Regular transient limb ischemia improves endothelial function and inhibits endothelial cell apoptosis to prevent atherosclerosis in rabbit.

AIMS: Regular transient limb ischemia (RTLI) can prevent atherosclerosis (AS) progression in hypercholesterolemic rabbits. This study aimed to investigate the minimum effective intensity and possible mechanisms of RTLI for preventing atherosclerosis. METHODS: Eighty rabbits were divided into eight groups: normal (N), high cholesterol (H), three RTLI [three RTLI cycles every other day (R3qod), three RTLI cycles daily (R3qd), and six RTLI cycles daily (R6qd), each cycle of RTLI included 5 min of limb ischemia followed by 5 min limb reperfusion], and three correlated sham RTLI [sham ischemia for 30 min once every other day (S3qod), sham ischemia for 30 min once daily (S3qd), and sham ischemia for 60 min once daily (S6qd)]. Rabbits in group N were kept normally, while the others were fed 1% cholesterol diet for 12 weeks. The RTLI and sham RTLI groups were received RTLI or sham RTLI procedure, respectively. The plaque area in the thoracic aorta was determined by oil red O staining, and quantifying the ratio of plaque area to intimal area (PA/IA). Endothelium-dependent and -independent relaxation were also determined. Endothelial cell were isolated from abdominal aorta of rabbits, and the apoptosis ratio was detected using flow cytometry. RESULTS: The PA/IA and early apoptotic cell ratio was significantly lower as well as the endothelium-dependent relaxation response was higher in group R6qd than those in groups H and S6qd, while those in the R3qod group was not significantly different from those in groups H and S3qod, as well as those in the R3qd group showed no significant difference compared to those in groups H and S3qd. CONCLUSIONS: Six cycles of RTLI daily was the optimal effective intensity to prevent AS progression in rabbits. Endothelial function improvement and apoptosis inhibition might contribute to the anti-AS effects.

Incidence, characteristics and risk factors for alveolar recruitment maneuver-related hypotension in patients undergoing laparoscopic colorectal cancer resection.

BACKGROUND: Alveolar recruitment maneuvers (ARMs) may lead to transient hypotension, but the clinical characteristics of this induced hypotension are poorly understood. We investigated the characteristics of ARM-related hypotension in patients who underwent laparoscopic colorectal cancer resection. AIM: To investigate the characteristics of ARM-related hypotension in patients who underwent laparoscopic colorectal cancer resection. METHODS: This was a secondary analysis of the PROtective Ventilation using Open Lung approach Or Not trial and included 140 subjects. An ARM was repeated every 30 min during intraoperative mechanical ventilation. The primary endpoint was ARM-related hypotension, defined as a mean arterial pressure (MAP) < 60 mmHg during an ARM or within 5 min after an ARM. The risk factors for hypotension were identified. The peri-ARM changes in blood pressure were analyzed for the first three ARMs (ARM1,2,3) and the last ARM (ARMlast). RESULTS: Thirty-four subjects (24.3%) developed ARM-related hypotension. Of all 1027 ARMs, 37 (3.61%) induced hypotension. More ARMs under nonpneumoperitoneum (33/349, 9.46%) than under pneumoperitoneum conditions (4/678, 0.59%) induced hypotension (P < 0.01). The incidence of hypotension was higher at ARM1 points than at non-ARM1 points (18/135, 13.3% vs 19/892, 2.1%; P < 0.01). The median percentage decrease in the MAP at ARM1 was 14%. Age ≥ 74 years, blood loss ≥ 150 mL and peak inspiratory pressure under pneumoperitoneum < 24 cm H2O were risk factors for ARM-related hypotension. CONCLUSION: When the ARM was repeated intraoperatively, a quarter of subjects developed ARM-related hypotension, but only 3.61% of ARMs induced hypotension. ARM-related hypotension most occurred in a hemodynamically unstable state or a hypovolemic state, and in elderly subjects. Fortunately, ARMs that were performed under pneumoperitoneum conditions had less impact on blood pressure.

