Sex-specific associations between AD genotype and the microbiome of human amyloid beta knock-in (hAß-KI) mice.

INTRODUCTION: Emerging evidence links changes in the gut microbiome to late-onset Alzheimer's disease (LOAD), necessitating examination of AD mouse models with consideration of the microbiome. METHODS: We used shotgun metagenomics and untargeted metabolomics to study the human amyloid beta knock-in (hAß-KI) murine model for LOAD compared to both wild-type (WT) mice and a model for early-onset AD (3xTg-AD). RESULTS: Eighteen-month female (but not male) hAß-KI microbiomes were distinct from WT microbiomes, with AD genotype accounting for 18% of the variance by permutational multivariate analysis of variance (PERMANOVA). Metabolomic diversity differences were observed in females, however no individual metabolites were differentially abundant. hAß-KI mice microbiomes were distinguishable from 3xTg-AD animals (81% accuracy by random forest modeling), with separation primarily driven by Romboutsia ilealis and Turicibacter species. Microbiomes were highly cage specific, with cage assignment accounting for more than 40% of the PERMANOVA variance between the groups. DISCUSSION: These findings highlight a sex-dependent variation in the microbiomes of hAß-KI mice and underscore the importance of considering the microbiome when designing studies that use murine models for AD. HIGHLIGHTS: Microbial diversity and the abundance of several species differed in human amyloid beta knock-in (hAß-KI) females but not males. Correlations to Alzheimer's disease (AD) genotype were stronger for the microbiome than the metabolome. Microbiomes from hAß-KI mice were distinct from 3xTg-AD mice. Cage effects accounted for most of the variance in the microbiome and metabolome.

RNA Viromics of Southern California Wastewater and Detection of SARS-CoV-2 Single-Nucleotide Variants.

Municipal wastewater provides an integrated sample of a diversity of human-associated microbes across a sewershed, including viruses. Wastewater-based epidemiology (WBE) is a promising strategy to detect pathogens and may serve as an early warning system for disease outbreaks. Notably, WBE has garnered substantial interest during the coronavirus disease 2019 (COVID-19) pandemic to track disease burden through analyses of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA. Throughout the COVID-19 outbreak, tracking SARS-CoV-2 in wastewater has been an important tool for understanding the spread of the virus. Unlike traditional sequencing of SARS-CoV-2 isolated from clinical samples, which adds testing burden to the health care system, in this study, metatranscriptomics was used to sequence virus directly from wastewater. Here, we present a study in which we explored RNA viral diversity through sequencing 94 wastewater influent samples across seven wastewater treatment plants (WTPs), collected from August 2020 to January 2021, representing approximately 16 million people in Southern California. Enriched viral libraries identified a wide diversity of RNA viruses that differed between WTPs and over time, with detected viruses including coronaviruses, influenza A, and noroviruses. Furthermore, single-nucleotide variants (SNVs) of SARS-CoV-2 were identified in wastewater, and we measured proportions of overall virus and SNVs across several months. We detected several SNVs that are markers for clinically important SARS-CoV-2 variants along with SNVs of unknown function, prevalence, or epidemiological consequence. Our study shows the potential of WBE to detect viruses in wastewater and to track the diversity and spread of viral variants in urban and suburban locations, which may aid public health efforts to monitor disease outbreaks. IMPORTANCE Wastewater-based epidemiology (WBE) can detect pathogens across sewersheds, which represents the collective waste of human populations. As there is a wide diversity of RNA viruses in wastewater, monitoring the presence of these viruses is useful for public health, industry, and ecological studies. Specific to public health, WBE has proven valuable during the coronavirus disease 2019 (COVID-19) pandemic to track the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) without adding burden to health care systems. In this study, we used metatranscriptomics and reverse transcription-droplet digital PCR (RT-ddPCR) to assay RNA viruses across Southern California wastewater from August 2020 to January 2021, representing approximately 16 million people from Los Angeles, Orange, and San Diego counties. We found that SARS-CoV-2 quantification in wastewater correlates well with county-wide COVID-19 case data, and that we can detect SARS-CoV-2 single-nucleotide variants through sequencing. Likewise, wastewater treatment plants (WTPs) harbored different viromes, and we detected other human pathogens, such as noroviruses and adenoviruses, furthering our understanding of wastewater viral ecology.

