A modified Mediterranean-style diet enhances brain function via specific gut-microbiome-brain mechanisms

Alzheimer's disease (AD) is a debilitating brain disorder with rapidly mounting prevalence worldwide, yet no proven AD cure has been discovered. Using a multi-omics approach in a transgenic AD mouse model, the current study demonstrated the efficacy of a modified Mediterranean-ketogenic diet (MkD) on AD-related neurocognitive pathophysiology and underlying mechanisms related to the gut-microbiome-brain axis. The findings revealed that MkD induces profound shifts in the gut microbiome community and microbial metabolites. Most notably, MkD promoted growth of the Lactobacillus population, resulting in increased bacteria-derived lactate production. We discovered elevated levels of microbiome- and diet-derived metabolites in the serum as well, signaling their influence on the brain. Importantly, these changes in serum metabolites upregulated specific receptors that have neuroprotective effects and induced alternations in neuroinflammatory-associated pathway profiles in hippocampus. Additionally, these metabolites displayed strong favorable co-regulation relationship with gut-brain integrity and inflammatory markers, as well as neurobehavioral outcomes. The findings underscore the ameliorative effects of MkD on AD-related neurological function and the underlying gut-brain communication via modulation of the gut microbiome-metabolome arrays.

Early Biomarker Signatures in Surgical Sepsis

INTRODUCTION

Sepsis has complex, time-sensitive pathophysiology and important phenotypic subgroups. The objective of this study was to use machine learning analyses of blood and urine biomarker profiles to elucidate the pathophysiologic signatures of subgroups of surgical sepsis patients.

METHODS

This prospective cohort study included 243 surgical sepsis patients admitted to a quaternary care center between January 2015 and June 2017. We applied hierarchical clustering to clinical variables and 42 blood and urine biomarkers to identify phenotypic subgroups in a development cohort. Clinical characteristics and short-term and long-term outcomes were compared between clusters. A naïve Bayes classifier predicted cluster labels in a validation cohort.

RESULTS

The development cohort contained one cluster characterized by early organ dysfunction (cluster I, n = 18) and one cluster characterized by recovery (cluster II, n = 139). Cluster I was associated with higher Acute Physiologic Assessment and Chronic Health Evaluation II (30 versus 16, P < 0.001) and SOFA scores (13 versus 5, P < 0.001), greater prevalence of chronic cardiovascular and renal disease (P < 0.001) and septic shock (78% versus 17%, P < 0.001). Cluster I had higher mortality within 14 d of sepsis onset (11% versus 1.5%, P = 0.001) and within 1 y (44% versus 20%, P = 0.032), and higher incidence of chronic critical illness (61% versus 30%, P = 0.001). The Bayes classifier achieved 95% accuracy and identified two clusters that were similar to development cohort clusters.

CONCLUSIONS

Machine learning analyses of clinical and biomarker variables identified an early organ dysfunction sepsis phenotype characterized by inflammation, renal dysfunction, endotheliopathy, and immunosuppression, as well as poor short-term and long-term clinical outcomes.

Optimizing predictive strategies for acute kidney injury after major vascular surgery

BACKGROUND

Postoperative acute kidney injury is common after major vascular surgery and is associated with increased morbidity, mortality, and cost. High-performance risk stratification using a machine learning model can inform strategies that mitigate harm and optimize resource use. It is hypothesized that incorporating intraoperative data would improve machine learning model accuracy, discrimination, and precision in predicting acute kidney injury among patients undergoing major vascular surgery.

METHODS

A single-center retrospective cohort of 1,531 adult patients who underwent nonemergency major vascular surgery, including open aortic, endovascular aortic, and lower extremity bypass procedures, was evaluated. The validated, automated MySurgeryRisk analytics platform used electronic health record data to forecast patient-level probabilistic risk scores for postoperative acute kidney injury using random forest models with preoperative data alone and perioperative data (preoperative plus intraoperative). The MySurgeryRisk predictions were compared with each other as well as with the American Society of Anesthesiologists physical status classification.

