A Comparison of Injectable Diazepam and Lorazepam in the Goal-Directed Management of Severe Alcohol Withdrawal.

BACKGROUND: Benzodiazepines are the gold standard for treatment of alcohol withdrawal, yet the selection of a preferred benzodiazepine is limited due to a lack of comparative studies. OBJECTIVES: The primary objective of this study was to compare the efficacy and safety of injectable lorazepam (LZP) and diazepam (DZP) in the treatment of severe alcohol withdrawal syndrome (AWS). METHODS: Retrospective cohort study of adult patients admitted to an intensive care unit with a primary diagnosis of AWS. Subjects who received at least 12 LZP equivalent units (LEU) of injectable DZP or LZP within 24 hours of initiation of the severe AWS protocol were included. The primary outcome was time with Clinical Institute Withdrawal Assessment for Alcohol-Revised (CIWA-Ar) scores at goal over the first 24 hours of treatment. RESULTS: A total of 191 patients were included (DZP n = 89, LZP n = 102). Time with CIWA-Ar scores at goal during the first 24 hours was similar between groups (DZP 12 hours [interquartile range, IQR, = 9-15] vs LZP 14 hours [IQR = 10-17]), P = 0.06). At 24 hours, LEU requirement was similar (DZP 40 [IQR = 22-78] vs LZP 32 [IQR = 18-56], P = 0.05). Drug cost at 24 hours was higher in the DZP group ($204.6 [IQR = 112.53-398.97] vs $8 [IQR = 4.5-14], P < 0.01). CONCLUSION AND RELEVANCE: DZP or LZP are equally efficacious for the treatment of severe AWS. LZP may be preferred due to cost but both medications can be used interchangeably based on availability.

Mammographic and Sonographic Findings of Intraductal Papilloma of the Right Breast: A Case Report.

Intraductal papillomas are tumors that arise in the epithelial cells of the mammary duct. Common presenting symptoms for intraductal papilloma include serous or serosanguinous nipple discharge or a palpable mass. We present a case of a 48-year-old woman who presented with spontaneous right breast nipple discharge and a palpable mass. Diagnostic imaging for the patient included mammography and ultrasound with color doppler imaging that revealed a mass at eight o'clock in the right breast at a distance of 2 cm from the nipple and that corresponded to the area of palpable concern. Percutaneous ultrasound-guided biopsy of the mass confirmed a diagnosis of intraductal papilloma. Surgical excision may be required in many cases of an intraductal papilloma due to the variety of diagnoses that can be included on the differential, the increased risk for cellular atypia, and the treatment for spontaneous nipple discharge.

Cefepime Versus Piperacillin-Tazobactam for the Treatment of Intra-Abdominal Infections Secondary to Potential AmpC Beta-Lactamase-Producing Organisms.

Background: Recent studies have established cefepime as an effective treatment option for AmpC beta-lactamase (AmpC) Enterobacterales; however, the efficacy of beta-lactam/beta-lactamase inhibitors is unclear. Objective: The objective of this study was to determine if piperacillintazobactamis an appropriate alternative to cefepime for the treatment of intra-abdominal infections (IAIs) secondary to AmpC-producing organisms. Methods: This multicenter, retrospective cohort study was conducted in hospitalized adults with an IAI caused by an AmpC-producing organism and received either cefepime or piperacillin-tazobactam for definitive treatment after a source control procedure. The primary outcome was a composite of surgical site infections, recurrent IAIs, or in-hospital mortality. Secondary outcomes included the individual components of the composite outcome, hospital length of stay (LOS), microbiologic failure, study antibiotic duration, time to clinical resolution, and incidence of Clostridioides difficile infection (CDI). Results: This study included 119 patients. There was no difference in the primary outcome between the cefepime and piperacillin-tazobactam groups (35% vs 27%, P = 0.14). Microbiological failure was the only secondary outcome with an observed difference between groups (17% vs 0%, P = 0.01): hospital LOS (15 vs 13 days, P = 0.09), days of therapy (7 vs 7 days, P = 0.87), time to clinical resolution (7 vs 4 days, P = 0.30), and CDI (1% vs 2%, P = 0.58) were all similar.

