Arizona Veterans Research and Education Foundation

“Knowing is not enough; we must apply. Willing is not enough; we must do.”—Goethe Introduction People and the communities they are a part of—defined as “groups of people affiliated by geographic proximity . . . or similar situations to address issues affecting the well-being of those people”—are deeply impacted by the systems that […]

PURPOSE OF REVIEW: Antibiotic stress can evoke considerable genotypic and phenotypic changes in Gram-positive bacteria. Here, we review recent studies describing altered virulence expression in response to cell wall-acting antibiotics and discuss mechanisms that coordinate regulation of the antibiotic response. RECENT FINDINGS: Pleiotropic effects induced by antibiotic exposure include alterations to bacterial metabolism, cell wall structure and antibiotic resistance. In addition, subinhibitory concentrations of cell wall-active (CWA) antibiotics have increasingly been shown to induce the production of exotoxins and biofilm formation that may influence virulence. Remarkably, phenotypes associated with comparable antibiotic stresses can vary considerably, emphasizing the need to better understand the response to CWA antibiotics. Recent studies support both direct antibiotic recognition and recognition of antibiotic-induced stress to the bacterial cell wall. Specifically, bacterial two-component systems, penicillin-binding protein and serine/threonine kinase-associated kinases and conserved oxidative-stress sensors each contribute to modulating the antibiotic stress response. SUMMARY: Bacterial sensory systems and global regulators coordinate signaling in response to CWA antibiotics. Regulation of the antibiotic response is complex and involves integration of signals from multiple response pathways. A better definition of the antibiotic stress response among Gram-positive pathogens may yield novel therapeutic targets to counter antibiotic resistance and virulence factor expression.

Recent preclinical studies have suggested an antifibrotic role for tricyclic antidepressants (TCA). Using the Electronically Retrieved Cohort of hepatitis C virus (HCV) Infected Veterans, we aimed to evaluate the impact of TCA use on fibrosis progression and development of hepatocellular carcinoma (HCC) among HCV-infected persons. Subjects were categorized according to use of TCAs, selective serotonin reuptake inhibitors (SSRI) or no antidepressants. TCAs or selective serotonin uptake inhibitors use was defined according to cumulative defined daily dose (cDDD), and categories were mutually exclusive. Subjects with HIV coinfection, hepatitis B surface antigen (HbsAg) positivity, cirrhosis or HCC at baseline were excluded. Outcomes were liver fibrosis progression measured by APRI scores and incident HCC. We utilized Cox proportional hazards regression to determine predictors of cirrhosis, defined as APRI > 2, and incident hepatocellular carcinoma (iHCC). Among 128 201 eligible HCV+ persons, 4% received TCAs, 43% received selective serotonin uptake inhibitors, and 53% received no antidepressants. Fewer TCAs users had drug abuse (34% and 43%) and alcohol abuse (32% vs 42%) compared to selective serotonin uptake inhibitor users. After adjusting for age, baseline APRI score, diabetes, hypertension, alcohol use, drug abuse and HCV RNA levels, TCAs use was associated with decreased risk of cirrhosis (hazard ratio [HR] = 0.77, 95% CI = 0.60, 0.99) and delayed time to development of cirrhosis, but not with decreased iHCC. In conclusion among a large cohort of HCV-positive Veterans, TCAs use was associated with decreased fibrosis progression and lower risk of developing cirrhosis. These data provide supportive evidence for the beneficial effects of TCAs on progression of liver fibrosis in patients with chronic HCV infection.

ABSTRACT Post-influenza Staphylococcus aureus pneumonia, particularly methicillin-resistant S. aureus (MRSA), remains a major cause of mortality, highlighting the urgent need for newer therapeutic options. Omadacycline is an aminomethylcycline antibiotic that has demonstrated efficacy against MRSA across many infection models, but its potential in post-influenza A virus (IAV)-MRSA pneumonia remains unexplored. Using a murine model of this infection, we evaluated the effects of omadacycline and a comparator antibiotic, linezolid, on survival, inflammation, bacterial load, toxin production, and lung histopathology. In survival studies, omadacycline matched the effectiveness of oral linezolid at clinically relevant doses. In addition, both antibiotics, particularly omadacycline, attenuated the production of multiple pro-inflammatory cytokines and reduced neutrophil infiltration in the lungs, independent of their effects on pulmonary microbial burden, suggesting an immunomodulatory mechanism of action. Panton-Valentine leukocidin (PVL) toxin production in vitro and in vivo was also assessed, and while the role of PVL in this murine model remains unclear, both agents reduced PVL production. These findings provide the first preclinical demonstration of in vivo efficacy for omadacycline against IAV-MRSA pneumonia and its ability to modulate the host immune response, thereby reducing the excessive inflammation that is linked to mortality in this disease state. Further investigation into the precise interplay between omadacycline and immunomodulation in this disease state is warranted.

