SIRT1 downregulation in pneumonia is associated with an immature neutrophil response and increased disease severity.

BACKGROUND: Pneumonia remains a common complication in trauma patients. Sirtuin 1 (SIRT1) is an anti-inflammatory NAD + -dependent deacetylase that has been shown to reduce the severity of ARDS in polymicrobial sepsis. The impact of SIRT1 in acute pneumonia, however, remains unknown. We hypothesized that SIRT1 deletion in pneumonia would worsen the inflammatory response and clinical severity, and that increased SIRT1 expression would be protective. METHODS: Ten- to 14-week-old male and female SIRT1 knockout (S1KO) mice, SIRT1 overexpressor (S1OE) mice, and their wildtype (WT) littermates underwent intra-tracheal inoculation with Pseudomonas aeruginosa . Rectal temperature was recorded, SIRT1 lung protein was quantified by western blotting, Sirt1 mRNA was measured by qPCR, and lung leukocyte subpopulations were analyzed by flow cytometry. Data were analyzed by one-way ANOVA using Prism software. RESULTS: Pneumonia created a functional SIRT1 knockdown in the lungs of WT mice by 4 hours, resulting in comparable SIRT1 levels and temperatures to the S1KO mice by 12 hours. Pneumonia also partially reduced SIRT1expression in S1OE mice, but S1OE mice still had improved thermoregulation 12 hours after pneumonia. In all groups, Sirt1 mRNA expression was not affected by infection. Sirtuin 1 deletion was associated with decreased neutrophil infiltration in the lung, as well as a shift toward a more immature neutrophil phenotype. SIRT1 deletion was also associated with decreased myeloperoxidase-positive neutrophils in the lungs following pneumonia, indicating decreased neutrophil activity. S1OE mice had no change in lung leukocyte subpopulations when compared to WT. CONCLUSION: Pneumonia creates a functional SIRT1 knockdown in mice. SIRT1 deletion altered the early inflammatory cell response to pneumonia, resulting in a neutrophil response that would be less favorable for bacterial clearance. Despite overexpression of SIRT1, S1OE mice also developed low SIRT1 levels and exhibited only minimal improvement. This suggests increasing SIRT1 transcription is not sufficient to overcome pneumonia-induced downregulation and has implications for future treatment options. Targeting SIRT1 through increasing protein stability may promote a more efficient inflammatory cell response to pneumonia, thereby preventing subsequent lung injury.

Sirt3 Deletion Increases Inflammation and Mortality in Polymicrobial Sepsis.

Background: Sirtuin 3 (SIRT3) is a nicotinamide adenine dinucleotide (NAD)-dependent deacetylase that confers resilience to cellular stress by promoting mitochondrial activity. Mitochondrial dysfunction is a major driver of inflammation during sepsis. We hypothesize that Sirt3 expression improves survival in polymicrobial sepsis by mitigating the inflammatory response. Materials and Methods: Sirt3 knockout (S3KO) and wild-type (WT) mice underwent cecal ligation and puncture (CLP) or sham surgery. mRNA expression was quantified using quantitative polymerase chain reaction (qPCR) and protein expression was quantified using enzyme-linked immunosorbent assay (ELISA). Spectrophotometric assays were used to quantify serum markers of organ dysfunction. For in vitro studies, bone marrow-derived macrophages (BMDMs) were harvested from S3KO and WT mice and treated with lipopolysaccharide (LPS). Results: After CLP, hepatic Sirt3 levels decreased from baseline by nine hours and remained depressed at 24 hours. Peak serum interleukin-6 (IL-6) protein levels were higher in S3KO mice. In LPS-treated BMDMs, IL-6 mRNA levels peaked earlier in S3KO cells, although peak levels were comparable to WT. Although S3KO mice had decreased median survival after CLP compared with WT, there was no difference in five-day survival or organ dysfunction. Conclusions: Although S3KO mice initially had increased inflammation and mortality, this difference abated with time, and overall survival was comparable between the groups. This pattern is consistent with the timeline of sepsis-induced Sirt3 downregulation in WT mice, and suggests that Sirt3 downregulation occurring in sepsis is at least partially responsible for the initial hyperinflammatory response and subsequent mortality. Our data support upregulation of Sirt3 as a promising therapeutic strategy for further research in sepsis.

