The impact of high nicotine concentrations on the viability and cardiac differentiation of mesenchymal stromal cells: a barrier to regenerative therapy for smokers.

Background: Current treatment methods are not successful in restoring the lost cardiomyocytes after injury. Stem cell-based strategies have attracted much attention in this regard. Smoking, as a strong cardiovascular risk factor, not only affects the cardiac cells adversely but also deteriorates the function of stem cells. Since mesenchymal stem cells (MSCs) are one of the popular candidates in cardiovascular disease (CVD) clinical trials, we investigated the impact of nicotine on the regenerative properties (viability and cardiac differentiation) of these cells. Methods: MSCs were isolated from rat bone marrow and characterized based on morphology, differentiation capability, and the expression of specific mesenchymal markers. The MTT assay was used to assess the viability of MSCs after being exposed to different concentrations of nicotine. Based on MTT findings and according to the concentration of nicotine in smokers' blood, the growth curve and population doubling time were investigated for eight consecutive days. Cells were treated with 5-azacytidine (an inducer of cardiac differentiation), and then the expressions of cardiac-specific markers were calculated by qPCR. Results: MSCs were spindle-shaped, capable of differentiating into adipocyte and osteocyte, and expressed CD73 and CD90. The viability of MSCs was reduced upon exposure to nicotine in a concentration- and time-dependent manner. The growth curve showed that nicotine reduced the proliferation of MSCs, and treated cells needed more time to double. In addition, the expressions of GATA4 and troponin were downregulated in nicotine-treated cells on day 3. However, these two cardiac markers were overexpressed on day 7. Conclusion: Nicotine decreased normal growth and reduced the expression of cardiac markers in MSCs. This aspect is of eminent importance to smokers with cardiovascular disease who are candidates for stem cell therapy.

The impact of diabetic glucose concentration on viability and cardiac differentiation of mesenchymal stem cells.

INTRODUCTION: Hyperglycemia may be a stumbling block for delivery of regenerative benefits of mesenchymal stem cells (MSCs) to diabetic patients with cardiovascular diseases. Our study aims to assess the viability and cardiac differentiation potential of MSCs after being exposed to diabetic glucose concentration. METHODS: MSCs were extracted from rat bone marrow. Cells were characterized based on morphology, differentiation potential, and expression of mesenchymal specific markers. MTT assay was done to evaluate the viability of MSCs after treatment with different glucose concentrations. Case group was MSCs treated with diabetic concentration of glucose versus cells treated with PBS as the control group. Growth curve and population doubling time were calculated in both groups. Expression of GATA4 and troponin, as the early and late markers during cardiac differentiation, were measured following 5-azacytidine exposure. RESULTS: Proliferated cells at passage three had fibroblastic-shape, was able to differentiate into adipocytes or osteocytes, and expressed CD73 and CD90. MSCs viability was gradually decreased by increasing glucose concentration. Irrespective of nicotine concentration, three-day exposure imposed more severe detrimental effects on viability compared with one-day treatment. Proliferation rate of the MSCs was lower in the case group, and they need more time for population doubling. Expression of both cardiac markers were downregulated in the case group at day three. However, their expression became higher at day seven. CONCLUSION: Diabetic glucose concentration inhibits normal proliferation and cardiac differentiation of MSCs. This effect should be considered in stem cell therapy of cardiovascular patients who are concurrently affected by hyperglycemia, a common comorbidity in such individuals. Why carry out this study? What was learned from the study?

Genotyping and In Vitro Antifungal Susceptibility Profile of Neoscytalidium Species Isolates from Respiratory Tract.