There are limited data directly comparing SARS-CoV-2 sequencing methods using two major commercial approaches, Oxford Nanopore Technologies Clear DX (ONTDX) and Illumina. RNA was extracted from 1,513 SARS-CoV-2 RNA-positive respiratory samples, split into two aliquots, and sequenced using both ONTDX and Illumina sequencing methods. FASTQ sequences generated by the ONTDX and Illumina (550 or 2,000) platforms used to test these samples were analyzed using either the same assembly and alignment strategy or using the platform default methodologies. ONTDX and Illumina sequencing results were not significantly different in generating consensus genomes, though slightly better coverage was obtained with ONTDX compared to Illumina. The results were similar using the harmonized assembly and alignment strategy and using the "real-world" platform default assembly and alignment. Approximately 2.5% of samples sequenced were assigned to different sublineages by the different methods, and two samples were assigned to different clades. Median sample storage time ranged from 594 to 970 days before RNA extraction and sequencing, yet >90% genome coverage was achieved in >91.5% of samples. ONTDX and Illumina-based deep sequencing platforms both generate high coverage sequences for SARS-CoV-2. ONTDX performed slightly better than Illumina-based sequencing. Despite a high degree of overall agreement, lineage and clade assignment may differ based on the sequencing and alignment methods used, illustrating the need for caution when comparing phylogenetic relationships based on sequences generated by different platforms. Respiratory samples were also stable and provided high-quality sequencing results following storage for up to 970 days.IMPORTANCESARS-CoV-2-positive respiratory samples from 1,513 individuals were sequenced using the Oxford Nanopore Clear DX platform. Matching aliquots for these were sequenced using either Illumina NextSeq 550 or NextSeq 2000. A harmonized bioinformatic approach compared raw FASTQ files generated by each platform. Differences in coverage and, surprisingly, phylogenetic lineage assignments were observed; thus, assembly and alignments were also compared using the platform default methods. Both platforms generated high coverage for SARS-CoV-2; the Nanopore method was as good, if not slightly better, than Illumina-based sequencing in these studies. Two of 1,546 samples were assigned to different clades by different platforms, and 2.5% of sequences were assigned to different sub-lineages when sequenced by different platforms. These data illustrate that different methods may lead to small differences in phylogenetic assignments and highlight one limitation in the interpretation of outbreak diversity.

This study uses data from the Veterans Health Administration (VA) Corporate Data Warehouse to analyze trends in annual inhaler-related emissions by inhaler type (metered-dose, dry powder, soft mist) in the VA from 2008 to 2023.

Purpose: Mirtazapine (Mirt.) is an antidepressant commonly used in the clinical practice for irritable bowel syndrome. Our previous studies reported that mirt. reduced visceral hypersensitivity in rodent model of colonic sensitization. However, the effect of mirt. on gastrointestinal motility is unknown. The aims of this study were to investigate the effects of mirt. on gastrointestinal motility including solid gastric emptying, antral contractions, small intestinal contractions, small intestinal transit and colonic transit in dogs. Methods: Eleven dogs were used in this study, 6 of the dogs were chronically implanted with two cannulas, one was located at the duodenum and the other at the ascending colon; 5 of the dogs were implanted with one gastric cannula for measuring antral contractions. Each of the motility tests was performed in 2 randomized sessions (control, mirtazapine 45 mg/kg). Two additional sessions were included for the gastric emptying experiment: rectal distention (RD) and mirt. plus RD. RD was accomplished with 120 ml balloon distension during 60 min to 90 min after a test meal, mirt. was administered 90 minutes before the study. The solid gastric emptying was assessed by collecting the gastric chyme every 15 or 30 min from the duodenal cannula for 3 hours after feeding 375 g solid food; the phenol red solution was injected through the duodenal cannula immediately after the food ingestion, small intestinal transit was assessed by the first appearance of phenol red collected from the colonic cannula. The antral and small intestinal contractions were measured by manometry. Colonic transit was assessed by counting the numbers of radiopaque markers from abdominal X-ray films at different time points (2, 4, 6 hours after inserting the markers via the colon cannula). Results: 1) Mirt. accelerated gastric emptying during the entire 3 hours in normal dogs, the gastric emptying was increased from 25.6±6.5% to 43.0±5.5% at 60 min (P < 0.01), 53.1±5.8% to 73.4±5.7% at 120 min (P=0.02) and 68.9±6.3% to 81.1±6.1% (P=0.03) at 180 min. Moreover, mirt. accelerated delayed gastric emptying induced by RD from 45 min to 180 min after the meal (P < 0.04). 2) Mirt. enhanced antral contractions from 12.5±1.9 to 22.5±4.6 (P=0.06). 3) No significant changes were noted on the small intestinal contractions and transit with mirt. (P > 0.1). 4). Mirt. accelerated colonic transit at 2 and 4 hours but not 6 hours. The geometric center was increased from 1.9±0.6 to 3.0±0.5, 3.9±0.5 to 4.7±0.1 at 2 and 4 hours respectively (P=0,04 vs. corresponding control). Conclusion: Mirt. improves gastric and colonic motility and may have a therapeutic potential for gastrointestinal motility disorders.

