Sundeep G. Keswani

Enhanced epithelial gap closure and increased angiogenesis in wounds of diabetic mice treated with adult murine bone marrow stromal progenitor cells.

The direct application of bone marrow (BM) can accelerate the healing of chronic wounds. We hypothesized that this effect is due to the presence of stromal progenitor cells (SPCs) found within whole BM preparations. To test this hypothesis, we isolated adult murine SPCs from whole BM and examined their ability to enhance impaired wound healing compared with ficoll separated BM cells in the diabetic (db/db) mouse model. SPCs significantly enhanced reepithelialization, granulation tissue formation, and neovascularization compared with control wounds treated with BM or PBS alone. Higher frequencies of donor SPC cells compared with donor BM cells were observed in treated wounds at 7 days. Transdifferentiation into GFP‐positive mature endothelial cells was not observed. These observations suggest that SPCs improve wound healing through indirect mechanisms which lead to enhanced vascularization rather than through direct participation and incorporation into tissue. We conclude that topical application of BM‐derived SPCs may represent an effective strategy for the treatment of chronic diabetic wounds.

Permissive environment in postnatal wounds induced by adenoviral-mediated overexpression of the anti-inflammatory cytokine interleukin-10 prevents scar formation

Wound healing in the mid‐gestation fetus is scarless with minimal inflammation and a unique extracellular matrix. We have previously documented the relative lack of inflammatory cytokines in this environment. We demonstrate that interleukin (IL)‐10 is highly expressed in mid‐gestation human fetal skin but is absent in postnatal human skin. We hypothesize that overexpression of IL‐10 in postnatal skin may replicate a permissive environment for scarless healing. To study the mechanism underlying this process we performed immunohistochemistry for IL‐10 in human mid‐gestation fetal and postnatal skin. We also determined if adenoviral‐mediated overexpression of IL‐10 could allow for scarless wound healing in a murine incisional wound model. Wounds were analyzed at 1–90 days postwounding for effects on scar formation, inflammatory response, and biomechanical properties. Ad‐IL‐10 reconstitutes a permissive environment for scarless healing as shown by reconstitution of a normal dermal reticular collagen pattern and distribution of dermal elements. Compared with controls, Ad‐IL‐10 treated wounds showed reduced inflammatory response and no difference in biomechanical parameters. Therefore, overexpression of IL‐10 in postnatal wounds results in a permissive environment for scarless wound repair, possibly by replicating a fetal wound environment.

Fetal wound healing: implications for minimal scar formation.

Purpose of review The mid-gestation fetus is capable of regenerative healing with wound healing indistinguishable from surrounding skin. This review aims to evaluate the current knowledge of how the mid-gestation fetus heals without scar and the implications of these findings in efforts to recapitulate the fetal regenerative phenotype in the postnatal environment. Recent findings It has been over 30 years since the empirical observation that the fetus heals without scar; yet, the underlying mechanisms of this phenomenon have not been elucidated. Fetal wound healing is characterized by a distinct growth factor profile, an attenuated inflammatory response with an anti-inflammatory cytokine profile, an extracellular matrix rich in type III collagen and hyaluronan, attenuated biomechanical stress, and a potential role for stem cells. Current therapies to minimize scarring in postnatal wounds have attempted to recapitulate singular aspects of the fetal regenerative phenotype and have met with varying degrees of clinical success. We now have the molecular tools to more completely comprehend the fundamental mechanisms of fetal regenerative wound repair, which has the potential to provide insights into the identification of therapeutic targets to minimize the scar formation. Summary Successful therapies that help minimize postnatal scar formation can be realized through understanding the cellular and molecular mechanisms of fetal regenerative wound healing. These insights will have implications not only for cutaneous wound healing, but also potentially for any disease process characterized by excessive fibroplasia.

Late gestation fetal magnetic resonance imaging–derived total lung volume predicts postnatal survival and need for extracorporeal membrane oxygenation support in isolated congenital diaphragmatic hernia