Factors associated with prolonged postoperative length of hospital stay after laparoscopic colorectal cancer resection: a secondary analysis of a randomized controlled trial.

BACKGROUND: The postoperative length of hospital stay (PLOS) is an important indicator of surgical quality. We identified perioperative factors that affect prolonged PLOS (PPLOS) after laparoscopic colorectal cancer resection, which is the preferred surgical approach for colorectal cancer, the third most common cancer. METHODS: This study was a secondary analysis of a randomized trial (clinicaltrials.gov ID: NCT03160144) that included 280 patients who underwent laparoscopic colorectal cancer resection. The primary outcome was a PPLOS, defined as a PLOS that was longer than the median PLOS. Baseline, anesthetic, surgical, and postoperative management factors were included in the univariate and multivariate analyses to identify factors influencing PPLOS. RESULTS: The median PLOS was 10 days, and 117 patients had a PPLOS. We identified six influencing factors for PPLOS: preoperative pulse oxygen saturation < 96% (odds ratio [OR], 3.09 [95% confidence interval (CI) 1.38-6.92]; P = 0.006), distant tumor metastasis (OR, 0.34 [95% CI 0.13-0.91]; P = 0.031), the Miles procedure or left hemicolectomy (OR, 4.51 [95% CI 1.67-12.18]; P = 0.003), perioperative surgical events (OR, 2.44 [95% CI 1.25-4.76]; P = 0.009), postoperative albumin infusion (OR, 2.19 [95% CI 1.14-4.19]; P = 0.018), and postoperative early ambulation (OR, 0.35 [95% CI 0.18-0.68]; P = 0.002). Further stratified analysis showed that postoperative albumin infusion might be a risk factor for PPLOS, even in patients with a preoperative albumin level < 40 g/L (OR, 2.29 [95% CI 0.98-5.34]; P = 0.056) or duration of surgery ≥ 3 h (OR, 2.52 [95% CI 1.08-5.87]; P = 0.032). CONCLUSIONS: A low preoperative pulse oximetry reading, complex surgical procedures, perioperative surgical events, and postoperative albumin infusion may be risk factors for PPLOS after laparoscopic colorectal cancer resection, whereas distant tumor metastasis and postoperative early ambulation might be protective factors. The association between postoperative albumin infusion, a modifiable factor, and PLOS or clinical outcomes warrants further investigation.

Microbial spectrum and drug resistance of pathogens cultured from gallbladder bile specimens of patients with cholelithiasis: A single-center retrospective study.

BACKGROUND: Bacterial infection is an important cause of cholelithiasis or gallstones and interferes with its treatment. There is no consensus on bile microbial culture profiles in previous studies, and identified microbial spectrum and drug resistance is helpful for targeted preventive and therapeutic drugs in the perioperative period. AIM: To analyze the bile microbial spectrum of patients with cholelithiasis and the drug susceptibility patterns in order to establish an empirical antibiotic treatment for cholelithiasis-associated infection. METHODS: A retrospective single-center study was conducted on patients diagnosed with cholelithiasis between May 2013 and December 2018. RESULTS: This study included 185 patients, of whom 163 (88.1%) were diagnosed with gallstones and 22 (11.9%) were diagnosed with gallstones and common bile duct stones (CBDSs). Bile culture in 38 cases (20.5%) was positive. The presence of CBDSs (OR = 5.4, 95%CI: 1.3-21.9, P = 0.03) and longer operation time (> 80 min) (OR = 4.3, 95%CI: 1.4-13.1, P = 0.01) were identified as independent risk factors for positive bile culture. Gram-negative bacteria were detected in 28 positive bile specimens, and Escherichia coli (E. coli) (19/28) and Klebsiella pneumoniae (5/28) were the most frequently identified species. Gram-positive bacteria were present in 10 specimens. The resistance rate to cephalosporin in E. coli was above 42% and varied across generations. All the isolated E. coli strains were sensitive to carbapenems, with the exception of one imipenem-resistant strain. K. pneumoniae showed a similar resistance spectrum to E. coli. Enterococcus spp. was largely sensitive to glycopeptides and penicillin, except for a few strains of E. faecium. CONCLUSION: The presence of common bile duct stones and longer operation time were identified as independent risk factors for positive bile culture in patients with cholelithiasis. The most commonly detected bacterium was E. coli. The combination of ß-lactam antibiotics and ß-lactamase inhibitors prescribed perioperatively appears to be effective against bile pathogens and is recommended. Additionally, regular monitoring of emerging resistance patterns is required in the future.

