Search Results Heading

MBRLSearchResults

mbrl.module.common.modules.added.book.to.shelf
Title added to your shelf!
View what I already have on My Shelf.
Oops! Something went wrong.
Oops! Something went wrong.
While trying to add the title to your shelf something went wrong :( Kindly try again later!
Are you sure you want to remove the book from the shelf?
Oops! Something went wrong.
Oops! Something went wrong.
While trying to remove the title from your shelf something went wrong :( Kindly try again later!
    Done
    Filters
    Reset
  • Discipline
      Discipline
      Clear All
      Discipline
  • Is Peer Reviewed
      Is Peer Reviewed
      Clear All
      Is Peer Reviewed
  • Item Type
      Item Type
      Clear All
      Item Type
  • Subject
      Subject
      Clear All
      Subject
  • Year
      Year
      Clear All
      From:
      -
      To:
  • More Filters
24 result(s) for "Hock, Alison"
Sort by:
Bovine milk-derived exosomes enhance goblet cell activity and prevent the development of experimental necrotizing enterocolitis
Necrotizing enterocolitis (NEC) is characterized by intestinal injury and impaired mucin synthesis. We recently showed that breast milk exosomes from rodents promote intestinal cell viability, epithelial proliferation, and stem cell activity, but whether they also affect mucus production is unknown. Therefore, the aim of this study was to investigate the effects of bovine milk-derived exosomes on goblet cell expression in experimental NEC and delineate potential underlying mechanisms of action. Exosomes were isolated from bovine milk by ultracentrifugation and confirmed by Nanoparticle Tracking Analysis and through the detection of exosome membrane markers. To study the effect on mucin production, human colonic LS174T cells were cultured and exposed to exosomes. Compared to control, exosomes promoted goblet cell expression, as demonstrated by increased mucin production and relative expression levels of goblet cell expression markers trefoil factor 3 (TFF3) and mucin 2 (MUC2). In addition, exosome treatment enhanced the expression of glucose-regulated protein 94 (GRP94), the most abundant intraluminal endoplasmic reticulum (ER) chaperone protein that aids in protein synthesis. Furthermore, experimental NEC was induced in mouse pups by hyperosmolar formula feeding, lipopolysaccharide administration and hypoxia exposure on postnatal days 5-9. Milk exosomes were given with each gavage feed. NEC was associated with ileal morphological injury and reduction in MUC2+ goblet cells and GRP94+ cells per villus. Exosome administration to NEC pups prevented these changes. This research highlights the potential novel application of milk-derived exosomes in preventing the development of NEC in high-risk infants when breast milk is not available.
Inhibition of corticotropin-releasing hormone receptor 1 and activation of receptor 2 protect against colonic injury and promote epithelium repair
Maternal separation (MS) in neonates can lead to intestinal injury. MS in neonatal mice disrupts mucosal morphology, induces colonic inflammation and increases trans-cellular permeability. Several studies indicate that intestinal epithelial stem cells are capable of initiating gut repair in a variety of injury models but have not been reported in MS. The pathophysiology of MS-induced gut injury and subsequent repair remains unclear, but communication between the brain and gut contribute to MS-induced colonic injury. Corticotropin-releasing hormone (CRH) is one of the mediators involved in the brain–gut axis response to MS-induced damage. We investigated the roles of the CRH receptors, CRHR1 and CRHR2, in MS-induced intestinal injury and subsequent repair. To distinguish their specific roles in mucosal injury, we selectively blocked CRHR1 and CRHR2 with pharmacological antagonists. Our results show that in response to MS, CRHR1 mediates gut injury by promoting intestinal inflammation, increasing gut permeability, altering intestinal morphology, and modulating the intestinal microbiota. In contrast, CRHR2 activates intestinal stem cells and is important for gut repair. Thus, selectively blocking CRHR1 and promoting CRHR2 activity could prevent the development of intestinal injuries and enhance repair in the neonatal period when there is increased risk of intestinal injury such as necrotizing enterocolitis.
Activation of Wnt signaling by amniotic fluid stem cell-derived extracellular vesicles attenuates intestinal injury in experimental necrotizing enterocolitis
Necrotizing enterocolitis (NEC) is a devastating intestinal disease primarily affecting preterm neonates and causing high morbidity, high mortality, and huge costs for the family and society. The treatment and the outcome of the disease have not changed in recent decades. Emerging evidence has shown that stimulating the Wnt/β-catenin pathway and enhancing intestinal regeneration are beneficial in experimental NEC, and that they could potentially be used as a novel treatment. Amniotic fluid stem cells (AFSC) and AFSC-derived extracellular vesicles (EV) can be used to improve intestinal injury in experimental NEC. However, the mechanisms by which they affect the Wnt/β-catenin pathway and intestinal regeneration are unknown. In our current study, we demonstrated that AFSC and EV attenuate NEC intestinal injury by activating the Wnt signaling pathway. AFSC and EV stimulate intestinal recovery from NEC by increasing cellular proliferation, reducing inflammation and ultimately regenerating a normal intestinal epithelium. EV administration has a rescuing effect on intestinal injury when given during NEC induction; however, it failed to prevent injury when given prior to NEC induction. AFSC-derived EV administration is thus a potential emergent novel treatment strategy for NEC.