A Comparison of Midazolam and Propofol for Deep Sedation in Patients with Acute Respiratory Distress Syndrome Requiring Neuromuscular Blocking Agents.

Purpose: The optimal agent for deep sedation in patients undergoing continuous infusion (CI) neuromuscular blocking agent (NMBA) use for acute respiratory distress syndrome (ARDS) is unknown. The purpose of this study is to compare the efficacy and safety of propofol and midazolam in ARDS patients requiring CI NMBA. Methods: A multi-center, retrospective study was performed in mechanically ventilated (MV) adult patients requiring CI NMBA for management of ARDS. The primary outcome was to compare the time to liberation from MV in patients sedated with propofol vs midazolam. Results: In the 109 patients included, there was no difference in time to MV liberation with propofol as compared to midazolam (121 hr [Interquartile range (IQR) 67 195] vs 98 hr [IQR 48, 292], P = .72). Median time to sedation emergence after NMBA discontinuation was shorter in patients receiving propofol (12.9 hr [IQR 19.8, 72.5] vs 31.5 hr [IQR 6.4, 34.6], P < .01). There were no significant differences in time to therapeutic sedation, ICU stay, mortality, and adverse events. Conclusion: Propofol may be an effective and safe alternative to midazolam for patients undergoing CI NMBA for ARDS. Additionally, patients receiving propofol may have a quicker return to light sedation after NMBA discontinuation.

Multimodal Prehabilitation During Neoadjuvant Therapy Prior to Esophagogastric Cancer Resection: Effect on Cardiopulmonary Exercise Test Performance, Muscle Mass and Quality of Life-A Pilot Randomized Clinical Trial.

BACKGROUND: Neoadjuvant therapy reduces fitness, muscle mass, and quality of life (QOL). For patients undergoing chemotherapy and surgery for esophagogastric cancer, maintenance of fitness is paramount. This study investigated the effect of exercise and psychological prehabilitation on anaerobic threshold (AT) at cardiopulmonary exercise testing (CPET). Secondary endpoints included peak oxygen uptake (peak VO2), skeletal muscle mass, QOL, and neoadjuvant therapy completion. METHODS: This parallel-arm randomized controlled trial assigned patients with locally advanced esophagogastric cancer to receive prehabilitation or usual care. The 15-week program comprised twice-weekly supervised exercises, thrice-weekly home exercises, and psychological coaching. CPET was performed at baseline, 2 weeks after neoadjuvant therapy, and 1 week preoperatively. Skeletal muscle cross-sectional area at L3 was analyzed on staging and restaging computed tomography. QOL questionnaires were completed at baseline, mid-neoadjuvant therapy, at restaging laparoscopy, and postoperatively at 2 weeks, 6 weeks and 6 months. RESULTS: Fifty-four participants were randomized (prehabilitation group, n = 26; control group, n = 28). No difference in AT between groups was observed post-neoadjuvant therapy. Prehabilitation resulted in an attenuated peak VO2 decline {-0.4 [95% confidence interval (CI) -0.8 to 0.1] vs. -2.5 [95% CI -2.8 to -2.2] mL/kg/min; p = 0.022}, less muscle loss [-11.6 (95% CI -14.2 to -9.0) vs. -15.6 (95% CI -18.7 to -15.4) cm2/m2; p = 0.049], and improved QOL. More prehabilitation patients completed neoadjuvant therapy at full dose [prehabilitation group, 18 (75%) vs. control group, 13 (46%); p = 0.036]. No adverse events were reported. CONCLUSIONS: This study has demonstrated some retention of cardiopulmonary fitness (peak VO2), muscle, and QOL in prehabilitation subjects. Further large-scale trials will help determine whether these promising findings translate into improved clinical and oncological outcomes. Trial Registration ClinicalTrials.gov NCT02950324.

