Comparison of Diabetic Remission Rates following Roux en-Y Gastric Bypass and Longitudinal Sleeve Gastrectomy
Introduction: Bariatric surgery is being increasingly investigated as treatment for Type II Diabetes Mellitus (T2DM). As Sleeve Gastrectomy (SG) surpasses Roux-en-Y Gastric Bypass (RYGB) as the new standard in bariatric surgery, it is still unknown if its efficacy in achieving remission is comparable to RYGB. This study compared diabetic remission rates between SG and RYGB in order to identify the predictive factors for remission and the mechanisms of achieving remission.
Methods: This was a retrospective cohort study comparing all diabetic patients undergoing RYGB and SG at an academic medical center from 1/1/11-7/1/15. Patients were followed preoperatively and at 6 week, 6 month, and 1, 2, and 3 year intervals. We defined diabetic remission as HbA1c under 7 without insulin or hypoglycemic use and excess body weight (EBW) as percent over ideal body weight. Data were analyzed using Cox analysis, Fisher’s Exact Tests, and Student T Tests.
Results: During the study, 96 patients underwent RYGB and 89 underwent SG. Preoperatively, patients from both groups had similar age, weight, gender, preoperative weight loss, HbA1c at onset and at surgery, oral hypoglycemic use, insulin use, and HOMA2 parameters. At one year postoperatively, patients who underwent RYGB showed a statistically greater postoperative EBW loss (62% vs. 36% p < 0.0001). Kaplan Meier analysis showed a significantly higher rate of remission, (83% vs. 66%) in patients who underwent SG (p=0.02). After using Cox analysis to account for differences in delta BMI (p=0.04), EBW loss (p=0.04), preoperative HOMA2 parameters (p=0.008-0.011), and preoperative factors such as HbA1c and insulin use (p=0.001 for both), there was no change in RYGB’s impact on diabetic remission compared to SG.
Conclusion: Our results confirm that RYGB achieves a significantly greater rate of diabetic remission and a significantly higher weight loss than SG. Additionally, the difference in rate of diabetic remission is not explained by weight loss or preoperative predictors of less reversible diabetes (HOMA2 parameters, use of insulin). Identification of the factor(s) responsible for this differential effect on diabetes may afford opportunity for therapeutic intervention.
Differences in Complication Rates Between Roux-en-Y Gastric Bypass and Longitudinal Sleeve Gastrectomy
Introduction: Sleeve Gastrectomy (SG) has surpassed Roux-en-Y Gastric Bypass (RYGB) as the most commonly performed bariatric operation. Though the beneficial effect of SG on Type 2 Diabetes Mellitus is less than that of RYGB, it is perceived to have a lower complication rate. The purpose of this study was to quantify the complication rates between of SG and RYGB in a severely obese diabetic population.
Methods: This was a retrospective cohort study that included all diabetic patients undergoing RYGB and SG at an academic medical center from January 1, 2011 to July 1, 2015. Patients were followed at 6 week, 6 month, 1 year, 2 year, and 3 year postoperatively. Outpatient and emergency visits were identified in the EMR system. Continuous data was analyzed using Student T tests and discrete data was analyzed using Fisher’s Exact Test. We defined early complications as those occurring within 30 days postoperatively, and late complications as those after 30 days.
Results: A total of 96 patients underwent RYGB and 89 underwent SG. The groups were concurrent and similar with regards to preoperative demographic factors such as age, gender, Hgb-A1c, HOMA2 parameters, excess body weight, BMI, and diabetic medication use. In terms of early complications, the rate of hemorrhage requiring transfusion was higher in the SG group compared to RYGB (10.1% vs. 3.1%, p=0.073). Postoperative length of stay was lower in the SG group (m=1.7 d vs. m=2 d, p=0.02), but the early readmission rate was also higher in the SG group (7.9% vs. 2.1%, p=0.09). For late postoperative complications, there were 4 anastomotic ulcer perforations and one case of internal hernia in the RYGB group. There were 6 late postoperative reoperations in the RYGB group (6% vs. 0%, p=0.03). In addition, 13 patients underwent 16 total upper endoscopies in the RYGB group (13.5% vs. 0%, p=0.0002). The cumulative rate of early and late interventions was higher in the RYGB group (20% vs. 3.4%, p=0.0005).
Conclusions: While the rate of early postoperative complication is similar between SG and RYGB, the need for late intervention is higher after RYGB. The cumulative need for reintervention (early and late) is higher after RYGB. This may explain the shift from Roux-en-Y Gastric Bypass to Sleeve Gastrectomy as the most commonly performed bariatric intervention.
