Objective:To evaluate the effect of tubastatin A (TubA) on pyroptosis during brain injury after cardiac arrest and resuscitation in swine.Methods:Twenty-two conventional male white swine, weighing 34-39 kg, aged 4-6 months, were divided into 3 groups using a random number table: sham operation group (group S, n=6), cardiac arrest-cardiopulmonary resuscitation (CA-CPR) group ( n=8) and CA-CPR+ TubA group ( n=8). The swine model of CA-CPR was established by 9 min of cardiac arrest and 6 min of cardiopulmonary resuscitation in CA-CPR group and CA-CPR+ TubA group. TubA 4.5 mg/kg (in 50 ml of normal saline) was infused over 1 h via the femoral vein starting from 5 min after resuscitation in CA-CPR+ TubA group. Before developing the model and at 1, 2, 4 and 24 h after resuscitation (T 0-4), blood samples were collected from the femoral vein for determination of the concentrations of neuron specific enolase (NSE) and S100β protein in serum (by enzyme-linked immunosorbent assay). Neurological deficit score (NDS) was evaluated at T 4. The animals were then sacrificed, and their brain cortex tissues were harvested to measure the expression of histone deacetylase 6 (HDAC6), caspase-3, cleaved caspase-3, gasdermin E (GSDME) and GSDME N-terminal (N-GSDME) (by Western blot) and contents of high mobility group box 1 (HMGB1), interleukin-1β (IL-1β) and IL-18 (by enzyme-linked immunosorbent assay). Results:Compared with group S, the serum concentrations of NSE and S100β were significantly increased at T 1-4, NDS was increased at T 4, the expression of HDAC6, caspase-3, cleaved caspase-3, GSDME and N-GSDME in brain cortex was up-regulated, and the contents of HMGB1, IL-1β and IL-18 were increased in CA-CPR and CA-CPR+ TubA groups ( P<0.05). Compared with group CA-CPR, the serum concentrations of NSE and S100β were significantly decreased at T 3, 4, NDS was decreased at T 4, the expression of HDAC6, caspase-3, cleaved caspase-3, GSDME and N-GSDME in brain cortex was down-regulated, and the contents of HMGB1, IL-1β and IL-18 were decreased in group CA-CPR+ TubA ( P<0.05). Conclusions:The mechanism by which TubA alleviates brain injury after cardiac arrest and resuscitation may be related to inhibition of pyroptosis in swine.

Objective:To investigate the effect of early protein supplementation on the clinical outcomes of elderly ICU patients with critically ill.Methods:The study was a post-hoc analysis of a multicenter, cluster randomized controlled trial (NEED trial), which aimed to evaluate the impact of feeding protocol on nutritional implementation and outcomes in ICU patients. It was planned to include elderly patients aged ≥70 years from the NEED trial, and patients who had not started nutritional therapy by the Day 3 after enrolment, stayed in the ICU less than 7 days, missing the primary outcome were excluded. The primary outcome of this study was 28-day mortality of enrolment. Patients were categorized into Q1 (<0.6 g/kg/d), Q2 (0.6-0.83 g/kg/d), and Q3 (≥0.83 g/kg/d) groups according to the tertiles of protein supply. The log-rank test was used to compare the Kaplan-Meier survival curves for 28-day mortality. The associations between different protein groups and 28-day mortality were tested by Cox proportional hazards regression models. Subgroup analysis was conducted in patients with high (mNUTRIC score≥5) nutritional risk or patients with baseline acute kidney injury.Results:A total of 789 elderly (≥70 years) patients was included in the study, with a mean protein amount of 0.69 (0.53, 0.91) g/(kg·d) during days 3-7 after ICU admission, and mean protein amounts in the Q1 low-protein group, the Q2 medium-protein group, and the Q3 high-protein group were 0.46 (0.36, 0.53), 0.69 (0.63, 0.76), and 1.03 (0.91, 1.23) g/(kg·d), respectively. The results showed that the medium protein group associated with lower 28-day mortality compared to the high protein group, and the association between the medium protein group and lower 28-day mortality still held after controlling for possible confounders by Cox multivariate regression analysis. In the high-nutritional risk subgroup (mNUTRIC≥5), a significant association was also found between the medium protein group and lower 28-day mortality.Conclusions:Early high protein supply are not beneficial for elderly ICU patients by this large sample size post-hoc analysis, and medium protein supply associate with lower 28-day mortality compared with the high protein group. This study may provide a theoretical basis for the optimal dose of early protein supply in elderly ICU patients, as well as a reference for clinical implementation.