The fungus genus Neoscytalidium is mainly distributed in (sub) tropical regions of the world and has been essentially considered as a phytopathogen. There are however several reports of human infection caused by Neoscytalidium spp. through direct or indirect contact with contaminated plants or soil. Reliable and accurate identification to species level is critical for implementing proper therapeutic strategies. In the present study we investigated the genotypes and in vitro antifungal susceptibility patterns of Neoscytalidium species identified from respiratory tracts of patients with various underlying diseases. The identity and diversity of the isolates were done using PCR and sequencing of five different loci (the ITS region, D1/D2 domains of 28S rRNA gene, and part of the beta tubulin, elongation factor 1α and chitin synthase genes). The in-vitro antifungal susceptibility was also performed using the Clinical and Laboratory Standards Institute (CLSI) M38-Ed3-2017 guidelines. Overall, 13 isolates were identified as Neoscytalidium species (eight N. dimidiatum and five N. novaehollandiae). Two sequence types (STs) were identified by the alignment of 1846 combined base pairs among 13 clinical isolates. All isolates classified as N. dimidiatum were clustered in ST6 (61.5%) and those of N. novaehollandiae were in ST7 (38.5%). Luliconazole was the most active antifungal in vitro against species. This is the first report of N. novaehollandiae isolation from respiratory tracts samples. Further study from other regions of the world with a larger set of clinical specimens is required to provide additional insight into diversity of Neoscytalidium species.

Galactomannan detection in bronchoalveolar lavage fluids: A diagnostic approach for fungus ball in patients with pulmonary tuberculosis?

BACKGROUND: Several previous studies have shown cavitary lung lesions in old pulmonary tuberculosis (PTB) increase the risk of fungus ball. Detection of galactomannan (GM) in bronchoalveolar lavage (BAL) is also proposed as a diagnostic approach for the fungus ball. OBJECTIVES: We evaluated the diagnosis of fungus balls and GM levels in BAL samples in PTB patients. METHODS: A total of 110 PTB patients were evaluated for fungus ball during 2017-2019. The patients were evaluated for radiological, histopathological results and mycological findings of BAL including GM detection and culture. The sensitivity, specificity and positive and negative predictive value for GM test were calculated. The optimal cut-off for BAL GM testing was determined by receiver operating characteristic (ROC). RESULTS: Of 110 PTB patients, nine (8.18%) showed fungus ball, all with old PTB. The molecularly confirmed Aspergillus species were A. flavus, A. fumigatus and A. ochraceus. The sensitivity and specificity of BAL GM ≥ 0.5 in old PTB patients with fungus ball were 100%, 41.5%, respectively. The statistical analysis of the mean ± SEM of BAL GM levels was demonstrated a higher levels of GM in patients with fungus ball/aspergilloma compared to old PTB patients without fungus ball/aspergilloma. The optimal cut-off value for BAL GM was determined as 0.50 by ROC curve analysis. CONCLUSION: According to our results, we can recommend the detection of GM in BAL samples as a diagnostic approach for fungus ball in PTB patients.

Fungal epidemiology in cystic fibrosis patients with a special focus on Scedosporium species complex.

In this present study, for the first time, we evaluated the cystic fibrosis (CF) patients for the Scedosporium species and their antifungal susceptibility against eight antifungal agents. During one-year period, 90 Sputum samples were collected from Iranian CF patients. All samples were evaluated by direct microscopic examination, culture onto four different media including Malt extract agar, Inhibitory mold agar, Brain Heart Infusion and Scedo-Select III. The mold isolated fungi were identified by PCR-Sequencing of ITS and ß-tubulin genes. In-vitro antifungal susceptibility was performed according to the Clinical & Laboratory Standards Institute (CLSI) M38-A2 guidelines. Out of 90 CF patients, 47 (52.2%) were male. The age of the patients ranged from 1 to 34 years (median of 15.84 ±â€¯7.41 years). Overall, 3 (3.3%) cases were positive for Scedosporium spp. of which two isolates were characterized as Scedosporium boydii and one isolate as S. ellipsoideum. Among Aspergillus genus, A. flavus (29.4%) was the most prevalent species followed by A. tubingensis (24.7%), A. niger (17.0%) and A. fumigatus (14.5%). The minimum effective concentration ranges of micafungin, anidulafungin, and caspofungin were 0.008-0.031 µg/mL, 0.0625-0.25 µg/mL, and 0.0625-0.25 µg/mL, respectively. All isolates of Scedosporium species showed high minimum inhibitory concentration to the triazoles tested, except voriconazole. Our results showed that A. flavus and Scedosporium species are the most prevalent molds isolated from CF patient populations in Iran. Our findings have also showed that Scedo-Select III can be used as a reliable culture media for isolation of Scedosporium spp. in clinical samples.