BACKGROUND: Anastomotic leaks remain one of the most dreaded complications in gastrointestinal surgery causing significant morbidity, that negatively affect the patients\' quality of life. Experimental studies play an important role in understanding the pathophysiological background of anastomotic healing and there are still many fields that require further investigation. Knowledge drawn from these studies can lead to interventions or techniques that can reduce the risk of anastomotic leak in patients with high-risk features. Despite the advances in experimental protocols and techniques, designing a high-quality study is still challenging for the investigators as there is a plethora of different models used.
OBJECTIVE: To review current state of the art for experimental protocols in high-risk anastomosis in rats.
METHODS: This systematic review was performed according to The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. To identify eligible studies, a comprehensive literature search was performed in the electronic databases PubMed (MEDLINE) and Scopus, covering the period from conception until 18 October 2023.
RESULTS: From our search strategy 102 studies were included and were categorized based on the mechanism used to create a high-risk anastomosis. Methods of assessing anastomotic healing were extracted and were individually appraised.
CONCLUSIONS: Anastomotic healing studies have evolved over the last decades, but the findings are yet to be translated into human studies. There is a need for high-quality, well-designed studies that will help to the better understanding of the pathophysiology of anastomotic healing and the effects of various interventions.

BACKGROUND: A dysregulated immune system is a major driver of the mortality and long-term morbidity from sepsis. With respect to macrophages, it has been shown that phenotypic changes are critical to effector function in response to acute infections, including intra-abdominal sepsis. Invariant natural killer T cells (iNKT cells) have emerged as potential central regulators of the immune response to a variety of infectious insults. Specifically, various iNKT cell:macrophage interactions have been noted across a spectrum of diseases, including acute events such as sepsis. However, the potential for iNKT cells to affect peritoneal macrophages during an abdominal septic event is as yet unknown.
METHODS: Cecal ligation and puncture (CLP) was performed in both wild type (WT) and invariant natural killer T cell knockout (iNKT-/-) mice. 24 h following CLP or sham operation, peritoneal macrophages were collected for analysis. Analysis of macrophage phenotype and function was undertaken to include analysis of bactericidal activity and cytokine or superoxide production.
RESULTS: Within iNKT-/- mice, a greater degree of intraperitoneal macrophages in response to the sepsis was noted. Compared to WT mice, within iNKT-/- mice, CLP did induce an increase in CD86+ and CD206+, but no difference in CD11b+. Unlike WT mice, intra-abdominal sepsis within iNKT-/- mice induced an increase in Ly6C-int (5.2% versus 14.9%; P < 0.05) and a decrease in Ly6C-high on peritoneal macrophages. Unlike phagocytosis, iNKT cells did not affect macrophage bactericidal activity. Although iNKT cells did not affect interleukin-6 production, iNKT cells did affect IL-10 production and both nitrite and superoxide production from peritoneal macrophages.
CONCLUSIONS: The observations indicate that iNKT cells affect specific phenotypic and functional aspects of peritoneal macrophages during polymicrobial sepsis. Given that pharmacologic agents that affect iNKT cell functioning are currently in clinical trial, these findings may have the potential for translation to critically ill surgical patients with abdominal sepsis.

UNASSIGNED: Intra-abdominal infection is a complex pathophysiological process involving multiple systems and organs of the body. Abdominal infections complicated by severe sepsis or septic shock have a high mortality rate of 30-50%. Therefore, novel strategies to treat sepsis are urgently needed.
UNASSIGNED: Andrographolide (AD), the main active ingredient of Andrographis paniculata, reportedly exerts beneficial effects on mice with sepsis. However, its exact mechanism of action in attenuating inflammation due to intra-abdominal sepsis remains unclear to date. Hence, this study aimed to examine the therapeutic effects of AD on cecal ligation and puncture (CLP)-induced sepsis and elucidate the underlying mechanisms.
UNASSIGNED: Results showed that AD therapy could significantly improve the 7-day survival rate and alleviate pathological organ injury in mice with CLP. In addition, AD treatment decreased the levels of proinflammatory factors, such as tumor necrosis factor-α and interleukin (IL)-6 in the peritoneal cavity fluid and blood and increased the level of anti-inflammatory factor IL-10 in the peritoneal cavity fluid of mice with CLP. Moreover, bacterial counts in the blood and peritoneal lavage fluid were lower in the mice treated with AD than in those untreated. Mechanistically, AD treatment increased the percentage and phagocytic activity of macrophages in the peritoneal cavity.
UNASSIGNED: These data showed that AD can improve the survival of mice with intra-abdominal sepsis by enhancing bacterial clearance, as evidenced by the increased percentages and phagocytic activity of macrophages in the peritoneal cavity. This study is the first to demonstrate the protective effects of AD against intra-abdominal sepsis.

