Investigation of PML locus on chr15 for susceptibility to Paget’s disease of bone

Paget’s disease of bone (PDB) is a common bone disorder. The disease is characterised by localised abnormalities in bone turnover (Ralston et al. 2008). Genetic factors are important for PDB. Genome-wide association studies (GWAS) identified a susceptibility locus for PDB on chromosome 15q24.1 in addition to six other loci (Albagha et al. 2010; Albagha et al. 2011). The strongest signal for disease association from this locus is located within Promyelocytic Leukemia (PML). PML is a tumour suppressor gene involved in chromosomal translocation leading to acute promyelocytic leukaemia (APL). PML is involved in multiple cellular functions like cell growth, senescence, DNA repair, antiviral response and apoptosis but has never been implicated directly in bone metabolism. The aim of my PhD was to explore role of PML in bone biology. Fine mapping of the 15q locus was performed using targeted next generation sequencing. In chapter 4, Targeted DNA sequencing of the PDB susceptibility locus on chr15 identified variants within PML that are associated with the disease. In chapter 5, expression analysis revealed expression of Pml in bone cells from murine and human tissue and its expression varies during the development and differentiation of these cells. PML expression was found to be downregulated in patients with PDB. In chapters 6 and 7, experiments with RAW 264.7 cell line and Pml knock out mice point to a negative regulatory role of PML in osteoclast differentiation. Osteoclasts from Pml knockout mice show increased formation, fusion and activity in response to RANKL compared to wt mice. The expression levels of osteoclast related genes such as Ctsk (Cathepsin K), Dcstamp and Nfatc1 were also higher in Pml knockout mice. Osteoblasts differentiated from these mice show increased mineralised nodule formation in vitro compared to wt mice. Skeletal phenotyping by micro CT revealed no significant differences in structure and bone density between Pml knockout and wt mice irrespective of age. Interferon gamma (IFN-γ) is a cytokine which is known to induce Interferon Regulatory Factor 8 (IRF-8) and PML in mouse peritoneal macrophages (Dror et al. 2007). IRF-8 is a transcription factor downregulated during RANKL mediated osteoclastogenesis (Zhao et al. 2009) and an essential regulator of PML gene in activated macrophages (Dror et al. 2007). In chapter 8, it was found that IFN-γ inhibited osteoclastogenesis in wt mice but failed to have a pronounced effect on osteoclasts in mice lacking Pml. Thus, lack of PML possibly renders IFN-γ and IRF-8, ineffective in suppressing osteoclastogenesis. Thus, PML controls osteoclast development probably by modulating response of IRF-8 and IFN-γ in association with direct or indirect regulation of osteoclast related genes such as Ctsk (encoding Cathepsin K), Dcstamp and Nfatc1. Osteoclasts are already primed for increased formation, differentiation, fusion and activity due to upregulation of these factors in absence of PML. My doctoral study therefore identifies PML as a novel regulator of bone metabolism. Functional genetic variants within PML gene possibly contribute to reduced PML expression thereby predisposing to PDB by increasing osteoclast differentiation and activity with an increase in osteoblast mineralisation possibly to counteract increased bone resorption

COVID-19 and pregnancy- review of cases from a tertiary public hospital in Mumbai

Background: In December 2019 a novel strain of coronavirus, was first isolated by the Chinese Center for Disease Control and Prevention. This strain connected to the cluster of acute respiratory illness cases from Wuhan, China was later officially named as severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2). On 30th January 2020, WHO declared the outbreak of SARS-Cov-2 a public health emergency of international concern, and on 11th March 2020 declared it to be a pandemic. Pregnant women are known to be at higher risk of severe morbidity and mortality from respiratory infections such as influenza and SARS, making a strong case for pregnant women to be considered an at-risk population for COVID-19. This study aimed to assess the clinical picture, obstetric outcome and neonatal outcome in COVID positive pregnant cases.Methods: We did a retrospective observational cohort study in the department of Obstetrics and Gynecology at a tertiary teaching hospital in Mumbai.Results: In the study duration, 148 were diagnosed as COVID positive (~12%). 9 patients had COVID related symptoms on admission. The obstetric outcome in symptomatic patients was noted to be good. We noted 79.01% of the pregnancies reached term. Cesarean section rate in COVID positive patients was comparable to non-COVID patients in the study duration. Neonatal outcome was only 4 babies of COVID positive mothers were diagnosed positive.Conclusions: Our study shows pregnancy outcomes are not significantly worsened by the COVID-19 infection in spite of the risk factors associated with pregnancy per se and influenza infection in pregnancy

