Current status of the microbiome in renal transplantation. Curr Opin Nephrol Hypertens. 2016;25:570-576. [PMID: 27517135 DOI: 10.1097/mnh.0000000000000262]

The effect and mechanism of Fushen Granule on gut microbiome in the prevention and treatment of chronic renal failure

Background

Fushen Granule is an improved granule based on the classic formula Fushen Formula, which is used for the treatment of peritoneal dialysis-related intestinal dysfunction in patients with end-stage renal disease. However, the effect and mechanism of this granule on the prevention and treatment of chronic renal failure have not been fully elucidated.

Methods

A 5/6 nephrectomy model of CRF was induced and Fushen Granule was administered at low and high doses to observe its effects on renal function, D-lactate, serum endotoxin, and intestinal-derived metabolic toxins. The 16SrRNA sequencing method was used to analyze the abundance and structure of the intestinal flora of CRF rats. A FMT assay was also used to evaluate the effects of transplantation of Fushen Granule fecal bacteria on renal-related functional parameters and metabolic toxins in CRF rats.

Results

Gavage administration of Fushen Granule at low and high doses down-regulated creatinine, urea nitrogen, 24-h urine microalbumin, D-lactate, endotoxin, and the intestinal-derived toxins indophenol sulphateand p-cresol sulphate in CRF rats. Compared with the sham-operated group in the same period, CRF rats had a decreased abundance of the firmicutes phylum and an increased abundance of the bacteroidetes phylum at the phylum level, and a decreasing trend of the lactobacillus genus at the genus level. Fushen Granule intervention increased the abundance of the firmicutes phylum, decreased the abundance of the bacteroidetes phylum, and increased the abundance of the lactobacillus genus. The transplantation of Fushen Granule fecal bacteria significantly reduced creatinine(Cr), blood urea nitrogen(Bun), uric acid(UA), 24-h urinary microalbumin, D-lactate, serum endotoxin, and enterogenic metabolic toxins in CRF rats. Compared with the sham-operated group, the transplantation of Fushen Granule fecal bacteria modulated the Firmicutes and Bacteroidetes phyla and the Lactobacillus genus.

Conclusion

Fushen Granule improved renal function and intestinal barrier function by regulating intestinal flora, inhibiting renal fibrosis, and delaying the progression of chronic renal failure.

After Bone Marrow Transplantation, the Cell-Intrinsic Th2 Pathway Promotes Recipient T Lymphocyte Survival and Regulates Graft-versus-Host Disease

Recipient T cells can aggravate or regulate lethal and devastating graft-versus-host disease (GVHD) after bone marrow transplantation (BMT). In this context, we have shown before that intestinal immune conditioning with helminths is associated with survival of recipient T cells and Th2 pathway-dependent regulation of GVHD. We investigated the mechanism of survival of recipient T cells and their contribution to GVHD pathogenesis in this helminth infection and BMT model after myeloablative preparation with total body irradiation in mice. Our results indicate that the helminth-induced Th2 pathway directly promotes the survival of recipient T cells after total body irradiation. Th2 cells also directly stimulate recipient T cells to produce TGF-β, which is required to regulate donor T cell-mediated immune attack of GVHD and can thereby contribute to recipient T cell survival after BMT. Moreover, we show that recipient T cells, conditioned to produce Th2 cytokines and TGF-β after helminth infection, are fundamentally necessary for GVHD regulation. Taken together, reprogrammed or immune-conditioned recipient T cells after helminth infection are crucial elements of Th2- and TGF-β-dependent regulation of GVHD after BMT, and their survival is dependent on cell-intrinsic Th2 signaling.

