The route and timing of hydrogen sulfide therapy critically impacts intestinal recovery following ischemia and reperfusion injury

PURPOSE: Hydrogen sulfide (H2S) has many beneficial properties and may serve as a novel treatment in patients suffering from intestinal ischemia-reperfusion injury (I/R). The purpose of this study was to examine the method of delivery and timing of administration of H2S for intestinal therapy during ischemic injury. We hypothesized that 1) route of administration of hydrogen sulfide would impact intestinal recovery following acute mesenteric ischemia and 2) preischemic H2S conditioning using the optimal mode of administration as determined above would provide superior protection compared to postischemic application. METHODS: Male C57BL/6J mice underwent intestinal ischemia by temporary occlusion of the superior mesenteric artery. Following ischemia, animals were treated according to one of the following (N=6 per group): intraperitoneal or intravenous injection of GYY4137 (H2S-releasing donor, 50mg/kg in PBS), vehicle, inhalation of oxygen only, inhalation of 80ppm hydrogen sulfide gas. Following 24-h recovery, perfusion was assessed via laser Doppler imaging, and animals were euthanized. Perfusion and histology data were assessed, and terminal ileum samples were analyzed for cytokine production following ischemia. Once the optimal route of administration was determined, preischemic conditioning with H2S was undertaken using that route of administration. All data were analyzed using Mann-Whitney. P-values <0.05 were significant. RESULTS: Mesenteric perfusion following intestinal I/R was superior in mice treated with intraperitoneal (IP) GYY4137 (IP vehicle: 25.6±6.0 vs. IP GYY4137: 79.7±15.1; p=0.02) or intravenous (IV) GYY4137 (IV vehicle: 36.3±5.9 vs. IV GYY4137: 100.7±34.0; p=0.03). This benefit was not observed with inhaled H2S gas (O2 vehicle: 66.6±11.4 vs. H2S gas: 81.8±6.0; p=0.31). However, histological architecture was only preserved with intraperitoneal administration of GYY4127 (IP vehicle: 3.4±0.4 vs. IP GYY4137: 2±0.3; p=0.02). Additionally, IP GYY4137 allowed for significant attenuation of inflammatory chemokine production of IL-6, IP-10 and MIP-2. We then analyzed whether there was a difference between pre- and postischemic administration of IP GYY4137. We found that preconditioning of animals with intraperitoneal GYY4137 only added minor improvements in outcomes compared to postischemic application. CONCLUSION: Therapeutic benefits of H2S are superior with intraperitoneal application of an H2S donor compared to other administration routes. Additionally, while intraperitoneal treatment in both the pre- and postischemic period is beneficial, preischemic application of an H2S donor was found to be slightly better. Further studies are needed to examine long term outcomes and further mechanisms of action prior to widespread clinical application. TYPE OF STUDY: Basic science. LEVEL OF EVIDENCE: N/A

Loss of Endothelial Nitric Oxide Synthase Exacerbates Intestinal and Lung Injury in Experimental Necrotizing Enterocolitis

Background Necrotizing enterocolitis (NEC) continues to be a devastating condition among preterm infants. Nitric oxide, which is synthesized in the intestine by endothelial nitric oxide synthase (eNOS), acts as a potent vasodilator and antioxidant within the mesentery and may play a role in prevention of NEC. We hypothesized that loss of endothelial nitric oxide would worsen both intestinal and associated lung injury and increase local and systemic inflammation during experimental NEC. Methods NEC was induced in five-day-old wild type (WT) and eNOS-knockout (eNOSKO) mouse pups. Experimental groups (n = 10) were formula fed and subjected to intermittent hypoxic and hypothermic stress, while control groups (n = 10) remained with their mother to breastfeed. Pups were monitored by daily clinical assessment. After sacrifice on day nine, intestine and lung were assessed for injury, and cytokines were measured in tissue homogenates by ELISA. Data were compared with Mann–Whitney, and p < 0.05 was significant. Results Each NEC group was compared to its respective strain’s breastfed control to facilitate comparisons between the groups. Both NEC groups were significantly sicker than their breastfed controls. eNOSKO NEC animals had a median clinical assessment score of 3 (IQR = 1–5), and the WT NEC animal’s median score was 3 (IQR = 2–5). Despite similar clinical scores, intestinal injury was significantly worse in the eNOSKO NEC groups compared to WT NEC groups (median injury scores of 3.25 (IQR = 2.25–3.625) and 2 (IQR = 1–3), respectively (p = 0.0474). Associated lung injury was significantly worse in the eNOSKO NEC group as compared to the WT NEC group (median scores of 8.5 (IQR = 6.75–11.25) and 6.5 (IQR = 5–7.5), respectively, p = 0.0391). Interestingly, cytokines in both tissues were very different between the two groups, with varying effects noted for each cytokine (IL-6, IL-1β, VEGF, and IL-12) in both tissues. Conclusion Nitric oxide from eNOS plays a key role in preventing the development of NEC. Without eNOS function, both intestinal and lung injuries are more severe, and the inflammatory cascade is significantly altered. Further studies are needed to determine how eNOS-derived nitric oxide facilitates these beneficial effects

