Prevalence of osteoporosis among patients after stem cell transplantation: a systematic review and meta-analysis.

The prevalence of osteoporosis in post stem cell transplantation (SCT) is poorly defined. We performed a systematic review and meta-analysis to determine the prevalence of osteoporosis in patients with hematologic diseases who underwent SCT. PubMed, EMBASE, and Web of Science were searched (from inception to 30th April 2023) using Medical Subject Headlines to find studies that assessed the prevalence of osteoporosis among post SCT. Thirteen articles meeting the inclusion criteria were included in the analysis. The pooled prevalence rates of osteoporosis, osteopenia, and decreased bone mineral density (BMD) were determined to be 14.2% (95% CI 9.7-18.8), 36.0% (95% CI 23.8-48.2), and 47.8% (95% CI 36.6-58.9), respectively. Substantial heterogeneity was observed among the included studies (I² values ranged from 81% to 99%). Subgroup analyses revealed variations in prevalence based on gender, follow-up duration, age, region, sample size, and study quality. These findings suggest a high prevalence of osteoporosis in post-SCT patients. Given the negative impact of osteoporosis on prognosis and recipient survival, clinicians should prioritize preventive measures, early diagnosis, and effective treatments to minimize its impact.

Damaging effect of cigarette smoke extract on primary cultured human umbilical vein endothelial cells and its mechanism.

OBJECTIVE: To investigate the cellular effects of cigarette smoke extract (CSE) on primarily cultured human umbilical vein endothelial cells (HUVEC). METHODS: The effects of CSE (5%-20%) and nicotine (10(-4) mol/L) on HUVEC viability, proliferation, angiogenesis and apoptosis were observed. RESULTS: CSE decreased HUVEC survival rate and angiogenesis after 24 h as well as its proliferation after 48 h in a dose-dependent manner. Moreover, CSE induced apoptosis of HUVEC as indicated in condensation of nuclear chromatin and the presence of hypodiploid DNA. HUVEC incubated with CSE for 24 h gave a significant decrease in the expression of Bcl-2 as well as the decline in the Bcl-2/Bax ratio accompanied with the loss of mitochondrial membrane potential and excess cytosolic calcium. Our study also observed that p53 protein level decreased, rather than increased in cells treated with CSE. Nicotine had no discernible inhibitory effects on the above indices of HUVEC. CONCLUSION: Exposure to CSE other than nicotine causes inhibition of viability, proliferation and differentiation of HUVEC. CSE-induced HUVEC injury is mediated in partthrough accelerated apoptosis but independent of p53 pathway. It appears that mitochondria have played a key role in the apoptosis of HUVEC induced by CSE.

Injury of mouse brain mitochondria induced by cigarette smoke extract and effect of vitamin C on it in vitro.

OBJECTIVE: To investigate the toxicity of cigarette smoke extract (CSE) and nicotine on mouse brain mitochondria as well as the protective effect of vitamin C in vitro. METHOD: Mouse brain mitochondria in vitro was incubated with CSE or nicotine in the absence or presence of vitamin C for 60 minutes, and the changes of mitochondrial function and structure were measured. RESULTS: CSE inhibited mitochondrial ATPase and cytochrome C oxidase activities in a dose-dependent manner. However, no significant changes in the peroxidation indices were observed when mitochondrial respiratory enzymes activity was inhibited, and protection of mitochondria from CSE-induced injury by vitamin C was not displayed in vitro. The effect of CSE on mouse brain mitochondria swelling response to calcium stimulation was dependent on calcium concentrations. CSE inhibited swelling of mitochondria at 6.5 mumol/L Ca2+, but promoted swelling response at 250 mumol/L Ca2+. Nicotine, the major component of cigarette smoke, showed no significant damage in mouse brain mitochondria in vitro. The CSE treatment induced mitochondrial inner membrane damage and vacuolization of the matrix, whereas the outer mitochondrial membrane appeared to be preserved. CONCLUSION: The toxic effect of CSE on brain mitochondria may be due to its direct action on enzymatic activity rather than through oxygen free radical injury. Nicotine is not the responsible component for the toxicity of CSE to brain mitochondria.