Hydrogen sulfide (H
S) has been shown to improve outcomes in a murine model of necrotizing enterocolitis (NEC). There is evidence in humans that H
S relies on endothelial nitric oxide synthase (eNOS) ...to exert its protective effects, potentially through the persulfidation of eNOS at the Cysteine 443 residue. We obtained a novel mouse strain with a mutation at this residue (eNOS
) and hypothesized that this locus would be critical for GYY4137 (an H
S donor) to exert its protective effects.
Necrotizing enterocolitis was induced in 5-day old wild type (WT) and eNOS
mice using intermittent exposure to hypoxia and hypothermia in addition to gavage formula feeds. On postnatal day 9, mice were humanely euthanized. Data collected included daily weights, clinical sickness scores, histologic lung injury, intestinal injury (macroscopically and histologically), and intestinal perfusion. During the NEC model, pups received daily intraperitoneal injections of either GYY4137 (50 mg/kg) or PBS (vehicle). Data were tested for normality and compared using t-test or Mann-Whitney, and a p-value <0.05 was considered significant.
In WT mice, the administration of GYY4137 significantly improved clinical sickness scores, attenuated intestinal and lung injury, and improved mesenteric perfusion compared to vehicle (p < 0.05). In eNOS
mice, the treatment and vehicle groups had similar clinical sickness scores, intestinal and lung injury scores, and intestinal perfusion.
GYY4137 administration improves clinical outcomes, attenuates intestinal and lung injury, and improves perfusion in a murine model of necrotizing enterocolitis. The beneficial effects of GYY4137 are dependent on the Cys440 residue of eNOS.
Introduction
Pediatric patients with acute life‐threatening consequences of interstitial and diffuse lung disease are often treated with empiric systemic corticosteroids, immune modulators, and/or ...broad antibiotic therapy. Histological evaluation of lung tissue represents the final necessary step in diagnosis—however, a definitive diagnosis may still remain elusive and medical therapies may not be changed following biopsy. We hypothesized that lung biopsy from pediatric patients with children's interstitial and diffuse lung disease (chILD) without a defined lesion on computed tomography (CT) imaging would guide diagnosis, but not substantially alter clinical management.
Methods
After IRB approval, patients who underwent a lung biopsy at a single large children's hospital between 2013 and 2018 were retrospectively reviewed. Patients without a defined lesion were included. Demographics, length of stay, oxygen‐requirements, steroid, unique number of immune modulators, and antibiotics prebiopsy and postbiopsy were reviewed. Nonparametric data were compared by the Mann Whitney U and Kruskal Wallace tests and expressed as median with interquartile range. Decision tree alterations were analyzed by t test. P < .05 was significant.
Results
Sixty‐four patients underwent lung biopsy during the period. Nineteen (30%) did not have a defined lesion on CT scan, and were included. A significant difference was seen between prebiopsy, 2 weeks, and 2 months postbiopsy prednisone dosing (P = .03), while the number of unique immune modulators, antibiotics, type of oxygen support and FiO2 were not significantly different before or after obtaining biopsy results. Pathology results provided additional information in 12 of 19 (63%) patients which resulted in management changes.
Conclusions
Lung biopsy in chILD may guide clinical management, especially influencing the management of steroid dosing. Although on aggregate the number of antibiotics, immune modulators, mode of oxygen support and FiO2 did not differ significantly before and after biopsy, the pathologic evaluation provided diagnostic information that led to a variety of changes in therapeutic management in greater than half of the population.