PURPOSE Magnetic resonance imaging (MRI) has been used as an imaging modality to assess pulmonary hypoplasia in congenital diaphragmatic hernias (CDHs). The objective of this study was to determine if there is a correlation between late gestational fetal MRI-derived total lung volumes (TLVs) and CDH outcomes. METHODS From 2006 to 2009, 44 patients met criteria of an isolated CDH with a late gestational MRI evaluation. The prenatal TLV (in milliliters) was obtained between 32 and 34 weeks gestation. The measured study outcomes included survival, need for extracorporeal membrane oxygenation (ECMO), and length of stay. RESULTS There were 39 left and 5 right CDH patients. The average TLV was significantly lower for nonsurvivors (P = .01), and there was a significant association between lower TLV and the need for ECMO (P = .0001). When stratified by TLV, patients with a TLV of greater than 40 mL had a 90% survival vs 35% survival for a TLV of less than 20 mL. Furthermore, patients with a TLV greater than 40 mL had a lower rate of ECMO use (10%) than patients with a TLV of less than 20 mL (86%). Shorter length of stay was found to correlate with increasing TLV (P = .022). CONCLUSION Late gestation fetal MRI-derived TLV significantly correlates with postnatal survival and need for ECMO. Fetal MRI may be useful for the evaluation of patients who present late in gestation with a CDH.

Prenatal Diagnosis and Management of Mainstem Bronchial Atresia

The prenatal diagnosis, natural history and management of mainstem bronchial atresia have not been described previously. We report two cases of prenatally diagnosed proximal bronchial atresia. The first patient presented at 18 weeks with sonographic and MRI findings consistent with bronchial atresia with fetal hydrops. The mother developed the mirror syndrome and labor was induced. A non-viable fetus was delivered at 25 weeks. The second patient presented at 16 weeks gestation with evidence of an intrathoracic mass that was subsequently prenatally diagnosed as a right mainstem bronchial atresia. The right lung increased rapidly in size and was associated with the onset of fetal hydrops. At 24 weeks, fetal pneumonectomy was performed but the fetus expired intraoperatively due to cardiovascular collapse. Post-mortem findings in both cases confirmed the presence of an atretic mainstem bronchus with massive enlargement of the lung. Bronchial atresia involving the mainstem bronchus is associated with a poor prognosis.

A Quality-Improvement Collaborative Project to Reduce Pressure Ulcers in PICUs

BACKGROUND AND OBJECTIVE: Pediatric patients are at risk for developing pressure ulcers (PUs) and associated pain, infection risk, and prolonged hospitalization. Stage III and IV ulcers are serious, reportable events. The objective of this study was to develop and implement a quality-improvement (QI) intervention to reduce PUs by 50% in our ICUs. METHODS: We established a QI collaborative leadership team, measured PU rates during an initial period of rapid-cycle tests of change, developed a QI bundle, and evaluated the PU rates after the QI implementation. The prospective study encompassed 1425 patients over 54 351 patient-days in the PICU and NICU. RESULTS: The PU rate in the PICU was 14.3/1000 patient-days during the QI development and 3.7/1000 patient-days after QI implementation (P < .05), achieving the aim of 50% reduction. The PICU rates of stages I, II, and III conventional and device-related PUs decreased after the QI intervention. The PU rate in the NICU did not change significantly over time but remained at a mean of 0.9/1000 patient-days. In the postimplementation period, 3 points were outside the control limits, primarily due to an increase in PUs associated with pulse oximeters and cannulas. CONCLUSIONS: The collaborative QI model was effective at reducing PUs in the PICU. Pediatric patients, particularly neonates, are at risk for device-related ulcers. Heightened awareness, early detection, and identification of strategies to mitigate device-related injury are necessary to further reduce PU rates.

Impact of Continuous Intraoperative Monitoring on Outcomes in Open Fetal Surgery

Objectives: There are shifts in fetal hemodynamics during open fetal surgery that were not appreciated until the use of intraoperative fetal echocardiography. We have developed an intraoperative monitoring strategy to continuously assess fetal hemodynamics. We hypothesized that this approach would enhance intraoperative management and survival. Methods: Medical records of open fetal surgery patients were reviewed since the implementation of this approach. Intraoperative fetal monitoring was accomplished by continuous echocardiography, pulse oximetry, establishment of intravenous access, and arterial blood gas and hemoglobin measurement. Overall survival was compared to fetal surgeries performed prior implementation of this monitoring strategy. Results: Resections of a congenital cystic adenomatoid malformation or a sacrococcygeal teratoma in nine hydropic fetuses were performed while using this monitoring strategy. Intraoperative echocardiography resulted in a change of management in 7 of 9 fetuses. The main observations on fetal echocardiography resulting in intraoperative intervention were decreased ventricular filling, bradycardia, and decreased ventricular contractility. Therapy included administration of volume expanders and/or inotropic agents. Overall fetal survival was 78% compared to a survival of 42% prior to the implementation of this approach. Conclusion: Continuous intraoperative fetal monitoring provides real time assessment of fetal hemodynamics which results in changes in intraoperative management. The overall outcomes in these critically ill fetuses have been improved.

Placental gene transfer: transgene screening in mice for trophic effects on the placenta.

