Intestinal ischemia is a frequently observed phenomenon. Morbidity and mortality rates are extraordinarily high and did not improve over the past decades. This is in part attributable to limited ...knowledge on the pathophysiology of intestinal ischemia-reperfusion(IR) in man, the paucity in preventive and/or therapeutic options and the lack of early diagnostic markers for intestinal ischemia. To improve our knowledge and solve clinically important questions regarding intestinal IR, we developed a human experimental intestinal IR model. With this model, we were able to gain insight into the mechanisms that allow the human gut to withstand short periods of IR without the development of severe inflammatory responses. The purpose of this review is to overview the most relevant recent advances in our understanding of the pathophysiology of human intestinal IR, as well as the(potential) future clinical implications.
Background
Esophageal surgery is associated with complications and mortality. It is highly important to develop tools predicting unfavorable postoperative outcome. Esophageal cancer and neoadjuvant ...chemoradiotherapy (CRT) induce skeletal muscle wasting, which leads to diminished physiologic reserves. The purpose of this study was to investigate whether the degree of muscle mass lost during neoadjuvant CRT predicts postoperative mortality.
Methods
A total of 123 consecutive patients undergoing surgery for esophageal malignancy in the period 2008–2012 were included, of whom 114 received neoadjuvant CRT. Skeletal muscle mass was measured on routinely performed CT scans by assessing L3 muscle index (according to the Prado method) before and after neoadjuvant CRT, and the amount of muscle mass lost during neoadjuvant CRT (muscle loss index) was calculated. It was investigated whether this amount was associated with postoperative 30-day or in-hospital mortality and morbidity.
Results
In the complete cohort, no significant association between loss of muscle mass and mortality was found. However, skeletal muscle mass was significantly lower in patients with stage III–IV tumors compared with stage I–II tumors, prior to neoadjuvant CRT. In the stage III–IV subgroup, the amount of muscle mass lost during neoadjuvant CRT was predictive of postoperative mortality: −13.5 % (standard deviation 6.2 %) in patients who died postoperatively compared with −5.0 % (standard deviation 8.3 %) in surviving patients,
p
= 0.02.
Conclusions
Measurement of muscle mass loss during neoadjuvant chemoradiotherapy may provide a readily available and inexpensive assessment to identify patients at risk for developing unfavorable postoperative outcome after resection of esophageal malignancies, especially in patients with stage III–IV tumors.
Abstract Early and accurate diagnosis of intestinal ischemia is important in order to provide rapid and correct treatment and reduce morbidity and mortality rates. Clinical signs and symptoms are ...often unspecific. This systemic review sums up literature regarding human plasma biomarkers for acute mesenteric ischemia reported during the last ten years. Classic, general markers, including lactate, white cell count, base excess, show poor diagnostic accuracy for intestinal ischemia. Preliminary results for ischemia-modified albumin are promising, which is also true for the inflammatory marker procalcitonin. Best diagnostic accuracy is described for D-dimer, a-Glutathione S-transferase (a-GST) and Intestinal fatty acid binding protein (I-FABP), reflecting coagulation activity and mucosal damage respectively. Future studies should be directed at phase four questions (Do patients who undergo the diagnostic test fare better (in their ultimate health outcomes) than similar patients who do not?) for these markers and the identification of additional, novel plasma biomarkers signaling various types and stages of intestinal ischemia.
This study aims at improving diagnosis of intestinal ischemia, by measuring plasma and urinary fatty acid binding protein (FABP) levels.
Fifty consecutive patients suspected of intestinal ischemia ...were included and blood and urine were sampled at time of suspicion. Plasma and urinary concentrations of intestinal FABP (I-FABP), liver FABP (L-FABP) and ileal bile acid binding protein (I-BABP) were measured using enzyme-linked immunosorbent assays.
Twenty-two patients suspected of intestinal ischemia were diagnosed with intestinal ischemia, 24 patients were diagnosed with other diseases, and 4 patients were excluded from further analysis fulfilling exclusion criteria. Median plasma concentrations of I-FABP and L-FABP and urinary concentrations of all 3 markers were significantly higher in patients with proven intestinal ischemia than in patients suspected of intestinal ischemia with other final diagnoses (plasma I-FABP; 653 pg/mL vs. 109 pg/mL, P = 0.02, plasma L-FABP; 117 ng/mL vs. 25 ng/mL, P = 0.006, urine I-FABP; 3377 pg/mL vs. 115 pg/mL, P = 0.001, urine L-FABP; 1,199 ng/mL vs. 37 ng/mL, P =0.004, urine I-BABP; 48.6 ng/mL vs. 0.6 ng/mL, P = 0.002). Positive and negative likelihood ratios significantly increased positive posttest probability and decreased negative posttest probability on intestinal ischemia. In patients with intestinal ischemia a trend to higher plasma I-BABP levels was observed when the ileum was involved (18.4 ng/mL vs. 2.9 ng/mL, P = 0.05).
Plasma and especially urinary I-FABP and L-FABP levels and urinary I-BABP levels can improve early diagnosis of intestinal ischemia. Furthermore, plasma I-BABP levels can help in localizing ileal ischemia.
