A novel insight into the key gene signature associated with the immune landscape in the progression of sarcopenia.

Sarcopenia is an age-related skeletal muscle disorder that causes falls, disability and death in the elderly, but its exact mechanism remains unknown. In this study, we merged three GEO datasets into the expression profiles of 118 samples and screened 22 differentially expressed genes (DEGs) as candidate genes. Pathway analysis demonstrated that the functional enrichment of DEGs is mainly in the cellular response to insulin stimulus, PPAR signaling pathway and other metabolism-related pathways. Then, we identified six key genes by machine learning, which were confirmed to be closely associated with sarcopenia by bioinformatics analysis. It was experimentally verified that SCD1 exhibits the most substantial alterations in the progression of sarcopenia with disturbed lipid metabolism and myosteatosis. In addition, the immune microenvironment of sarcopenia was found to be affected by these key genes, with Th17 cells down-regulated and NK cells up-regulated. Sarcopenic patients consequently presented a more significant systemic inflammatory state with higher CAR (p = 0.028) and PAR (p = 0.018). For the first time, we identified key genes in sarcopenia with high-throughput data and demonstrated that key genes can regulate the progression of sarcopenia by affecting the immune microenvironment. Among them, SCD1 may influence lipid metabolism and myosteatosis process. Screening of key genes and analyzing of immune microenvironment provide a more accurate target for treating sarcopenia.

Thoracic sarcopenia predicts clinical outcomes in patients undergoing coronary artery bypass grafting: A 6-year cohort study.

BACKGROUND: The relationship between thoracic sarcopenia and clinical outcomes in patients underwent coronary artery bypass grafting (CABG) is unclear. This study aims to evaluate whether thoracic sarcopenia has a satisfactory prognostic effect on adverse outcomes after CABG. METHODS: From December 2015 to May 2021, 338 patients who underwent isolated CABG at our institution were recruited in this study. Skeletal muscle area at T12 level acquired by chest computed tomography (CT) was normalized to assess thoracic sarcopenia. Univariate and multivariate analyses were performed to evaluate the risk factors of postoperative complications and overall survival (OS). RESULTS: The prevalence of thoracic sarcopenia in patients underwent CABG was 13.02%. The incidence of total major complication was significantly higher in thoracic sarcopenia group (81.8% vs 61.9%, p = 0.010). Thoracic sarcopenic patients also had longer postoperative hospital stays (p = 0.047), intensive care unit (ICU) stays (p = 0.001), higher costs (p = 0.001) and readmission rates within 30 days of discharge (18.2% vs 4.4%, p = 0.001). Patients without thoracic sarcopenia showed significantly higher OS at the 2-year follow-up period (93.9% vs 72.7%, p<0.001). Multivariate analyses demonstrated that thoracic sarcopenia was significantly and independently associated with postoperative complications and long-term OS after CABG. CONCLUSION: Thoracic sarcopenia is an effective clinical predictor of adverse postoperative complications and long-term OS in patients underwent CABG. Thoracic sarcopenia based on chest CT should be included in preoperative risk assessment of CABG.

Prognostic significance of postoperative loss of skeletal muscle mass in patients underwent coronary artery bypass grafting.

Background: Increasing life expectancy of coronary artery bypass grafting (CABG) remains to be the major concern of cardiac surgeons. However, few studies have investigated the effect of postoperative skeletal muscle index (SMI) loss on prognosis. This study aims to evaluate the prognostic role of postoperative SMI loss ≥ 5% after CABG, in order to develop a novel nomogram to predict overall survival (OS). Methods: Patients underwent CABG via midline sternotomy from December 2015 to March 2021 were recruited in this study. Preoperative and postoperative 3 months chest computed tomography (CT) images were compared to assess changes in SMI at T12 level. Based on this, patients were classified into the presence or absence of SMI loss ≥ 5%. The association between postoperative SMI loss ≥ 5% and OS was then analyzed by the Kaplan-Meier curves and Cox model. A novel nomogram incorporating independent clinical prognostic variables was also developed. Results: The study enrolled 506 patients receiving CABG, of whom 98 patients experienced T12 SMI loss ≥ 5% and had a significantly worse OS (P < 0.0001). Multivariate regression analysis showed that T12 SMI per cent change (%T12 SMI-change) was an independent prognostic factor for OS (HR = 0.809, 95% CI = 0.749-0.874). The nomogram incorporating %T12 SMI-change with other variables was accurate for predicting OS. Besides, we also found that postoperative oral nutritional supplement (ONS) can rescue T12 SMI loss. Conclusion: Postoperative SMI loss can predict survival outcome after CABG. The nomogram incorporating changes in SMI provides a superior performance than existing systems.