To deal with intra-abdominal sepsis, one of the major global causes of death in hospitalized patients, efficient abscess drainage is crucial. Despite decades of advances, traditional catheters have demonstrated poor drainage and absorption properties due to their simple tubular structures and their dense nonporous surface. Herein, inspired by porous sponges and fractal roots, a multifaceted hydrogel catheter with effective drainage, absorptive, and robust properties, is presented. Its unique fractal structures provide extensive internal branching and a high specific surface area for effective drainage, while the hierarchical porous structures provide a wide range of absorption capabilities. Additionally, its distinctive multi-interpenetration network maintains robust and appropriate mechanical properties, even after absorption multiple times of liquid and mechanical disturbance, allowing for intact removal from the abdominal cavity without harm to the animal in vivo. Besides, the loaded antimicrobial peptides are capable of being released in situ to inhibit the potential for infections. In vivo experiments have demonstrated that this hydrogel catheter efficiently removes lethal abscesses and improves survival. It is believed that this innovative and practical catheter will create a future precedent for hydrogel drainage devices for more effective management of intra-abdominal sepsis.

BACKGROUND: Studies on prognostic factors for older patients with intra-abdominal sepsis are scarce, and the association between skeletal muscle mass and prognosis among such patients remains unclear.
OBJECTIVE: To develop a nomogram to predict in-hospital mortality among older patients with intra-abdominal sepsis.
METHODS: Older patients with intra-abdominal sepsis were prospectively recruited. Their demographics, clinical features, laboratory results, abdominal computed tomography-derived muscle mass, and in-hospital mortality were recorded. The predictors of mortality were selected via least absolute shrinkage and selection operator and multivariable logistic regression analyses, and a nomogram was developed. The nomogram was assessed and compared with Sequential Organ Failure Assessment score, Acute Physiology and Chronic Health Evaluation II score, and Simplified Acute Physiology Score II.
RESULTS: In total, 464 patients were included, of whom 104 (22.4%) died. Six independent risk factors (skeletal muscle index, cognitive impairment, frailty, heart rate, red blood cell distribution width, and blood urea nitrogen) were incorporated into the nomogram. The Hosmer-Lemeshow goodness-of-fit test and calibration plot revealed a good consistency between the predicted and observed probabilities. The area under the receiver operating characteristic curve was 0.875 (95% confidence interval = 0.838-0.912), which was significantly higher than those of commonly used scoring systems. The decision curve analysis indicated the nomogram had good predictive performance.
CONCLUSIONS: Our nomogram, which is predictive of in-hospital mortality among older patients with intra-abdominal sepsis, incorporates muscle mass, a factor that warrants consideration by clinicians. The model has a high prognostic ability and might be applied in clinical practice after external validation.

UNASSIGNED: In emergency surgeries, open abdomen or laparostomy, especially with perforated viscus, has been used primarily to prevent delayed ventral hernia, burst abdomen, and abdominal compartment syndrome. In the present study, the clinical and resuscitative factors that are linked with open abdomen morbidity are evaluated.
UNASSIGNED: A retrospective analysis was done for all the subjects who were admitted at the tertiary care center between May 2020 and May 2022 for the open abdomen surgeries. These patients were examined to see whether they needed more postoperative care than usual, including the need for resuscitative treatments and other critical clinical indicators. Patients were evaluated if they had any complications. The data that were collected were analysed for any variance using analysis of variance considering P <.05 as significant.
UNASSIGNED: A total of 100 subjects were analysed in this study. Forty nine patients had intra-abdominal sepsis of the 100 cases examined from historical case records and 1 had entero-cutaneous fistulas. These patients did not necessitate additional actions for intensive care unit care, resuscitation, an chest infection, extended hospital stay, or any disabilities compared to those who did not undergo laparotomy during the same period. In this group of patients with open abdomens, the immediate postoperative period was not linked to an increase in resuscitation efforts or a load on clinical staff. Once patients are stabilized, early definitive abdominal closure is advised to prevent problems associated to laparostomies.
UNASSIGNED: The quantity of initial fluid revival and the coagulation factors at the time of admission are not related to intra-abdominal sepsis and enteric fistula following laparostomy after significant abdominal injuries.