Interleukin-6 Therapy Improves Intestinal Recovery Following Ischemia

Background: Interleukin-6 (IL6) has both proinflammatory and anti-inflammatory pathways, but its effects on intestinal recovery following ischemia are unknown. We hypothesized that administration of IL6 following intestinal ischemia would improve mesenteric perfusion and mucosal injury. Methods: Adult male C57Bl6J mice were anesthetized, and a laparotomy was performed. Baseline intestinal perfusion was assessed by laser Doppler imaging. Intestinal ischemia was induced for 60 min by temporarily occluding the superior mesenteric artery. After ischemia, treatments were administered intraperitoneally before closure (Vehicle: 250 μL phosphate-buffered-saline, IL6 low dose (20 ng), IL6 medium dose (200 ng), or IL6 high dose (2 μg)). Animals were allowed to recover for 24 h, were reanesthetized, and their mesenteric perfusion was reassessed. Perfusion was expressed as percentage of baseline. Animals were then sacrificed, and the intestines were explanted for histological analysis. Separate frozen samples were homogenized and analyzed by ELISA for vascular endothelial growth factor (VEGF) and interferon gamma-induced protein 10. Results: IL6 increased mesenteric perfusion in low dose groups only, whereas it improved postischemic mucosal injury scores in both low and medium dose groups. No differences in perfusion or histology were seen when high dose IL6 was utilized. Intestinal VEGF was higher in the low dose IL6 group compared to vehicle, whereas IP-10 levels were lower in low and medium dose groups compared to vehicle. No differences were noted compared to vehicle in intestinal VEGF and IP-10 with high dose IL6 therapy

Aggravated bone density decline following symptomatic osteonecrosis in children with acute lymphoblastic leukemia

Osteonecrosis and decline of bone density are serious side effects during and after treatment of childhood acute lymphoblastic leukemia. It is unknown whether osteonecrosis and low bone density occur together in the same patients, or whether these two osteogenic side-effects can mutually influence each other's development. Bone density and the incidence of symptomatic osteonecrosis were prospectively assessed in a national cohort of 466 patients with acute lymphoblastic leukemia (4-18 years of age) who were treated according to the dexamethasone-based Dutch Child Oncology Group-ALL9 protocol. Bone mineral density of the lumbar spine (BMDLS) (n= 466) and of the total body (BMDTB) (n=106) was measured by dual X-ray absorptiometry. Bone density was expressed as age-and gender-matched standard deviation scores. Thirty patients (6.4%) suffered from symptomatic osteonecrosis. At baseline, BMDLS and BMDTB did not differ between patients who did or did not develop osteonecrosis. At cessation of treatment, patients with osteonecrosis had lower mean BMDLS and BMDTB than patients without osteonecrosis (respectively, with osteonecrosis: -2.16 versus without osteonecrosis: -1.21, P</p

Inhibiting hydrogen sulfide production in umbilical stem cells reduces their protective effects during experimental necrotizing enterocolitis