RESULTS

Machine learning models using perioperative data had greater accuracy, discrimination, and precision than models using either preoperative data alone or the American Society of Anesthesiologists physical status classification (accuracy: 0.70 vs 0.64 vs 0.62, area under the receiver operating characteristics curve: 0.77 vs 0.68 vs 0.61, area under the precision-recall curve: 0.70 vs 0.58 vs 0.48).

CONCLUSION

In predicting acute kidney injury after major vascular surgery, machine learning approaches that incorporate dynamic intraoperative data had greater accuracy, discrimination, and precision than models using either preoperative data alone or the American Society of Anesthesiologists physical status classification. Machine learning methods have the potential for real-time identification of high-risk patients who may benefit from personalized risk-reduction strategies.

Older Sepsis Survivors Suffer Persistent Disability Burden and Poor Long-Term Survival

As in-hospital sepsis mortality has decreased, more “sepsis survivors” are progressing into poorly characterized long-term outcomes. The purpose of this study was to describe the current epidemiology of sepsis in older adults compared to middle-aged and young adults. Design: Prospective longitudinal study with patients categorized into young (≤ 45 years), middle-aged (46-64 years) and older (≥ 65 years) patient groups. 328 sepsis patients were characterized by a) baseline demographics and predisposition factors, b) septic event, c) hospital outcomes and discharge disposition, d) 12-month mortality and e) Zubrod Performance status, physical function and cognitive function at three, six and 12-month follow-up. Follow-up visits were not completed due to death (in 68) and withdrawal of consent (in 32). Compared to young and middle-aged patients, older patients had: 1) significantly more comorbidities at presentation (example chronic renal disease 6% vs 12 % vs 21%), intra-abdominal infections (14% vs 25% vs 37%), septic shock (12% vs 25% vs 36%) and organ dysfunctions, 2) higher 30 day mortality (6% vs 4% vs 17%) and fewer ICU free days (median 25 vs 23 vs 20), 3) more progression into CCI (22%, vs 34% vs 42%) with higher poor disposition discharge to non-home destinations (19% vs 40% vs 62%), 4) worse 12-month mortality (11% vs 14 % vs 33%) and, 5) poorer Zubrod Performance status and objectively-measured physical and cognitive functions with slight improvement over 12 month follow-up. Conclusion: Compared to younger patients, older sepsis survivors suffer with both a higher persistent disability burden and 12-month mortality.

Myeloid-derived suppressor cells modulate aortic aneurysm formation via CXCR2 and IL-17 signaling

Aortic aneurysm formation is associated with vascular inflammation and remodeling mediated via CD4+ T cell-secreted IL-17A production. Our hypothesis is that innate myeloid-derived suppressor cells (MDSCs), which are a heterogeneous population of myeloid precursor and progenitor cells, exhibit an immunoregulatory role in the progression of aortic inflammation during abdominal aortic aneurysm (AAA) formation. The trafficking and migration of MDSCs to the aortic tissue and role of CXCR2 and programmed death-1 (PD-1) receptor signaling was deciphered using an in vivo elastase-treatment model of AAA as well as in vitro co-culture experiments. We used an established murine AAA model of topical elastase-treatment in the present study. Preliminary data showed that elastase-treatment of C57BL/6 (wild-type; WT) mice resulted in significant increase in infrarenal aortic diameter causing AAA formation on day 14 that was significantly inhibited by a combined treatment with anti-CXCR2 and PD-1 antibodies. A multi-fold increase in MDSCs (CD11b+Gr-1+) in aortic tissue of elastase-treated WT mice on days 7 and 14 occurred compared to controls. Co-culture of MDSCs with aortic endothelial cells in the presence of anti-CXCR2 antibody inhibited the transmigration of MDSCs through the endothelial barrier. Moreover, transient elastase treatment of co-cultures of anti-CD3/CD28 treated mononuclear cells with MDSCs significantly enhanced IL-17A secretion compared to cultures without MDSCs. Our results indicate that MDSCs may play a contributory role in aortic inflammation by trafficking in a CXCR2-dependent manner and promotion of IL-17A secretion, signifying the importance of MDSC-mediated immunoregulation of aortic aneurysms.

