Cell-to-Cell Variation in p53 Dynamics Leads to Fractional Killing.

Many chemotherapeutic drugs kill only a fraction of cancer cells, limiting their efficacy. We used live-cell imaging to investigate the role of p53 dynamics in fractional killing of colon cancer cells in response to chemotherapy. We found that both surviving and dying cells reach similar levels of p53, indicating that cell death is not determined by a fixed p53 threshold. Instead, a cell's probability of death depends on the time and levels of p53. Cells must reach a threshold level of p53 to execute apoptosis, and this threshold increases with time. The increase in p53 apoptotic threshold is due to drug-dependent induction of anti-apoptotic genes, predominantly in the inhibitors of apoptosis (IAP) family. Our study underlines the importance of measuring the dynamics of key players in response to chemotherapy to determine mechanisms of resistance and optimize the timing of combination therapy.

MICU3 Regulates Mitochondrial Calcium and Cardiac Hypertrophy.

BACKGROUND: Calcium (Ca2+) uptake by mitochondria occurs via the mitochondrial Ca2+ uniporter. Mitochondrial Ca2+ uniporter exists as a complex, regulated by 3 MICU (mitochondrial Ca2+ uptake) proteins localized in the intermembrane space: MICU1, MICU2, and MICU3. Although MICU3 is present in the heart, its role is largely unknown. METHODS: We used CRISPR-Cas9 to generate a mouse with global deletion of MICU3 and an adeno-associated virus (AAV9) to overexpress MICU3 in wild-type mice. We examined the role of MICU3 in regulating mitochondrial calcium ([Ca2+]m) in ex vivo hearts using an optical method following adrenergic stimulation in perfused hearts loaded with a Ca2+-sensitive fluorophore. Additionally, we studied how deletion and overexpression of MICU3, respectively, impact cardiac function in vivo by echocardiography and the molecular composition of the mitochondrial Ca2+ uniporter complex via Western blot, immunoprecipitation, and Blue native-PAGE analysis. Finally, we measured MICU3 expression in failing human hearts. RESULTS: MICU3 knock out hearts and cardiomyocytes exhibited a significantly smaller increase in [Ca2+]m than wild-type hearts following acute isoproterenol infusion. In contrast, heart with overexpression of MICU3 exhibited an enhanced increase in [Ca2+]m compared with control hearts. Echocardiography analysis showed no significant difference in cardiac function in knock out MICU3 mice relative to wild-type mice at baseline. However, mice with overexpression of MICU3 exhibited significantly reduced ejection fraction and fractional shortening compared with control mice. We observed a significant increase in the ratio of heart weight to tibia length in hearts with overexpression of MICU3 compared with controls, consistent with hypertrophy. We also found a significant decrease in MICU3 protein and expression in failing human hearts. CONCLUSIONS: Our results indicate that increased and decreased expression of MICU3 enhances and reduces, respectively, the uptake of [Ca2+]m in the heart. We conclude that MICU3 plays an important role in regulating [Ca2+]m physiologically, and overexpression of MICU3 is sufficient to induce cardiac hypertrophy, making MICU3 a possible therapeutic target.

Global Inhibition with Specific Activation: How p53 and MYC Redistribute the Transcriptome in the DNA Double-Strand Break Response.

In response to stresses, cells often halt normal cellular processes, yet stress-specific pathways must bypass such inhibition to generate effective responses. We investigated how cells redistribute global transcriptional activity in response to DNA damage. We show that an oscillatory increase of p53 levels in response to double-strand breaks drives a counter-oscillatory decrease of MYC levels. Using RNA sequencing (RNA-seq) of newly synthesized transcripts, we found that p53-mediated reduction of MYC suppressed general transcription, with the most highly expressed transcripts reduced to a greater extent. In contrast, upregulation of p53 targets was relatively unaffected by MYC suppression. Reducing MYC during the DNA damage response was important for cell-fate regulation, as counteracting MYC repression reduced cell-cycle arrest and elevated apoptosis. Our study shows that global inhibition with specific activation of transcriptional pathways is important for the proper response to DNA damage; this mechanism may be a general principle used in many stress responses.

