Comparison of Vascular Smooth Muscle Cell Apoptosis and Fibrous Cap Morphology in Symptomatic and Asymptomatic Carotid Artery Disease

The biological cascades that lead to carotid plaque disruptions and symptoms are largely unknown. Certain cellular events within the plaque might be responsible for destabilizing the plaque, though the popular belief is that the plaque size is directly related to symptoms. The aim of our study was to assess the morphology of the fibrous cap and apoptosis in the plaque and compare these two pathological features in symptomatic and asymptomatic carotid artery disease. Our work was carried out in plaques obtained following carotid endarterectomy performed for symptomatic disease (including hemispheric transient ischemic attacks, amaurosis fugax, or stroke) or asymptomatic high-grade severe stenosis. Scion images of Gomori's stained sections were used to measure fibrous cap thickness and area. TUNEL assay was performed to assess the extent of apoptosis. The results indicated that the area of the fibrous cap did not significantly correlate with the presence of symptoms. There was a higher percentage of apoptotic nuclei and the thinner fibrous cap in symptomatic plaques than in asymptomatic plaques. This finding suggests that these factors might be involved in destabilizing plaque, causing rupture and leading to symptomatic carotid disease.     

Nano-opto-mechanical characterization of neuron membrane mechanics under cellular growth and differentiation

We designed and fabricated silicon probe with nanophotonic force sensor to directly stimulate neurons (PC12) and measured its effect on neurite initiation and elongation. A single-layer pitch-variable diffractive nanogratings was fabricated on silicon nitride probe using e-beam lithography, reactive ion etching and wet-etching techniques. The nanogratings consist of flexure folding beams suspended between two parallel cantilevers of known stiffness. The probe displacement, therefore the force, can be measured through grating transmission spectrum. We measured the mechanical membrane characteristics of PC12 cells using the force sensors with displacement range of 10 mum and force sensitivity 8 muN/mum. Young's moduli of 425 +/- 30 Pa are measured with membrane deflection of 1% for PC12 cells cultured on polydimethylsiloxane (PDMS) substrate coated with collagen or laminin in Ham's F-12K medium. In a series of measurements, we have also observed stimulation of directed neurite contraction up to 6 mum on extended probing for a time period of 30 min. This method is applicable to measure central neurons mechanics under subtle tensions for studies on development and morphogenesis. The close synergy between the nano-photonic measurements and neurological verification can improve our understanding of the effect of external conditions on the mechanical properties of cells during growth and differentiation.     

Human lung epithelial cells express a functional cold-sensing TRPM8 variant

Several transient receptor potential (TRP) ion channels sense and respond to changes in ambient temperature. Chemical agonists of TRP channels, including menthol and capsaicin, also elicit sensations of temperature change. TRPM8 is a cold- and menthol-sensing ion channel that converts thermal and chemical stimuli into neuronal signals and sensations of cooling/cold. However, the expression and function of TRPM8 receptors in non-neuronal cells and tissues is a relatively unexplored area. Results presented here document the expression and function of a truncated TRPM8 variant in human bronchial epithelial cells. Expression of the TRPM8 variant was demonstrated by RT-PCR, cloning, and immunohistology. Receptor function was characterized using the prototypical TRPM8 agonist, menthol, and exposure of cells to reduced temperature (18 degrees C). The TRPM8 variant was expressed primarily within endoplasmic reticulum membranes of lung epithelial cells and its activation was attenuated by thapsigargin, the cell-permeable TRPM8 antagonist N-(4-tert-butylphenyl)-4-(3-chloropyridin-2-yl)piperazine-1-carboxamide, and shRNA-induced suppression of TRPM8 expression. Activation of the TRPM8 variant in lung cells was coupled with enhanced expression of the inflammatory cytokines IL-6 and IL-8. Collectively, our results suggest that this novel TRPM8 variant receptor may function as a modulator of respiratory physiology caused by cold air, and may partially explain asthmatic respiratory hypersensitivity to cold air.     