Perceptions regarding vasopressin use and practices in septic shock, and cost containment strategies.

Background: Clinician preferences and practices regarding appropriate vasopressin use in light of its increased acquisition cost secondary to rebranding has not been evaluated or described since the most recent iteration of the Surviving Sepsis Campaign Guideline was published. Objective: To assess vasopressin cost containment initiatives and pharmacists' opinions regarding appropriate vasopressin use. Methods: A scenario-based survey was distributed to critical care and emergency medicine pharmacists. Responses were characterized using frequency and descriptive statistics. Categorical variables between those who implemented changes (Vasopressin Cost Consideration) and those who did not (Usual Care) were compared using chi-square or Fisher's exact tests. McNemar's test was used to compare responses in clinical scenarios between Vasopressin Cost Consideration and Usual Care groups. Results: Among 1757 pharmacists surveyed, 200 (11.3%) responded. When respondents considered vasopressin cost and evidence (vs evidence alone), fewer respondents would use vasopressin adjunctively with norepinephrine (21% vs 26.6%, P = 0.031), to raise mean arterial pressure compared with epinephrine (65.2% vs 72.3%, P = 0.012), or to reduce norepinephrine infusion rates (71.4% vs 81.4%, P < 0.001), but would use with steroids (62.4% vs 28.3%, P < 0.001). Most (72%) respondents had implemented vasopressin cost containment and/or education initiatives. The Vasopressin Cost Consideration group respondents were more likely to initiate vasopressin at 0.03 units/minute without titrating (47.9% vs 33.9%, P = 0.045). Conclusion: Since vasopressin was generically rebranded, most institutions have implemented at least one initiative to reduce vasopressin use and/or educate clinicians about its appropriate use. When vasopressin acquisition costs were considered, pharmacists recommended its use less frequently, particularly in clinical scenarios where its use is controversial.

Clinical update on thrombolytic use in pulmonary embolism: A focus on intermediate-risk patients.

PURPOSE: Current literature on clinical controversies surrounding the use of thrombolytic agents in patients with intermediate-risk pulmonary embolism (PE) is reviewed. SUMMARY: PE is a major cause of morbidity and mortality. When used in conjunction with anticoagulation, thrombolysis has been shown to reduce hemodynamic decompensation in select patients, but thrombolytic therapy is associated with high risks of bleeding and intracranial hemorrhage and its role in treating patients with intermediate-risk PE remains controversial. In the PEITHO study, the largest trial to date involving only patients with intermediate-risk PE (n = 1,006), patients receiving the thrombolytic agent tenecteplase were significantly (p = 0.02) less likely than those receiving unfractionated heparin to develop the primary outcome, a composite of death from any cause and hemodynamic decompensation or collapse within 7 days. However, a meta-analysis of data from clinical trials of systemic thrombolytic therapy in intermediate-risk PE generally showed a lack of benefit in terms of all-cause mortality and long-term complications. Novel strategies for treatment of intermediate-risk PE, including low-dose thrombolysis and catheter-directed thrombolysis, are being investigated in an attempt to identify strategies that provide therapeutic outcomes equivalent to those provided by traditional thrombolytic modalities but with a decreased risk of bleeding. CONCLUSION: The use of thrombolysis in the treatment of intermediate-risk PE is complicated by high rates of bleeding and should be limited to patients who clinically deteriorate rather than given as a standard-of-care treatment in this population. Data for low-dose thrombolysis remain limited.

Defining the inflammatory signature of human lung explant tissue in the presence and absence of glucocorticoid.