Diagnosis and management of choledochal cysts.

BACKGROUND: Choledochal cysts (CCs) are rare cystic dilatations of the intrahepatic and/or extrahepatic bile ducts. We review the pathophysiology, diagnosis, and management of CCs. METHODS: MEDLINE/PubMed and Web of Science databases were queried for "choledochal cyst", "bile duct cyst", "choledochocele", and "Caroli disease". Data were synthesized and systematically reviewed. RESULTS: Classified according to the Todani Classification, CCs are generally believed to arise secondary to reflux of pancreatic enzymes into the biliary tree due to anomalous pancreaticobiliary duct union. Complications of CCs include abdominal pain, jaundice, cystolithiasis, cholecystitis, pancreatitis, liver abscess, liver cirrhosis and malignant transformation (3-7.5%). Radiological and endoscopic imaging is the cornerstone of CC diagnosis and full delineation of cyst anatomy is imperative for proper management. Management is generally guided by cyst classification with complete cyst excision necessary for CCs with high potential of malignant transformation such as types I and IV. 5-year overall survival after choledochal cyst excision is 95.5%. CONCLUSION: Most CCs should undergo surgical intervention to mitigate the risk of cyst related complications such as cholangitis and malignant transformation.

Surgical resection rates after neoadjuvant therapy for localized pancreatic ductal adenocarcinoma: meta-analysis.

BACKGROUND: Neoadjuvant therapy is increasingly being used before surgery for localized pancreatic cancer. Given the importance of completing multimodal therapy, the aim of this study was to characterize surgical resection rates after neoadjuvant therapy as well as the reasons for, and long-term prognostic impact of, not undergoing resection. METHODS: A systematic review and meta-analysis of prospective trials and high-quality retrospective studies since 2010 was performed to calculate pooled resection rates using a generalized random-effects model for potentially resectable, borderline resectable, and locally advanced pancreatic cancer. Median survival times were calculated using random-effects models for patients who did and did not undergo resection. RESULTS: In 125 studies that met the inclusion criteria, neoadjuvant therapy consisted of chemotherapy (36.8 per cent), chemoradiation (15.2 per cent), or chemotherapy and radiation (48.0 per cent). Among 11 713 patients, the pooled resection rates were 77.4 (95 per cent c.i. 71.3 to 82.5), 60.6 (54.8 to 66.1), and 22.2 (16.7 to 29.0) per cent for potentially resectable, borderline resectable, and locally advanced pancreatic cancer respectively. The most common reasons for not undergoing resection were distant progression for resectable and borderline resectable cancers, and local unresectability for locally advanced disease. Among 42 studies with survival data available, achieving surgical resection after neoadjuvant therapy was associated with improved survival for patients with potentially resectable (median 38.5 versus 13.3 months), borderline resectable (32.3 versus 13.9 months), and locally advanced (30.0 versus 14.6 months) pancreatic cancer (P < 0.001 for all). CONCLUSION: Although rates of surgical resection after neoadjuvant therapy vary based on anatomical stage, surgery is associated with improved survival for all patients with localized pancreatic cancer. These pooled resection and survival rates may inform patient-provider decision-making and serve as important benchmarks for future prospective trials.

Sirtuin 1 deletion increases inflammation and mortality in sepsis.