Abstract TMP91: Pre-Sepsis P-wave Terminal Force in Lead V1 (PTFV1) as a Predictor of Atrial Fibrillation, In-Hospital Mortality, and Cognition in Sepsis Patients

Introduction: Enlarged P-wave terminal force in lead V1 (PTFV1) >5000 μV*ms is a long-term predictor of the left atrial abnormality such as atrial fibrillation (AF), cognitive dysfunction, and stroke at age ≤ 60. Sepsis patients are at high risk of cardiac dysfunction, AF, stroke, and impaired cognition acutely and longitudinally, but predictive value pre-sepsis PTFV1 has not been studied.

Hypothesis: Higher PTFV1 before sepsis onset is associated with AF events, left atrial enlargement, mortality, and 1-year cognitive impairment in patients who developed sepsis.

Methods: Patients with acute sepsis were prospectively screened and enrolled in an observational study years 2015-2019. Of the 360 consented, 287 had pre-sepsis electrocardiograms (ECG), and 272 were evaluable. PTFV1 was measured using the Mitutoyo 500-195-30CAL Absolute Digimatic Caliper. Left atrial diameter index (LADI) pre-sepsis and post enrollment were recorded (median of 2 days [interquartile range (IQR) 1-13]). Occurrence of AF was assessed on the next available ECG, 3 days [IQR 1-11] post-enrollment. Cognitive function at 1-year follow-up was assessed by the mini-mental state examination (MMSE) and the Hopkins Verbal Learning test (HVLT). Statistical significance was evaluated using linear and logistic univariate regression.

Results: In this cohort, the median age was 63 years [IQR 53-71], 44% women. The median PTVF1, LADI at pre-sepsis and follow up were 3219 μV*ms [IQR 0 - 5487], 1.86 cm/mm 2 [IQR 1.58 - 2.14], and 1.89 cm/mm 2 [IQR 1.59 - 2.17], respectively. Pre-sepsis PTFV1 was > 5,000 μV*ms in 32%. Elevated PTFV1 at age ≥ 60 was not associated with AF (p=0.06) or in-hospital mortality (p=0.17). Similarly, high PTFV1 at age < 60 was not associated in-hospital mortality (p=0.50), and only 3 in this cohort had AF. There was no association with pre-sepsis LADI (p=0.55), follow-up LADI (p=0.70), MMSE (p=0.35), or HVLT (p=0.78) and PTFV1.

Conclusions: Here, PTFV1 values were not associated with AF or measures of cognitive impairment. While our findings differ from other longitudinal studies, the early time interval and setting of sepsis in our study is unique. Future studies will include multivariate analysis and evaluation of long term outcome measures linked to PTFV1 such as stroke.

Minimum Quality Threshold in Pre-Clinical Sepsis Studies (MQTiPSS): an international expert consensus initiative for improvement of animal modeling in sepsis

Purpose

Pre-clinical animal studies precede the majority of clinical trials. While the clinical sepsis definitions and recommended treatments are regularly updated, a systematic review of pre-clinical models of sepsis has not been done and clear modeling guidelines are lacking. To address this deficit, a Wiggers-Bernard Conference on pre-clinical sepsis modeling was held in Vienna in May, 2017. The conference goal was to identify limitations of pre-clinical sepsis models and to propose a set of guidelines, defined as the “Minimum Quality Threshold in Pre-Clinical Sepsis Studies” (MQTiPSS), to enhance translational value of these models.

Methods

31 experts from 13 countries participated and were divided into 6 thematic Working Groups (WG): (1) Study Design, (2) Humane modeling, (3) Infection types, (4) Organ failure/dysfunction, (5) Fluid resuscitation and (6) Antimicrobial therapy endpoints. As basis for the MQTiPSS discussions, the participants conducted a literature review of the 260 most highly cited scientific articles on sepsis models (2002–2013).

