Paneth Cell Alterations During Ischemia-reperfusion, Follow-up, and Graft Rejection After Intestinal Transplantation

BACKGROUND Ischemia-reperfusion (IR) injury is inevitable during intestinal transplantation (ITx) and executes a key role in the evolution towards rejection. Paneth cells (PC) are crucial for epithelial immune defense and highly vulnerable to IR injury. We investigated the effect of ITx on PC after reperfusion (T0), during follow-up, and rejection. Moreover, we investigated whether PC loss was associated with impaired graft homeostasis. METHODS Endoscopic biopsies, collected according to center-protocol and at rejection episodes, were retrospectively included (n=28 ITx, n=119 biopsies) Biopsies were immunohistochemically co-stained for PC (lysozyme) and apoptosis, and PC/crypt and lysozyme intensity were scored. RESULTS We observed a decrease in PC/crypt and lysozyme intensity in the first week after ITx (W1) compared to T0. There was a tendency towards a larger decline in PC/crypt (p=0.08) and lysozyme intensity (p=0.08) in W1 in patients who later developed rejection compared to patients without rejection. Follow-up biopsies showed that the PC number recovered, whereas lysozyme intensity remained reduced. This persisting innate immune defect may contribute to the well-known vulnerability of the intestine to infection. There was no clear evidence that PC were affected throughout rejection. CONCLUSION This study revealed a transient fall in PC numbers in the early post-ITx period, but a permanent reduction in lysozyme intensity following ITx. Further research is needed to determine the potential clinical impact of PC impairment after ITx

Females Are More Resistant to Ischemia-Reperfusion-induced Intestinal Injury Than Males A Human Study

BACKGROUND AND OBJECTIVE: Sex differences in responses to intestinal ischemia-reperfusion (IR) have been recognized in animal studies. We aimed to investigate sexual dimorphism in human small intestinal mucosal responses to IR. METHODS: In 16 patients (8 men and 8 women) undergoing pancreaticoduodenectomy, an isolated part of jejunum was subjected to IR. In each patient, intestinal tissue and blood was collected directly after 45 minutes of ischemia without reperfusion (45I-0R), after 30 minutes of reperfusion (45I-30R), and after 120 minutes of reperfusion (45I-120R), as well as a control sample not exposed to IR, to assess epithelial damage, unfolded protein response (UPR) activation, and inflammation. RESULTS: More extensive intestinal epithelial damage was observed in males compared to females. Intestinal fatty acid binding protein (I-FABP) arteriovenous (V-A) concentrations differences were significantly higher in males compared to females at 45I-0R (159.0 [41.0-570.5] ng/mL vs 46.9 [0.3-149.9] ng/mL). Male intestine showed significantly higher levels of UPR activation than female intestine, as well as higher number of apoptotic Paneth cells per crypt at 45I-30R (16.4% [7.1-32.1] vs 10.6% [0.0-25.4]). The inflammatory response in male intestine was significantly higher compared to females, with a higher influx of neutrophils per villus at 45I-30R (4.9 [3.1-12.0] vs 3.3 [0.2-4.5]) and a higher gene expression of TNF-α and IL-10 at 45I-120R. CONCLUSION: The human female small intestine seems less susceptible to IR-induced tissue injury than the male small intestine. Recognition of such differences could lead to the development of novel therapeutic strategies to reduce IR-associated morbidity and mortality

Females Are More Resistant to Ischemia-Reperfusion-induced Intestinal Injury Than Males: A Human Study

BACKGROUND AND OBJECTIVE: Sex differences in responses to intestinal ischemia-reperfusion (IR) have been recognized in animal studies. We aimed to investigate sexual dimorphism in human small intestinal mucosal responses to IR. METHODS: In 16 patients (8 men and 8 women) undergoing pancreaticoduodenectomy, an isolated part of jejunum was subjected to IR. In each patient, intestinal tissue and blood was collected directly after 45 minutes of ischemia without reperfusion (45I-0R), after 30 minutes of reperfusion (45I-30R), and after 120 minutes of reperfusion (45I-120R), as well as a control sample not exposed to IR, to assess epithelial damage, unfolded protein response (UPR) activation, and inflammation. RESULTS: More extensive intestinal epithelial damage was observed in males compared to females. Intestinal fatty acid binding protein (I-FABP) arteriovenous (V-A) concentrations differences were significantly higher in males compared to females at 45I-0R (159.0 [41.0-570.5] ng/mL vs 46.9 [0.3-149.9] ng/mL). Male intestine showed significantly higher levels of UPR activation than female intestine, as well as higher number of apoptotic Paneth cells per crypt at 45I-30R (16.4% [7.1-32.1] vs 10.6% [0.0-25.4]). The inflammatory response in male intestine was significantly higher compared to females, with a higher influx of neutrophils per villus at 45I-30R (4.9 [3.1-12.0] vs 3.3 [0.2-4.5]) and a higher gene expression of TNF-α and IL-10 at 45I-120R. CONCLUSION: The human female small intestine seems less susceptible to IR-induced tissue injury than the male small intestine. Recognition of such differences could lead to the development of novel therapeutic strategies to reduce IR-associated morbidity and mortality

Human small intestine is capable of restoring barrier function after short ischemic periods

AIM: To assess intestinal barrier function during human intestinal ischemia and reperfusion (IR). METHODS: In a human experimental model, 6 cm of jejunum was selectively exposed to 30 min of ischemia (I) followed by 30 and 120 min of reperfusion (R). A sham procedure was also performed. Blood and tissue was sampled at all-time points. Functional barrier function was assessed using dual-sugar absorption tests with lactulose (L) and rhamnose (R). Plasma concentrations of citrulline, an amino acid described as marker for enterocyte function were measured as marker of metabolic enterocytes restoration. Damage to the epithelial lining was assessed by immunohistochemistry for tight junctions (TJs), by plasma marker for enterocytes damage (I-FABP) and analyzed by electron microscopy (EM) using lanthanum nitrate as an electrondense marker. RESULTS: Plasma L/R ratio's were significantly increased after 30 min of ischemia (30I) followed by 30 min of reperfusion (30R) compared to control (0.75 ± 0.10vs0.20 ± 0.09,P< 0.05). At 120 min of reperfusion (120R), ratio's normalized (0.17 ± 0.06) and were not significantly different from control. Plasma levels of I-FABP correlated with plasma L/R ratios measured at the same time points (correlation: 0.467,P< 0.01). TJs staining shows distortion of staining at 30I. An intact lining of TJs was again observed at 30I120R. Electron microscopy analysis revealed disrupted TJs after 30I with paracellular leakage of lanthanum nitrate, which restored after 30I120R. Furthermore, citrulline concentrations closely paralleled the histological perturbations during intestinal IR. CONCLUSION: This study directly correlates histological data with intestinal permeability tests, revealing that the human gut has the ability of to withstand short episodes of ischemia, with morphological and functional recovery of the intestinal barrier within 120 min of reperfusion

Evaluating the safety of two human experimental intestinal ischemia reperfusion models:A retrospective observational study

BackgroundWe 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.MethodsA 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.ResultsFollowing 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.ConclusionThis study showed that human experimental intestinal IR models are safe in patients undergoing pancreatic or colorectal surgery