Pathogenic mechanism of a catecholaminergic polymorphic ventricular tachycardia causing-mutation in cardiac calcium release channel RyR2.

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a condition that is characterized by an abnormal heart rhythm in response to physical or emotional stress. The majority CPVT patients carry mutations in the RYR2 gene that encodes the calcium release channel/ryanodine receptor (RyR2) in cardiomyocytes. The pathogenic mechanisms that account for the clinical phenotypes of CPVT are still elusive. We have identified a de novo mutation, A165D, from a CPVT patient. We found that CPVT phenotypes are recapitulated in A165D knock-in mice. The mutant RyR2 channels enhanced sarcoplasmic reticulum Ca2+ release, triggered delayed afterdepolarization in cardiomyocytes. Structural analysis revealed that the A165D mutation is located in a loop that is involved in inter-subunit interactions in the RyR2 tetrameric structure, it disrupted conformational stability of the RyR2, which favored a closed-to-open state transition, resulting in a leaky channel. The loop also harbors several other CPVT mutations, which suggests a common pathogenic molecular mechanism of CPVT-causing mutations. Our data illustrated disease-relevant functional defects and provide a deeper mechanistic understanding of a life-threatening cardiac arrhythmia.

Total Endovascular Repair of Post-dissection Aortic Arch Aneurysm With Chimney Technique.

Open surgery remains the standard procedure for treatment of aortic arch pathologies. However, total endovascular repair can be a safe option for patients who are poor candidates for surgery because of compromised physiology. We report the case of a 63-year-old man with a post-dissection aortic arch aneurysm. We repaired the aneurysm using thoracic endovascular aortic repair (TEVAR) and used the chimney technique to reconstruct the supra-aortic branches. The patient is doing well after 12-month follow-up, demonstrating that TEVAR with the chimney technique can be used successfully for the treatment of post-dissection arch aneurysm.

Pregnancy mitigates cardiac pathology in a mouse model of left ventricular pressure overload.

In Western countries heart disease is the leading cause of maternal death during pregnancy. The effect of pregnancy on the heart is difficult to study in patients with preexisting heart disease. Since experimental studies are scarce, we investigated the effect of pressure overload, produced by transverse aortic constriction (TAC) in mice, on the ability to conceive, pregnancy outcome, and maternal cardiac structure and function. Four weeks of TAC produced left ventricular (LV) hypertrophy and dysfunction with marked interstitial fibrosis, decreased capillary density, and induced pathological cardiac gene expression. Pregnancy increased relative LV and right ventricular weight without affecting the deterioration of LV function following TAC. Surprisingly, the TAC-induced increase in relative heart and lung weight was mitigated by pregnancy, which was accompanied by a trend towards normalization of capillary density and natriuretic peptide type A expression. Additionally, the combination of pregnancy and TAC increased the cardiac phosphorylation of c-Jun, and STAT1, but reduced phosphoinositide 3-kinase phosphorylation. Finally, TAC did not significantly affect conception rate, pregnancy duration, uterus size, litter size, and pup weight. In conclusion, we found that, rather than exacerbating the changes associated with cardiac pressure overload, pregnancy actually attenuated pathological LV remodeling and mitigated pulmonary congestion, and pathological gene expression produced by TAC, suggesting a positive effect of pregnancy on the pressure-overloaded heart.