Results

Overall, the participants reached consensus on 29 points; 20 at “recommendation” (R) and 9 at “consideration” (C) strength. This Executive Summary provides a synopsis of the MQTiPSS consensus (Tables 1, 2 and 3).

Conclusions

We believe that these recommendations and considerations will serve to bring a level of standardization to pre-clinical models of sepsis and ultimately improve translation of pre-clinical findings. These guideline points are proposed as “best practices” that should be implemented for animal sepsis models. In order to encourage its wide dissemination, this article is freely accessible in Shock, Infection and Intensive Care Medicine Experimental.

Part I: Minimum Quality Threshold in Preclinical Sepsis Studies (MQTiPSS) for Study Design and Humane Modeling Endpoints

Preclinical animal studies are mandatory before new treatments can be tested in clinical trials. However, their use in developing new therapies for sepsis has been controversial because of limitations of the models and inconsistencies with the clinical conditions. In consideration of the revised definition for clinical sepsis and septic shock (Sepsis-3), a Wiggers-Bernard Conference was held in Vienna in May 2017 to propose standardized guidelines on preclinical sepsis modeling. The participants conducted a literature review of 260 most highly cited scientific articles on sepsis models published between 2003 and 2012. The review showed, for example, that mice were used in 79% and euthanasia criteria were defined in 9% of the studies. Part I of this report details the recommendations for study design and humane modeling endpoints that should be addressed in sepsis models. The first recommendation is that survival follow-up should reflect the clinical time course of the infectious agent used in the sepsis model. Furthermore, it is recommended that therapeutic interventions should be initiated after the septic insult replicating clinical care. To define an unbiased and reproducible association between a new treatment and outcome, a randomization and blinding of treatments as well as inclusion of all methodological details in scientific publications is essential. In all preclinical sepsis studies, the high standards of animal welfare must be implemented. Therefore, development and validation of specific criteria for monitoring pain and distress, and euthanasia of septic animals, as well as the use of analgesics are recommended. A set of four considerations is also proposed to enhance translation potential of sepsis models. Relevant biological variables and comorbidities should be included in the study design and sepsis modeling should be extended to mammalian species other than rodents. In addition, the need for source control (in case of a defined infection focus) should be considered. These recommendations and considerations are proposed as "best practices" for animal models of sepsis that should be implemented.

Minimum Quality Threshold in Pre-Clinical Sepsis Studies (MQTiPSS): An International Expert Consensus Initiative for Improvement of Animal Modeling in Sepsis

Preclinical animal studies precede the majority of clinical trials. While the clinical definitions of sepsis and recommended treatments are regularly updated, a systematic review of preclinical models of sepsis has not been done and clear modeling guidelines are lacking. To address this deficit, a Wiggers-Bernard Conference on preclinical sepsis modeling was held in Vienna in May, 2017. The goal of the conference was to identify limitations of preclinical sepsis models and to propose a set of guidelines, defined as the "Minimum Quality Threshold in Preclinical Sepsis Studies" (MQTiPSS), to enhance translational value of these models. A total of 31 experts from 13 countries participated and were divided into six thematic Working Groups: Study Design, Humane modeling, Infection types, Organ failure/dysfunction, Fluid resuscitation, and Antimicrobial therapy endpoints. As basis for the MQTiPSS discussions, the participants conducted a literature review of the 260 most highly cited scientific articles on sepsis models (2002-2013). Overall, the participants reached consensus on 29 points; 20 at "recommendation" and nine at "consideration" strength. This Executive Summary provides a synopsis of the MQTiPSS consensus. We believe that these recommendations and considerations will serve to bring a level of standardization to preclinical models of sepsis and ultimately improve translation of preclinical findings. These guideline points are proposed as "best practices" for animal models of sepsis that should be implemented. To encourage its wide dissemination, this article is freely accessible on the Intensive Care Medicine Experimental and Infection journal websites. In order to encourage its wide dissemination, this article is freely accessible in Shock, Infection, and Intensive Care Medicine Experimental.

