Cell-Cell Contact Preserves Cell Viability via Plakoglobin

Control over cell viability is a fundamental property underlying numerous physiological processes. Cell spreading on a substrate was previously demonstrated to be a major factor in determining the viability of individual cells. In multicellular organisms, cell-cell contact is likely to play a significant role in regulating cell vitality, but its function is easily masked by cell-substrate interactions, thus remains incompletely characterized. In this study, we show that suspended immortalized human keratinocyte sheets with persisting intercellular contacts exhibited significant contraction, junctional actin localization, and reinforcement of cell-cell adhesion strength. Further, cells within these sheets remain viable, in contrast to trypsinized cells suspended without either cell-cell or cell-substrate contact, which underwent apoptosis at high rates. Suppression of plakoglobin weakened cell-cell adhesion in cell sheets and suppressed apoptosis in suspended, trypsinized cells. These results demonstrate that cell-cell contact may be a fundamental control mechanism governing cell viability and that the junctional protein plakoglobin is a key regulator of this process. Given the near-ubiquity of plakoglobin in multicellular organisms, these findings could have significant implications for understanding cell adhesion, modeling disease progression, developing therapeutics and improving the viability of tissue engineering protocols

Effects of Early Placement of Transjugular Portosystemic Shunts in Patients With High-Risk Acute Variceal Bleeding: a Meta-analysis of Individual Patient Data

Background & Aims: Compared with drugs plus endoscopy, placement of transjugular portosystemic shunt within 72 hours of admission to the hospital (early or preventive transjugular intrahepatic portosystemic shunt [TIPS], also called preemptive TIPS) increases the proportion of high-risk patients with cirrhosis and acute variceal bleeding who survive for 1 year. However, the benefit of preemptive TIPS is less clear for patients with a Child-Pugh score of B and active bleeding (CP-B+AB). We performed an individual data meta-analysis to assess the efficacy of preemptive TIPS in these patients and identify factors associated with reduced survival of patients receiving preemptive TIPS. Methods: We searched publication databases for randomized controlled trials and observational studies comparing the effects of preemptive TIPS versus endoscopy plus nonselective beta-blockers in the specific population of high-risk patients with cirrhosis and acute variceal bleeding (CP-B+AB or Child-Pugh C, below 14 points), through December 31, 2019. We performed a meta-analysis of data from 7 studies (3 randomized controlled trials and 4 observational studies), comprising 1327 patients (310 received preemptive TIPS and 1017 received drugs plus endoscopy). We built adjusted models to evaluate risk using propensity score for baseline covariates. Multivariate Cox regression models were used to assess the factors associated with survival time. The primary endpoint was effects of preemptive TIPS versus drugs plus endoscopy on 1-year survival in the overall population as well as CP-B+AB and Child-Pugh C patients. Results: Overall, preemptive TIPS significantly increased the proportion of high-risk patients with cirrhosis and acute variceal bleeding who survived for 1 year, compared with drugs plus endoscopy (hazard ratio [HR] 0.443; 95% CI 0.323\u20130.607; P < .001). This effect was observed in CP-B+AB patients (HR 0.524; 95% CI 0.307\u20130.896; P = .018) and in patients with Child-Pugh C scores below 14 points (HR 0.374; 95% CI 0.253\u20130.553; P < .001). Preemptive TIPS significantly improved control of bleeding and ascites without increasing risk of hepatic encephalopathy in Child-Pugh C and CP-B+AB patients, compared with drugs plus endoscopy. Cox analysis of patients who received preemptive TIPS showed that patients could be classified into 3 categories for risk of death, based on age, serum level of creatinine, and Child-Pugh score. In each of these risk categories, preemptive TIPS increased the proportion of patients who survived for 1 year, compared with drugs plus endoscopy. Conclusions: In a meta-analysis of data from 1327 patients with cirrhosis, acute variceal bleeding, and Child-Pugh score between 10 and 13 points or CP-B+AB, preemptive TIPS increased the proportion who survived for 1 year, in both subgroups separately, compared with drugs plus endoscopy