BACKGROUND:  Airway inflammation is a feature of many respiratory diseases and there is a need for newer, more effective anti-inflammatory compounds. The aim of this study was to develop an ex vivo human lung explant model which can be used to help study the mechanisms underlying inflammatory responses and which can provide a tool to aid drug discovery for inflammatory respiratory diseases such as asthma and COPD. METHOD:  Parenchymal lung tissue from 6 individual donors was dissected and cultured with two pro-inflammatory stimuli, lipopolysaccharide (LPS) (1 µg/ml) and interleukin-1 beta (IL-1ß) (10 ng/ml) in the presence or absence of dexamethasone (1 µM).  Inflammatory responses were assessed using Luminex analysis of tissue culture supernatants to measure levels of 21 chemokines, growth factors and cytokines. RESULTS:  A robust and reproducible inflammatory signal was detected across all donors for 12 of the analytes measured following LPS stimulation with a modest fold increase (<2-fold) in levels of CCL22, IL-4, and IL-2; increases of 2-4-fold in levels of CXCL8, VEGF and IL-6 and increases >4-fold in CCL3, CCL4, GM-CSF, IL-10, TNF-α and IL-1ß.  The inflammatory signal induced by IL-1ß stimulation was less than that observed with LPS but resulted in elevated levels of 7 analytes (CXCL8, CCL3, CCL4, GM-CSF, IL-6, IL-10 and TNF-α).  The inflammatory responses induced by both stimulations was supressed by dexamethasone for the majority of analytes. CONCLUSIONS:  These data provide proof of concept that this ex vivo human lung explant model is responsive to inflammatory signals and could be used to investigate the anti-inflammatory effects of existing and novel compounds.  In addition this model could be used to help define the mechanisms and pathways involved in development of inflammatory airway disease. ABBREVIATIONS:  COPD: Chronic Obstructive Pulmonary Disease; ICS: inhaled corticosteroids; LPS: lipopolysaccharide; IL-1ß: interleukin-1 beta; PSF: penicillin, streptomycin and fungizone.

The Ser82 RAGE Variant Affects Lung Function and Serum RAGE in Smokers and sRAGE Production In Vitro.

INTRODUCTION: Genome-Wide Association Studies have identified associations between lung function measures and Chronic Obstructive Pulmonary Disease (COPD) and chromosome region 6p21 containing the gene for the Advanced Glycation End Product Receptor (AGER, encoding RAGE). We aimed to (i) characterise RAGE expression in the lung, (ii) identify AGER transcripts, (iii) ascertain if SNP rs2070600 (Gly82Ser C/T) is associated with lung function and serum sRAGE levels and (iv) identify whether the Gly82Ser variant is functionally important in altering sRAGE levels in an airway epithelial cell model. METHODS: Immunohistochemistry was used to identify RAGE protein expression in 26 human tissues and qPCR was used to quantify AGER mRNA in lung cells. Gene expression array data was used to identify AGER expression during lung development in 38 fetal lung samples. RNA-Seq was used to identify AGER transcripts in lung cells. sRAGE levels were assessed in cells and patient serum by ELISA. BEAS2B-R1 cells were transfected to overexpress RAGE protein with either the Gly82 or Ser82 variant and sRAGE levels identified. RESULTS: Immunohistochemical assessment of 6 adult lung samples identified high RAGE expression in the alveoli of healthy adults and individuals with COPD. AGER/RAGE expression increased across developmental stages in human fetal lung at both the mRNA (38 samples) and protein levels (20 samples). Extensive AGER splicing was identified. The rs2070600T (Ser82) allele is associated with higher FEV1, FEV1/FVC and lower serum sRAGE levels in UK smokers. Using an airway epithelium model overexpressing the Gly82 or Ser82 variants we found that HMGB1 activation of the RAGE-Ser82 receptor results in lower sRAGE production. CONCLUSIONS: This study provides new information regarding the expression profile and potential role of RAGE in the human lung and shows a functional role of the Gly82Ser variant. These findings advance our understanding of the potential mechanisms underlying COPD particularly for carriers of this AGER polymorphism.