Purpose: Obesity is an eating disorder but it is unclear whether the responses of gastric and autonomic functions to food ingestion are altered in obese. The aims of this study were to investigate gastric myoelectrical activity (GMA) and autonomic functions in obese subjects and to compare their responses to different meals with lean subjects. Methods: The study was performed in 12 healthy lean and 12 healthy obese subjects. GMA was measured using electrogastrography and autonomic functions were assessed using spectral analysis of heart rate variability derived from the electrocardiogram. The recordings were made in two sessions each composed of a 30-min fasting period and a 30-min period after a fatty soup or protein soup (160cal from fat or protein). Results: 1) The obese showed enhanced responses to both soups. The percentage of normal slow waves was reduced with the fatty soup in lean (73.9±5.3% vs. 59.7±6.0%, P<0.02) but not in obese (68.9±5.1% vs. 67.7±4.8%, P>0.3); The power of gastric slow waves was not altered with the protein soup in the lean but increased in the obese (34.3±2.9 dB vs. 30.8±2.5 dB, P<0.05). 2) Autonomic functions were altered in obese subjects in both fasting and fed states. The obese showed a reduced vagal activity (0.45±0.05 vs. 0.58±0.03, P<0.04), and increased sympathetic activity (0.55±0.05 vs. 0.42±0.03, P<0.04) and sympathovagal balance (1.59±0.27 vs. 0.78±0.10) in the fasting state, and a complete absence of normal postprandial autonomic responses to the test meal. Conclusion: The findings on gastric slow waves demonstrate that obese subjects are more receptive to fatty meals and more responsive to protein meals. Obese subjects have impaired autonomic functions in both fasting and fed states. The alterations in gastric and autonomic functions may contribute to eating disorders in obese subjects.

Purpose: To investigate associations between cardiopulmonary, neuropsychiatric, and multisystem long COVID phenotypes, and sequence-defined SARS-CoV-2 viral variant and sociodemographic predictors in a population from a rural state. Methods: SARS-CoV-2 clinical samples were collected from 1,120 veterans treated at the Veterans Affairs (VA) Medical Center in Boise, Idaho from April 2, 2020 to December 20, 2022. Viral variants were identified through sequencing and annotated with clinical data from the VA Corporate Data Warehouse, as well as CDC rurality and social vulnerability. Cardiopulmonary, neuropsychiatric, and multisystem long COVID phenotypes were determined by the addition of one or more ICD-10 codes 90-270 days post-infection. Multinomial logistic regression was used to estimate phenotype prevalence in a base model with predictors viral variant, age, sex, rurality, and social vulnerability, as well as in models that adjusted for patient health (comorbidity, healthcare utilization, and smoking status), and treatments (vaccination and Paxlovid). Findings: Female patients experienced more neuropsychiatric long COVID and less recovery, whereas the neuropsychiatric phenotype was less prevalent among older patients. Omicron variants had less recovery and more multisystem long COVID relative to pre-Delta-a finding that may indicate an association between infection with Omicron and post-acute gastrointestinal symptoms. Conclusion: This study is perhaps the largest to investigate viral variant effects on long COVID using sequence rather than date-based variant definitions, and is also unique in its focus on a population living in one of the most rural states in the United States. Our results are consistent with other studies finding contributions from both biological and social predictors to long COVID outcomes.