Despite advancements in surgical technique and perioperative care, intestinal anastomoses still have a 10-15 per cent risk of leakage, which results in considerable morbidity and/or mortality. Recent ...animal studies have suggested that administration of butyrate to the anastomotic site results in enhanced anastomotic strength, which may prevent leakage. This systematic review and meta-analysis summarises current evidence concerning the effect of butyrate administration on anastomotic healing and will form a scientific basis for the development of new research into this subject.
Animal studies on the effect of butyrate-based interventions in models of intestinal anastomotic healing were systematically retrieved from online databases. Bibliographical data, study characteristics and outcome data were extracted, and internal validity of the studies was assessed. Outcomes studied through meta-analysis concerned: anastomotic strength, anastomotic leakage, collagen metabolism and general histologic parameters of wound healing.
A comprehensive search and selection identified 19 relevant studies containing 41 individual comparisons. Design and conduct of most experiments were poorly reported resulting in an unclear risk of bias. Meta-analyses showed that butyrate administration significantly increases anastomotic strength (SMD 1.24, 0.88 to 1.61), collagen synthesis (SMD 1.44, 0.72 to 2.15) and collagen maturation, making anastomoses less prone to leakage in the early postoperative period (OR 0.37, 0.15 to 0.93).
This systematic review and meta-analysis shows that there is potential ground to investigate the use of butyrate in clinical trials to prevent anastomotic leakage in intestinal surgery. However, more research is necessary to define the best application form, dosage and administration route.
To determine the association of sarcopenia with postoperative morbidity and mortality after colorectal surgery.
Functional compromise in elderly colorectal surgical patients is considered as a ...significant factor of impaired postoperative recovery. Therefore, the predictive value of preoperative functional compromise assessment was investigated. Sarcopenia is a hallmark of functional compromise.
A total of 310 consecutive patients who underwent oncologic colorectal surgery were included in a prospective digital database. Sarcopenia was assessed using the L3 muscle index utilizing Osirix on preoperative computed tomography. Groningen Frailty Indicator and Short Nutritional Assessment Questionnaire scores were used to assess frailty and nutritional compromise. Predictors for anastomotic leakage, sepsis, and mortality were analyzed by logistic regression analysis.
Age was an independent predictor of mortality P = 0.04; odds ratio, 1.17; 95% confidence interval (CI), 1.01-1.37. Thirty-day/in-hospital mortality rate in sarcopenic patients was 8.8% versus 0.7% in nonsarcopenic patients (P = 0.001; odds ratio, 15.5; 95% CI, 2.00-120). Sarcopenia was not predictive for anastomotic leakage or sepsis. Combination of high Short Nutritional Assessment Questionnaire score, high Groningen Frailty Indicator score, and sarcopenia strongly predicted sepsis (P = 0.001; odds ratio, 25.1; 95% CI, 5.11-123), sensitivity, 46%; specificity, 97%; positive likelihood ratio, 13 (95% CI, 4.4-38); negative likelihood ratio, 0.57 (95% CI, 0.33-0.97).
Functional compromise in colorectal cancer surgery is associated with adverse postoperative outcome. Assessment of functional compromise by means of a nutritional questionnaire (Short Nutritional Assessment Questionnaire), a frailty questionnaire (Groningen Frailty Indicator), and sarcopenia measurement (L3 muscle index) can accurately predict postoperative sepsis.
Although the fetal immune system is considered tolerogenic, preterm infants can suffer from severe intestinal inflammation, including necrotizing enterocolitis (NEC). Here, we demonstrate that human ...fetal intestines predominantly contain tumor necrosis factor-α (TNF-α)+CD4+CD69+ T effector memory (Tem) cells. Single-cell RNA sequencing of fetal intestinal CD4+ T cells showed a T helper 1 phenotype and expression of genes mediating epithelial growth and cell cycling. Organoid co-cultures revealed a dose-dependent, TNF-α-mediated effect of fetal intestinal CD4+ T cells on intestinal stem cell (ISC) development, in which low T cell numbers supported epithelial development, whereas high numbers abrogated ISC proliferation. CD4+ Tem cell frequencies were higher in inflamed intestines from preterm infants with NEC than in healthy infant intestines and showed enhanced TNF signaling. These findings reveal a distinct population of TNF-α-producing CD4+ T cells that promote mucosal development in fetal intestines but can also mediate inflammation upon preterm birth.
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•Human fetal intestinal CD4+ Tem cells preferentially produce TNF-α•Fetal intestinal TNF-α+CD4+ Tem cells are present from the end of the first trimester•Fetal TNF-α+CD4+ Tem cells promote intestinal epithelial tissue growth•Premature birth can result in TNF-α-mediated intestinal tissue damage
The fetal immune system is considered anti-inflammatory; nonetheless, preterm infants are at risk for necrotizing enterocolitis (NEC), a severe intestinal inflammatory disease. Schreurs et al. demonstrate that fetal TNF-α+CD4+ T cells promote gut development early in life. However, in preterm babies these TNFα+CD4+ T cells can mediate intestinal inflammation, providing a potential mechanism for NEC.