Airway pressure release ventilation for in-vivo donor lung management and lung transplant outcomes

Background:Airway pressure release ventilation (APRV) can be used for cadaveric donor lung recruitment. APRV elevates PaO₂ in donor lungs; however, reported outcomes in recipients with APRV-managed donor lungs are limited. Methods:We retrospectively reviewed patients who underwent lung transplantation (LTx) from 2012 to 2013 and divided them into two groups based on mode of ventilation used during donor management and organ extraction (A: non-APRV; B: APRV). Kaplan-Meier method and multivariate Cox regression were used for analysis. Results:We found 126 LTx recipients (LTxRs); 9 were excluded for use of portable ventilation perfusion systems. Of the remaining 117 patients, 81 (69%) were in Group A; 36 (31%) were in Group B. Preoperative LTxR characteristics (age, sex, lung allocation score, end-stage lung disease type) were comparable between groups. Donors for Group B were older (P=0.03) and had higher body mass index (BMI) (P<0.001), higher incidence of death from chest trauma (P=0.008), longer ventilation duration after brain death (P<0.001), and higher pre-explant PaO₂/FiO₂ ratios (P<0.001). Post-LTx duration of mechanical ventilation, hospital stay, and median survival were similar in both groups. Risk of death was comparable between the two groups at the end of follow-up (HR =1.42; 95% CI: 0.57-3.56; P=0.45). Conclusions:APRV is a safe and effective pre-LTx donor lung management strategy. Short- and long-term survival outcomes were comparable in LTx recipients, irrespective of donor ventilation mode. APRV may help recruit lungs from older donors with higher BMI who die from chest trauma and have anticipated longer ventilation duration.     

Gut microbiota profiling in hematopoietic stem cell transplant recipients: Towards personalized medicine

BackgroundAntibiotic resistance in bacteria is a cause for concern, especially in hematopoietic stem cell transplant (HSCT) patients. Endogenous bowel microflora in HSCT patients get replaced by hospital multidrug resistant flora and pose risk of serious bacterial infection during the pre-engraftment stage. For decades, many methods to reduce the translocation of gut microbiota in HSCT patients have been attempted. Despite the logic, of using prophylactic antibiotics, there is no consensus on standard regimen. Personalized antibiotic prophylaxis-based on gut microbiota and clinical profile has been suggested by researchers. In this study, gut microbiota in HSCT recipients has been studied with antimicrobial susceptibility testing and detection of various antibiotic resistance phenotypes.MethodsSeventy-six HSCT patients (2016–2018) were included. Stool surveillance cultures and antibiotic susceptibility testing were performed. Bacterial isolates were classified into various antibiotic resistance phenotypes.ResultsThis study revealed that 73.75% HSCT recipients had gut colonized with antibiotic resistance microbiota which included extended-spectrum β-lactamase-, multidrug- and extensively drug-resistant phenotypes.ConclusionThis study reiterates the importance of individual profiling of gut microbiota in HSCT patients.     

Current trends in candidate selection,contraindications, and indications for lung transplantation

Lung transplantation is an established treatment option that can improve quality of life and prolong survival for select patients diagnosed with end-stage lung disease. Given the gaps in organ donation and failures to make effective use of available organs, careful selection of candidates for lung transplant remains one of the most important considerations of the transplant community. Toward this end, we briefly reviewed recent trends in pretransplant evaluation, candidate selection, organ allocation, and organ preservation techniques. Since the latest consensus statement regarding appropriate selection of lung transplant candidates, many advances in the science and practice of lung transplantation have emerged and influenced our perspective of ‘contraindications’ to transplant. These advances have made it increasingly possible to pursue lung transplant in patients with risk factors for decreased survival—namely, older recipient age, increased body mass index, previous chest surgery, poorer nutritional status, and presence of chronic infection, cardiovascular disease, or extrapulmonary comorbid conditions. Therefore, we reviewed the updated evidence demonstrating the prognostic impact of these risk factors in lung transplant recipients. Lastly, we reviewed the salient evidence for current trends in disease-specific indications for lung transplantation, such as chronic obstructive pulmonary disease, idiopathic pulmonary fibrosis, cystic fibrosis, emphysema due to alpha-1 antitrypsin deficiency, and pulmonary arterial hypertension, among other less common end-stage diseases. Overall, lung transplant remains an exciting field with considerable hope for patients as they experience remarkable improvements in quality of life and survival in the modern era.