BACKGROUND: Sepsis is a hyperinflammatory response to infection that can lead to multiorgan failure and eventually death. Often, the onset of multiorgan failure is heralded by renal dysfunction. Sirtuin 1 (SIRT1) promotes cellular stress resilience by inhibiting inflammation and promoting mitochondrial function. We hypothesize that SIRT1 plays an important role in limiting the inflammatory responses that drive organ failure in sepsis, predominantly via expression in myeloid cells. METHODS: We performed cecal ligation and puncture (CLP) on whole body SIRT1 knockout (S1KO) and myeloid cell-specific S1KO (S1KO-LysMCre) mice on a C57BL/6J background. Serum interleukin (IL)-6 was quantified by enzyme-linked immunosorbent assay. Renal mitochondrial complex activity was measured using Oxygraph-2k (Oroboros Instruments, Innsbruck, Austria). Blood urea nitrogen (BUN) was measured from serum. Survival was monitored for up to 5 days. RESULTS: Following CLP, S1KO mice had decreased renal mitochondrial complex I-dependent respiratory capacity (241.7 vs. 418.3 mmolO2/mg/min, p = 0.018) and renal mitochondrial complex II-dependent respiratory capacity (932.3 vs. 1,178.4, p = 0.027), as well as reduced rates of fatty acid oxidation (187.3 vs. 250.3, p = 0.022). Sirtuin 1 knockout mice also had increased BUN (48.0 mg/dL vs. 16.0 mg/dL, p = 0.049). Interleukin-6 levels were elevated in S1KO mice (96.5 ng/mL vs. 45.6 ng/mL, p = 0.028) and S1KO-LysMCre mice (35.8 ng/mL vs. 24.5 ng/mL, p = 0.033) compared with controls 12 hours after surgery. Five-day survival in S1KO (33.3% vs. 83.3%, p = 0.025) and S1KO-LysMCre (60% vs. 100%, p = 0.049) mice was decreased compared with controls. CONCLUSION: Sirtuin 1 deletion increases systemic inflammation in sepsis. Renal mitochondrial dysfunction, kidney injury, and mortality following CLP were all exacerbated by SIRT1 deletion. Similar effects on inflammation and survival were seen following myeloid cell-specific SIRT1 deletion, indicating that SIRT1 activity in myeloid cells may be a significant contributor for the protective effects of SIRT1 in sepsis.

Women Empowering Women: Assessing the American College of Surgeons Women in Surgery Committee Mentorship Program.

BACKGROUND: Mentorship is an important factor for career promotion and professional development. The Women in Surgery Committee developed a mentorship program that matched early career female surgeons to senior female surgeons for 1 year. We hypothesized participation in the program would empower junior surgeons by providing opportunities to network and hone skills necessary to attain their career goals. METHODS: Survey was sent 4 to 6 weeks after program completion. Statements about mentorship and value of the Women in Surgery Committee program were ranked on a 5-point Likert scale ranging from strongly disagree (1) to strongly agree (5). Participants were compared based on frequency of encounters using Student's t-test. RESULTS: A total of 105 pairs were identified; response rate was 60%. Results reported as (mean ± SD). Participants believed mentorship was essential for young surgeons (4.5 ± 1.0), and limiting the program to female surgeons added value (4.4 ± 0.6). When compared with mentees who met less than 4 times in a year, those who met 4 or more times perceived the program as beneficial (4.4 ± 0.82, p < 0.001). Mentees who met 4 or more times in a year benefitted from creating and achieving goals (4.3 ± 0.75, p < 0.001), setting expectations (4.5 ± 0.6, p < 0.001), providing networking opportunities (4.1 ± 1.1, p < 0.05), and developing professional skills (3.9 ± 0.98). CONCLUSION: The Women in Surgery Committee Mentorship Program provides an opportunity for young female surgeons; however, perceived benefit is dependent on mentee engagement.

Safety, efficacy, and tolerability of immune checkpoint inhibitors in the treatment of hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is a major cause of mortality worldwide with an increasing incidence due to escalating rates of obesity and non-alcoholic fatty liver disease. Unfortunately, a majority of patients with HCC present with advanced disease. The immune checkpoint inhibitor atezolizumab, a PD-L1 inhibitor, in combination with bevacizumab, anti-VEGF, has become the new standard of care for patients with advanced HCC after demonstrating improved overall and progression free survival over sorafenib. In this review, we discuss the evolving role of immune checkpoint inhibitors in the treatment of HCC and their safety, efficacy, and tolerability.

Social Vulnerability Subtheme Analysis Improves Perioperative Risk Stratification in Hepatopancreatic Surgery.