Stereodivergent Synthesis of 1,4-Dicarbonyl Compounds through Sulfonium Rearrangement: Mechanistic Investigation, Stereocontrolled Access to γ-Lactones and γ-Lactams, and Total Synthesis of Paraconic Acids.

Although simple γ-lactones and γ-lactams have received considerable attention from the synthetic community, particularly due to their relevance in biological and medicinal contexts, stereoselective synthetic approaches to more densely substituted derivatives remain scarce. The in-depth study presented herein, showcasing a straightforward method for the stereocontrolled synthesis of γ-lactones and γ-lactams, builds on and considerably expands the stereodivergent synthesis of 1,4-dicarbonyl compounds by a ynamide/vinyl sulfoxide coupling. A full mechanistic and computational study of the rearrangement was conducted, uncovering the role of all of the reaction components and providing a rationale for stereoselection. The broad applicability of the developed tools to streamlining synthesis is demonstrated by concise enantioselective total syntheses of (+)-nephrosteranic acid, (+)-rocellaric acid, and (+)-nephromopsinic acid.

Mechanisms of reduced myocardial energetics of the dystrophic heart.

Heart disease is a leading cause of death in patients with Duchenne muscular dystrophy (DMD), characterized by the progressive replacement of contractile tissue with scar tissue. Effective therapies for dystrophic cardiomyopathy will require addressing the disease before the onset of fibrosis, however, the mechanisms of the early disease are poorly understood. To understand the pathophysiology of DMD, we perform a detailed functional assessment of cardiac function of the mdx mouse, a model of DMD. These studies use a combination of functional, metabolomic, and spectroscopic approaches to fully characterize the contractile, energetic, and mitochondrial function of beating hearts. Through these innovative approaches, we demonstrate that the dystrophic heart has reduced cardiac reserve and is energetically limited. We show that this limitation does not result from poor delivery of oxygen. Using spectroscopic approaches, we provide evidence that mitochondria in the dystrophic heart have attenuated mitochondrial membrane potential and deficits in the flow of electrons in complex IV of the electron transport chain. These studies provide evidence that poor myocardial energetics precede the onset of significant cardiac fibrosis and likely results from mitochondrial dysfunction centered around complex IV and reduced membrane potential. The multimodal approach used here implicates specific molecular components in the etiology of reduced energetics. Future studies focused on these targets may provide therapies that improve the energetics of the dystrophic heart leading to improved resiliency against damage and preservation of myocardial contractile tissue.NEW & NOTEWORTHY Dystrophic hearts have poor contractile reserve that is associated with a reduction in myocardial energetics. We demonstrate that oxygen delivery does not contribute to the limited energy production of the dystrophic heart even with increased workloads. Cytochrome optical spectroscopy of the contracting heart reveals alterations in complex IV and evidence of depolarized mitochondrial membranes. We show specific alterations in the electron transport chain of the dystrophic heart that may contribute to poor myocardial energetics.

Distinct effects of cardiac mitochondrial calcium uniporter inactivation via EMRE deletion in the short and long term.