Pre-exposure prophylaxis with OspA-specific human monoclonal antibodies protects mice against tick transmission of Lyme disease spirochetes
Background. Tick transmission of Borrelia spirochetes to humans results in significant morbidity from Lyme disease worldwide. Serum concentrations of antibodies against outer surface protein A (OspA) were shown to correlate with protection from infection with Borrelia burgdorferi, the primary cause of Lyme disease in the United States.
Methods. Mice transgenic for human immunoglobulin genes were immunized with OspA protein of B. burgdorferi to generate human monoclonal antibodies (HuMabs) against OspA. HuMabs were generated and tested in in vitro borreliacidal assays and animal protection assays.
Results. Nearly 100 unique OspA specific HuMabs were generated and four HuMabs (221-7, 857-2, 319-44, and 212-55) were selected as lead candidates based on borreliacidal activity. HuMab 319-44, 857-2 and 212-55 were borreliacidal against one or two Borrelia genospecies, whereas 221-7 was borreliacidal (IC50 < 1nM) against B. burgdorferi, B. afzelii and B. garinii, the three main genospecies endemic in the US, Europe and Asia. All four HuMabs completely protected mice from infection at 10 mg/kg in a murine model of tick-mediated transmission of B. burgdorferi.
Conclusions. Our study indicates that OspA-specific HuMabs can prevent the transmission of Borrelia and administration of these antibodies could be employed as pre-exposure prophylaxis for Lyme disease.
Glioblastoma Multiforme (GBM) is an aggressive cancer that originates from astrocytes and spreads to spinal cord and other parts of the brain. Increase in replication of glial cells leads to advantageous mutations in the tumor. In 2015 about 15,320 deaths were reported due to GBM. Five-year survival is less than 5% making GBM a dreadful cancer. Current treatment involves complex invasive surgery, followed by chemotherapy and radiation. There is a desperate unmet need for a targeted treatment of GBM with minimum damage to the surrounding normal tissue. Combination treatments are increasingly being used to target multiple hallmarks of cancer. The goal of this study is to develop a combination therapy to treat GBM using Poly (lactic-co-glycolic acid) (PLGA) nanoparticles encapsulated with three different drugs namely gefitinib, temozolomide (TMZ) and GSK461364 each with a unique target. Nanoparticles facilitate combination of multiple drugs for simultaneous delivery to cancer cells in a single nano-sized platform. Gefitinib is a Tyrosine Kinase inhibitor, which competes for ATP-binding site of EGFR-TK. TMZ methylates DNA of tumor cells, resulting in apoptosis. GSK461364 is a Polo-like Kinase (PLK-1) inhibitor that blocks the G2/M transition in tumor cell cycle. These three distinct hydrophobic drugs are tested on U-87 MG (human malignant glioma) and MDA-MB-231 (triple negative breast cancer) cell lines. PLGA is attached to Polyethylene glycol (PEG), which is conjugated to transferrin receptor (TfR) binding peptide for targeting TfR overexpression, common in GBM. PEG is known to increase the circulation half-life in vivo and improves colloidal stability of nanoparticles. These transferrin peptides bind to TfR (or CD71) and enable the entry of PLGA across Blood Brain Barrier (BBB). Results of characterization, in vitro drug release profiles, stability at 37C and 4C, cytotoxicity assay, electron micrographs of nanoparticles containing drugs and fluorescent imaging will be presented.
Background: The association between atrial fibrillation (AF) and thyroid disease as defined by thyroid stimulating hormone (TSH) is established in literature. However, the relationship between TSH and recurrence of AF post ablation has not been established.
Methods: We studied 207 patients (60.54±9.39yrs, 35.7% female) with persistent or paroxysmal AF who underwent either Cryo or RFA ablation between April 2011 and Jan 2015 at our center. Patients were stratified into hypothyroid (TSH > >4.5 U/mL), euthyroid (TSH 0.5-4.5 U/mL) and hyperthyroid (TSH < 0.5 U/mL) based on pre procedure testing. Heart age was computed based on Framingham risk factors. Excess heart age was defined as the difference between actual age and heart age. Logistic regression and cox-proportional hazards model were implemented using R statistical software (v3.2.0).
Results: There was a statistically significant lower rate of AF recurrence among male patients (OR 2.92, p=0.003). In univariate analysis, there was no statistically significant relationship between TSH and incidence of AF recurrence (OR 1.05, p=0.74). Cox proportional hazards models did not show an association between recurrence and TSH states (HR 0.85, p=0.74 for hypothyroid and HR 0.75, p=0.56 for hyperthyroid).