Longitudinal Analysis of the Microbiome and Metabolome in the 5xfAD Mouse Model of Alzheimer's Disease.

Recent reports implicate gut microbiome dysbiosis in the onset and progression of Alzheimer's disease (AD), yet studies involving model animals overwhelmingly omit the microbial perspective. Here, we evaluate longitudinal microbiomes and metabolomes from a popular transgenic mouse model for familial AD (5xfAD). Cecal and fecal samples from 5xfAD and wild-type B6J (WT) mice from 4 to 18 months of age were subjected to shotgun Illumina sequencing. Metabolomics was performed on plasma and feces from a subset of the same animals. Significant genotype, sex, age, and cage-specific differences were observed in the microbiome, with the variance explained by genotype at 4 and 18 months of age rising from 0.9 to 9% and 0.3 to 8% for the cecal and fecal samples, respectively. Bacteria at significantly higher abundances in AD mice include multiple Alistipes spp., two Ligilactobacillus spp., and Lactobacillus sp. P38, while multiple species of Turicibacter, Lactobacillus johnsonii, and Romboutsia ilealis were less abundant. Turicibacter is similarly depleted in people with AD, and members of this genus both consume and induce the production of gut-derived serotonin. Contradicting previous findings in humans, serotonin is significantly more concentrated in the blood of older 5xfAD animals compared to their WT littermates. 5xfAD animals exhibited significantly lower plasma concentrations of carnosine and the lysophospholipid lysoPC a C18:1. Correlations between the microbiome and metabolome were also explored. Taken together, these findings strengthen the link between Turicibacter abundance and AD, provide a basis for further microbiome studies of murine models for AD, and suggest that greater control over animal model microbiomes is needed in AD research. IMPORTANCE Microorganisms residing within the gastrointestinal tract are implicated in the onset and progression of Alzheimer's disease (AD) through the mediation of inflammation, exchange of small-molecules across the blood-brain barrier, and stimulation of the vagus nerve. Unfortunately, most animal models for AD are housed under conditions that do not reflect real-world human microbial exposure and do not sufficiently account for (or meaningfully consider) variations in the microbiome. An improved understanding of AD model animal microbiomes will increase model efficacy and the translatability of research findings into humans. Here, we present the characterization of the microbiome and metabolome of the 5xfAD mouse model, which is one of the most common animal models for familial AD. The manuscript highlights the importance of considering the microbiome in study design and aims to lay the groundwork for future studies involving mouse models for AD.

The use of prosthetic grafts in complex military vascular trauma: a limb salvage strategy for patients with severely limited autologous conduit.

BACKGROUND: The use of prosthetic grafts for reconstruction of military vascular trauma has been consistently discouraged. In the current conflict, however, the signature wound involves multiple extremities with significant loss of soft tissue and potential autogenous venous conduits. We reviewed the experience with the use of prosthetic grafts for the treatment of vascular injuries sustained during recent conflicts in Iraq and Afghanistan. METHODS: Trauma registry records with combat-related vascular injuries repaired using prosthetic grafts were retrospectively reviewed from March 2003 to April 2006. Data collected included age, gender, mechanism of injury, vessel injured, conduit, graft patency, complications, including amputation and eventual outcome of repair. RESULTS: Prosthetic grafts were placed in 14 of 95 (15%) patients undergoing extremity bypass for vascular injuries. Patients were men with an average age of 25 years (range, 19-39 years). All prosthetic grafts in this series were made of polytetrafluoroethylene. Mechanism of injury included blast (n = 6), gunshot wounds (n = 6), and blunt trauma (n = 2), resulting in prosthetic repair of injuries to the superficial femoral (n = 8), brachial (n = 3), common carotid (n = 1), subclavian (n = 1), and axillary (n = 1) arteries. Mean evacuation time from injury to stateside arrival was 7 days (range, 3-9 days). Twelve grafts were placed initially at the time of injury, and two after vein graft blow out with secondary hemorrhage. The mean follow-up period was 427 days (range, 49-1,285 days). Seventy-nine percent of prosthetic grafts stayed patent in the short term, allowing patient stabilization, transport to a stateside facility, and elective revascularization with the remaining autologous vein graft. Three prosthetic grafts were replaced urgently for thrombosis. The remaining seven grafts were replaced electively for severe stenosis (3) or exposure (4) with presumed infection. There were no prosthetic graft blow outs or deaths in this series. No patients required amputation because of prosthetic graft failure. Three (21%) patients went on to have elective lower extremity amputation, despite patent grafts for nonsalvagable limbs. CONCLUSIONS: When managing patients with multiple extremity trauma and limited noninjured autogenous venous conduits, emergent use of prosthetic grafts may provide an effective limb salvage strategy. Despite being placed in multisystem trauma patients with large contaminated soft tissue wounds, emergent revascularization with polytetrafluoroethylene allowed patient stabilization, transport to a higher echelon of care, and elective revascularization with remaining limited autologous vein.