Manganese porphyrins (MnPs), MnTE-2-PyP
, MnTnHex-2-PyP
and MnTnBuOE-2-PyP
, are superoxide dismutase (SOD) mimetics and form a redox cycle between O
and reductants, including ascorbic acid, ...ultimately producing hydrogen peroxide (H
O
). We previously found that MnPs oxidize hydrogen sulfide (H
S) to polysulfides (PS; H
S
, n = 2-6) in buffer. Here, we examine the effects of MnPs for 24 h on H
S metabolism and PS production in HEK293, A549, HT29 and bone marrow derived stem cells (BMDSC) using H
S (AzMC, MeRho-AZ) and PS (SSP4) fluorophores. All MnPs decreased intracellular H
S production and increased intracellular PS. H
S metabolism and PS production were unaffected by cellular O
(5% versus 21% O
), H
O
or ascorbic acid. We observed with confocal microscopy that mitochondria are a major site of H
S production in HEK293 cells and that MnPs decrease mitochondrial H
S production and increase PS in what appeared to be nucleoli and cytosolic fibrillary elements. This supports a role for MnPs in the metabolism of H
S to PS, the latter serving as both short- and long-term antioxidants, and suggests that some of the biological effects of MnPs may be attributable to sulfur metabolism.
Stem cell research and the use of stem cells in therapy have seen tremendous growth in the last two decades. Neonatal intestinal disorders such as necrotizing enterocolitis, Hirschsprung disease, and ...gastroschisis have high morbidity and mortality and limited treatment options with varying success rates. Stem cells have been used in several pre-clinical studies to address various neonatal disorders with promising results. Stem cell and patient population selection, timing of therapy, as well as safety and quality control are some of the challenges that must be addressed prior to the widespread clinical application of stem cells. Further research and technological advances such as the use of cell delivery technology can address these challenges and allow for continued progress towards clinical translation.
Angiotensin‐converting enzyme 2 (ACE2) is the primary enzyme of the vasoprotective axis of the renin angiotensin system (RAS). We tested the hypothesis that loss of ACE2 would exacerbate diabetic ...retinopathy by promoting bone marrow dysfunction. ACE2–/y were crossed with Akita mice, a model of type 1 diabetes. When comparing the bone marrow of the ACE2–/y‐Akita mice to that of Akita mice, we observed a reduction of both short‐term and long‐term repopulating hematopoietic stem cells, a shift of hematopoiesis toward myelopoiesis, and an impairment of lineage–c‐kit+ hematopoietic stem/progenitor cell (HS/PC) migration and proliferation. Migratory and proliferative dysfunction of these cells was corrected by exposure to angiotensin‐1‐7 (Ang‐1‐7), the protective peptide generated by ACE2. Over the duration of diabetes examined, ACE2 deficiency led to progressive reduction in electrical responses assessed by electroretinography and to increases in neural infarcts observed by fundus photography. Compared with Akita mice, ACE2–/y‐Akita at 9‐months of diabetes showed an increased number of acellular capillaries indicative of more severe diabetic retinopathy. In diabetic and control human subjects, CD34+ cells, a key bone marrow HS/PC population, were assessed for changes in mRNA levels for MAS, the receptor for Ang‐1‐7. Levels were highest in CD34+ cells from diabetics without retinopathy. Higher serum Ang‐1‐7 levels predicted protection from development of retinopathy in diabetics. Treatment with Ang‐1‐7 or alamandine restored the impaired migration function of CD34+ cells from subjects with retinopathy. These data support that activation of the protective RAS within HS/PCs may represents a therapeutic strategy for prevention of diabetic retinopathy. Stem Cells 2018;36:1430–1440
Hematopoietic stem/progenitor cells (HS/PC) are important for vascular repair. This study showed that ACE2 deficiency exacerbates diabetes‐induced dysfunction of HS/PCs in bone marrow and promotes the development of diabetic retinopathy in both murine model and in humans. Two downstream peptides of ACE2, Ang‐(1‐7) and alamandine, improve diabetic HS/PC functions and may serve as novel therapeutic targets for prevention of diabetic retinopathy.