Conclusions: This exploratory showed that TSH may not play a role in AF recurrence. While there is a tendency towards an association between TSH and AF recurrence, this was not statistically significant. We hypothesize that overt hyperthyroidism prior to ablation will not increase chance of recurrence. This was true after adjustment for Framingham risk factors. The limitation of this study was the small sample size of the patients with TSH in the hyperthyroid range. Further analysis using larger dataset is indicated.
Introduction: Depression and anxiety disorders are prevalent among older adults, as is pain. These conditions are independently associated with reduced functioning and quality of life. Despite the frequent co-occurrence of all three of these disorders, little is known about the epidemiology and treatment of these disorders in nursing homes. The objectives of this study were to: 1) describe the prevalence of depression, anxiety disorders, and pain among newly admitted nursing home residents; and 2) describe the treatment of these disorders.
Methods: We used national Minimum Data Set (MDS) version 3.0 data from 2011-2012. Federally-mandated for all residents living in Medicare/Medicaid-certified nursing facilities, the MDS is a comprehensive clinical assessment including > 400 items on sociodemographics, mood and behavior, symptoms, pain, clinical diagnoses, and treatments. We identified residents with MDS assessments performed at admission between 2011-2012 who were 65 years of age or older; were non-comatose; were not admitted to a swing bed provider; did not have mental retardation or developmental delays; & were able to complete a pain assessment (n = 783,826).
Results: At admission, 36% of residents (n = 283,050) had a documented active diagnosis of depression (other than bipolar disorder), anxiety disorder, or both. Having pain in the last 5 days was reported by 53% of residents. Rates of self-reported pain were similar across psychiatric disorders. 60-62% of residents reporting pain received a combination of pain management interventions. More than a third of residents did not receive any psychiatric treatment.
Conclusions: Many nursing home residents experience pain, depression, and anxiety at admission. Pain management is common. An improved understanding of the relationships between pain, mental health, and analgesic use is necessary since older adults, particularly those in nursing homes, are routinely excluded from clinical trials despite being at high risk for adverse effects of analgesics and other treatments.
Objective: To synthesize the current literature on the magnitude and impact of multiple chronic conditions on clinical outcomes, including total in-hospital and post discharge mortality and hospitalizations, in older patients with cardiovascular disease (CVD).
Methods: A systematic review was conducted. Four electronic databases and article bibliographies were searched for publications from 2005 to 2015 which assessed the impact of multimorbidity on clinical outcomes in the elderly with CVD. Identified studies were screened using pre-defined criteria for eligibility.
Results: Fifteen studies met our inclusion criteria. Multimorbidity was assessed by simple counting of morbidities and by the Charlson and Elixhauser indices. Case-fatality rates ranged from between 13% and 21% for patients with a myocardial infarction. Long-term mortality ranged from 28% to 73% among patients with heart failure, and 24% of patients with heart failure and presenting multimorbidities had at least one readmission during a follow-up period of 17 months. Most of the studies reported a significant association between number of multimorbidities or particular morbidities and the risk of dying, the most frequent morbidities examined were diabetes, chronic kidney disease, anemia, chronic pulmonary disease and dementia/cognitive impairment
Conclusions: There are limited data on the magnitude and impact of multimorbidities on clinical outcomes, and even less data on patient centered outcomes among elderly patients with CVD. There are also inconsistencies in the manner by which multimorbidities are assessed; very few studies have approached the “real” complexity of patients with CVD and multimorbidities and how best to manage these high risk patients.
Multiple Chronic Conditions and Psychosocial Limitations in a Contemporary Cohort of Patients Hospitalized with an Acute Coronary Syndrome
Background: As adults live longer, multiple chronic conditions have become more prevalent over the past several decades. We describe the prevalence of, and patient characteristics associated with, cardiac and non-cardiac-related multimorbidities in patients discharged from the hospital after an acute coronary syndrome (ACS).
Methods: We studied 2,174 patients discharged from the hospital after an ACS at 6 medical centers in Massachusetts and Georgia between April, 2011 and May, 2013. Hospital medical records yielded clinical information including presence of 8 cardiac-related and 8 non-cardiac-related morbidities on admission. We assessed multiple psychosocial characteristics during the index hospitalization using standardized in-person instruments.