Are prophylactic anti-reflux medications effective after esophageal atresia repair? Systematic review and meta-analysis
PurposeGastroesophageal reflux after surgical repair of esophageal atresia (EA) can be associated with complications, such as esophageal stricture. Recent guidelines recommend prophylactic anti-reflux medication (PARM) after EA repair. However, the effectiveness of PARM is still unclear. The aim of this study was to review evidence surrounding the use of PARM in children operated for EA.MethodsWe performed a systematic review and meta-analysis. We searched Medline, EMBASE, and the Cochrane Databases from inception until the end of 2016 for comparative studies of PARM versus no PARM (control). Primary outcome was postoperative esophageal stricture. Quality of evidence was assessed using GRADE system.ResultsWe identified four observational studies that focused on esophageal stricture as an outcome. A total of 362 patients were included in meta-analysis. There was no significant difference in esophageal stricture rates between PARM and control (OR = 1.14; 95% CI = 0.61–2.13; p = 0.68; I2 = 38%). The quality of the evidence was very low, due to lack of precision as a consequence of small study sizes.ConclusionsOur results indicate that PARM does not reduce the incidence of esophageal stricture after EA repair. Future well-controlled prospective studies are needed to obtain higher quality evidence.
Osmolality of enteral formula and severity of experimental necrotizing enterocolitis
Purpose Administration of hyperosmolar formula is regarded as a risk factor for the development of necrotizing enterocolitis (NEC). However, there are limited number of reports about the relationship between formula osmolality and NEC. The aim of this study is to evaluate the effects of formula concentration in an experimental model of NEC. Methods We studied experimental NEC in C57BL/6 mice. NEC was induced by giving hypoxia, gavage administration of lipopolysaccharide and gavage formula feeding from postnatal day 5–9. We used two types of formula: (1) hyperosmolar formula (HF): 15 g Similac + 75 ml Esbilac (849 mOsm/kg); (2) diluted formula (DF): dilute hyperosmolar formula with an equal amount of water (325 mOsm/kg). Controls were fed by the mother. On postnatal day 9, the ileum was harvested and evaluated for severity of mucosal injury (hematoxylin/eosin staining) and inflammation (PCR for IL6 and TNFα mRNA expression). Results The incidence of NEC was same in both HF and DF (80%). The intestinal inflammatory response was similar between HF and DF (IL6: p  = 0.26, TNFα: p  = 0.69). Conclusions This study indicates the osmolality of enteral formula does not affect incidence of experimental NEC. This experimental study provides new insights into the relationship between formula feeding and NEC.
Bovine milk-derived exosomes attenuate NLRP3 inflammasome and NF-κB signaling in the lung during neonatal necrotizing enterocolitis
PurposeNecrotizing enterocolitis (NEC), an inflammatory intestinal disease common in premature infants, has been associated with the development of lung damage. Toll-like receptor 4 has been shown to regulate inflammation in the NEC lungs, however, other important inflammatory mechanisms have not been thoroughly investigated. In addition, we reported that milk-derived exosomes were able to attenuate intestinal injury and inflammation in experimental NEC. This study aims to (i) investigate the role of the NLRP3 inflammasome and NF-κB pathway in regulating lung damage during experimental NEC; and (ii) evaluate the therapeutic potential of bovine milk exosomes in reducing lung inflammation and injury during NEC.MethodsNEC was induced by gavage feeding of hyperosmolar formula, hypoxia, and lipopolysaccharide administration in neonatal mice from postnatal days 5–9. Exosomes were obtained by ultracentrifugation of bovine milk and administered during each formula feed.ResultsThe lung of NEC pups showed increased inflammation, tissue damage, NLRP3 inflammasome expression, and NF-κB pathway activation, which were attenuated upon exosome administration.ConclusionOur findings suggest that the lung undergoes significant inflammation and injury following experimental NEC which are attenuated by bovine milk-derived exosomes. This emphasizes the therapeutic potential of exosomes not just on the intestine but also on the lung.