Acute Kidney Injury in Kidney Transplant Patients in Intensive Care Unit: From Pathogenesis to Clinical Management

Kidney transplantation is the first-choice treatment for end-stage renal disease (ESRD). Kidney transplant recipients (KTRs) are at higher risk of experiencing a life-threatening event requiring intensive care unit (ICU) admission, mainly in the late post-transplant period (more than 6 months after transplantation). Urosepsis and bloodstream infections account for almost half of ICU admissions in this population; in addition, potential side effects related to immunosuppressive treatment should be accounted for cytotoxic and ischemic changes induced by calcineurin inhibitor (CNI), sirolimus/CNI-induced thrombotic microangiopathy and posterior reversible encephalopathy syndrome. Throughout the ICU stay, Acute Kidney Injury (AKI) incidence is common and ranges from 10% to 80%, and up to 40% will require renal replacement therapy. In-hospital mortality can reach 30% and correlates with acute illness severity and admission diagnosis. Graft survival is subordinated to baseline estimated glomerular filtration rate (eGFR), clinical presentation, disease severity and potential drug nephrotoxicity. The present review aims to define the impact of AKI events on short- and long-term outcomes in KTRs, focusing on the epidemiologic data regarding AKI incidence in this subpopulation; the pathophysiological mechanisms underlying AKI development and potential AKI biomarkers in kidney transplantation, graft and patients' outcomes; the current diagnostic work up and management of AKI; and the modulation of immunosuppression in ICU-admitted KTRs.

Pain Interference in End Stage Kidney Disease is Associated with Changes in Gut Microbiome Features Before and After Kidney Transplantation

BACKGROUND

Pain, a common debilitating symptom among kidney transplant recipients (KTRs), is among the most common and undertreated symptoms after kidney transplantation.

AIMS

Characterize associations between gut microbiome features and pain interference before and after kidney transplantation.

DESIGN

Longitudinal, repeated measures study, collecting fecal specimens and pain interference data pretransplant and 3 months posttransplant.

SETTING

Participants were recruited at the kidney transplant clinic at the University of Illinois Hospital & Health Sciences System.

PARTICIPANTS/SUBJECTS

19 living donor kidney transplant recipients.

METHODS

We assessed fecal microbial community structure with shotgun metagenomic sequencing; we used pain interference scores derived from the Patient-Reported Outcomes Measurement Information System-57.

RESULTS

We measured a reduction in the Shannon diversity index in both groups after transplantation but observed no significant differences between groups at either time point. We did observe significant differences in fecal microbial Bray-Curtis similarity index among those reporting pain interference pre- transplant versus no pain interference at 3-months posttransplant (R = .306, p = .022), and between pain interference groups at posttransplant (R = .249, p = .041). Pairwise models showed significant differences between groups posttransplant in relative abundances of several taxa, including a 5-fold reduction.ßin Akkermansia among those with pain interference and a higher relative abundance of taxa associated with chronic inflammation in those with pain interference posttransplant. Functional gene analysis identified two features that were significantly enriched in those with pain interference, including a peptide transport system gene.

CONCLUSIONS

Gut microbiota community structure differs between groups with and without pain interference at 3 months after kidney transplantation. Several taxa involved in intestinal barrier integrity and chronic inflammation were associated with posttransplant pain.

Fecal Microbiota Transplantation in Reducing Uremic Toxins Accumulation in Kidney Disease: Current Understanding and Future Perspectives

During the past decades, the gut microbiome emerged as a key player in kidney disease. Dysbiosis-related uremic toxins together with pro-inflammatory mediators are the main factors in a deteriorating kidney function. The toxicity of uremic compounds has been well-documented in a plethora of pathophysiological mechanisms in kidney disease, such as cardiovascular injury (CVI), metabolic dysfunction, and inflammation. Accumulating data on the detrimental effect of uremic solutes in kidney disease supported the development of many strategies to restore eubiosis. Fecal microbiota transplantation (FMT) spread as an encouraging treatment for different dysbiosis-associated disorders. In this scenario, flourishing studies indicate that fecal transplantation could represent a novel treatment to reduce the uremic toxins accumulation. Here, we present the state-of-the-art concerning the application of FMT on kidney disease to restore eubiosis and reverse the retention of uremic toxins.