OBJECTIVES: Experiential avoidance is the unwillingness to come into contact with aversive internal experiences. Trauma exposure is associated with greater experiential avoidance and insomnia symptoms. Experiential avoidance may perpetuate insomnia symptoms in patients with posttraumatic stress disorder (PTSD). We examined the relationship between experiential avoidance and insomnia symptoms among veterans with PTSD (based on the Clinician-Administered PTSD Scale for DSM-5). METHOD: = 54.7 years; 86.0% male) who attributed their sleep disturbance onset to experiences of trauma on the CAPS-5. Experiential avoidance, insomnia, sleep disturbance, daytime sleepiness, and daytime consequences were measured with the Brief Experiential Avoidance Questionnaire (BEAQ), Insomnia Severity Index (ISI), Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), and International Classification of Sleep Disorders (ICSD) items. We conducted multiple linear regressions with age, sex, and BEAQ as the independent variables and sleep variables as the dependent variables. RESULTS: There were significant positive associations between the BEAQ and the ISI, PSQI daily disturbance factor, ESS, and ICSD daytime consequences. CONCLUSIONS: Greater experiential avoidance was associated with worse insomnia symptoms and consequences, particularly daytime dysfunction. Experiential avoidance may be an overlooked, but relevant treatment target for patients with comorbid insomnia and PTSD.

Purpose: The aim of this study was to investigate the effects and mechanisms of gastric electrical stimulation (GES) on proximal stomach distention-induced visceral sensitivity. Methods: Isobaric gastric distention was performed using a barostat system in 8 normal and 6 vagotomized dogs and animal behaviors were noted and graded. The normal dogs were studied in 4 sessions: control (no GES), short pulse GES, long pulse GES, and dual-pulse GES, and the vagotomized dogs were studied in three sessions: control (no GES), long pulse GES and guanethidine. Results: It was found that: 1) proximal stomach distention-induced behavioral changes were mediated by vagal and sympathetic pathways. The total behavior score (TBS) was 40.6±7.4 in the controls, 15.3±8.9 in vagotomized dogs (P=0.006 vs. control) and 8.8±0.9 in the vagotomized dogs with guanethidine (P=0.04 vs. vagotomy). The behavioral changes were mediated via the vagal pathway at distention pressures below 20 mmHg, but mediated via both the vagal and sympathetic pathways at distention pressures equal to and above 20 mmHg. 2) GES with long pulses or dual pulses but not short pulses reduced the distention-induced behavioral score (P=0.003, P=0.006 and P=0.7, respectively) and the effects of GES of long pulses might be mediated via the vagal and sympathetic pathways. Conclusion: Gastric distention-induced visceral sensitivity is mediated via the vagal pathway at low distention pressures but via both vagal and sympathetic pathways at high distention pressures. GES with long but not short pulses reduces distention-induced visceral sensitivity.

Background: Micronutrient deficiencies (MiDs) can increase medical complexity in hospitalized adults, but the prevalence in those without alcohol use disorder (AUD) is unknown. Our objectives were to prospectively determine the prevalence of thiamine, cobalamin, folate, magnesium, and cholecalciferol deficiencies in hospitalized veterans without AUD. Methods: Newly hospitalized veterans without AUD were recruited. Plasma thiamine, cholecalciferol, cyanocobalamin, folate, magnesium, C-reactive protein, albumin, and prealbumin were obtained. Interviews, physical exams, and medical record reviews were completed to assess clinical signs of MiDs, food insecurity, malnutrition, and hospitalization metrics. Pearson chi-square, Fisher’s exact, and logistic regression evaluated relationships among MiDs, malnutrition, food insecurity, demographics, and hospitalization metrics. Results: A total of 206 participants were enrolled, and 183 had partial results while 155 had complete results. The prevalences of deficiencies were 31.32% for magnesium, 27.07% for thiamine, 25.27% for cholecalciferol, 4.40% for cyanocobalamin, and 0.55% for folate. Malnutrition was reported by 50.60% of participants, and 56.00% reported food insecurity. Of those with biomarker MiDs, signs and symptoms were found in 97.92% with thiamine, 85.96% with magnesium, 67.39% with cholecalciferol, and 37.5% with cyanocobalamin deficiency. Cholecalciferol deficiency was associated with thiamine deficiency (p = 0.011, OR 3.180, CI 1.556–6.529), food insecurity (p = 0.0073, OR 2.690, CI 1.289–5.662), and longer length of hospital stay (p = 0.0401, IRR 1.295). All other associations were not statistically significant. Conclusions: In this exploratory pilot study, MiDs affected more than half of hospitalized veterans without AUD and were frequently associated with clinical signs and symptoms. TD affected one quarter of participants. Cholecalciferol deficiency was associated with longer hospital stays.