Effect of Body Weight on Hemodynamic Response in Patients Receiving Fixed-Dose Vasopressin for Septic Shock.

BACKGROUND: Fixed-dose vasopressin is an adjunctive therapy to norepinephrine (NE) to raise mean arterial pressure (MAP) and decrease NE requirements in patients with septic shock. It is unknown if weight affects hemodynamic response to vasopressin or if a weight-based vasopressin strategy is superior to fixed dosing. OBJECTIVE: The primary objective was to evaluate effect of body weight on response to vasopressin as measured by change in MAP 1 hour post-vasopressin initiation. METHODS: A single-center, retrospective study was performed in patients with septic shock. Baseline characteristics, catecholamine and vasopressin requirement, response to therapy, and adverse events were collected. RESULTS: Forty patients were included who received a fixed-dose vasopressin in addition to catecholamine infusions. No correlation was found in the primary outcome of change in MAP at 1 hour after vasopressin initiation compared with vasopressin dose relative to patient weight or body mass index (BMI). Change in MAP at 6 and 12 hours was not significant. In the obese population (n = 9), there was a significant negative correlation between BMI and change in MAP at 6 hours (correlation coefficient r = -0.951; P = 0.0009). Linear regression analysis confirmed that vasopressin dose relative toweight was independently associated with change in MAP at 1, 6, and 12 hours, whereas changes in NE dosing were not. CONCLUSION: Increasing weight-based dosing of vasopressin did not correlate with change in MAP when used with catecholamine vasopressors in septic shock. However, fixed-dose vasopressin may not be sufficient in obese septic shock patients with a BMI ≥30 kg/m(2).

Reduced Ets Domain-containing Protein Elk1 Promotes Pulmonary Fibrosis via Increased Integrin αvß6 Expression.

Idiopathic pulmonary fibrosis (IPF) is a progressive fibrotic lung disease with high mortality. Active TGFß1 is considered central to the pathogenesis of IPF. A major mechanism of TGFß1 activation in the lung involves the epithelially restricted αvß6 integrin. Expression of the αvß6 integrin is dramatically increased in IPF. How αvß6 integrin expression is regulated in the pulmonary epithelium is unknown. Here we identify a region in the ß6 subunit gene (ITGB6) promoter acting to markedly repress basal gene transcription, which responds to both the Ets domain-containing protein Elk1 (Elk1) and the glucocorticoid receptor (GR). Both Elk1 and GR can regulate αvß6 integrin expression in vitro We demonstrate Elk1 binding to the ITGB6 promoter basally and that manipulation of Elk1 or Elk1 binding alters ITGB6 promoter activity, gene transcription, and αvß6 integrin expression. Crucially, we find that loss of Elk1 causes enhanced Itgb6 expression and exaggerated lung fibrosis in an in vivo model of fibrosis, whereas the GR agonist dexamethasone inhibits Itgb6 expression. Moreover, Elk1 dysregulation is present in epithelium from patients with IPF. These data reveal a novel role for Elk1 regulating ITGB6 expression and highlight how dysregulation of Elk1 can contribute to human disease.

Large-scale genome-wide association studies and meta-analyses of longitudinal change in adult lung function.