BACKGROUND: There has been increased interest in understanding how social determinants of health (SDH) may affect care both in the medical and surgical setting. We sought to define the impact of various aspects of social vulnerability on the ability of patients to achieve a "textbook outcome" (TO) following hepatopancreatic surgery. METHODS: Medicare beneficiaries who underwent hepatopancreatic resection between 2013 and 2017 were identified using the Medicare database. Social vulnerability was defined using the Centers for Disease Control Social Vulnerability Index (SVI), which is comprised of four subthemes: socioeconomic (SE), household composition and disability (HCD), minority status and language (MSL), and housing type and transportation (HTT). TO was defined as the composite endpoint: absence of 90-day mortality or readmission, absence of an extended length of stay (LOS), and no complications during the index admission. Cluster analysis was used to identify vulnerability cohorts, and multivariable logistic regression was utilized to assess the impact of these SVI subthemes on the likelihood to achieve a textbook outcome. RESULTS: Among 37,707 Medicare beneficiaries, 64.9% (n = 24,462) of patients underwent pancreatic resection while 35.1% (n = 13,245) underwent hepatic resection. Median patient age was 72 years (IQR: 68-77), just over one-half were male (51.9%; n = 19,558), and the median CCI was 3 (IQR: 2-8). Cluster analysis revealed five distinct SVI profiles with wide variability in the distribution of SVI subthemes, ranging from 15 (profile 1 IQR: 7-26) to 83 (profile 5 IQR: 66-93). The five profiles were grouped into 3 categories based on median composite SVI: "low vulnerability" (profile 1), "average vulnerability" (profiles 2 and 3), or "high vulnerability" (profiles 4 and 5). The rate of TO ranged from 44.6% in profile 5 (n = 4022) to 49.2% in profile 1 (n = 4836). Multivariable analyses comparing patients categorized into the two average SVI profiles revealed that despite having similar composite SVI scores, the risk of adverse postoperative outcomes was not similar. Specifically, patients from profile 5 had lower odds of achieving a TO (OR 0.89, 95%CI: 0.83-0.95) and higher odds of 90-day mortality (OR 1.29, 95%CI: 1.15-1.44) versus patients in profile 4. CONCLUSION: Distinct profiles of SVI subtheme characteristics were independently associated with postoperative outcomes among Medicare beneficiaries undergoing HP surgery, even among patients with similar overall composite SVI scores.

Impact of care fragmentation on the outcomes of patients receiving neoadjuvant and adjuvant therapy for pancreatic adenocarcinoma.

INTRODUCTION: Neoadjuvant therapy (NT) is increasingly used for localized pancreatic ductal adenocarcinoma (PDAC). The impact of care fragmentation during NT on the outcomes of patients with PDAC is unknown. METHODS: Adult patients with Stage I-III PDAC who received NT and patients who underwent surgery first followed by adjuvant therapy (AT) between 2004 and 2016 were queried from the National Cancer Database. Short- and long-term outcomes were compared between patients who received fragmented care (FC; care provided at >1 hospital) versus integrated care (IC; care at a single institution). RESULTS: Among 6522 patients who underwent NT before pancreatectomy, 3755 (57.6%) received FC and 2767 (42.4%) received IC. While patients who received FC had a longer time to initiation of treatment (33.2 vs. 29.7 days, p < 0.001), there was no difference in median overall survival (OS) (26.7 vs. 26.5 months, p = 0.6). Among patients who underwent upfront surgery followed by AT (n = 15 291), patients who received FC had a longer time from diagnosis to undergoing surgery but less time from surgery to AT and no difference in OS (24.0 vs. 24.0 months, p = 0.910). CONCLUSION: Although care fragmentation was associated with slightly longer times to initiate and complete treatment among patients with localized PDAC, long-term survival outcomes were similar.

Virtual Recruitment in Surgical Residency Programs.