Preserving prostaglandin E2 level prevents rejection of implanted allogeneic mesenchymal stem cells and restores postinfarction ventricular function.

BACKGROUND: Allogeneic mesenchymal stem cells (MSCs) were immunoprivileged early after cardiac implantation and improved heart function in preclinical and clinical studies. However, long-term preclinical studies demonstrated that allogeneic MSCs lost their immunoprivilege and were rejected in the injured myocardium, resulting in recurrent ventricular dysfunction. This study identifies some of the mechanisms responsible for the immune switch in MSCs and suggests a new treatment to maintain immunoprivilege and preserve heart function. METHODS AND RESULTS: Rat MSC immunoprivilege was mediated by prostaglandin E2 (PGE2)-induced secretion of 2 critical chemokines, CCL12 and CCL5. These chemokines stimulated the chemoattraction of T cells toward MSCs, suppressed cytotoxic T-cell proliferation, and induced the production of T regulatory cells. MSCs treated with 5-azacytidine for 24 hours differentiated into myogenic cells after 2 weeks, which was associated with decreased PGE2 and chemokine production and the loss of immunoprivilege. Treatment of differentiated MSCs with PGE2 restored chemokine levels and preserved MSC immunoprivilege. In a rat myocardial infarction model, allogeneic MSCs (3 × 10(6) cells/rat) were injected into the infarct region with or without a biodegradable hydrogel that slowly released PGE2. Five weeks later, the transplanted MSCs expressed myogenic lineage markers and were rejected in the control group, but in the PGE2-treated group, the transplanted cells survived and heart function improved. CONCLUSIONS: Allogeneic MSCs maintained immunoprivilege by PGE2-induced secretion of chemokines CCL12 and CCL5. Differentiation of MSCs decreased PGE2 levels, and immunoprivilege was lost. Maintaining PGE2 levels preserved immunoprivilege after differentiation, prevented rejection of implanted MSCs, and restored cardiac function.

Interleukin-6 downregulation with mesenchymal stem cell differentiation results in loss of immunoprivilege.

Allogeneic mesenchymal stem cell (MSC) transplantation improves cardiac function, but cellular differentiation results in loss of immunoprivilege and rejection. To explore the mechanism involved in this immune rejection, we investigated the influence of interleukin-6 (IL-6), a factor secreted by MSCs, on immune privilege after myogenic, endothelial and smooth muscle cell differentiation induced by 5-azacytidine, VEGF, and transforming growth factor-ß (TGF-ß), respectively. Both RT-PCR and ELISA showed that myogenic differentiation of MSCs was associated with significant downregulation of IL-6 expression (P < 0.01), which was also observed following endothelial (P < 0.01) and smooth muscle cell differentiation (P < 0.05), indicating that IL-6 downregulation was dependent on differentiation but not cell phenotype. Flow cytometry demonstrated that IL-6 downregulation as a result of myogenic differentiation was associated with increased leucocyte-mediated cell death in an allogeneic leucocyte co-culture study (P < 0.01). The allogeneic reactivity associated with IL-6 downregulation was also observed following MSC differentiation to endothelial and smooth muscle cells (P < 0.01), demonstrating that leucocyte-mediated cytotoxicity was also dependent on differentiation but not cell phenotype. Restoration of IL-6 partially rescued the differentiated cells from leucocyte-mediated cell death. These findings suggest that rejection of allogeneic MSCs after implantation may be because of a reduction in cellular IL-6 levels, and restoration of IL-6 may be a new target to retain MSC immunoprivilege.

Mutations of the epidermal growth factor receptor gene in NSCLC patients.