BACKGROUND: Genome-wide association studies (GWAS) have identified numerous loci influencing cross-sectional lung function, but less is known about genes influencing longitudinal change in lung function. METHODS: We performed GWAS of the rate of change in forced expiratory volume in the first second (FEV1) in 14 longitudinal, population-based cohort studies comprising 27,249 adults of European ancestry using linear mixed effects model and combined cohort-specific results using fixed effect meta-analysis to identify novel genetic loci associated with longitudinal change in lung function. Gene expression analyses were subsequently performed for identified genetic loci. As a secondary aim, we estimated the mean rate of decline in FEV1 by smoking pattern, irrespective of genotypes, across these 14 studies using meta-analysis. RESULTS: The overall meta-analysis produced suggestive evidence for association at the novel IL16/STARD5/TMC3 locus on chromosome 15 (P  =  5.71 × 10(-7)). In addition, meta-analysis using the five cohorts with ≥3 FEV1 measurements per participant identified the novel ME3 locus on chromosome 11 (P  =  2.18 × 10(-8)) at genome-wide significance. Neither locus was associated with FEV1 decline in two additional cohort studies. We confirmed gene expression of IL16, STARD5, and ME3 in multiple lung tissues. Publicly available microarray data confirmed differential expression of all three genes in lung samples from COPD patients compared with controls. Irrespective of genotypes, the combined estimate for FEV1 decline was 26.9, 29.2 and 35.7 mL/year in never, former, and persistent smokers, respectively. CONCLUSIONS: In this large-scale GWAS, we identified two novel genetic loci in association with the rate of change in FEV1 that harbor candidate genes with biologically plausible functional links to lung function.

GSTCD and INTS12 regulation and expression in the human lung.

Genome-Wide Association Study (GWAS) meta-analyses have identified a strong association signal for lung function, which maps to a region on 4q24 containing two oppositely transcribed genes: glutathione S-transferase, C-terminal domain containing (GSTCD) and integrator complex subunit 12 (INTS12). Both genes were found to be expressed in a range of human airway cell types. The promoter regions and transcription start sites were determined in mRNA from human lung and a novel splice variant was identified for each gene. We obtained the following evidence for GSTCD and INTS12 co-regulation and expression: (i) correlated mRNA expression was observed both via Q-PCR and in a lung expression quantitative trait loci (eQTL) study, (ii) induction of both GSTCD and INTS12 mRNA expression in human airway smooth muscle cells was seen in response to TGFß1, (iii) a lung eQTL study revealed that both GSTCD and INTS12 mRNA levels positively correlate with percent predicted FEV1, and (iv) FEV1 GWAS associated SNPs in 4q24 were found to act as an eQTL for INTS12 in a number of tissues. In fixed sections of human lung tissue, GSTCD protein expression was ubiquitous, whereas INTS12 expression was predominantly in epithelial cells and pneumocytes. During human fetal lung development, GSTCD protein expression was observed to be highest at the earlier pseudoglandular stage (10-12 weeks) compared with the later canalicular stage (17-19 weeks), whereas INTS12 expression levels did not alter throughout these stages. Knowledge of the transcriptional and translational regulation and expression of GSTCD and INTS12 provides important insights into the potential role of these genes in determining lung function. Future work is warranted to fully define the functions of INTS12 and GSTCD.

HTR4 gene structure and altered expression in the developing lung.

BACKGROUND: Meta-analyses of genome-wide association studies (GWAS) have identified single nucleotide polymorphisms (SNPs) spanning the 5-hydroxytryptamine receptor 4 (5-HT4R) gene (HTR4) associated with lung function. The aims of this study were to i) investigate the expression profile of HTR4 in adult and fetal lung tissue and cultured airway cells, ii) further define HTR4 gene structure and iii) explore the potential functional implications of key SNPs using a bioinformatic approach. METHODS: Following reverse transcription (RT)-PCR in human brain, 5' rapid amplification of cDNA ends (5' RACE) was used to examine the exonic structure of HTR4 at the 5' end. Quantitative (Q)-PCR was used to quantify HTR4 mRNA expression in total RNA from cultured airway cells and whole lung tissue. Publically available gene microarray data on fetal samples of estimated gestational age 7-22 weeks were mined for HTR4 expression. Immunohistochemistry (IHC; in adult and fetal lung tissue) and a radioligand binding assay (in cultured airway cells) were used to analyze 5-HT4R protein expression. RESULTS: IHC in adult lung, irrespective of the presence of chronic obstructive pulmonary disease (COPD), suggested low level expression of 5-HT4R protein, which was most prominent in alveolar pneumocytes. There was evidence of differential 5-HT4R protein levels during gestation in fetal lung, which was also evident in gene expression microarray data. HTR4 mRNA expression, assessed by Q-PCR, was <0.5% relative to brain in total adult lung tissue and in human airway smooth muscle (HASM) and bronchial epithelial cells (HBEC) derived from adult donors. Radioligand binding experiments also indicated that HBEC and HASM cells did not express a significant 5-HT4R population. 5' RACE in brain identified a novel N-terminal variant, containing an extended N-terminal sequence. The functional significance of key HTR4 SNPs was investigated using the encyclopedia of DNA elements consortium (ENCODE) dataset. These analyses identified multiple alterations in regulatory motifs for transcription factors implicated in lung development, including Foxp1. CONCLUSIONS: Taken together, these data suggest a role for HTR4 in lung development, which may at least in part explain the genetic association with lung function.