Minimum quality threshold in pre-clinical sepsis studies (MQTiPSS): an international expert consensus initiative for improvement of animal modeling in sepsis

Background

Pre-clinical animal studies precede the majority of clinical trials. While the clinical definitions of sepsis and recommended treatments are regularly updated, a systematic review of pre-clinical models of sepsis has not been done and clear modeling guidelines are lacking.

Objective

To address this deficit, a Wiggers-Bernard Conference on pre-clinical sepsis modeling was held in Vienna in May 2017. The goal of the conference was to identify limitations of pre-clinical sepsis models and to propose a set of guidelines, defined as the “Minimum Quality Threshold in Pre-Clinical Sepsis Studies” (MQTiPSS), to enhance translational value of these models.

Methods

A total of 31 experts from 13 countries participated and were divided into 6 thematic working groups (WG): (1) study design, (2) humane modeling, (3) infection types, (4) organ failure/dysfunction, (5) fluid resuscitation, and (6) antimicrobial therapy endpoints. As basis for the MQTiPSS discussions, the participants conducted a literature review of the 260 most highly cited scientific articles on sepsis models (2002–2013).

Results

Overall, the participants reached consensus on 29 points; 20 at “recommendation” (R) and 9 at “consideration” (C) strength. This executive summary provides a synopsis of the MQTiPSS consensus (Tables 1, 2, and 3). Detailed commentaries to all Rs and Cs are simultaneously published in three separate full-length papers.

Conclusions

We believe that these recommendations and considerations will serve to bring a level of standardization to pre-clinical models of sepsis and ultimately improve translation of pre-clinical findings. These guideline points are proposed as “best practices” for animal models of sepsis that should be implemented. In order to encourage its wide dissemination, this article is freely accessible in Shock, Infection and Intensive Care Medicine Experimental.

Soybean oil: a potentially new intravascular perfusate

BACKGROUND

Given that micelles of lipids are colloids, the hypothesis was generated that the rapid administration of large volumes of soybean oil micelles would be an effective perfusion fluid. We also hypothesized that oxygen loading would be enhanced due to the greater solubility of oxygen in lipids compared to water.

METHODS

A 100% lethal mouse model of blood loss was used to compare the ability of soybean oil micelles to that of Ringer's lactate, blood and other fluids, with respect to raising and maintaining the blood pressure for one hour. Oxygen on- and off-loading of various concentrations of soybean oil micelles was determined using mass spectroscopy. Nitric oxide uptake by micelles was also determined in a similar fashion.

RESULTS

A 20% soybean oil emulsion was superior to Ringer's lactate in raising and maintaining blood pressure. A 20% soybean oil emulsion with 5% albumin added was superior to shed blood as well as solutions comprised of 5% albumin added to either normal saline or Ringer's lactate. There was a linear relationship between oxygen content and micelle concentration between 10% and 30%. Off-loading of oxygen from the micelles was nearly as fast as off-loading from water. Nitric oxide also loaded preferentially onto soybean oil micelles.

CONCLUSIONS

(1) Soybean oil emulsions were superior to other fluids in restoring and maintaining the blood pressure; (2) oxygen-carrying ability of soybean oil micelles exceeds that of water and follows Henry's law between 10% and 30% w/v oil content; (3) nitric oxide was carried by the micelles; (4) animals receiving soybean oil micelles did not exhibit fat embolization; (5) colloids comprised of soybean oil-containing micelles may be used to replace blood loss and may be used to deliver oxygen and other potentially therapeutic gases such as nitric oxide to tissues.