The Effect of the Gut Microbiota on Transplanted Kidney Function

The intestinal microflora is extremely important, not only in the processes of absorption, digestion and biosynthesis of vitamins, but also in shaping the immune and cognitive functions of the human body. Several studies demonstrate a correlation between microbiota composition and such events as graft rejection, kidney interstitial fibrosis, urinary tract infections, and diarrhoea or graft tolerance. Some of those changes might be directly linked with pathologies such as colonization with pathogenic bacterial strains. Gut microbiota composition also plays an important role in metabolic complications and viral infections after transplantation. From the other side, gut microbiota might induce graft tolerance by promotion of T and B regulatory cells. Graft tolerance induction is still an extremely important issue regarding transplantology and might allow the reduction or even avoidance of immunosuppressive treatment. Although there is a rising evidence of the pivotal role of gut microbiota in aspects of kidney transplantation there is still a lack of knowledge on the direct mechanisms of microbiota action. Furthermore, some of those negative effects could be reversed by probiotics of faecal microbiota trapoinsplantation. While diabetes and hypertension as well as BKV and CMV viremia are common and important complications of transplantation, both worsening the graft function and causing systemic injuries, it opens up potential clinical treatment options. As has been also suggested in the current review, some bacterial subsets exhibit protective properties. However, currently, there is a lack of evidence on pro- and prebiotic supplementation in kidney transplant patients. In the current review, we describe the effect of the microbiota on the transplanted kidney in renal transplant recipients.

Application of Various Techniques to Gain Insights Into the Complex Urinary Tract Microbial Communities of Renal Transplant Recipients

Urinary tract infections (UTIs) are prevalent in renal transplant (RT_X) recipients and associated with worse outcomes. Early detection by sensitive diagnostic tests and appropriate treatment strategies in this cohort is therefore crucial, but evidence has shown that current methods may miss genuine infections. Research has shed light on the urinary tract microbial ecology of healthy individuals and nontransplant patients with UTI, but information on the RTx cohort is scant. We conducted a cross-sectional study to (i) compare the gold standard diagnostic culture with alternative techniques and (ii) characterize RTx patient urinary microbial communities.

Methods

Midstream urine specimens were collected from 51 RTx patients attending a renal transplant clinic and 27 asymptomatic controls. Urinary microscopy, dipstick, and routine culture were performed. To improve sensitivity of microbial detection, we cultured the urinary cell sediment and performed 16S rRNA gene sequencing on urine. Uroplakin-positive urothelial cells shed in urine were analyzed by immunofluorescence staining for any bacterial association.

Results

Sediment culture and 16S rRNA sequencing confirmed detection deficiencies of diagnostic culture and revealed differences in the urobiomes of RTx patients and controls. Specifically, Gardnerella, Escherichia, and Lactobacillus were most abundant in patients, whereas Lactobacillus, Streptococcus, and Gardnerella were most abundant in controls. The application of both culture and sequencing provided a more nuanced view of the urinary microbial communities.

Conclusions

This study provides insight into the potential problems of diagnostic culture within RTx patients and sheds light on their urinary microbial inhabitants. Further work may identify key microbial signatures and facilitate the development of better tools for UTI detection within this cohort, which could allow targeted intervention before an infection leads to serious consequences. http://links.lww.com/TXD/A479.

Gut microbiome and renal transplantation

Gut microbiome research has been a surge of interest in many branches of medicine in the last decade. Our main aim is to show ability of microbes to infuence the functions of human body, especially in the immune system, and on the other hand to clarify changes in composition of gut microbiome in the post-transplantation period and their function for the long-term survival of the graft and the patient in the context of the occurrence of a wide range of complications. Kidney transplantation with the subsequent use of immunosuppressants and antibiotics affects the composition of gut microbiome. The subsequent development of dysbiosis significantly increases the risk of acute rejection, interstitial fibrosis and tubular atrophy of the graft, post-transplant diarrhoea, organ´s infections and metabolic complications such as post-transplant diabetes mellitus. Also important is the influence of the microorganisms of the gut microbiome on metabolism of immunosuppressants with the production of less effective components and the subsequent necessity of modifying their levels with a higher risk of underdosing and the occurrence of graft rejection. Support of the composition of the gut microbiome in the post-transplantation period in favor of bacteria producing short chain fatty acids (SCFA) is possible by changing of diet with predominance of fiber, the application of probiotics, prebiotics. According to available studies, it can lead to benefits in term of metabolic compensation, to the induction of donor-specific tolerance and many others, with an overall improvement in the quality of patient and graft survival.