Results: The mean age of the study sample was 61 years, 67% were men, and 81% were non-Hispanic whites. The most common cardiac-related morbidities were hypertension, hyperlipidemia, and diabetes (76%, 69%, and 31%, respectively). Arthritis, chronic pulmonary disease, and depression (20%, 18%, and 13%, respectively) were the most common non-cardiac morbidities. Patients with ≥4 morbidities (37% of the population) were slightly older and more frequently female than those with 0-1 morbidity; they were also heavier and more likely to be cognitively impaired (26% vs. 12%), have symptoms of moderate/severe depression (31% vs. 15%), high perceived stress (48% vs. 32%), a limited social network (22% vs. 15%), low health literacy (42% vs. 31%), and low health numeracy (54% vs. 42%).
Conclusions: Multimorbidity, highly prevalent in patients hospitalized with an ACS, is strongly associated with indices of psychosocial deprivation. This emphasizes the challenge of caring for these patients, which extends well beyond ACS management.
Mammalian target of rapamycin (mTOR), also known as mechanistic target of rapamycin, is a known metabolic master-switch. In conditions of starvation, mTOR suppresses biosynthetic programs and increases the recycling of proteins and organelles. Upon stimulation by nutrients and growth factors, however, mTOR causes activation of biosynthesis and suppression of autophagy. The mTOR-centered molecular pathway is a major pathway of growth regulation and metabolism, linked to aging and the development of cancer, obesity, type 2 diabetes, neurodevelopmental and neurodegenerative diseases. Currently, the role of environmental factors in the modulation of the mTOR pathway remains largely unknown. The present study suggests that perinatal exposure to environmentally-relevant doses of polybrominated diphenyl ethers (PBDEs), a group of ubiquitous flame-retardants, results in long-lasting reprogramming of the mTOR pathway in mouse liver. This reprogramming includes suppression of mTORC1 and mTORC2 activity, accompanied by coordinated up-regulation of protein synthesis machinery and increased concentrations of circulating IGF-1. Further, experiments with MCF-7 breast cancer cells demonstrate that exposure to PBDEs results in fast induction of the REDD1/DDIT4 gene – a potent suppressor of mTORC1. This data indicates that the response of liver tissue to PBDE exposure during this critical developmental window is a dynamic process, and is likely triggered via a REDD1-dependent mechanism, ultimately resulting in long-lasting changes in the metabolic profile of the tissue. This study suggests that environmental exposures to brominated flame retardants may have profound and long-term effects on the central regulation hub of metabolic health, and may be implicated in the pathogenesis of the most relevant diseases of modern society.
Stem cells, especially human pluripotent stem cells (hPSCs), hold significant promise for modeling developmental and disease processes, drug and toxicology screening, and cell-based regenerative medicine. Most hPSC studies have so far focused on identifying extrinsic soluble factors, intracellular signaling pathways, and transcriptional regulatory networks involved in regulating hPSC behaviors. We focus on the development and applications of some novel synthetic micromechanical systems to understand the mechano-sensitive and -responsive properties of hPSCs and their functional regulation of self-renewal, directed differentiation, and survival of hPSCs. First, we have demonstrated that rigid PDMS micropost arrays (PMAs) support the maintenance of pluripotency of hPSCs. Blocking cytoskeleton contractility by blebbistatin and inhibiting E-cadherin functions by DECMA-1 antibody both impair mechanoresponsive self-renewal of hPSCs on rigid substrates. We have further achieved efficient neuroepithelial induction, caudalization, and motor neuron differentiation from hPSCs combining soft PMAs (Eeff < 5kPa) with dual Smad inhibition. The purity and yield of functional motor neurons derived from hPSCs within 23 days of culture using soft PMAs were improved four- and twelve-fold, respectively, compared to coverslips or rigid PMAs. Our mechanistic work has helped reveal for the first time that biomechanical cues, including intracellular contractile forces and cell shape, converge and reinforce signal integration of TGF-β, Wnt, Hippo/YAP, Rho GTPase, and the actomyosin cytoskeleton to regulate the neural plate specification. We also developed a novel acoustic tweezing cytometry (ATC) utilizing ultrasound pulses to actuate functionalized lipid-encapsulated microbubbles (MBs) targeted to cell surface integrin receptors to exert subcellular mechanical forces in the pN - nN range. ATC can robustly induce cell traction force changes through acoustic radiation forces and bubble cavitation induced shear stresses. Importantly, ATC stimulations increased the survival rate and cloning efficiency of hESCs by 3-fold, suggesting its potential application in large-scale expansion of hPSCs.