Introduction Umbilical mesenchymal stem cells (USC) have been shown to reduce illness in animal models of necrotizing enterocolitis (NEC), possibly through the paracrine release of hydrogen sulfide (H2S). We hypothesized that animals treated with USCs with inhibited H2S synthesis would exhibit more severe disease. Methods NEC was induced in five-day-old mouse pups by formula feeding and hypoxic and hypothermic stress. Experimental groups received intraperitoneal injection of either saline vehicle or 80,000cells/gram of one of the following cell types: USC, USCs with negative-control siRNA, or USCs with targeted siRNA inhibition of the H2S-producing enzymes. Pups were monitored by clinical assessment and after euthanasia, intestine and lung histologic injury were scored. Tissue was homogenized, and concentrations of IL-6, IL-10, and VEGF were determined by ELISA. For statistical analysis, p < 0.05 was considered significant. Results Animals treated with negative-control siRNA USCs were significantly improved compared to vehicle. Clinical sickness scores as well as intestinal and lung histologic injury scores in the targeted siRNA groups were significantly worse when compared to the negative-control siRNA group. IL-6, IL-10, and VEGF had varying patterns of expression in the different groups. Conclusion Inhibition of H2S production in USCs reduces the beneficial effects of these cells during therapy in experimental NEC

The validity of the DSM-IV diagnostic classification system of non-affective psychoses

Objective: The schizophrenia and other non-affective disorders categories listed in the DSM-IV, are currently under revision for the development of the fifth edition. The aim of the present study is to demonstrate the validity of these categories by investigating possible differences between diagnostic patient subgroups on various measures. Methods: 1064 patients with a diagnosis of non-affective psychosis (schizophrenia N = 731 (paranoid type 82%), schizoaffective N = 63, schizophreniform N = 120, psychosis not otherwise specified/brief psychotic disorder N = 150) participated in this study. Dependent variables were demographic and clinical characteristics, severity of psychopathology, premorbid and current functioning, and indicators of quality of life. Results: Within the diagnostic group of schizophrenia, no significant differences were observed between paranoid schizophrenia, disorganized, and undifferentiated schizophrenia. Patients with schizophrenia experienced more severe psychopathology and had poorer levels of current functioning compared to patients with psychosis not otherwise specified or brief psychotic disorder. Differences between schizophrenia and schizoaffective disorder were less clear. Conclusion: Our results do not support the validity of schizophrenia subtypes. Schizophrenia can be distinguished from brief psychotic disorder and psychotic disorder not otherwise specified. These findings may fuel the actual DSM-V discussion

Association of Hospital Volume with Perioperative Mortality of Endovascular Repair of Complex Aortic Aneurysms: A Nationwide Cohort Study

Objective: We evaluate nationwide perioperative outcomes of complex EVAR and assess the volume-outcome association of complex EVAR. Summary of Background Data: Endovascular treatment with fenestrated (FEVAR) or branched (BEVAR) endografts is progressively used for excluding complex aortic aneurysms (complex AAs). It is unclear if a volumeoutcome association exists in endovascular treatment of complex AAs (complex EVAR). Methods: All patients prospectively registered in the Dutch Surgical Aneurysm Audit who underwent complex EVAR (FEVAR or BEVAR) between January 2016 and January 2020 were included. The effect of annual hospital volume on perioperative mortality was examined using multivariable logistic regression analyses. Patients were stratified into quartiles based on annual hospital volume to determine hospital volume categories. Results: We included 694 patients (539 FEVAR patients, 155 BEVAR patients). Perioperative mortality following FEVAR was 4.5% and 5.2% following BEVAR. Postoperative complication rates were 30.1% and 48.7%, respectively. The first quartile hospitals performed <9 procedures/ yr; second, third, and fourth quartile hospitals performed 9-12, 13-22, and 23 procedures/yr. The highest volume hospitals treated significantly more complex patients. Perioperative mortality of complex EVAR was 9.1% in hospitals with a volume of <9, and 2.5% in hospitals with a volume of 13 (P = 0.008). After adjustment for confounders, an annual volume of 13 was associated with less perioperative mortality compared to hospitals with a volume of <9. Conclusions: Data from this nationwide mandatory quality registry shows a significant effect of hospital volume on perioperative mortality following complex EVAR, with high volume complex EVAR centers demonstrating lower mortality rates