Background We developed a jejunal and colonic experimental human ischemia-reperfusion (IR) model to study pathophysiological intestinal IR mechanisms and potential new intestinal ischemia biomarkers. ...Our objective was to evaluate the safety of these IR models by comparing patients undergoing surgery with and without in vivo intestinal IR. Methods A retrospective study was performed comparing complication rates and severity, based on the Clavien-Dindo classification system, in patients undergoing pancreatoduodenectomy with (n = 10) and without (n = 20 matched controls) jejunal IR or colorectal surgery with (n = 10) and without (n = 20 matched controls) colon IR. Secondary outcome parameters were operative time, blood loss, 90-day mortality and length of hospital stay. Results Following pancreatic surgery, 63% of the patients experienced one or more postoperative complications. There was no significant difference in incidence or severity of complications between patients undergoing pancreatic surgery with (70%) or without (60%, P = 0.7) jejunal IR. Following colorectal surgery, 60% of the patients experienced one or more postoperative complication. Complication rate and severity were similar in patients with (50%) and without (65%, P = 0.46) colonic IR. Operative time, amount of blood loss, postoperative C-reactive protein, length of hospital stay or mortality were equal in both intervention and control groups for jejunal and colon IR. Conclusion This study showed that human experimental intestinal IR models are safe in patients undergoing pancreatic or colorectal surgery.
To evaluate the value of biomarkers to detect severe NEC.
The time point of surgery in necrotizing enterocolitis (NEC) is critical. Therefore, there is a need for markers that detect severe NEC, ...because clinical signs of severe NEC often develop late. This study evaluated the value of biomarkers reflecting intestinal cell damage and inflammation to detect severe NEC.
29 neonates with NEC were included. Two definitions of moderate versus severe NEC were analyzed: medical NEC (n = 12) versus surgical or fatal NEC (n = 17); and Bell stage II NEC (n = 13) versus stage III NEC (n = 16). Urinary intestinal fatty acid binding protein (I-FABP), serum amyloid A (SAA), C3a and C5a, and fecal calprotectin were measured. C-reactive protein (CRP), white blood cell count (WBC) and platelet count data were measured in blood.
In both definitions of moderate versus severe NEC, urinary SAA levels were significantly higher in severe NEC. A cut-off value of 34.4 ng/ml was found in surgical NEC versus medical NEC (sensitivity, 83%; specificity, 83%; LR+, 4.88 (95% CI, 1.37-17.0); LR-, 0.20 (95% CI, 0.07-0.60)) at diagnosis of NEC and at one day prior to surgery in neonates who were operated later on. Combination of urinary SAA and platelet count increased the accuracy, with a sensitivity, 94%; specificity, 83%; LR+, 5.53 (95% CI, 1.57-20.0); and LR-, 0.07 (95% CI, 0.01-0.48).
Urinary SAA is an accurate marker in differentiating severe NEC from moderate NEC; particularly if combined with serum platelet count.
Chorioamnionitis is the most significant source of prenatal inflammation and preterm delivery. Prematurity and prenatal inflammation are associated with compromised postnatal developmental outcomes, ...of the intestinal immune defence, gut barrier function and the vascular system. We developed a sheep model to study how the antenatal development of the gut was affected by gestation and/or by endotoxin induced chorioamnionitis.Chorioamnionitis was induced at different gestational ages (GA). Animals were sacrificed at low GA after 2d or 14d exposure to chorioamnionitis. Long term effects of 30d exposure to chorioamnionitis were studied in near term animals after induction of chorioamnionitis. The cellular distribution of tight junction protein ZO-1 was shown to be underdeveloped at low GA whereas endotoxin induced chorioamnionitis prevented the maturation of tight junctions during later gestation. Endotoxin induced chorioamnionitis did not induce an early (2d) inflammatory response in the gut in preterm animals. However, 14d after endotoxin administration preterm animals had increased numbers of T-lymphocytes, myeloperoxidase-positive cells and gammadelta T-cells which lasted till 30d after induction of chorioamnionitis in then near term animals. At early GA, low intestinal TLR-4 and MD-2 mRNA levels were detected which were further down regulated during endotoxin-induced chorioamnionitis. Predisposition to organ injury by ischemia was assessed by the vascular function of third-generation mesenteric arteries. Endotoxin-exposed animals of low GA had increased contractile response to the thromboxane A2 mimetic U46619 and reduced endothelium-dependent relaxation in responses to acetylcholine. The administration of a nitric oxide (NO) donor completely restored endothelial dysfunction suggesting reduced NO bioavailability which was not due to low expression of endothelial nitric oxide synthase.Our results indicate that the distribution of the tight junctional protein ZO-1, the immune defence and vascular function are immature at low GA and are further compromised by endotoxin-induced chorioamnionitis. This study suggests that both prematurity and inflammation in utero disturb fetal gut development, potentially predisposing to postnatal intestinal pathology.
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