Transport of Ca2+ into mitochondria is thought to stimulate the production of ATP, a critical process in the heart's fight or flight response, but excess Ca2+ can trigger cell death. The mitochondrial Ca2+ uniporter complex is the primary route of Ca2+ transport into mitochondria, in which the channel-forming protein MCU and the regulatory protein EMRE are essential for activity. In previous studies, chronic Mcu or Emre deletion differed from acute cardiac Mcu deletion in response to adrenergic stimulation and ischemia/reperfusion (I/R) injury, despite equivalent inactivation of rapid mitochondrial Ca2+ uptake. To explore this discrepancy between chronic and acute loss of uniporter activity, we compared short-term and long-term Emre deletion using a novel conditional cardiac-specific, tamoxifen-inducible mouse model. After short-term Emre deletion (3 weeks post-tamoxifen) in adult mice, cardiac mitochondria were unable to take up Ca2+, had lower basal mitochondrial Ca2+ levels, and displayed attenuated Ca2+-induced ATP production and mPTP opening. Moreover, short-term EMRE loss blunted cardiac response to adrenergic stimulation and improved maintenance of cardiac function in an ex vivo I/R model. We then tested whether the long-term absence of EMRE (3 months post-tamoxifen) in adulthood would lead to distinct outcomes. After long-term Emre deletion, mitochondrial Ca2+ handling and function, as well as cardiac response to adrenergic stimulation, were similarly impaired as in short-term deletion. Interestingly, however, protection from I/R injury was lost in the long-term. These data suggest that several months without uniporter function are insufficient to restore bioenergetic response but are sufficient to restore susceptibility to I/R.

Astrocyte-specific knockout of YKL-40/Chi3l1 reduces Aß burden and restores memory functions in 5xFAD mice.

Glial cell-mediated neuroinflammation and neuronal attrition are highly correlated with cognitive impairment in Alzheimer's disease. YKL-40 is a secreted astrocytic glycoprotein that serves as a diagnostic biomarker of Alzheimer's disease. High levels of YKL-40 are associated with either advanced Alzheimer's disease or the normal aging process. However, the functional role of YKL-40 in Alzheimer's disease development has not been firmly established. In a 5xFAD mouse model of Alzheimer's disease, we observed increased YKL-40 expression in the cerebrospinal fluid of 7-month-old mice and was correlated with activated astrocytes. In primary astrocytes, Aß1-42 upregulated YKL-40 in a dose-dependent manner and was correlated with PI3-K signaling pathway activation. Furthermore, primary neurons treated with YKL-40 and/or Aß1-42 resulted in significant synaptic degeneration, reduced dendritic complexity, and impaired electrical parameters. More importantly, astrocyte-specific knockout of YKL-40 over a period of 7 days in symptomatic 5xFAD mice could effectively reduce amyloid plaque deposition in multiple brain regions. This was also associated with attenuated glial activation, reduced neuronal attrition, and restored memory function. These biological phenotypes could be explained by enhanced uptake of Aß1-42 peptides, increased rate of Aß1-42 degradation and acidification of lysosomal compartment in YKL-40 knockout astrocytes. Our results provide new insights into the role of YKL-40 in Alzheimer's disease pathogenesis and demonstrate the potential of targeting this soluble biomarker to alleviate cognitive defects in symptomatic Alzheimer's disease patients.

A Communitywide Collaboration to Increase Enrollment, Retention, and Success in Evidence-Based Lifestyle-Change Programs in Racial and Ethnic Minority Populations.

PURPOSE AND OBJECTIVES: Chronic diseases (eg, diabetes, hypertension) are the leading causes of death in the US and disproportionally affect racial and ethnic minority populations. This disparity is partially due to the unequal burden of unmet social needs that stem from several factors, including racism. INTERVENTION APPROACH: The Alliance is a collaboration among health care, public health, and community organizations formed to improve referral, enrollment, and successful completion of evidence-based lifestyle-change programs, particularly among Black people. The Alliance built 1) a system to assess and address social barriers through the screening and referral process and 2) a training center for frontline staff (eg, community health workers). EVALUATION METHODS: From January 2020 through September 2022, we conducted an evaluation that included both quantitative and qualitative methods. We developed an electronic database to make referrals and track key barriers to participation. Additionally, we conducted a focus group among frontline staff (N = 15) to understand the challenges in making referrals and discussing, documenting, and addressing barriers to participation. We used surveys that collected quantitative and open-ended qualitative responses to evaluate the training center and to understand perceptions of training modules as well as the skills gained. RESULTS: Frontline staff engaged with 6,036 people, of whom 847 (14%) were referred to a lifestyle-change program from January 2020 through September 2022. Of those referred, 257 (30%) were eligible and enrolled in a program. Food access and unreliable internet were the most common barriers to participation. Thirteen of 15 frontline staff participated in trainings, and, on average, trainees completed 4.2 trainings and gained several skills (eg, ability to monitor personal bias, de-escalate a crisis, educate on mental health, understand community and environmental factors). IMPLICATIONS FOR PUBLIC HEALTH: The Alliance is an example of how health care, public health, and community partners can work together to increase enrollment in lifestyle-change programs of residents disproportionately affected by chronic diseases. Lessons learned from implementation and evaluation can inform other complex partnerships to improve public health.

