Fecal metabolite profiling identifies liver transplant recipients at risk for postoperative infection

Folic acid supplementation is associated with a decreased mortality and reduced hospital readmission in patients with decompensated alcohol-related liver cirrhosis

BACKGROUND AND AIMS

Thiamine and folic acid malnutrition is highly frequent in patients with decompensated alcohol-related liver cirrhosis (aLC). Current guidelines therefore recommend vitamin supplementation in these patients. However, implementation and its impact on the clinical outcome remains unknown. Therefore, we aimed to analyze the use of thiamine and folic acid and their effects on mortality and morbidity in patients with decompensated aLC.

METHODS

A number of 289 consecutive patients with decompensated aLC who received a paracentesis at Hannover Medical School between 2011 and 2023 were retrospectively investigated. The use of folic acid and thiamine-containing supplements was assessed in the discharge medication. Patients were followed for up to one year regarding liver transplant (LTx)-free survival and the incidence of hepatic encephalopathy, infections and hepatic decompensation requiring rehospitalization.

RESULTS

Median baseline MELD was 15, median age 56.6 years. 73.0% (n = 211) were male patients. At hospital discharge, thiamine-containing supplements and folic acid were prescribed to 48.1% (n = 139) and 18.0% (n = 52) patients, respectively. Neither thiamine nor folic acid prescription were linked to improved clinical outcomes within 90 days. However, folic acid intake was associated with a higher one-year LTx-free survival (HR = 0.48; p = 0.04) in the multivariable analysis. Furthermore, folic acid substitution was linked to a decreased risk of rehospitalization within one year (HR = 0.55; p = 0.01) in the multivariable competing risk model. In contrast, thiamine prescription did neither affect LTx-free survival nor the here investigated liver-related complications.

CONCLUSION

Folic acid, but not thiamine substitution was linked to an improved outcome in patients with decompensated aLC.

Social determinants of health, the microbiome, and surgical injury

ABSTRACT

Postinjury infection continues to plague trauma and emergency surgery patients fortunate enough to survive the initial injury. Rapid response systems, massive transfusion protocols, and the development of level 1 trauma centers, among others, have improved the outcome for millions of patients worldwide. Nonetheless, despite this excellent initial care, patients still remain vulnerable to postinjury infections that can result in organ failure, prolonged critical illness, and even death. While risk factors have been identified (degree of injury, blood loss, time to definitive care, immunocompromise, etc.), they remain probabilistic, not deterministic, and do not explain outcome variability at the individual case level. Here, we assert that analysis of the social determinants of health, as reflected in the patient's microbiome composition (i.e., community structure, membership) and function (metabolomic output), may offer a "window" with which to define individual variability following traumatic injury. Given emerging knowledge in the field, a more comprehensive evaluation of biomarkers within the patient's microbiome, from stool-based microbial metabolites to those in plasma and those present in exhaled breath, when coupled with clinical metadata and machine learning, could lead to a more deterministic assessment of an individual's risk for a poor outcome and those factors that are modifiable. The aim of this piece is to examine how measurable elements of the social determinants of health and the life history of the patient may be buried within the ecologic memory of the gut microbiome. Here we posit that interrogation of the gut microbiome in this manner may be used to inform novel approaches to drive recovery following a surgical injury.

Therapeutic manipulation of the microbiome in liver disease

Myriad associations between the microbiome and various facets of liver physiology and pathology have been described in the literature. Building on descriptive and correlative sequencing studies, metagenomic studies are expanding our collective understanding of the functional and mechanistic role of the microbiome as mediators of the gut-liver axis. Based on these mechanisms, the functional activity of the microbiome represents an attractive, tractable, and precision medicine therapeutic target in several liver diseases. Indeed, several therapeutics have been used in liver disease even before their description as a microbiome-dependent approach. To bring successful microbiome-targeted and microbiome-inspired therapies to the clinic, a comprehensive appreciation of the different approaches to influence, collaborate with, or engineer the gut microbiome to coopt a disease-relevant function of interest in the right patient is key. Herein, we describe the various levels at which the microbiome can be targeted-from prebiotics, probiotics, synbiotics, and antibiotics to microbiome reconstitution and precision microbiome engineering. Assimilating data from preclinical animal models, human studies as well as clinical trials, we describe the potential for and rationale behind studying such therapies across several liver diseases, including metabolic dysfunction-associated steatotic liver disease, alcohol-associated liver disease, cirrhosis, HE as well as liver cancer. Lastly, we discuss lessons learned from previous attempts at developing such therapies, the regulatory framework that needs to be navigated, and the challenges that remain.

Intestinal colonization resistance in the context of environmental, host, and microbial determinants

Microbial communities that colonize the human gastrointestinal (GI) tract defend against pathogens through a mechanism known as colonization resistance (CR). Advances in technologies such as next-generation sequencing, gnotobiotic mouse models, and bacterial cultivation have enhanced our understanding of the underlying mechanisms and the intricate microbial interactions involved in CR. Rather than being attributed to specific microbial clades, CR is now understood to arise from a dynamic interplay between microbes and the host and is shaped by metabolic, immune, and environmental factors. This evolving perspective underscores the significance of contextual factors, encompassing microbiome composition and host conditions, in determining CR. This review highlights recent research that has shifted its focus toward elucidating how these factors interact to either promote or impede enteric infections. It further discusses future research directions to unravel the complex relationship between host, microbiota, and environmental determinants in safeguarding against GI infections to promote human health.

The gut microbiome as a guidepost for infection risk in liver transplantation

In this issue, Lehmann et al. addresses the high infection risk in liver transplantation by examining the gut microbiome in a patient cohort. By uncovering a predictive role of the microbiome for the clinical course, the study unravels the gut microbiome as a guidepost for infection risk in liver transplantation.