Regular transient limb ischemia protects endothelial function against hypercholesterolemic damage in rabbits.

Regular transient limb ischemia (RTLI) can prevent atherosclerosis in hypercholesterolemic rabbits. As endothelial dysfunction is the initial factor leading to atherosclerosis, we investigated the effect of RTLI on endothelial function in hypercholesterolemic rabbits. We randomly allocated 15 New Zealand white rabbits to three groups, five animals per group: the hypercholesterolemic group (Group H), the sham RTLI group (Group S), and the RTLI group (Group L). All rabbits received hypercholesterolemic fodder daily. No intervention was performed on the rabbits in Group H. Rabbits in Group S were kept in hutches, with a deflated cuff applied to their left hind limb for 60 min every day. For rabbits in Group L, RTLI (six cycles of 5-min ischemia and 5-min reperfusion of the left hind limb) was applied once daily for 12 weeks. At the end of week 12, a segment of the abdominal aorta was isolated from each rabbit for in vitro measurement of the endothelium-dependent vasodilation (EDV) response to different concentrations of acetylcholine and the endothelium-independent vasodilation (EIV) response to sodium nitroprusside. The EDV response was significantly higher in Group L than in Groups S and H (p < 0.05), with no significant difference between Groups S and H (p > 0.05). There was no difference in the EIV response among the three groups. RTLI could improve the EDV response, protecting endothelial function against hypercholesterolemic damage.

Intra-operative open-lung ventilatory strategy reduces postoperative complications after laparoscopic colorectal cancer resection: A randomised controlled trial.

BACKGROUND: The role of the positive end-expiratory pressure (PEEP) and lung recruitment manoeuvre (LRM) combination (termed open-lung strategy, OLS) during intra-operative mechanical ventilation is not clear. OBJECTIVE: To determine whether an open-lung strategy constituting medium PEEP (6-8 cmH2O) and repeated LRMs protects against postoperative complications in at-risk patients undergoing laparoscopic colorectal cancer resection under low-tidal-volume ventilation. DESIGN: A prospective, assessor-blinded, randomised controlled trial. SETTING: Single university-affiliated hospital, conducted from January 2017 to October 2018. PATIENTS: A total of 280 patients at risk of pulmonary complications, scheduled for laparoscopic colorectal cancer resection under general anaesthesia and low-tidal-volume (6-8 ml kg-1 predicted body weight) ventilation. INTERVENTION: The patients were randomly assigned (1 : 1) to a PEEP of 6-8 cmH2O with LRMs repeated every 30 min (OLS group) or a zero PEEP without LRMs (non-OLS group). MAIN OUTCOME MEASURES: The primary outcome was a composite of major pulmonary and extrapulmonary complications occurring within 7 days after surgery. The secondary outcomes included intra-operative potentially harmful hypotension and the need for vasopressors. RESULTS: A total of 130 patients from each group were included in the primary outcome analysis. Primary outcome events occurred in 24 patients (18.5%) in the OLS group and 43 patients (33.1%) in the non-OLS group [relative risk, 0.46; 95% confidence interval (CI), 0.26 to 0.82; P = 0.009). More patients in the OLS group developed potentially harmful hypotension (OLS vs. non-OLS, 15% vs. 4.3%; P = 0.004) and needed vasopressors (25% vs. 8.6%; P < 0.001). CONCLUSION: Among at-risk patients undergoing laparoscopic colorectal cancer resection under low-tidal-volume ventilation, an open-lung strategy with a PEEP of 6-8 cmH2O and repeated LRMs reduced postoperative complications compared with a strategy using zero PEEP without LRMs. Of note, LRMs should be used with caution in patients with haemodynamic instability. TRIAL REGISTRATION: Clinicaltrials.gov identifier: NCT03160144.