Impaired Wnt/β-catenin pathway leads to dysfunction of intestinal regeneration during necrotizing enterocolitis
Necrotizing enterocolitis (NEC) is a devastating neonatal disease characterized by acute intestinal injury. Intestinal stem cell (ISC) renewal is required for gut regeneration in response to acute injury. The Wnt/β-catenin pathway is essential for intestinal renewal and ISC maintenance. We found that ISC expression, Wnt activity and intestinal regeneration were all decreased in both mice with experimental NEC and in infants with acute active NEC. Moreover, intestinal organoids derived from NEC-injured intestine of both mice and humans failed to maintain proliferation and presented more differentiation. Administration of Wnt7b reversed these changes and promoted growth of intestinal organoids. Additionally, administration of exogenous Wnt7b rescued intestinal injury, restored ISC, and reestablished intestinal epithelial homeostasis in mice with NEC. Our findings demonstrate that during NEC, Wnt/β-catenin signaling is decreased, ISC activity is impaired, and intestinal regeneration is defective. Administration of Wnt resulted in the maintenance of intestinal epithelial homeostasis and avoidance of NEC intestinal injury.
Value of abdominal ultrasound in management of necrotizing enterocolitis: a systematic review and meta-analysis
PurposeNecrotizing enterocolitis (NEC) remains a life-threatening disease among infants in the NICU. Early diagnosis and careful monitoring are essential to improve outcomes. Abdominal ultrasound (AUS) seems a promising addition to current diagnostic modalities, but its clinical utility is uncertain. The aim of this study was to identify AUS features associated with definite NEC (i.e. Bell stage ≥ II), failed medical treatment, surgery, and death.MethodsEmbase, MEDLINE, Web of Science and CINAHL databases were searched for studies that addressed any NEC-related AUS feature in relation to any of the four outcomes. After critical appraisal of relevant study methods, meta-analyses were conducted using a random-effect model.Results15 out of 1215 studies were included. All AUS features had sensitivities below 70% and specificities largely above 80% for diagnosing definite NEC; several AUS features were significantly associated with failed medical treatment and surgery. Substantial heterogeneity, poor reporting quality and uncertain risk of bias were found.ConclusionsWhile clear associations of AUS features with failed medical treatment exist and AUS may detect definite NEC, substantial heterogeneity, poor reporting quality and an uncertain risk of bias impair the use of AUS for clinical decision making. A prospective, well-designed validation study is needed.
Deficiency of the mitochondrial ribosomal subunit, MRPL50, causes autosomal recessive syndromic premature ovarian insufficiency
Premature ovarian insufficiency (POI) is a common cause of infertility in women, characterised by amenorrhea and elevated FSH under the age of 40 years. In some cases, POI is syndromic in association with other features such as sensorineural hearing loss in Perrault syndrome. POI is a heterogeneous disease with over 80 causative genes known so far; however, these explain only a minority of cases. Using whole-exome sequencing (WES), we identified a MRPL50 homozygous missense variant (c.335T > A; p.Val112Asp) shared by twin sisters presenting with POI, bilateral high-frequency sensorineural hearing loss, kidney and heart dysfunction. MRPL50 encodes a component of the large subunit of the mitochondrial ribosome. Using quantitative proteomics and western blot analysis on patient fibroblasts, we demonstrated a loss of MRPL50 protein and an associated destabilisation of the large subunit of the mitochondrial ribosome whilst the small subunit was preserved. The mitochondrial ribosome is responsible for the translation of subunits of the mitochondrial oxidative phosphorylation machinery, and we found patient fibroblasts have a mild but significant decrease in the abundance of mitochondrial complex I. These data support a biochemical phenotype associated with MRPL50 variants. We validated the association of MRPL50 with the clinical phenotype by knockdown/knockout of mRpL50 in Drosophila, which resulted abnormal ovarian development. In conclusion, we have shown that a MRPL50 missense variant destabilises the mitochondrial ribosome, leading to oxidative phosphorylation deficiency and syndromic POI, highlighting the importance of mitochondrial support in ovarian development and function.
Examining research systems and models for local government: a systematic review
Background:Local authorities (LA) are key in improving population health, and LA public health decision makers need support from appropriately organised research capacity; however, few models of LA research systems are known to exist. Aims and objectives:To explore potential and existing models of LA-based research systems. Methods:This mapping review and time-constrained systematic review synthesises conceptual and empirical literature from 12 health and social science databases, grey literature and reference/citation tracking. Three reviewers screened titles, abstracts and full texts of retrieved records, and extracted key data from included papers. Evidence was synthesised based on characteristics of research systems and quality-assessed for relevance, rigour and richness. Findings:Nine models were examined in depth. From these, we developed a typology of research systems. Few models were specifically designed for LA research activity; as a Whole System approach, the Local Authority Champions of Research model offers a potential blueprint. Useful lessons may be learned from UK Collaborations for Leadership in Applied Health Research, Academic Collaborative Centres in the Netherlands, local Research and Development units in Sweden, and generic University-Community partnerships. Discussion and conclusions:An optimal research system requires the coexistence of multiple systems including Centre, Partnership, Collaboration, Network and Community types. The review is UK-focused, but the models appear to have wider relevance. Our classification offers those planning an LA research system the opportunity to choose an approach that meets their requirements and resources. A Whole System approach is optimal, with egalitarian input from the LA and academia.