Quality Indicators in Barrett’s Esophagus: Time to Change the Status Quo

The push for high quality care in all fields of medicine highlights the importance of establishing and adhering to quality indicators. In response, several gastrointestinal societies have established quality indicators specific to Barrett’s esophagus, which serve to create thresholds for performance while standardizing practice and guiding value-based care. Recent studies, however, have consistently demonstrated the lack of adherence to these quality indicators, particularly in surveillance (appropriate utilization of endoscopy and obtaining biopsies using the Seattle protocol) and endoscopic eradication therapy practices. These findings suggest that innovative interventions are needed to address these shortcomings in order to deliver high quality care to patients with Barrett’s esophagus

Role of per-oral pancreatoscopy in the evaluation of suspected pancreatic duct neoplasia: a 13-year U.S. singlecenter experience

Background and Aims The role of per-oral pancreatoscopy (POP) in the evaluation of occult pancreatic duct (PD) lesions remains limited to case series. The aim of this study was to evaluate the ability of POP to differentiate malignant from benign diseases of the PD. Methods Patients who underwent POP between 2000 and 2013 for the evaluation of indeterminate PD strictures, dilatations, or with suspected or known main duct intraductal papillary mucinous neoplasm were identified. Main outcome measurements were visual impression accuracy, POP tissue sampling, efficacy, and safety of POP. Results During the study period, 79 patients who underwent POP for the evaluation of pancreatic stricture or dilatation were identified. Technical success was achieved in 78 (97%). In the PD neoplasia group (n = 33), the final diagnosis was based on index confirmatory POP-guided tissue sampling in 29 (88%). For the detection of PD neoplasia, POP visual impression had a sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 87%, 86%, 83%, 91%, and 87%, respectively. When combined with POP-guided tissue sampling, the values were 91%, 95%, 94%, 93%, and 94%, respectively. Of 102 POPs performed, adverse events were noted in 12 (12%) cases. Conclusions This study demonstrates a high technical success rate, visual impression accuracy, and tissue sampling capability of POP. Examinations were performed by endoscopists with expertise in pancreatoscopy interpretation, and the results may not be generalizable

Patient Factors Associated With Gastroesophageal Reflux Disease Diagnostic Evaluation Strategies: A Retrospective Cohort Study Using Real-World Evidence From a Large U.S. Medical Claims Database.

BACKGROUND AND AIMS: Barretts esophagus (BE) screening is not highly utilized in the United States, and there are few data describing providers approach to screening. To fill this gap and guide the implementation of future BE screening strategies, we studied evaluation practice patterns for gastroesophageal reflux disease (GERD) by nongastroenterologists. METHODS: We performed a retrospective cohort study of patients with chronic GERD using health claims data from the United States between 2005 and 2019. We used up to 5 years of data after the diagnosis of chronic GERD to determine patient factors associated with completion of a gastroenterology encounter. We also identified patient factors associated with whether the first gastroenterology encounter was a direct-access upper endoscopy or an office visit. RESULTS: We identified 484,023 patients diagnosed with chronic GERD by a nongastroenterology provider. The cumulative incidence of completing a gastroenterology encounter within 5 years was 38.7%. Gastrointestinal symptoms, such as dysphagia (adjusted hazard ratio [aHR] = 2.11, 95% confidence interval [CI] = 1.94-2.30), abdominal pain (aHR = 1.89, 95% CI = 1.85-1.94), and melena (aHR = 1.73, 95% CI = 1.65-1.82), were strongly associated with completion of a gastroenterology encounter. The patient factors strongly associated with direct-access upper endoscopy included dysphagia (aHR = 1.68, 95% CI = 1.52-1.85), weight loss (aHR = 1.46, 95% CI = 1.28-1.63), and melena (aHR = 1.42, 95% CI = 1.28-1.56). CONCLUSION: A total of 38.7% of patients with chronic GERD complete a gastroenterology encounter within 5 years of diagnosis, and gastrointestinal alarm symptoms are the most strongly associated factors for receiving gastroenterology care. These findings highlight the importance of incorporating primary care providers in the development of new BE screening programs