Mutations of the epidermal growth factor receptor (EGFR) in patients with non-small cell lung cancer (NSCLC) were identified by re-sequencing all exons of this gene to evaluate the frequencies of EGFR gene mutation and identify rare or novel EGFR mutations. A total of 55 NSCLC samples from 55 patients were included in the study. Genomic DNA was extracted and exons 1-28 of the EGFR gene were sequenced to identify mutations. The cDNA of the EGFR gene with P848L and T790M double mutants was constructed by introducing point mutations into the wild-type EGFR vector using a site-directed mutagenesis kit. Among the 55 patients with NSCLC, 8 patients carried mutations of the EGFR gene. Notably, of the mutation-harboring patients with a pathological type of adenocarcinoma, 6 were non-smokers. The in vitro study demonstrated that the P848L mutant had a similar response to that of the wild-type EGFR after gefitinib treatment, and the P848L and T790M double mutant exhibited high resistance to gefitinib. These EGFR mutations preferentially occurred in lung adenocarcinoma patients, most of whom were non-smokers. In the in vitro study, P848L mutant EGFR had a similar response as the wild-type EGFR to gefitinib treatment, suggesting that lung cancer patients with a rare mutation of EGFR, such as the P848L mutation, do not respond to gefitinib treatment.

Surgical treatment of cardiac pheochromocytoma: a case report.

Primary cardiac pheochromocytoma is an extremely rare neoplasm. We report a 15-year-old girl who was presented with paroxysmal hypertension. An iodine-131 metaiodobenzylguanidine scintigraphy scanning showed a pheochromocytoma in her right atrial and ventricular wall. The tumor was subsequently confirmed by magnetic resonance imaging and coronary angiogram. This patient underwent a successful surgical resection of the tumor, a reconstruction of the atrial ventricular wall and right coronary artery bypass grafting. Her blood pressure remained normal thereafter. A follow-up coronary angiogram revealed a patent saphenous vein graft 4 months after the operation.

An experimental research on cryopreserving rabbit trachea by vitrification.

Vitrification is a promising alternative to tissue preservation, in which the tissue is permeated with cryoprotective agents (CPAs) in order to circumvent the hazardous effects associated with ice formation. In this study, we evaluate the effect of vitreous cryopreservation of rabbit trachea, by comparing vitrification procedure with conventional computer-programmed slow freezing approaches. Harvested rabbit trachea were tailored and divided into groups and cryopreserved by vitrification and programmed freezing, respectively. The morphology and ultrastructure of the thawed tracheal fragments including HE dyes, terminal deoxynucleotidyl transferase-mediated dUTP-digoxigenin nick end-labeling (TUNEL) staining, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were studied to assess the integrity of the tracheal fragments. Morphological studies demonstrated that both cryopreservation procedure retained the integrity of trachea, both epithelial cells, cilia and cartilage cells were in good shape. Compared with slow freezing methods, vitrification was less detrimental to cartilage cells and had a higher survival rate of chondrocytes and coverage of epithelium and cilia. Therefore, vitrification procedure can be a more satisfactory method to preserve trachea and the survival of chondrocytes in situ in cartilage tissue is adequate and respiratory epithelium is soundly present.

A primary right atrium paraganglioma in a 15-year-old patient.

Thoracic pheochromocytomas account for less than 2% of reported cases, while primary cardiac paragangliomas are even rare. The following case illustrates a 15-year-old patient with primary right atrium paraganglioma. This patient was referred for paroxysmal hypertension and excessive perspiration. Pheochromocytoma was suspected and then confirmed by very high serum nor-metanephrine which increased more than 30-fold above the upper limit of normal. 131I-metaiodobenzylguanidine (MIBG) scintigraphy showed high uptake only in the middle mediastinum, but not in the adrenal glands or elsewhere. Both contrast CT and gated MRI of the chest disclosed a 5.0 x 4.0 cm2 mass in the right atrium. Coronary angiography demonstrated the mass with feeding vessels from the right coronary artery. When the patient's blood pressure was well controlled with doxazosin and metoprolol, surgery was then performed. A 6.0 x 4.9 x 4.0 cm3 round solid right atrium paraganglioma weighing 41.7 g was resected. The second day after surgery, serum nor-metanephrine and urinary noradrenaline levels dropped rapidly to normal range, and the patient was free of clinical symptoms with normal BP. Postoperative cardiac function, as measured by echocardiogram, was normal. Although cardiac paraganglioma may be difficult to resect, it can be cured.