Introduction: In 2013, approximately 2.8 million children worldwide died within the neonatal period. India is at the epicenter of this tragedy, accounting for one-third of all neonatal mortalities. Prematurity and/or with low birth weight are the leading cause of neonatal mortality and India has the highest number of neonates born preterm and weighing less than 2,500 grams worldwide. It is estimated that Kangaroo Care can avert up to 48% of all neonatal deaths among premature babies by 2025. However, the promise of Kangaroo Care as a low-cost, safe, and efficacious intervention to reduce neonatal mortality in India has not been realized due to suboptimal implementation. Physician champions can improve Kangaroo Care implementation, but the magnitude of their impact is unknown.
Methods: A retrospective cohort study of 648 infants identified using clinical data from a NICU located in rural western India. Physicians who led Kangaroo Care training sessions with neonates and coached peer healthcare professionals were considered champions. Two Kangaroo Care champions were on staff full-time from January 2010 through June 2011, part-time from July 2011 through June 2012, and absent thereafter. We examined the effect of the withdrawal of physician champions on overall use using logistic regression, time to initiation using competing risk cox regression, and intensity using linear regression models of the two main components of Kangaroo Care, skin-to-skin care and breastfeeding, separately.
Findings: In comparison to when Kangaroo Care champions were present, their absence was associated with a 45% decrease in the odds of receiving skin-to-skin care (95% CI): 64% to 17%), 38% decrease in the rate of initiation of skin-to-skin care (95% CI: 53% to 82%), and on average, 1.47 less hours of skin-to-skin care (95% CI: -2.07 to -0.86). Breastfeeding practices were similar across different champion environments.
Interpretation: Withdrawal of Kangaroo Care champions from neonatal intensive care unit in rural western India is associated with diminished administration, delayed initiation, and shorter duration of skin-to-skin care, but did not impact breastfeeding practices. Training healthcare workers and community stakeholders to become champions could help in scaling up and maintaining Kangaroo Care practices.
Funding: This research was supported by TL1-TR001454 (to A.S.) from National Center for Advancing Translational Sciences, and P60-MD006912-05 (to J.A.) from National Institute on Minority Health and Disparities. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.
The Plant Cell Culture Library (PCCL) at UMass Amherst contains more than 2,200 live plant cell cultures, representing diverse plant species from around the world. The availability of this collection offers a rich resource for us to discover bioactive phytochemicals and uncover their mechanisms of action. Using data-mining surveys of bioactive plant extracts, I have organized subsets of PCCL cell lines that are likely to possess antifungal, antibacterial, antiviral, anthelmintic, anti-trypanosomal, or anticancer properties, which prove to be useful when deciding which species to screen first against a specific pathogen. Another distinct advantage of using the live plant cells in this research is the ability to stimulate the biosynthesis of pathogen-specific phytochemicals upon simulation of an attack (elicitation) by the microorganism in question. This could be accomplished by pathogen homogenates or plant hormones responsible for mounting defenses to infection.
Over the past six months, I have been working to optimize elicitation, lysis, and extraction conditions for obtaining high-throughput screening materials to be used against variable pathogens. Equipped with crude extracts from appropriately elicited cells, I am collaborating with a multidisciplinary team of UMass scientists to develop and implement high-throughput screening protocols for profiling a large number of plant-derived materials against various pathogens. Recently, I have screened a small pool (40) of extracts derived from cell lines with predicted anti-fungal properties against the highly resistant strain of fungus Fusarium oxysporum, one of the causal agents of an opportunistic infection often seen in immunocompromised patients known as fusariosis. Gratifyingly, I have found several plant species that produced specialized metabolites with better antifungal activity than the leading antibiotic against F. oxysporum, Amphotericin B, validating this line of antimicrobial research. We are also actively reaching out to other academic labs partners to form partnerships in diverse antimicrobial research venues.
Background: Compared to other racial/ethnic subgroups in the U.S., Latinos experience increased rates of cardiovascular disease (CVD) and CVD risk factors such as hypertension, inactivity, and diabetes. Sedentary behavior has also been defined as an additional risk factor for CVD, independent of physical activity participation. However, while sedentary behavior has been associated with increased risk for CVD among primarily White samples, previous studies in Latinos have shown mixed results.
Purpose: To explore the relationships between sedentary behavior and CVD risk factors, including BMI, waist circumference, blood pressure, physical activity, dyslipidemia, and diabetes, among a sample of Latino adults.
Methods: Cross-sectional secondary analysis of the Latino Health and Well-Being Study. Latino adults were recruited from the Greater Lawrence Family Health Center (N= 602). Surveys of sedentary behavior and physical activity were verbally administered. Anthropometric measurements included weight, height, waist circumference and blood pressure. Medical record data for diabetes and dyslipidemia were obtained.