Urinary manifestations in African American and Caucasian inflammatory bowel disease patients: a retrospective cohort study.

BACKGROUND: Inflammatory bowel diseases (IBD), like ulcerative colitis (UC) and Crohn's disease (CD), are associated with urinary extra-intestinal manifestations, like urolithiasis and uncomplicated urinary tract infections (UTIs). The literature reviewed for this study identifies an increased association of CD and urolithiasis against the general population as well as UC. Furthermore, the rates in which urinary comorbidities manifest have not been well characterized in cross-race analyses. The purpose of this study is to establish the prevalence of common urinary extra-intestinal manifestations in CD and UC and to further determine at what rate these affect the African American and Caucasian populations. METHODOLOGY: This is a retrospective cohort study using de-identified data collected from a research data base that included 6 integrated facilities associated with one tertiary healthcare center from 2012 to 2019. The electronic chart records for 3104 Caucasian and African American IBD patients were reviewed for frequency of urolithiasis and uncomplicated UTI via diagnosed ICD-10 codes. Comparison between data groups was made using multivariate regressions, t-tests, and chi square tests. RESULTS: Our study included 3104 patients of which 59% were female, 38% were African American, and 43% were diagnosed with UC. Similar proportions of UC and CD diagnosed patients developed urolithiasis (6.0% vs 6.7%, p = 0.46), as well as uncomplicated UTIs (15.6% vs. 14.9%, p = 0.56). Similar proportions of African American and Caucasian patients developed urolithiasis (5.4% vs 7.0%, p = 0.09), but a higher proportion of African Americans developed uncomplicated UTIs (19.4% vs 12.6%, p ≤ 0.001). CONCLUSION: We found similar rates of urolithiasis formation in both UC and CD in this study. Furthermore, these rates were not significantly different between African American and Caucasian IBD populations. This suggests that UC patients have an elevated risk of urolithiasis formation as those patients with CD. Additionally, African Americans with IBD have a higher frequency of uncomplicated UTI as compared to their Caucasian counterparts.

Small intestinal immunopathology and GI-associated antibody formation in hereditary alpha-tryptasemia.

BACKGROUND: Hereditary alpha-tryptasemia (HαT) is characterized by elevated basal serum tryptase due to increased copies of the TPSAB1 gene. Individuals with HαT frequently present with multisystem complaints, including anaphylaxis and seemingly functional gastrointestinal (GI) symptoms. OBJECTIVE: We sought to determine the prevalence of HαT in an irritable bowel syndrome cohort and associated immunologic characteristics that may distinguish patients with HαT from patients without HαT. METHODS: Tryptase genotyping by droplet digital PCR, flow cytometry, cytometry by time-of-flight, immunohistochemistry, and other molecular biology techniques was used. RESULTS: HαT prevalence in a large irritable bowel syndrome cohort was 5% (N = 8/158). Immunophenotyping of HαT PBMCs (N ≥ 27) revealed increased total and class-switched memory B cells. In the small bowel, expansion of tissue mast cells with expression of CD203c, HLA-DR, and FcεRI, higher intestinal epithelial cell pyroptosis, and increased class-switched memory B cells were observed. IgG profiles in sera from individuals with HαT (N = 21) significantly differed from those in individuals with quiescent Crohn disease (N = 20) and non-HαT controls (N = 19), with increased antibodies directed against GI-associated proteins identified in individuals with HαT. CONCLUSIONS: Increased mast cell number and intestinal epithelial cell pyroptosis in the small intestine, and class-switched memory B cells in both the gut and peripheral blood associated with IgG reactive to GI-related proteins, distinguish HαT from functional GI disease. These innate and adaptive immunologic findings identified in association with HαT are suggestive of subclinical intestinal inflammation in symptomatic individuals.