PURPOSE OF REVIEW: The Covid-19 pandemic forced residency programs to drastically change their interview processes and adopt virtual interviewing for the 2020-2021 match cycle. RECENT FINDINGS: While virtual interviewing decreased cost and increased convenience for applicants and programs involved in the match, it also introduced several potential disadvantages. Maximizing technological capabilities was an area of utmost concern at the start of the interview cycle, and multiple medical education organizations quickly recommended ways to move to virtual process, and to prevent and troubleshoot technical problems. However, other issues were less straightforward, such as how to address new sources of bias introduced by virtual interviewing, and how to ensure that programs and applicants could make informed decisions about their rank lists after only limited virtual interactions. Additionally, the increased convenience of interviewing raised concerns that students would accept more interviews, disrupting the established calculus programs used to determine how many interviews to offer per spot available. SUMMARY: In this review, we examine the benefits and disadvantages of virtual interviewing, review recommendations from the current literature on how to improve the process, and discuss what we learned from our own experience at an academic general surgery residency program over the course of this unprecedented interview season.

Moderately Macrosteatotic Livers Have Acceptable Long-Term Outcomes but Higher Risk of Immediate Mortality.

BACKGROUND AND AIMS: Liver transplantation is the most effective treatment for end-stage liver disease (ESLD). Whether moderately macrosteatotic livers (30%-60%) represent a risk for worsened graft function is controversial. The uncertainty, in large part, is owing to the heterogeneous steatosis grading. Our aim was to determine the short- and long-term outcomes of moderately macrosteatotic allografts that were graded according to a standardized institutional protocol. METHODS: We performed a retrospective analysis of transplants performed between 1994 and 2014. All patients with allografts biopsied pretransplantation were included. Relevant donor and recipient variable were recorded. Moderately macrosteatotic livers were compared with mildly macrosteatotic and nonsteatotic livers. Primary outcomes of interest were patient survival at 90 days, 1 year, and 5 years. Cox regression analyses were carried out to compare survival between the 2 groups. RESULTS: We compared 65 allografts with moderate macrosteatosis and 810 with no or mild macrosteatosis. Patients with moderately macrosteatotic allografts were 2.69 times as likely to die within the first 90 days after transplant (75.1% vs 91.6% survival) after adjusting for donor age, donor race, recipient age, recipient race, recipient body mass index, recipient diabetes, presence of hepatocellular carcinoma, days on waitlist, Model for End-Stage Liver Disease (MELD) score at transplantation, cold ischemia time. However, for recipients who survive 90 days, moderately macrosteatotic allografts had comparable long-term survival. CONCLUSION: Our study shows that moderate macrosteatosis is a strong predictor of early but not late mortality. Further studies are needed to distinguish the specific cohort of patients for whom moderately macrosteatotic allografts will lead to acceptable outcomes.

Longevity pathways in stress resistance: targeting NAD and sirtuins to treat the pathophysiology of hemorrhagic shock.

Stress resistance correlates with longevity and this pattern has been exploited to help identify genes that can influence lifespan. Reciprocally, genes and pharmacological agents that have been studied primarily in the context of longevity may be an untapped resource for treating acute stresses. Here we summarize the evidence that targeting SIRT1, studied primarily in the context of longevity, can improve outcomes in hemorrhagic shock and resuscitation. Hemorrhagic shock is a potentially fatal condition that occurs when blood loss is so severe that tissues no longer receive adequate oxygen. While stabilizing the blood pressure and reperfusing tissues are necessary, re-introducing oxygen to ischemic tissues generates a burst of reactive oxygen species that can cause secondary tissue damage. Reactive oxygen species not only exacerbate the inflammatory cascade but also can directly damage mitochondria, leading to bioenergetic failure in the affected tissues. Treatments with polyphenol resveratrol and with nicotinamide adenine dinucleotide (NAD) precursors have both shown promising results in rodent models of hemorrhagic shock and resuscitation. Although a number of different mechanisms may be at play in each case, a common theme is that resveratrol and NAD both enhance the activity of SIRT1. Moreover, many of the physiologic improvements observed with resveratrol and NAD precursors are consistent with modulation of known SIRT1 targets. Because small blood vessels and limited blood volume make mice very challenging for the development of hemorrhagic shock models, there is a paucity of direct genetic evidence testing the role of SIRT1. However, the development of more robust methods in mice as well as genetic modifications in rats should allow the study of SIRT1 transgenic and KO rodents in the near future. The potential therapeutic effect of SIRT1 in hemorrhagic shock may serve as an important example supporting the value of considering "longevity" pathways in the mitigation of acute stresses.