Results: This study showed that individuals in older age strata, females, and individuals with a less than high school education were more sedentary than their younger, male, and more educated counter parts. Sedentary behavior was positively associated with BMI (β = .164, p < .001) and waist circumference (β = .162, p < .001). There were no associations between sedentary behavior and blood pressure, high cholesterol, diabetes, or physical activity.
Conclusions: There is growing evidence that sedentary behavior may have its own unique set of metabolic consequences. However, the consequences of sedentary behavior may not be uniform across subgroups. Evaluating the relationship between sedentary behavior and CVD risk is critical in identifying behaviors, like sedentariness, that contribute to the development of CVD.
A Pilot Study to Assess the Feasibility, Safety and Acceptability of Soy-based Diet for Pregnant Women at High Risk for Gestational Diabetes Mellitus
Background: Diet plays an important role in the prevention and management of gestational diabetes mellitus (GDM). Previous studies suggest that soy protein and isoflavones may have beneficial effects on lipid and glucose metabolism. Little is known regarding the cardiometabolic effects of soy intake during pregnancy. This pilot study assessed the feasibility, safety and acceptability of daily consumption of soy foods during pregnancy in women at high risk for GDM, and participant adherence to their assigned treatment.
Methods: A randomized controlled trial (RCT) was conducted among pregnant women at high risk for GDM. The Soy group were counseled to consume a combination of foods designed to contain ~25 grams of soy protein and 60-75 mg of isoflavones daily from 14 weeks until birth. They were provided with recipes and contents of different soy foods. The Control group maintained their regular diet while minimizing intake of soy containing foods. Assessments, conducted at 14 and 28 weeks of pregnancy, and 6 week postpartum, included physical measurement, questionnaire, and fasting blood samples for lipid, glucose and isoflavone metabolism biomarkers. Monthly follow-up calls were conducted to assess safety and encourage adherence.
Results: Twenty-nine subjects were recruited over a 10 month period. Both Soy and Control groups demonstrated high adherence (80-90%), defined as ≥ 15 days consuming soy foods in the past four weeks for soy group and ≤ 5 days for controls. Only five adverse events were reported possibly associated with soy intake, including nausea, vomiting, diarrhea, and itchy mouth. They were all transient and resolved without sequelae.
Conclusion: Although adherence can be challenging in such a trial, this study used a variety of approaches such as recommended recipes, dietician consultation, and monthly follow-up calls to enhance feasibility and compliance. Results indicated feasibility and adherence to treatment assignment, including the soy-based diet intervention.
About three-quarters of human body surface is exposed to dense microbial population along the gastro-intestinal tract (GIT) that accommodates around 80% of immune cells. The GIT is one of the most critical sites for metabolic and immunologic homeostasis in the body. While large-scale genomic analysis and germ-free mice have been widely used, they are limited to capture the dynamic functional interaction between host-microbiome in a humanized setting. in-vitro recapitulation of GIT physiology can be a powerful alternative for hypothesis testing in diseases like IBD and cancer.
As a first step, we developed a simple transwell assembly to closely emulate GIT anatomy and the barrier function in a quantitative and analytical manner. The system enables us to sequentially house bacterial cells, a mucus layer, human intestinal epithelial cells and human peripheral blood mononuclear cells (hPBMCs) in a single co-culture platform. Porcine intestine-derived mucin formed a biophysically relevant barrier and also provided in-vivo like biochemical milieu to bacterial cells. Addition of human epithelial cell monolayer on a collagen coated semi-permeable membrane added another level of cellular and biophysical complexity. Finally, by introducing human peripheral blood mononuclear cells (hPBMCs), we simulated host-microbiome interactions and successfully captured responses relevant to gut inflammation. Initial data indicate that bacterial products successfully stimulate hPBMCs. Whereas, mucus and epithelial barriers demonstrated strong immunomodulatory functions. Further investigations are being carried out in order to create models that will incorporate differentiated epithelial cells (villi), physiologically relevant flow and stress conditions along with co-culture of aerobic (mucosal) and anaerobic (luminal) components of the human GIT. Hopefully, these models will enable us to study mechanistic interactions of the microbiome with the host and reveal novel therapeutic targets for diseases associated with the dysregulation of host-microbiome homeostasis in human GIT.