Departments of 1 Surgery, 2 Pulmonary and Critical Care Medicine, and 3 Cellular and Integrative Physiology and the 4 Center for Immunobiology, Indiana University School of Medicine, Indianapolis, ...Indiana
Submitted 27 May 2008
; accepted in final form 29 September 2008
Bone marrow mesenchymal stem cells (MSCs) may be a novel treatment modality for organ ischemia, possibly through the release of beneficial paracrine factors. However, an age threshold likely exists as to when MSCs gain their beneficial protective properties. We hypothesized that 1 ) VEGF would be a crucial stem cell paracrine mediator in providing postischemic myocardial protection and 2 ) small-interfering (si)RNA ablation of VEGF in adult MSCs (aMSCs) would equalize the differences observed between aMSC- and neonatal stem cell (nMSC)-mediated cardioprotection. Female adult Sprague-Dawley rat hearts were subjected to ischemia-reperfusion injury via Langendorff-isolated heart preparation (15 min equilibration, 25 min ischemia, and 60 min reperfusion). MSCs were harvested from adult and 2.5-wk-old neonatal mice and cultured under normal conditions. VEGF was knocked down in both cell lines by VEGF siRNA. Immediately before ischemia, one million aMSCs or nMSCs with or without VEGF knockdown were infused into the coronary circulation. The cardiac functional parameters were recorded. VEGF in cell supernatants was measured via ELISA. aMSCs produced significantly more VEGF than nMSCs and were noted to increase postischemic myocardial recovery compared with nMSCs. The knockdown of VEGF significantly decreased VEGF production in both cell lines, and the pretreatment of these cells impaired stem cell-mediated myocardial function. The knockdown of VEGF in adult stem cells equalized the myocardial functional differences observed between adult and neonatal stem cells. Therefore, VEGF is a critical paracrine mediator in facilitating postischemic myocardial recovery and likely plays a role in mediating the observed age threshold during stem cell therapy.
ischemia-reperfusion
Address for reprint requests and other correspondence: D. R. Meldrum, 635 Barnhill Dr., Van Nuys Medical Science Bldg., Rm. 2017, Indianapolis, IN 46202 (e-mail: dmeldrum{at}iupui.edu )
Determine short-term outcomes following peritoneal drain (PD), laparotomy (LAP) after PD (PD-LAP), and LAP in extremely low birth weight (ELBW) infants with spontaneous intestinal perforation ...(SIP).OBJECTIVEDetermine short-term outcomes following peritoneal drain (PD), laparotomy (LAP) after PD (PD-LAP), and LAP in extremely low birth weight (ELBW) infants with spontaneous intestinal perforation (SIP).ELBW infants with SIP were identified using the Children's Hospitals Neonatal Database. Mortality and length of stay (LOS) were compared among groups.STUDY DESIGNELBW infants with SIP were identified using the Children's Hospitals Neonatal Database. Mortality and length of stay (LOS) were compared among groups.Of 729 SIP infants from 6/2010-12/2016, 383(53%) received PD, 61(8%) PD-LAP, and 285(39%) LAP. PD infants had lower GA at birth, at SIP diagnosis and upon admission than PD-LAP or LAP; and higher sepsis rates than LAP. Bivariate analysis and Kaplan-Meier survival estimates suggested PD had increased mortality vs. PD-LAP and LAP (27%, 11.5%, and 15.8% respectively, p < 0.001). However, surgical approach was not significantly associated with mortality in multivariable analysis accounting for GA and illness severity. LOS did not differ by surgical approach.RESULTSOf 729 SIP infants from 6/2010-12/2016, 383(53%) received PD, 61(8%) PD-LAP, and 285(39%) LAP. PD infants had lower GA at birth, at SIP diagnosis and upon admission than PD-LAP or LAP; and higher sepsis rates than LAP. Bivariate analysis and Kaplan-Meier survival estimates suggested PD had increased mortality vs. PD-LAP and LAP (27%, 11.5%, and 15.8% respectively, p < 0.001). However, surgical approach was not significantly associated with mortality in multivariable analysis accounting for GA and illness severity. LOS did not differ by surgical approach.In ELBW infants with SIP, mortality, and LOS are independent of the initial surgical approach.CONCLUSIONSIn ELBW infants with SIP, mortality, and LOS are independent of the initial surgical approach.