Effects of atopy and grass pollen season on histamine H4 receptor expression in human leukocytes.

BACKGROUND: The histamine H4 receptor (H4R) is a novel therapeutic target to treat allergic inflammation. OBJECTIVE: To profile messenger RNA (mRNA) expression of H4R isoforms in human cells and evaluate the effects of atopy and grass pollen season on H4R expression in peripheral blood leukocytes ex vivo. METHODS: H4R isoform expression was assayed by quantitative polymerase chain reaction in human airway and peripheral RNA. During low and high grass pollen seasons, leukocytes were isolated from venous blood and fractionated into peripheral blood mononuclear cells and polymorphonuclear cells (PMN). H4R expression was determined and related to atopy, defined by a level of specific IgE to Timothy grass pollen of ≥0.35 kU(A)/L (n = 7 atopic patients and 9 controls). RESULTS: Expression of total and full length H4R was at the limit of detection but predominant in peripheral blood leukocytes, where truncated H4R was expressed exclusively (≤300-fold less). Suggestive evidence for total H4R in airway cells and brain indicated an expression ≤260-fold lower than in peripheral blood mononuclear cells. Total H4R mRNA expression was unaffected by atopy or grass pollen season, but truncated H4R was significantly reduced during high grass pollen season in total leukocytes, independently of atopy (P < .01). CONCLUSION: H4R mRNA is predominantly expressed in peripheral blood leukocytes, and total H4R expression levels are unrelated to atopy or grass pollen season. Atopy-independent seasonal variation in truncated H4R expression might affect putative negative regulation of full length H4R during high grass pollen season. If verified, this should be considered during the design of drugs targeting H4R to treat allergic inflammation, particularly for seasonal allergic rhinitis.

Excessive folate synthesis limits lifespan in the C. elegans: E. coli aging model.

BACKGROUND: Gut microbes influence animal health and thus, are potential targets for interventions that slow aging. Live E. coli provides the nematode worm Caenorhabditis elegans with vital micronutrients, such as folates that cannot be synthesized by animals. However, the microbe also limits C. elegans lifespan. Understanding these interactions may shed light on how intestinal microbes influence mammalian aging. RESULTS: Serendipitously, we isolated an E. coli mutant that slows C. elegans aging. We identified the disrupted gene to be aroD, which is required to synthesize aromatic compounds in the microbe. Adding back aromatic compounds to the media revealed that the increased C. elegans lifespan was caused by decreased availability of para-aminobenzoic acid, a precursor to folate. Consistent with this result, inhibition of folate synthesis by sulfamethoxazole, a sulfonamide, led to a dose-dependent increase in C. elegans lifespan. As expected, these treatments caused a decrease in bacterial and worm folate levels, as measured by mass spectrometry of intact folates. The folate cycle is essential for cellular biosynthesis. However, bacterial proliferation and C. elegans growth and reproduction were unaffected under the conditions that increased lifespan. CONCLUSIONS: In this animal:microbe system, folates are in excess of that required for biosynthesis. This study suggests that microbial folate synthesis is a pharmacologically accessible target to slow animal aging without detrimental effects.