The potential influence of common viral infections diagnosed during hospitalization among critically ill patients in the United States

Viruses are the most common source of infection among immunocompetent individuals, yet they are not considered a clinically meaningful risk factor among the critically ill. This work examines the association of viral infections diagnosed during the hospital stay or not documented as present on admission to the outcomes of ICU patients with no evidence of immunosuppression on admission. This is a population-based retrospective cohort study of University HealthSystem Consortium (UHC) academic centers in the U.S. from the years 2006 to 2009. The UHC is an alliance of over 90% of the non-profit academic medical centers in the U.S. A total of 209,695 critically ill patients were used in this analysis. Eight hospital complications were examined. Patients were grouped into four cohorts: absence of infection, bacterial infection only, viral infection only, and bacterial and viral infection during same hospital admission. Viral infections diagnosed during hospitalization significantly increased the risk of all complications. There was also a seasonal pattern for viral infections. Specific viruses associated with poor outcomes included influenza, RSV, CMV, and HSV. Patients who had both viral and bacterial infections during the same hospitalization had the greatest risk of mortality RR 6.58, 95% CI (5.47, 7.91); multi-organ failure RR 8.25, 95% CI (7.50, 9.07); and septic shock RR 271.2, 95% CI (188.0, 391.3). Viral infections may play a significant yet unrecognized role in the outcomes of ICU patients. They may serve as biological markers or play an active role in the development of certain adverse complications by interacting with coincident bacterial infection.

Delayed neutralization of interferon-gamma prevents lethality in primate Gram-negative bacteremic shock

OBJECTIVE

Whether anticytokine therapies have a place in the treatment of severe sepsis and septic shock remains a question. Although a number of preclinical studies have shown efficacy in primate models of bacteremic shock when administered prophylactically, these same therapies have a significantly diminished effectiveness when administered therapeutically. This study investigated whether delayed administration of a novel anti-human interferon-gamma monoclonal antibody could improve outcome and reduce organ injury in a lethal model of Escherichia coli bacteremia, when administered after the onset of shock.

DESIGN

Randomized, prospective, double-blinded intervention study.

SUBJECTS

Cynomolgus monkeys.

INTERVENTIONS

Treatment with a humanized monoclonal antibody directed against human interferon-gamma (INNO 202), administered after the onset of shock, induced by the infusion of live E. coli.

MEASUREMENTS AND MAIN RESULTS

Five of the six vehicle-treated monkeys died or were killed within 24-72 hrs after E. coli administration, and all died within 5 days. In contrast, six of the eight animals treated with the anti-interferon-gamma survived for 7 days, and three of the eight animals survived 14 days (p = .013 vs. vehicle). Delayed treatment with the anti-interferon-gamma monoclonal antibody did not restore hemodynamics or reduce the amount of crystalloid-containing fluid required to resuscitate the animals but did attenuate renal failure (p < .05) and the magnitude of the inflammatory cytokine response (p < .05).

CONCLUSIONS

In a primate model of E. coli bacteremic shock, delayed neutralization of interferon-gamma after the onset of shock improved survival and attenuated the pathologic changes associated with the development of organ dysfunction. These findings suggest that interferon-gamma blockade represents a potentially effective mode of late intervention in lethal septic shock.

Sepsis and the dendritic cell

Sepsis is a syndrome of significant morbidity and mortality. Unlike the advances made in other diseases processes, improvements in outcome from sepsis, severe sepsis, and septic shock have been modest. Current research has altered our understanding of sepsis pathogenesis such that present models and definitions are still evolving. One relatively novel cell type, the dendritic cell, is the subject of much current investigation in sepsis. Although our present understanding of dendritic cell biology is incomplete, growing evidence supports the importance of this antigen-presenting cell in the normal and maladaptive responses to microbial invasion and tissue injury. A better understanding of this cell's basic biology as well as its potential as a therapeutic target will undoubtedly play increasing roles in the development of new strategies for the treatment of the septic patient.

Anaphylactic reaction to isosulfan blue used for sentinel node biopsy: case report and literature review

Isosulfan blue is a commonly used agent in the detection of sentinel lymph nodes during cancer surgery. Similar to any drug, it is possible to have an allergic reaction to this increasingly popular chemical during breast cancer operations. We present one case of anaphylactic shock in response to injection of isosulfan blue for the purpose of localizing the sentinel node and review the medical literature. A thorough knowledge of possible isosulfan blue side effects, including their presentation and subsequent therapy, is essential for the modern breast surgeon.