Frontline Science: Rev-Erbα links blue light with enhanced bacterial clearance and improved survival in murine Klebsiella pneumoniae pneumonia.

The wavelength of light is a critical determinant of light's capacity to entrain adaptive biological mechanisms, such as enhanced immune surveillance, that precede and prepare us for the active circadian day, a time when the risk of encountering pathogen is highest. Light rich in the shorter wavelength visible blue spectrum maximally entrains these circadian rhythms. We hypothesized that exposure to blue light during sepsis will augment immunity and improve outcome. Using a clinically relevant Klebsiella pneumoniae acute lower respiratory tract infection model, we show that blue spectrum light shifts autonomic tone toward parasympathetic predominance and enhances immune competence, as characterized by accelerated pathogen clearance that is accompanied by reduced alveolar neutrophil influx, inflammation, and improved survival. Blue light functioned through an optic-cholinergic pathway and expansion of splenic Ccr2+ monocytes to increase control of the infection and improve survival. The "keystone" mediating these effects is the circadian clock protein Rev-Erbα, and biochemical activation with Rev-Erbα agonist SR9009 enhanced mononuclear cell phagocytosis in vitro and recapitulated the enhanced pathogen elimination in vivo observed with blue light. These findings underscore the potential therapeutic value of blue light and modulating Rev-Erbα to enhance host immunity against infection.

Bright environmental light improves the sleepiness of nightshift ICU nurses.

BACKGROUND: Shift work can disturb circadian homeostasis and result in fatigue, excessive sleepiness, and reduced quality of life. Light therapy has been shown to impart positive effects in night shift workers. We sought to determine whether or not prolonged exposure to bright light during a night shift reduces sleepiness and enhances psychomotor performance among ICU nurses. METHODS: This is a single-center randomized, crossover clinical trial at a surgical trauma ICU. ICU nurses working a night shift were exposed to a 10-h period of high illuminance (1500-2000 lx) white light compared to standard ambient fluorescent lighting of the hospital. They then completed the Stanford Sleepiness Scale and the Psychomotor Vigilance Test. The primary and secondary endpoints were analyzed using the paired t test. A p value <0.05 was considered significant. RESULTS: A total of 43 matched pairs completed both lighting exposures and were analyzed. When exposed to high illuminance lighting subjects experienced reduced sleepiness scores on the Stanford Sleepiness Scale than when exposed to standard hospital lighting: mean (sem) 2.6 (0.2) vs. 3.0 (0.2), p = 0.03. However, they committed more psychomotor errors: 2.3 (0.2) vs. 1.7 (0.2), p = 0.03. CONCLUSIONS: A bright lighting environment for ICU nurses working the night shift reduces sleepiness but increases the number of psychomotor errors. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03331822 . Retrospectively registered on 6 November 2017.

Casz1 is required for cardiomyocyte G1-to-S phase progression during mammalian cardiac development.

Organ growth occurs through the integration of external growth signals during the G1 phase of the cell cycle to initiate DNA replication. Although numerous growth factor signals have been shown to be required for the proliferation of cardiomyocytes, genetic studies have only identified a very limited number of transcription factors that act to regulate the entry of cardiomyocytes into S phase. Here, we report that the cardiac para-zinc-finger protein CASZ1 is expressed in murine cardiomyocytes. Genetic fate mapping with an inducible Casz1 allele demonstrates that CASZ1-expressing cells give rise to cardiomyocytes in the first and second heart fields. We show through the generation of a cardiac conditional null mutation that Casz1 is essential for the proliferation of cardiomyocytes in both heart fields and that loss of Casz1 leads to a decrease in cardiomyocyte cell number. We further report that the loss of Casz1 leads to a prolonged or arrested S phase, a decrease in DNA synthesis, an increase in phospho-RB and a concomitant decrease in the cardiac mitotic index. Taken together, these studies establish a role for CASZ1 in mammalian cardiomyocyte cell cycle progression in both the first and second heart fields.