Recurrence of intestinal metaplasia and early neoplasia after endoscopic eradication therapy for Barrett’s esophagus: A systematic review and meta-analysis

Abstract Background Conflicting data exist with regard to recurrence rates of intestinal metaplasia (IM) and dysplasia after achieving complete eradication of intestinal metaplasia (CE-IM) in Barrett’s esophagus (BE) patients. Aim (i) To determine the incidence of recurrent IM and dysplasia achieving CE-IM and (ii) to compare recurrence rates between treatment modalities [radiofrequency ablation (RFA) with or without endoscopic mucosal resection (EMR) vs stepwise complete EMR (SRER)]. Methods A systematic search was performed for studies reporting on outcomes and estimates of recurrence rates after achieving CE-IM. Pooled incidence [per 100-patient-years (PY)] and risk ratios with 95 %CI were obtained. Heterogeneity was measured using the I 2 statistic. Subgroup analyses, decided a priori, were performed to explore heterogeneity in results. Results A total of 39 studies were identified (25-RFA, 13-SRER, and 2 combined). The pooled incidence of any recurrence was 7.5 (95 %CI 6.1 – 9.0)/100 PY with a pooled incidence of IM recurrence rate of 4.8 (95 %CI 3.8 – 5.9)/100 PY, and dysplasia recurrence rate of 2.0 (95 %CI 1.5 – 2.5)/100 PY. Compared to the SRER group, the RFA group had significantly higher overall [8.6 (6.7 – 10.5)/100 PY vs. 5.1 (3.1 – 7)/100 PY, P = 0.01] and IM recurrence rates [5.8 (4.3 – 7.3)/100 PY vs. 3.1 (1.7 – 4)/100 PY, P &lt; 0.01] with no difference in recurrence rates of dysplasia. Significant heterogeneity between studies was identified. The majority of recurrences were amenable to repeat endoscopic eradication therapy (EET). Conclusion The results of this study demonstrate that the incidence rates of overall, IM, and dysplasia recurrence rates post-EET are not inconsiderable and reinforce the importance of close surveillance after achieving CE-IM.</jats:p

Reduced expression of PML predisposes to Paget's disease of bone by increasing osteoclast differentiation and bone resorption

Paget's disease of bone (PDB) is characterized by focal increases in bone remodelling. Genome-wide association studies identified a susceptibility locus for PDB tagged by rs5742915, which is located within the PML gene. Here, we have assessed the candidacy of PML as the predisposing gene for PDB at this locus. We found that the PDB-risk allele of rs5742915 was associated with lower PML expression and that PML expression in blood cells from individuals with PDB was lower than in controls. The differentiation, survival and resorptive activity of osteoclasts prepared from Pml-/- mice was increased compared with wild type. Furthermore, the inhibitory effect of IFN-γ on osteoclast formation from Pml-/- was significantly blunted compared with wild type. Bone nodule formation was also increased in osteoblasts from Pml-/- mice when compared with wild type. Although microCT analysis of trabecular bone showed no differences between Pml-/- mice and wild type, bone histomorphometry showed that Pml-/- mice had high bone turnover with increased indices of bone resorption and increased mineral apposition rate. These data indicate that reduced expression of PML predisposes an individual to PDB and identify PML as a novel regulator of bone metabolism. This article has an associated First Person interview with the first author of the paper