OBJECTIVE We hypothesized that gene transfer of select growth factors to the placenta may enhance placental and fetal growth. Thus, we examined the effect of 8 growth factor transgenes on murine placenta. STUDY DESIGN Adenoviral-mediated site-specific intraplacental gene transfer of 8 different growth factor transgenes at embryonic day (e) 14 was performed. Transgenes included angiopoietin-1, angiopoietin-2 (Ang-2), basic fibroblast growth factor, hepatocyte growth factor, insulin-like growth factor-1 (IGF-1), placenta growth hormone, platelet-derived growth factor-B (PDGF-B), and vascular endothelial growth factor(121). Fetuses and placentas were harvested at e17 and assessed for survival, gene transfer efficiency, placenta area, and fetal and placental weights. RESULTS Efficient gene transfer to the placenta was detected with minimal dissemination to the fetus. Overexpression of IGF-1, PDGF-B, and Ang-2 resulted in an increase in placenta cross-sectional area. Only Ang-2 gene transfer resulted in increased fetal weight, and only Ang-2 and basic fibroblast growth factor resulted in a change in placental weight. CONCLUSION Site-specific placental gene transfer results in efficient gene transfer with minimal dissemination to the fetus. Adenoviral-mediated IGF-1, adenoviral-mediated PDGF-B, and adenoviral-mediated Ang-2 significantly increase placenta growth.

Role of salivary vascular endothelial growth factor (VEGF) in palatal mucosal wound healing.

The mucosa of alimentary tract heals more rapidly than cutaneous wounds. The underlying mechanisms of this enhanced healing have not been completely elucidated. Constant exposure to salivary growth factors has been shown to play a critical role in mucosal homeostasis and tissue repair. Angiogenesis also has an essential role in successful wound repair. One of the main angiogenic growth factors, vascular endothelial growth factor (VEGF), has a pleiotropic role in tissue repair via neovascularization, reepithelialization, and regulation of extracellular matrix. We have previously reported a critical role for salivary VEGF in bowel adaptation after small bowel resection. We hypothesize that salivary VEGF is an essential stimulus for oral mucosal tissue repair, and use the murine palatal wound model to test our hypothesis. In a loss‐of‐function experiment, we removed the primary source of VEGF production through selective submandibular gland (SMG) sialoadenectomy in a murine model and observed the effects on wound closure and neovascularization. We then performed a selective loss‐of‐function experiment using the protein VEGF‐Trap to inhibit salivary VEGF. In a gain‐of‐function experiment, we supplemented oral VEGF following SMG sialoadenectomy. After SMG sialoadenectomy, there was significant reduction in salivary VEGF level, wound closure, and vessel density. Lower levels of salivary VEGF were correlated with impaired neovascularization and reepithelialization. The selective blockade of VEGF using VEGF‐Trap resulted in a similar impairment in wound healing and neovascularization. The sole supplementation of oral VEGF after SMG sialoadenectomy rescued the impaired wound healing phenotype and restored neovascularization to normal levels. These data show a novel role for salivary‐VEGF in mucosal wound healing, and provide a basis for the development of novel therapeutics aimed at augmenting wound repair of the oral mucosa, as well as wounds at other sites in the alimentary tract.

Characterization of endothelial progenitor cells mobilization following cutaneous wounding

Bone marrow (BM)‐derived endothelial progenitor cells (EPCs) are known to play an important role in neovascularization and wound healing. We investigated the temporal effects of cutaneous wounding on EPC surface markers within the peripheral blood and BM, and to better understand the role of the stromal cell‐derived factor‐1 alpha (SDF‐1α/CXCR4) axis on EPC mobilization after wounding. FVB/NJ mice were administered bilateral 8 mm circular full‐thickness skin wounds. Peripheral blood and BM were isolated at daily intervals postwounding through day 7 and analyzed for EPC mobilization characteristics and levels of SDF‐1α. Cutaneous wounding was found to cause a transient increase in EPC mobilization that peaked on day 3. In contrast, SDF‐1α protein within blood plasma was observed to significantly decrease on days 3, 4, and 7 following cutaneous wounding. BM levels of SDF‐1α protein decreased to a nadir on day 3, the same day as peak mobilization was observed to occur. The decrease in BM SDF‐1α protein levels was also associated with a decrease in SDF‐1α mRNA suggesting transcriptional down‐regulation as a contributing factor. This study for the first time characterizes EPC mobilization following cutaneous wounding in mice and supports a major role for the SDF‐1α/CXCR4 axis in regulating mobilization within the BM, without evidence for systemic increases in SDF‐1α.