Inflammatory cytokine interleukin-6 (IL-6) plays a pivotal role in skeletal muscle degradation after intra-abdominal sepsis (IAS), with mechanism remained to be elucidated. Indoleamine 2,3-dioxygenase 1 (IDO-1), a key enzyme in converting tryptophan into kynurenine, could be activated by IL-6, and kynurenine has been shown to be involved in muscle degradation. We hypothesized that IL-6 could promote muscle degradation via tryptophan-IDO-1-kynurenine pathway in IAS patients.
Serum and rectus abdominis (RA) were obtained from IAS or non-IAS patients. Mouse model of IAS-induced muscle wasting was generated by caecal ligation and puncture (CLP) and lipopolysaccharide (LPS) injection. IL-6 signalling was blocked by anti-mouse IL-6 antibody (IL-6-AB), and the IDO-1 pathway was blocked by navoximod. To elucidate the role of kynurenine in muscle mass and physiology, kynurenine was administered to IAS mice treated with IL-6-AB.
Compared to non-IAS patients, kynurenine levels in serum (+2.30-fold vs. non-IAS, P < 0.001) and RA (+3.11-fold vs. non-IAS, P < 0.001) were elevated, whereas tryptophan levels in serum (-53.65% vs. non-IAS, P < 0.01) and RA (-61.39% vs. non-IAS, P < 0.01) were decreased. Serum IL-6 level of the IAS group was significantly higher compared to non-IAS patients (+5.82-fold vs. non-IAS, P = 0.01), and muscle cross-sectional area (MCSA) was markedly reduced compared to non-IAS patients (-27.73% vs. non-IAS, P < 0.01). In animal experiments, IDO-1 expression was up-regulated in the small intestine, colon and blood for CLP or LPS-treated mice, and there was correlation (R2  = 0.66, P < 0.01) between serum and muscle kynurenine concentrations. Navoximod significantly mitigated IAS-induced skeletal muscle loss according to MCSA analysis (+22.94% vs. CLP, P < 0.05; +23.71% vs. LPS, P < 0.01) and increased the phosphorylated AKT (+2.15-fold vs. CLP, P < 0.01; +3.44-fold vs. LPS, P < 0.01) and myosin heavy chain (+3.64-fold vs. CLP, P < 0.01; +2.13-fold vs. LPS, P < 0.01) protein expression in myocytes. In the presence of anti-IL-6 antibody, a significantly decreased IDO-1 expression was observed in the small intestine, colon and blood in CLP or LPS mice (all P < 0.01), whereas the decrease of MCSA was alleviated (+37.43% vs. CLP + IgG, P < 0.001; +30.72% vs. LPS + IgG, P < 0.001). In contrast, additional supplementation of kynurenine decreased the MCSA in septic mice treated with IL-6-AB (both P < 0.01).
This study provided novel insights into the tryptophan-IDO-1-kynurenine-dependent mechanisms that underlie inflammatory cytokine-induced skeletal muscle catabolism during intra-abdominal sepsis.

A non-systematic review of the published scientific evidence has been carried out on the duration of empirical antibiotic treatment in surgical intra-abdominal infections (IIA) with effective focus control. Given the progressive increase in antibiotic resistance, it is urgent to have strategies to reduce the pressure on the microbiota. The American guidelines made by Mazuski et al. of 20171, as the central axis in the recommendations of the duration of empirical antibiotic treatment in intra-abdominal infections with control of the focus and a bibliographic search of all the articles that contained the keywords in Pubmed and Google Scholar is added. 21 articles referring to the duration of empirical antibiotic treatment in intra-abdominal infection with control of the focus are collected. With the American guidelines and these articles, a proposal is prepared for the duration of empirical antibiotic treatment in patients without risk factors between 24 and 72 h. And in those who present risk factors, it should be individualized with active monitoring every 24 h of fever, paralytic ileus and leukocytosis (FIL), before an early detection of complications or the need for changes in antibiotic treatment. Short treatments are just as effective as those of longer durations and are associated with fewer adverse effects, therefore, daily adjusting and reassessing the duration of empirical antibiotic treatment is essential for better practice.

Crohn\'s disease (CD) remains a chronic, incurable disorder that presents unique challenges to the surgeon. Multiple factors must be considered to allow development of an appropriate treatment plan. Medical therapy often precedes or complements the surgical management. The indications for operative management of CD include acute and chronic disease complications and failed medical therapy. Elective surgery comes into play when patients are refractory to medical treatment if they have an obstructive phenotype. Toxic colitis, acute obstruction, perforation, acute abscess, or massive hemorrhage represent indications for emergency surgery. These patients are generally in critical conditions and present with intra-abdominal sepsis and a preoperative status of immunosuppression and malnutrition that exposes them to a higher risk of complications and mortality. A multidisciplinary team including surgeons, gastroenterologists, radiologists, nutritional support services, and enterostomal therapists are required for optimal patient care and decision making. Management of each emergency should be individualized based on patient age, disease type and duration, and patient goals of care. Moreover, the recurrent nature of disease mandates that we continue searching for innovative medical therapies and operative techniques that reduce the need to repeat surgical operations. In this review, we aimed to discuss the acute complications of CD and their treatment.

Secondary peritonitis and intra-abdominal sepsis are a global health problem. The life-threatening systemic insult that results from intra-abdominal sepsis has been extensively studied and remains somewhat poorly understood. While local surgical therapy for perforation of the abdominal viscera is an age-old therapy, systemic therapies to control the subsequent systemic inflammatory response are scarce. Advancements in critical care have led to improved outcomes in secondary peritonitis. The understanding of the effect of secondary peritonitis on the human microbiome is an evolving field and has yielded potential therapeutic targets. This review of secondary peritonitis discusses the history, classification, pathophysiology, diagnosis, treatment, and future directions of the management of secondary peritonitis. Ongoing clinical studies in the treatment of secondary peritonitis and the open abdomen are discussed.