Increased ACE2 Levels and Mortality Risk of Patients With COVID-19 on Proton Pump Inhibitor Therapy.

INTRODUCTION: Proton pump inhibitor (PPI) use was recently reported to be associated with increased severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and worse clinical outcomes. The underlying mechanism(s) for this association are unclear. METHODS: We performed a prospective study of hospitalized coronavirus disease 2019 (COVID-19) patients and COVID-negative controls to understand how PPI use may affect angiotensin-converting enzyme 2 (ACE2) expression and stool SARS-CoV-2 RNA. Analysis of a retrospective cohort of hospitalized patients with COVID-19 from March 15, 2020 to August 15, 2020 in 6 hospitals was performed to evaluate the association of PPI use and mortality. Covariates with clinical relevance to COVID-19 outcomes were included to determine predictors of in-hospital mortality. RESULTS: Control PPI users had higher salivary ACE2 mRNA levels than nonusers, 2.39 ± 1.15 vs 1.22 ± 0.92 (P = 0.02), respectively. Salivary ACE2 levels and stool SARS-CoV-2 RNA detection rates were comparable between users and nonusers of PPI. In 694 hospitalized patients with COVID-19 (age = 58 years, 46% men, and 65% black), mortality rate in PPI users and nonusers was 30% (68/227) vs 12.1% (53/439), respectively. Predictors of mortality by logistic regression were PPI use (adjusted odds ratio [aOR] = 2.72, P < 0.001), age (aOR = 1.66 per decade, P < 0.001), race (aOR = 3.03, P = 0.002), cancer (aOR = 2.22, P = 0.008), and diabetes (aOR = 1.95, P = 0.003). The PPI-associated mortality risk was higher in black patients (aOR = 4.16, 95% confidence interval: 2.28-7.59) than others (aOR = 1.62, 95% confidence interval: 0.82-3.19, P = 0.04 for interaction). DISCUSSION: COVID-negative PPI users had higher salivary ACE2 expression. PPI use was associated with increased mortality risk in patients with COVID-19, particularly African Americans.

Is MCU dispensable for normal heart function?

The uptake of Ca2+ into mitochondria is thought to be an important signal communicating the need for increased energy production. However, dysregulated uptake leading to mitochondrial Ca2+ overload can trigger opening of the mitochondrial permeability transition pore and potentially cell death. Thus mitochondrial Ca2+ entry is regulated via the activity of a Ca2+-selective channel known as the mitochondrial calcium uniporter. The last decade has seen enormous momentum in the discovery of the molecular identities of the multiple proteins comprising the uniporter. Increasing numbers of studies in cultured cells and animal models have provided insight into how disruption of uniporter proteins affects mitochondrial Ca2+ regulation and impacts tissue function and physiology. This review aims to summarize some of these recent findings, particularly in the context of the heart.

Intra-gastrointestinal amyloid-ß1-42 oligomers perturb enteric function and induce Alzheimer's disease pathology.

