 [95 % confidence interval (CI) 1.20–1.46]). No significant interactions of FRAX risk factors or prior fracture site with diabetes were identified in analyses of MOF. For predicting hip fractures, age significantly modified the effect of diabetes (aHR age <60, 4.67 [95 % CI 2.76–7.89], age 60–69, 2.68 [1.77–4.04], age 70–79, 1.57 [1.20–2.04], age >80, 1.42 [1. 10–1.99]; pinteraction <0.001).

Conclusions

Diabetes is an independent risk factor for MOFs and does not significantly modify the effect of FRAX risk factors or prior fracture site. However, diabetes exerts a much stronger effect on hip fracture risk in younger than older individuals which needs to be considered in hip fracture prediction.     

Development of a transmission-blocking malaria vaccine: Progress,challenges, and the path forward

New interventions are needed to reduce morbidity and mortality associated with malaria, as well as to accelerate elimination and eventual eradication. Interventions that can break the cycle of parasite transmission, and prevent its reintroduction, will be of particular importance in achieving the eradication goal. In this regard, vaccines that interrupt malaria transmission (VIMT) have been highlighted as an important intervention, including transmission-blocking vaccines that prevent human-to-mosquito transmission by targeting the sexual, sporogonic, or mosquito stages of the parasite (SSM-VIMT). While the significant potential of this vaccine approach has been appreciated for decades, the development and licensure pathways for vaccines that target transmission and the incidence of infection, as opposed to prevention of clinical malaria disease, remain ill-defined. This article describes the progress made in critical areas since 2010, highlights key challenges that remain, and outlines important next steps to maximize the potential for SSM-VIMTs to contribute to the broader malaria elimination and eradication objectives.     

Perivascular Neuropilin-1 expression is an independent marker of improved survival in renal cell carcinoma

Renal cell carcinoma (RCC) treatment has improved in the last decade with the introduction of drugs targeting tumor angiogenesis. However, the 5-year survival of metastatic disease is still only 10–15%. Here, we explored the prognostic significance of compartment-specific expression of Neuropilin 1 (NRP1), a co-receptor for vascular endothelial growth factor (VEGF). NRP1 expression was analyzed in RCC tumor vessels, in perivascular tumor cells, and generally in the tumor cell compartment. Moreover, complex formation between NRP1 and the main VEGF receptor, VEGFR2, was determined. Two RCC tissue microarrays were used; a discovery cohort consisting of 64 patients and a validation cohort of 314 patients. VEGFR2/NRP1 complex formation in cis (on the same cell) and trans (between cells) configurations was determined by in situ proximity ligation assay (PLA), and NRP1 protein expression in three compartments (endothelial cells, perivascular tumor cells, and general tumor cell expression) was determined by immunofluorescent staining. Expression of NRP1 in perivascular tumor cells was explored as a marker for RCC survival in the two RCC cohorts. Results were further validated using a publicly available gene expression dataset of clear cell RCC (ccRCC). We found that VEGFR2/NRP1 trans complexes were detected in 75% of the patient samples. The presence of trans VEGFR2/NRP1 complexes or perivascular NRP1 expression was associated with a reduced tumor vessel density and size. When exploring NRP1 as a biomarker for RCC prognosis, perivascular NRP1 and general tumor cell NRP1 protein expression correlated with improved survival in the two independent cohorts, and significant results were obtained also at the mRNA level using the publicly available ccRCC gene expression dataset. Only perivascular NRP1 expression remained significant in multivariable analysis. Our work shows that perivascular NRP1 expression is an independent marker of improved survival in RCC patients, and reduces tumor vascularization by forming complexes in trans with VEGFR2 in the tumor endothelium. © 2019 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.     

Tubular aggregate myopathy and Stormorken syndrome: Mutation spectrum and genotype/phenotype correlation

Calcium (Ca²⁺) acts as a ubiquitous second messenger, and normal cell and tissue physiology strictly depends on the precise regulation of Ca²⁺ entry, storage, and release. Store‐operated Ca²⁺ entry (SOCE) is a major mechanism controlling extracellular Ca²⁺ entry, and mainly relies on the accurate interplay between the Ca²⁺ sensor STIM1 and the Ca²⁺ channel ORAI1. Mutations in STIM1 or ORAI1 result in abnormal Ca²⁺ homeostasis and are associated with severe human disorders. Recessive loss‐of‐function mutations impair SOCE and cause combined immunodeficiency, while dominant gain‐of‐function mutations induce excessive extracellular Ca²⁺ entry and cause tubular aggregate myopathy (TAM) and Stormorken syndrome (STRMK). TAM and STRMK are spectra of the same multisystemic disease characterized by muscle weakness, miosis, thrombocytopenia, hyposplenism, ichthyosis, dyslexia, and short stature. To date, 42 TAM/STRMK families have been described, and here we report five additional families for which we provide clinical, histological, ultrastructural, and genetic data. In this study, we list and review all new and previously reported STIM1 and ORAI1 cases, discuss the pathomechanisms of the mutations based on the known functions and the protein structure of STIM1 and ORAI1, draw a genotype/phenotype correlation, and delineate an efficient screening strategy for the molecular diagnosis of TAM/STRMK.     