Structural and Molecular Analysis of a Protective Epitope of Lyme Disease Antigen OspA and Antibody Interactions
The murine monoclonal antibody LA-2 recognizes a clinically protective epitope on outer surface protein (OspA) of Borrelia burgdorferi, the causative agent of Lyme disease in North America. Human antibody equivalence to LA-2 is the best serologic correlate of protective antibody responses following OspA vaccination. Understanding the structural and functional basis of the LA-2 protective epitope is important for developing OspA-based vaccines and discovering prophylactic antibodies against Lyme disease.
Here, we present a detailed structure-based analysis of the LA-2/OspA interaction interface and identification of residues mediating antibody recognition. Mutations were introduced into both OspA and LA-2 based on computational predictions on the crystal structure of the complex, and experimentally tested for in-vitro binding and borreliacidal activity. We find that Y32 and H49 on the LA-2 light chain, N52 on the LA-2 heavy chain and residues A208, N228 and N251 on OspA were the key constituents of OspA/LA-2 interface. These results reveal specific residues that may be exploited to modulate recognition of the protective epitope of OspA and have implications for design of vaccines against Lyme disease.
Association between First Trimester Pregnancy Associated Plasma Protein–A and the Development of Gestational Diabetes Mellitus
Background: Gestational diabetes (GDM) is a common pregnancy complication with significant cardiometabolic consequences for mothers and offspring. Previous research from our group suggests that adipose tissue IGFBP-5 and its unique metalloprotease PAPP-A (Pregnancy Associated Plasma Protein-A) may play mechanistic roles in GDM development by regulating functional IGF-1 levels and lipid storage and metabolism.
Aim: To examine the relationship between circulating PAPP-A levels and GDM development. We hypothesized that high first trimester PAPP-A levels would be associated with decreased GDM risk.
Methods: A retrospective cohort of women delivering singleton gestations at UMass Memorial Healthcare (2009, 2010, 2014, 2015) was assembled by abstracting electronic medical records. PAPP-A was measured in first trimester (11-14 weeks), and reported as quartiles of multiples of the mean (MoM) based on gestational age and adjusted for maternal weight and race/ethnicity. GDM diagnosis based on standard 2-step protocol (~24-28 weeks; failed 50g 1hr glucola screen then ≥2 abnormal values per Carpenter-Coustan criteria on 100g 3hr glucose tolerance test). Crude and multivariable-adjusted logistic regression models estimated the association between PAPP-A MoM quartiles and GDM.
Results: Women (N=1,251) were 29.7 (SD:5.7) years old and 12.5 (SD:0.6) weeks gestation at PAPP-A measurement. 7.6% (n=95) developed GDM. Median PAPP-A MoM were 0.7 (inter-quartile range [IQR]=0.5-1.0) among women with GDM and 0.9 (IQR=0.6-1.3) among controls; 39% versus 23% were in the 1st quartile, respectively. After adjusting for pre-pregnancy body mass index, nuchal translucency, crown rump length, smoking status, and parity, women with PAPP-A MoM in 2nd, 3rd, and 4th quartiles had 52% (OR=0.48, 95%CI=0.26-0.88), 45% (OR=0.55, 95%CI=0.30-0.99) and 73% (OR=0.27, 95%CI=0.13-0.53) lower odds of GDM compared to women in the 1st quartile.
Conclusion: Higher PAPP-A MoM levels were associated with lower GDM risk. Future studies will assess whether higher PAPP-A levels are associated with enhanced IGF-1 signaling and improved pregnancy metabolic homeostasis.
5-Hyroxymethylcytosine Immunohistochemical Staining Correlates with Overall Survival in Patients with Chronic Myelomonocytic Leukemia
Introduction Chronic myelomonocytic leukemia (CMML) is a myelodysplastic/myeloproliferative neoplasm that has been associated with a number of genetic mutations, most commonly TET2 mutations in up to 50-60% of cases. Mutations in epigenetic genes such as TET2 are known to disrupt the conversion of 5-methycytosine to 5-hydroxymethylcytosine (5hmC), contributing to oncogenesis. We hypothesized that CMML cases would exhibit decreased 5hmC expression, reflecting the propensity for TET2 mutations in CMML. We also sought to determine whether 5hmC IHC status reflected disease severity in terms of progression to AML and overall patient survival.
Methods Thirty-five cases of CMML from between 1/2006 and 12/2014 were identified from the pathology archives at UMass, under an IRB-approved protocol. IHC was performed on FFPE bone marrow biopsy specimens with an anti-5hmC antibody. Staining was scored based on intensity of nuclear staining: 0 (neg) to 3+ (strong); and proportion of cells staining: 0 ( < 1%), 1 (1-25%), 2 (26-50%), 3 (51-75%), 4 ( > 76%). A combined product score was calculated yielding scores of 0-12. Correlation to clinical parameters (age, blast count, progression to AML, and overall patient survival) was investigated.