KEY POINTS: Alzheimer's disease (AD) patients and transgenic mice have beta-amyloid (Aß) aggregation in the gastrointestinal (GI) tract. It is possible that Aß from the periphery contributes to the load of Aß in the brain, as Aß has prion-like properties. The present investigations demonstrate that Aß injected into the GI tract of ICR mice is internalised into enteric cholinergic neurons; at 1 month, administration of Aß into the body of the stomach and the proximal colon was observed to partly redistribute to the fundus and jejunum; at 1 year, vagal and cerebral ß-amyloidosis was present, and mice exhibited GI dysfunction and cognitive deficits. These data reveal a previously undiscovered mechanism that potentially contributes to the development of AD. ABSTRACT: Alzheimer's disease (AD) is the most common age-related cause of dementia, characterised by extracellular beta-amyloid (Aß) plaques and intracellular phosphorylated tau tangles in the brain. Aß deposits have also been observed in the gastrointestinal (GI) tract of AD patients and transgenic mice, with overexpression of amyloid precursor protein. In the present studies, we investigate whether intra-GI administration of Aß can potentially induce amyloidosis in the central nervous system (CNS) and AD-related pathology such as dementia. We micro-injected Aß1-42 oligomers (4 µg per site, five sites) or vehicle (saline, 5 µl) into the gastric wall of ICR mice under general anaesthesia. Immunofluorescence staining and in vivo imaging showed that HiLyte Fluor 555-labelled Aß1-42 had migrated within 3 h via the submucosa to nearby areas and was internalised into cholinergic neurons. At 1 month, HiLyte Fluor 555-labelled Aß1-42 in the body of the stomach and proximal colon had partly re-distributed to the fundus and jejunum. At 1 year, the jejunum showed functional alterations in neuromuscular coupling (P < 0.001), and Aß deposits were present in the vagus and brain, with animals exhibiting cognitive impairments in the Y-maze spontaneous alteration test (P < 0.001) and the novel object recognition test (P < 0.001). We found that enteric Aß oligomers induce an alteration in gastric function, amyloidosis in the CNS, and AD-like dementia via vagal mechanisms. Our results suggest that Aß load is likely to occur initially in the GI tract and may translocate to the brain, opening the possibility of new strategies for the early diagnosis and prevention of AD.

Acetylcholine exerts inhibitory and excitatory actions on mouse ileal pacemaker activity: role of muscarinic versus nicotinic receptors.

The effect of acetylcholine (ACh) on pacemaking and spontaneous contractions in the gastrointestinal tract is not well characterized. The current study aims to profile the effect of several muscarinic and nicotinic receptor agonists and antagonists on pacemaker potentials in the ICR mouse ileum. Pacemaker potentials of whole thickness mouse ileal segments were recorded extracellularly using a 60-channel microelectrode array (MEA) platform. A spatiotemporal analysis integrated the frequency, amplitude, and velocity measurements of pacemaker currents. Comparative data were obtained by recording spontaneous smooth muscle tone in a conventional organ bath. On the MEA, ACh (0.3-300 µM) and bethanechol (0.3-300 µM) significantly reduced ileal pacemaker potentials. The inhibitory effect of ACh was mimicked by donepezil (300 µM) but not nicotine (0.3-7 mM). Atropine (300 µM), but not hexamethonium (300 µM), reversed the inhibitory actions of ACh and bethanechol and revealed excitatory properties manifested as increases in pacemaker frequency. A spatial analysis also revealed that atropine, but not hexamethonium, reversed the ACh-induced distortion of pacemaker propagation activity. Atropine (0.001-3 mM) and hexamethonium (0.3-7 mM) alone were inactive. In the organ bath, ACh (300 nM) and bethanechol (30 µM) induced ileal tonic contractions, while inhibiting basal spontaneous contractions at 300 µM. Atropine (1 µM), but not hexamethonium (1-300 µM), reversed both the tonic contractions and the inhibition of the spontaneous contractions of ACh and bethanechol and revealed an excitatory effect manifested as an increasing in the frequency of contractions. Muscarinic, but not nicotinic, receptors appear to mediate the inhibitory actions of ACh on mouse ileal pacemaker potentials.NEW & NOTEWORTHY The study discovered an acute action of acetylcholine on pacemaker potentials that is mediated by muscarinic receptors on the mouse ileum. Bethanechol, but not nicotine, mimicked the inhibitory actions of acetylcholine on pacemaker potentials. Atropine, but not hexamethonium, reversed the inhibitory actions of acetylcholine. When introduced after acetylcholine, atropine exhibited excitatory actions that increased the pacemaker frequency. Acetylcholine and bethanechol distorted the propagation activity and pattern, and this was also reversed by atropine. These actions of acetylcholine on pacemaker potentials may contribute to pathophysiology in bowel diseases.