High dose daily interferon-alpha induction and secondary adjunction of ribavirin in treatment-naive patients with chronic hepatitis C. A multicentric, randomised, controlled trial

OBJECTIVES: To evaluate in naive patients with chronic hepatitis C 1- the efficacy and safety of one month interferon alpha (IFN-alpha) induction regimen; 2- the potential virological benefit of a secondary adjunction of ribavirin among HCV RNA negative patients after 20 weeks of IFN therapy, with or without an initial 4-week IFN induction. MATERIAL AND METHODS: 151 naive HCV-RNA positive patients presenting with biopsy- proven chronic hepatitis C and elevated ALT were randomised in a 2: 1 ratio in two arms: IFN-alpha 3 MU thrice a week (tiw) for 24 weeks (non-induced patients); IFN-alpha 6 MU daily for two weeks, then 3 MU daily for two weeks then 3 MU tiw for 20 weeks (induced patients). At week 24, HCV-RNA negative patients were randomised to receive in addition or not ribavirin 1-1.2 g daily for 24 additional weeks. Induction efficacy was assessed on the early viral response (EVR) defined as undetectable HCV RNA at week 4 then week 20. Ribavirin efficacy was assessed on the proportion of maintained complete response until the end of follow-up, 24 weeks after discontinuation of treatment. Data were analysed on an intent-to-treat basis. RESULTS: Efficacy of IFN-alpha induction: 104 patients were randomised to the non-induction group, 47 to the induction group. Gender, age, genotype distribution and HCV viral load at baseline did not differ significantly between the two groups. There was one treatment discontinuation because of adverse events in induced patients versus four in non-induced patients (P > 0.05). The 4 week EVR was significantly greater in induced patients in patients with HCV genotype 1, 4 or 5 (47% vs 12%, P=0.0002) only. There was no impact of induction in patients with HCV genotype 2 or 3. Efficacy of ribavirin: at week 24, 28 and 26 HCV-RNA negative patients were randomised to addition of ribavirin or not, respectively. Patients randomised to secondary additive ribavirin were more often HCV-RNA negative at the end of follow-up than patients treated with IFN-alpha alone: 18/28 (64%) vs 10/26 (39%); P=0.06. Among patients randomised to bitherapy, the relapse rate was significantly lower in patients with genotype 2 or 3 (0/12 vs 6/13, P=0.01) and not in those with genotype 1, 4 or 5 (5/11 vs 3/6, P=0.99). CONCLUSION: A 4 week IFN-alpha induction significantly increases the EVR rate in patients with HCV genotype 1, 4 or 5. Late secondary adjunction of ribavirin to IFN-alpha for 6 months in HCV-RNA negative patients after 6 months of IFN-alpha significantly decreases the relapse rate in patients with HCV genotype 2 or 3, but not in patients with genotypes 1, 4 or 5.     

In vitro study of continuous wave Doppler spectral changes resulting from stenoses and bulbs

Quantitative analysis of continuous wave (CW) Doppler spectra by measurements of peak frequency and spectral broadening is an important non-invasive method for detecting disturbed flow caused by carotid arterial stenosis. It is known that severe stenoses can be detected; however, the spectral changes associated with minor or moderate stenoses may not be detected or can potentially be confused with those produced by flow disturbances in the normal carotid bulb. In order to determine if the flow disturbances in a normal bulb and those associated with a minor stenosis produce significant spectral changes, Doppler spectra were recorded from straight tubes with bulbs or stenoses in an in vitro model with steady flow rates of 400, 600, and 800 cc/min (Reynolds numbers of 1700, 2600, and 3500). Stenoses greater than approximately 30% cross-sectional area were associated with an increased peak frequency and increased spectral broadening as measured by spectral broadening index (SBI), coefficient of variation (CV), coefficient of skewedness (CS) and coefficient of kurtosis (CK). Stenoses less than 30% were not detected. With flow rates of 400 and 600 cc/min, the presence of a bulb did not affect peak frequency or the extent of spectral broadening. With a higher flow rate (800 cc/min), there was an increase in SBI, CV and CS but no increase in peak frequency. Based on the results of these in vitro steady flow experiments in straight tubes, we conclude that increased peak frequency and spectral broadening are the result of a stenosis greater than 30% cross-sectional area.(ABSTRACT TRUNCATED AT 250 WORDS)