IMPORTANCE: The indications, safety, and efficacy of chemical venous thromboembolism prophylaxis (cVTE) in pediatric trauma patients remain unclear. A set of high-risk criteria to guide cVTE use was ...recently recommended; however, these criteria have not been evaluated prospectively. OBJECTIVE: To examine high-risk criteria and cVTE use in a prospective multi-institutional study of pediatric trauma patients. DESIGN, SETTING, AND PARTICIPANTS: This cohort study was completed between October 2019 and October 2022 in 8 free-standing pediatric hospitals designated as American College of Surgeons level I pediatric trauma centers. Participants were pediatric trauma patients younger than 18 years who met defined high-risk criteria on admission. It was hypothesized that cVTE would be safe and reduce the incidence of VTE. EXPOSURES: Receipt and timing of chemical VTE prophylaxis. MAIN OUTCOMES AND MEASURES: The primary outcome was overall VTE rate stratified by receipt and timing of cVTE. The secondary outcome was safety of cVTE as measured by bleeding or other complications from anticoagulation. RESULTS: Among 460 high-risk pediatric trauma patients, the median (IQR) age was 14.5 years (10.4-16.2 years); 313 patients (68%) were male and 147 female (32%). The median (IQR) Injury Severity Score (ISS) was 23 (16-30), and median (IQR) number of high-risk factors was 3 (2-4). A total of 251 (54.5%) patients received cVTE; 62 (13.5%) received cVTE within 24 hours of admission. Patients who received cVTE after 24 hours had more high-risk factors and higher ISS. The most common reason for delayed cVTE was central nervous system bleed (120 patients; 30.2%). There were 28 VTE events among 25 patients (5.4%). VTE occurred in 1 of 62 patients (1.6%) receiving cVTE within 24 hours, 13 of 189 patients (6.9%) receiving cVTE after 24 hours, and 11 of 209 (5.3%) who had no cVTE (P = .31). Increasing time between admission and cVTE initiation was significantly associated with VTE (odds ratio, 1.01; 95% CI, 1.00-1.01; P = .01). No bleeding complications were observed while patients received cVTE. CONCLUSIONS AND RELEVANCE: In this prospective study, use of cVTE based on a set of high-risk criteria was safe and did not lead to bleeding complications. Delay to initiation of cVTE was significantly associated with development of VTE. Quality improvement in pediatric VTE prevention may center on timing of prophylaxis and barriers to implementation.
Surgery residents complete their research training early in residency. Non-surgical trainees typically have research incorporated toward the last two years of their fellowship, conferring an ...advantage to apply for grants with recent research experience and preliminary data.
The NIH RePORTER database was queried for K08 awardees trained in medicine, pediatrics, and surgery from 2013 to 2017. 406 K08 recipients were identified and time from completion of clinical training to achieving a K08 award was measured. Data were compared using ANOVA and expressed as mean. P < 0.05 was considered significant.
Surgeons took longer to obtain a K08 than those trained in internal medicine (surgery = 3.7 years, internal medicine = 2.58 years p < 0.0001)). All K08 recipients without a PhD took longer to obtain a K08 than recipients with a PhD (MD = 3.50 years and MD/PhD = 2.42 years (p=<0.0001).
Surgeons take longer to achieve a K08 award than clinicians trained in internal medicine, possibly due to an inherent disadvantage in training structure.
•Fewer surgeons are performing research and obtaining funding.•Surgeons take longer to obtain a K08 award than internal medicine physicians.•Surgeons receive larger first-year funding than both internal medicine and pediatrics.•K08 recipients in surgery held a higher academic rank than non-surgeons.•Obtaining a PhD reduces the amount of time it takes to obtain a K08 award.
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.
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.
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.
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.
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