Evidence of Duodenal Epithelial Barrier Impairment and Increased Pyroptosis in Patients With Functional Dyspepsia on Confocal Laser Endomicroscopy and "Ex Vivo" Mucosa Analysis.

INTRODUCTION: Duodenal epithelial barrier impairment and immune activation may play a role in the pathogenesis of functional dyspepsia (FD). This study was aimed to evaluate the duodenal epithelium of patients with FD and healthy individuals for detectable microscopic structural abnormalities. METHODS: This is a prospective study using esophagogastroduodenoscopy enhanced with duodenal confocal laser endomicroscopy (CLE) and mucosal biopsies in patients with FD (n = 16) and healthy controls (n = 18). Blinded CLE images analysis evaluated the density of epithelial gaps (cell extrusion zones), a validated endoscopic measure of the intestinal barrier status. Analyses of the biopsied duodenal mucosa included standard histology, quantification of mucosal immune cells/cytokines, and immunohistochemistry for inflammatory epithelial cell death called pyroptosis. Transepithelial electrical resistance (TEER) was measured using Ussing chambers. Epithelial cell-to-cell adhesion proteins expression was assessed by real-time polymerase chain reaction. RESULTS: Patients with FD had significantly higher epithelial gap density on CLE in the distal duodenum than that of controls (P = 0.002). These mucosal abnormalities corresponded to significant changes in the duodenal biopsy samples of patients with FD, compared with controls, including impaired mucosal integrity by TEER (P = 0.009) and increased number of epithelial cells undergoing pyroptosis (P = 0.04). Reduced TEER inversely correlated with the severity of certain dyspeptic symptoms. Furthermore, patients with FD demonstrated altered duodenal expression of claudin-1 and interleukin-6. No differences in standard histology were found between the groups. DISCUSSION: This is the first report of duodenal CLE abnormalities in patients with FD, corroborated by biopsy findings of epithelial barrier impairment and increased cell death, implicating that duodenal barrier disruption is a pathogenesis factor in FD and introducing CLE a potential diagnostic biomarker in FD.

Personalized Inflammatory Bowel Disease Care Reduced Hospitalizations.

BACKGROUND AND AIMS: IBD patients with inadequately treated disease often relapse and require hospitalizations for further management. The purpose of this practice review was to determine whether personalized IBD care improved patient outcomes as measured by IBD-related hospitalizations. METHODS: A dedicated IBD clinic was created for personalized patient care in a tertiary veterans health care center in 2014. In the first year, the care program consisted of patient-centered medical home (PCMH). In the second year, personalized biologic therapy was incorporated into the program, based on the severity of mucosal barrier dysfunction measured by probe-based confocal laser endomicroscopy (pCLE) analysis of the terminal ileum during colonoscopy. IBD-related hospitalizations during these 2 years were compared to the year before the care program. RESULTS: The IBD-related admissions at baseline, year 1 and 2 of the program were: total number of admissions of 25, 24, 8 (P = 0.03) per year, total number of hospital days of 177, 144, 31 days per year (P < 0.01), median length of stay 7, 4, and 2 days per visit (P = 0.013), respectively. Patients had significant increases in serum hemoglobin (11.5 ± 2.7, 11.9 ± 2.6, 14.0 ± 1.4 g/dl; P = 0.035), albumin (2.7 ± 0.7, 3.0 ± 0.6 g/dl 3.7 ± 0.8 g/dl; P = 0.031) and body mass index (26.6 ± 2.9, 28.1 ± 5.9; 34.0 ± 10.8; P = 0.047). CONCLUSIONS: Personalized IBD care incorporating a PCMH model and tailored biologic therapy based on pCLE findings of mucosal barrier dysfunction significantly reduced IBD-related hospitalizations.