Increase in CD4+FOXP3+ regulatory T cell number and upregulation of the HGF/c-Met signaling pathway during the liver metastasis of colorectal cancer.

Colorectal cancer (CRC) is the third and second most common type of cancer diagnosed in males and females, respectively, and is the fourth leading cause of cancer-associated mortality worldwide. Liver metastasis is the primary cause of mortality in patients with CRC, and therefore requires therapeutic focus. Regulatory T cells (Tregs) and hepatic stellate cells (HSCs) are potentially involved in regulating the immune response during liver metastasis. The aim of the present study was to evaluate the influence of CD4+ forkhead box p3 (Foxp3)+ Tregs and the HGF/c-Met signaling pathway in the liver metastasis of CRC. A model of the latter was established using Balb/c mice via splenic injection of human CRC cells (CT-26 line). The mice were monitored for 3 weeks after being injected, and the spleens and livers were removed on day 22 for further analysis. Moreover, the single-cell suspensions were labeled with CD4 and Foxp3 antibodies, and were analyzed using flow cytometry. Expression levels of α-smooth muscle actin (SMA), hepatocyte growth factor (HGF) and hepatocyte growth factor receptor (c-Met) were analyzed using immunohistochemistry. Mice injected with CT-26 cells exhibited signs of illness and significant weight loss, compared with the control mice (P=0.013), and they also developed liver metastases, at an average of 20.5 tumors per mouse. Pathological evaluation using hematoxylin and eosin staining confirmed the tumors as liver metastases of CRC. The numbers of CD4+ T cells were significantly decreased in the spleen (P<0.001) and liver (P=0.003) of tumor-bearing mice, while the proportions of CD4+FOXP3+ Tregs increased significantly in the spleen (P<0.001) and liver (P=0.026) compared with that in the controls. Additionally, α-SMA, HGF and c-Met levels increased significantly during metastatic growth in the liver. In conclusion, CD4+FOXP3+ Treg levels increased and the HGF/c-Met pathway was upregulated during the liver metastasis of CRC in mice, indicating the presence of potential therapeutic targets.

Antitumor immunity of low-dose cyclophosphamide: changes in T cells and cytokines TGF-beta and IL-10 in mice with colon-cancer liver metastasis.

BACKGROUND: The tumor immune microenvironment is one of the most important prognostic factors in liver metastasis from colorectal cancer. Low-dose cyclophosphamide (CTX) is widely believed to be involved in the modulation of the immune system. However, the underlying mechanism of low-dose CTX remains unknown. This study aimed to investigate the antitumor immunity of low-dose CTX in the treatment of colon-cancer liver metastasis. METHODS: Thirty mice were randomly divided into five groups. After liver metastasis was established in colon-cancer models, mice in the treatment groups were injected with low-dose CTX (20 mg/kg) at different time points. Liver and spleen tissues were examined for T-cell markers via flow cytometry. Interleukin (IL)-10 and transforming growth factor (TGF)-ß1 expression levels in liver tissues were analysed by immunohistochemistry. Serum interferon (IFN)-γ and IL-10 levels were detected by enzyme-linked immunosorbent assay. An additional 20 mice were randomly allocated into two groups and the survival times were recorded. RESULTS: The expression levels of CD4+ T cells, CD8+ T cells, and IFN-γ were down-regulated, whereas those of IL-10 and TGF-ß1 were up-regulated in liver metastasis from colon cancer in mice. Furthermore, the local and systemic microenvironments of the liver were altered, which led to reduced antitumor immune responses and subsequently liver metastasis. However, treatment with low-dose CTX reversed these effects. The survival times of mice treated with low-dose CTX were significantly longer than those of the other groups. CONCLUSIONS: Low-dose CTX exerts its antitumor activity by changing the systemic and local immune microenvironments and enhancing immune regulation in mice. CTX could be used as a drug to prevent and treat liver metastasis from colon cancer.

Regular transient limb ischemia prevents atherosclerosis progression in hypercholesterolemic rabbits.