Results 60% (21/35) of CMML cases showed low expression of 5hmc (combined score < =4). This loss of 5hmC expression correlated significantly with poorer overall survival in Kaplan-Meier curves (p=0.0287). There was no significant correlation between 5hmC score and patient age, blast count, or AML progression.
Conclusion IHC detection of 5hmC in CMML is significantly correlated with patient overall survival and could potentially be utilized as a prognostic biomarker. Loss of 5hmC expression likely reflects mutations to epigenetic pathways and could be useful in guiding treatment with hypomethylating agents.
Identification of fully human monoclonal antibodies against the adhesin domain of colonizing factor antigen I of Escherichia coli
Enterotoxigenic Escherichia coli (ETEC) causes significant diarrheal illness in infants in the developing world and travelers to endemic countries including military personnel. Infection of the host involves bacterial colonization of the small intestinal epithelium and toxin secretion leading to watery diarrhea. CFA/I is the most common colonizing factor antigens expressed on the surface of ETEC isolates. The CFA/I adhesin, CfaE, appears to be required for ETEC binding to human intestinal cells for colonization. Human antibodies against the binding domain of CfaE have potential to block colonization of ETEC and serve as a potent immunoprophylactic therapeutic for ETEC-related diarrhea.
In the current study, we generated a panel of fully human monoclonal antibodies (HuMabs) against the adhesin domain of CfaE using mice transgenic for human immunoglobulin genes and identified lead antibodies utilizing a series of in vitro assays. Mice were immunized with the N-terminal binding domain of CfaE fused to maltose binding protein. Over thirty unique IgG1 HuMabs were identified with binding activity to recombinant CfaE. These antibodies were tested for inhibition of hemagglutination of type A human erythrocytes by ETEC. Two lead HuMabs, 837-6 and 840-53, inhibited hemagglutination at low concentrations (< 1 nM). Both antibodies also blocked the binding of ETEC with intestinal epithelial cells. Biacore analysis revealed an affinity of less than 2 nM with distinct epitopes of CfaE. Our analysis suggests that CfaE specific HuMabs 837-6 and 840-53, as the first isolated fully human monoclonal antibodies against CfaE adhesion domain, could potentially be used in combination with heat labile toxin neutralizing antibodies to prevent traveler’s diarrhea.
Effect of Left Atrial Function Index on Late Atrial Fibrillation Recurrence after Pulmonary Vein Isolation
Background: Although the rates of catheter ablation (CA) for atrial fibrillation (AF) are rapidly increasing, there are few predictors of outcome to help inform appropriate patient selection for this procedure. Traditional echocardiographic measures of atrial structure do not significantly reclassify risk of AF recurrence over and above the clinical risk factors. Left Atrial Function Index (LAFI) is a rhythm-independent measure of atrial function. We hypothesized that baseline LAFI would relate to AF recurrence after CA.
Methods: Pre-procedural echocardiograms from 170 participants, who underwent CA for AF and were enrolled in the UMMC AF Treatment Registry, were analyzed. LAFI was calculated by a previously validated formula. Primary outcome was late or clinically significant AF recurrence 3-12 months after CA. Baseline clinical, laboratory and echocardiographic variables were compared between the recurrence and non-recurrence groups.
Results: Study participants were middle aged (60+/10 years) and had a moderate-to-severe burden of cardiovascular comorbidities. 78 participants (46%) experienced late AF recurrence. Mean LAFI was 0.26+/-0.18. In multivariate analysis, lower LAFI was independently associated with the risk of recurrence (0.23 in recurrence group vs 0.29 in non-recurrence group, p < 0.01). Predictive value of LAFI for AF recurrence was similar to CHADS2 score (c-statistic 0.60 vs 0.58, p 0.76). In subgroup of patients with persistent AF, LAFI predicted AF recurrence more strongly than CHADS2 score (c-statistic: 0.79 vs 0.58, p 0.02).
Conclusions: In our cohort of 170 participants with AF undergoing index CA ablation, we observed that LAFI related to late AF recurrence after CA, independent of the traditional risk factors. Since LAFI can be calculated from almost any traditional echocardiographic recording, our findings suggest that LAFI may help guide therapeutic decision-making regarding application of CA, particularly among challenging patients with symptomatic persistent AF.