Intravascular ultrasound--guided inferior vena cava filter placement in the military multitrauma patients: a single-center experience.

BACKGROUND: High velocity fragments have resulted in a multitude of complex injuries in the military patients, placing them at increased risk of venous thromboembolism. METHODS: A retrospective analysis was performed of all the intravascular ultrasound (IVUS)-guided bedside inferior vena cava (IVC) filters placed between August 2003 and October 2007. RESULTS: Fourteen patients had bedside IVUS-guided retrievable filter placement. Thirteen males and one female and the mean (+SD) injury severity scores (ISS) was 37.2 (+9.9). The most common causes of injury were explosive devices (57%), gunshot wounds (28%), rocket-propelled grenades (7%), and motor vehicle crashes (7%). Indications for filter insertion were deep venous thrombosis in 36% of patients and pulmonary embolus in 28%. Thirty five percent had filters inserted prophylactically. CONCLUSIONS: Military trauma population ISS is considerably higher than what is reported in the civilian population. The bedside IVUS-guided IVC filter insertion is particularly useful in this population.

Inflammatory pseudotumor of the spleen managed laparoscopically. Can preoperative imaging establish the diagnosis? Case report and literature review.

BACKGROUND: Inflammatory pseudotumor of the spleen, or inflammatory myofibroblastic tumor, is an uncommon condition easily mistaken for a malignant process. Patients may be asymptomatic or may present with nonspecific abdominal complaints. Mild constitutional symptoms have also been reported. The ability to diagnose this entity radiographically preoperatively may allow the uniform application of laparoscopy to manage this condition and spare patients open splenectomy. METHODS: Chart review and literature review. RESULTS: Inflammatory pseudotumor of the spleen was successfully managed laparoscopically. Preoperative evaluation suggested but could not confirm the diagnosis. CONCLUSIONS: A hypovascular solid splenic mass by Doppler ultrasound or CT scan suggests the diagnosis of inflammatory pseudotumor. Stellate central calcifications seen on CT scan make the diagnosis very likely. Laparoscopic splenectomy can be used for definitive diagnosis and symptomatic relief with minimal morbidity and mortality.

The management of trauma venous injury: civilian and wartime experiences.

The management of venous trauma continues to be debated. Historically, ligation of injured veins is the most common modality of surgical treatment. In the past half-century, additional techniques have been used, including primary repair, interposition graft, and occasionally endovascular techniques. Venous repair, whether in the acute or chronic setting, is believed to prevent or ameliorate the complications of pain, edema, and phlegmasia. Venous repair in civilian trauma and in wartime is commonplace; however, overall treatment strategies remain largely unchanged since the Vietnam War.

Splenic infarction following laparoscopic Nissen fundoplication: management strategies.

Techniques for mobilizing the greater curve of the stomach during laparoscopic Nissen fundoplication (LNF) include division of the short gastric vessels (SGV). The splenic artery and vein lie directly posterior to the proper plane of dissection. Uncontrolled bleeding during SGV division places the splenic vessels at risk for inadvertent injury or ligation. We report herein on 2 patients referred to our institution who had left upper quadrant pain and radiographic evidence of segmental splenic infarction (SI) that resulted from a peripheral splenic artery branch injury during LNF. Management strategies included a trial of conservative management and splenectomy for persistent symptoms or complications resulting from SI. Intense inflammation and adhesion formation making laparoscopic splenectomy difficult should be anticipated when operating on the infarcted spleen.