BACKGROUND: Endothelial dysfunction, the initial pathogenic factor in atherosclerosis, can be alleviated via transient limb ischemia. We observed the effects of regular transient limb ischemia (RTLI) on atherosclerosis in hypercholesterolemic rabbits. METHODS: Twenty-eight rabbits were randomized to control, cholesterol, sham, ischemia groups (n = 7 each) between October 2010 and March 2011. They were fed a normal diet in the control group and hypercholesterolemic diet in other groups for 12 weeks. Six cycles of RTLI were performed once per day on the ischemia group. Serum samples were prepared to measure the total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) before the experiment (W0), at the end of weeks 4, 8, 12 (W4, W8, W12). The whole aorta was harvested at W12 and stained using Sudan IV to identify the plaque. The plaque area was measured using Image J. Results were analyzed by analysis of variance or rank sum test. RESULTS: Concentrations of TC in the cholesterol group were higher than those in the control group at W4 (29.60 [23.75, 39.30] vs. 1.00 [0.80, 1.55], Z = -2.745, P = 0.006), W8 (41.78 [28.08, 47.37] vs. 0.35 [0.10, 0.68], Z = -2.739, P = 0.006), W12 (48.32 [40.04, 48.95] vs. 0.61 [0.50, 0.86], Z = -2.739, P = 0.006). Similar results were obtained for HDL-C and LDL-C. Serum concentrations of TC, HDL-C, and LDL-C in the hypercholesterolemic groups had no differences (all P > 0.05). The percentage of plaque area in the cholesterol group was higher than that in the control group (47.22 ±â€Š23.89% vs. 0, Z = -2.986, P = 0.003). Square root of the percentage of plaque area was smaller in the ischemia group than that in the cholesterol (0.44 ±â€Š0.13 vs. 0.67 ±â€Š0.18, P = 0.014) or sham groups (0.44 ±â€Š0.13 vs. 0.61 ±â€Š0.12, P = 0.049). CONCLUSION: In hypercholesterolemic rabbits, RTLI might prevent atherosclerosis progression by reducing the percentage of plaque area.

[Clinical analysis of perioperative electrolyte imbalance in 999 patients undergoing gastrointestinal surgery].

OBJECTIVE: To investigate the perioperative electrolyte imbalance in patients undergoing gastrointestinal surgery. METHODS: Retrospective case analysis was used in this study. Patients who underwent gastrointestinal surgery under general anesthesia at the Sixth Affiliated Hospital of Sun Yat-sen University from January to April 2018 were selected through electronic medical records system. Blood gas analysis during surgery must be carried out in the enrolled patients. Patients with excessive fluid infusion, critical conditions or patients who had been enrolled in other clinical trials were excluded. A total of 999 patients were enrolled. The preoperative, intraoperative and postoperative concentrations of serum sodium, potassium and calcium were collected by the last biochemical examination before surgery, arterial blood gas analysis within 1 h after anesthesia and another biochemical examination within 24 hours after surgery respectively. The type and incidence of electrolyte imbalance were then analyzed, and logistic regression analysis was used to investigate the risk factors. RESULTS: In the 999 patients, 683 cases were male (63.9%) and 361 cases were female(36.1%), with an average age of (56.9±14.6) years old. Fifty-eight patients (5.8%) underwent emergency surgery and 941 patients (94.2%) underwent elective surgery; Sixty-two patients were treated with laxatives at least 3 times and 115 patients were treated with enema at least 3 times before operation. The incidence of hypokalemia was 49.6%(496/999) intraoperatively and decreased to 15.2%(152/999) postoperatively. No hyperkalemia cases were found. The incidence of hypocalcemia was 53.8%(537/999) intraoperatively and increased to 79.7% (796/999) postoperatively. The incidence of hypokalemia in ileus patients was 33.3%(17/51) before surgery, which was higher than that in patients with colorectal cancer [12.3%(86/703)], patients with gastric cancer [7.8%(8/104)] and patients with other gastrointestinal diseases[10.6%(15/141)] (all P<0.05). Similarly, the preoperative and intraoperative incidence of hyponatremia in ileus patients were both 15.7%(8/51), which were higher than those in patients with colorectal cancer [3.0% (21/703) and 2.3% (16/703)] and patients with gastric cancer [2.9%(3/104) and 1.9%(2/104)]. The incidence of hypocalcemia in ileus patients was 31.4%(16/51) preoperatively, which were also higher than those in patients with colorectal cancer [7.4%(52/703)] and patients with gastric cancer [8.7%(9/104)] (all P<0.05). Logistic regression analysis showed that ileus and emergency surgery were risk factors for patients with preoperative electrolyte imbalance; preoperative electrolyte imbalance was a risk factor for intraoperative electrolyte imbalance; intraoperative electrolyte imbalance was a risk factor for postoperative electrolyte imbalance; preoperative electrolyte imbalance was a risk factor for postoperative imbalance of sodium and potassium. CONCLUSIONS: The incidence of electrolyte imbalance is high in patients undergoing gastrointestinal surgery, especially hypocalcemia and hypokalemia. It is necessary to recognize the electrolyte abnormality timely and give active intervention and correction.