Localization of estrogen receptor ERα, ERß and GPR30 on myenteric neurons of the gastrointestinal tract and their role in motility.

Estrogen is well known to have a modulatory role on gastrointestinal tract, particularly through its interaction with nuclear estrogen receptors (ERs), alpha and beta (ERα/ß). Recent functional studies also indicate that estrogen can activate a G-protein coupled estrogen receptor, GPR30, or GPER1. The present study was designed to identify either the presence or absence of nuclear ERs and GPR30 in the myenteric plexus of the stomach, duodenum, jejunum, ileum and colon of female and male mice. Immunofluorescence staining revealed a high expression of GPR30 in the cytoplasm but not within the nucleus of enteric neurons in female and male mice. ERß localization was similar to GPR30, where it was expressed in cytoplasm of enteric neurons, but was absent from nuclei, opening up the possibility that ERß and GPR30 might work together to manifest estrogenic effects. Comparatively, ERα was mainly located in the nuclei of enteric neurons. ERα, ERß and GPR30 were also expressed in the cytoplasm of glial cells in the stomach and small intestine, but levels were lower in the colon. The expression nuclear:cytoplasm ratio of ERα was higher in male than female mice, which might relate to sex-dependent translocation of ERα from cytoplasm to nucleus in response to known plasma levels of estrogen. A functional study using isolated ileal segments showed that ERα, ERß and GPR30 are involved in the neuronal-mediated contractions in female tissues, but only ERα was involved in male tissues. This may indicate although expression level was similar between males and females, the downstream mechanisms of ERß and GPR30 could be different between sexes. The present study provides a rationale for the action of estrogen to modulate gastrointestinal function in health and disease in different sexes.

Platelets mediate protective neuroinflammation and promote neuronal plasticity at the site of neuronal injury.

It is generally accepted that inflammation within the CNS contributes to neurodegeneration after traumatic brain injury (TBI), but it is not clear how inflammation is initiated in the absence of infection and whether this neuroinflammation is predominantly beneficial or detrimental. We have previously found that brain-enriched glycosphingolipids within neuronal lipid rafts (NLR) induced platelet degranulation and secretion of neurotransmitters and pro-inflammatory factors. In the present study, we compared TBI-induced inflammation and neurodegeneration in wild-type vs. St3gal5 deficient (ST3-/-) mice that lack major CNS-specific glycosphingolipids. After TBI, microglial activation and CNS macrophage infiltration were substantially reduced in ST3-/- animals. However, ST3-/- mice had a larger area of CNS damage with marked neuronal/axonal loss. The interaction of platelets with NLR stimulated neurite growth, increased the number of PSD95-positive dendritic spines, and intensified neuronal activity. Adoptive transfer and blocking experiments provide further that platelet-derived serotonin and platelet activating factor plays a key role in the regulation of sterile neuroinflammation, hemorrhage and neuronal plasticity after TBI.

The ins and outs of mitochondrial calcium.

Calcium is thought to play an important role in regulating mitochondrial function. Evidence suggests that an increase in mitochondrial calcium can augment ATP production by altering the activity of calcium-sensitive mitochondrial matrix enzymes. In contrast, the entry of large amounts of mitochondrial calcium in the setting of ischemia-reperfusion injury is thought to be a critical event in triggering cellular necrosis. For many decades, the details of how calcium entered the mitochondria remained a biological mystery. In the past few years, significant progress has been made in identifying the molecular components of the mitochondrial calcium uniporter complex. Here, we review how calcium enters and leaves the mitochondria, the growing insight into the topology, stoichiometry and function of the uniporter complex, and the early lessons learned from some initial mouse models that genetically perturb mitochondrial calcium homeostasis.