Reliability of pressure cuff induced transient limb ischemia in conscious rabbits.

BACKGROUND: The protective effects of transient limb ischemia (TLI) induced by several cycles of intermittent pressure cuff inflation and deflation for a period have been widely investigated, however the reliability of this protocol has not been clearly verified. Our study aimed to investigate the reliability of pressure cuff induced TLI in conscious rabbits. METHODS: Eight New Zealand rabbits were subjected to TLI without anesthesia. TLI consisted of 3 cycles of ischemia and reperfusion induced by inflating the cuff placed on the left lower limb to 200 mmHg for 5 minutes followed by deflating the cuff for 5 minutes. Skin color, pulse oxygen saturation (SpO2), pulse rate (PR), plethysmogram waveform (Pleth), and ultrasound detection of the blood flow in the extremity distal to the ischemic segment were observed to confirm ischemia and reperfusion during TLI. The frequency of severe limb movement during TLI was also recorded to assess the amenability of this protocol in conscious rabbits. RESULTS: The skin color of the extremity distal to the ischemic segment changed from bright red to dark purple after inflating the cuff to 200 mmHg, and returned to normal after cuff deflation. Pleth, PR and SpO2 disappeared during ischemia and restored during reperfusion in the monitor. Blood flow of the left posterior tibial artery was completely blocked by a pressure of 200 mmHg during ischemia, and recovered immediately after cuff deflation. The frequency of severe limb movement in supine position was higher than that in prone position (P < 0.05), but there was no severe limb movement that could result in disturbance to ischemia when the rabbits were placed in prone position. CONCLUSION: Pressure cuff inflating to 200 mmHg for 5 minutes and deflating for 5 minutes is a reliable regimen to induce TLI in conscious rabbits.

Transient limb ischemia alters serum protein expression in healthy volunteers: complement C3 and vitronectin may be involved in organ protection induced by remote ischemic preconditioning.

The protective mechanism underlying remote ischemic preconditioning (RIPC) is unclear. This study aims to verify whether the protein expression profile in the serum could be altered by RIPC and to detect potential protein mediators. Transient limb ischemia consisting of three cycles of 5-min ischemia followed by 5-min reperfusion was performed on sixty healthy volunteers. Serum samples were collected at 30 min before transient limb ischemia and at 1 hour (h), 3 h, 8 h, 24 h, and 48 h after completion of three cycles. Changes in the serum protein profile were analyzed by two-dimensional gel electrophoresis and proteins were identified by MALDI-TOF/TOF mass spectrometry. Fourteen differentially expressed proteins were identified and, respectively, involved in immune system, lipid binding and metabolism, apoptosis, and blood coagulation. Complement C3, vitronectin, and apolipoprotein A-I were further confirmed by western blotting, and the results showed that their contents decreased significantly after transient limb ischemia. It is concluded that transient limb ischemia alters the serum protein expression profile in human being, and that reduction of serum contents of complement C3 and vitronectin may represent an important part of the mechanism whereby RIPC confers its protection.