The Impact of Human Microbiotas in Hematopoietic Stem Cell and Organ Transplantation

The human microbiota heavily influences most vital aspects of human physiology including organ transplantation outcomes and transplant rejection risk. A variety of organ transplantation scenarios such as lung and heart transplantation as well as hematopoietic stem cell transplantation is heavily influenced by the human microbiotas. The human microbiota refers to a rich, diverse, and complex ecosystem of bacteria, fungi, archaea, helminths, protozoans, parasites, and viruses. Research accumulating over the past decade has established the existence of complex cross-species, cross-kingdom interactions between the residents of the various human microbiotas and the human body. Since the gut microbiota is the densest, most popular, and most studied human microbiota, the impact of other human microbiotas such as the oral, lung, urinary, and genital microbiotas is often overshadowed. However, these microbiotas also provide critical and unique insights pertaining to transplantation success, rejection risk, and overall host health, across multiple different transplantation scenarios. Organ transplantation as well as the pre-, peri-, and post-transplant pharmacological regimens patients undergo is known to adversely impact the microbiotas, thereby increasing the risk of adverse patient outcomes. Over the past decade, holistic approaches to post-transplant patient care such as the administration of clinical and dietary interventions aiming at restoring deranged microbiota community structures have been gaining momentum. Examples of these include prebiotic and probiotic administration, fecal microbial transplantation, and bacteriophage-mediated multidrug-resistant bacterial decolonization. This review will discuss these perspectives and explore the role of different human microbiotas in the context of various transplantation scenarios.

Emerging Patient-Centered Concepts in Pain Among Adults With Chronic Kidney Disease, Maintenance Dialysis, and Kidney Transplant

Patient reports of moderate to severe pain are common across the spectrum of chronic kidney disease. The synergistic effects of comorbid depression and anxiety can lead to maladaptive coping responses to pain, namely pain catastrophizing and illness-related post-traumatic stress disorder. If underlying depression and anxiety and associated maladaptive coping responses are not treated, patients can experience an increased perception of pain, worsened disability, decreased quality of life, withdrawal from social activities, and increased morbidity and mortality. Meanwhile, interest in nonpharmacologic treatments for pain that targets coping as well as comorbid anxiety and depression has been increasing, particularly given the significant societal damage that has resulted from the opioid epidemic. Evidence-based, nonpharmacologic treatments have shown promise in treating pain in areas outside of nephrology. Currently, little is known about the effects of these treatments among adults with CKD, and particularly end-stage kidney disease, when chronic pain can become debilitating. In this review, we examine patient-centered concepts related to pain that have received little attention in the nephrology literature. We also describe emerging areas of research, including omics technologies for biomarker discovery and advanced symptom clustering methods for symptom phenotyping, which may be useful to future kidney disease research and treatment.

Impact of gut microbiota on kidney transplantation

Kidney transplantation is recognized as one of the most effective treatments for patients who suffer from end-stage renal disease. The major potential outcomes following kidney transplantation include engraftment, rejection, and associated complications. The outcomes are dependent on a variety of factors in those who underwent renal grafts or kidney transplant recipients. Those factors include the administration of immunosuppressive drugs and prophylactic antimicrobial agents to recipients. Recent studies have shown that gut microbiota play an important role in the outcome of subjects with kidney transplantation. An imbalance of the components/diversity of gut microbiota, known as gut dysbiosis, has been shown to have a big impact on the immune system of the host and the modification of host inflammatory cytokines. Although gut dysbiosis is affected by variation in diet and medication, a substantial amount of evidence showing a link between alteration in human gut microbiota and outcomes of kidney transplantation has recently been reported. Therefore, the objective of this review is to comprehensively summarize and discuss the major findings from in vivo and clinical data pertaining to the impact of gut microbiota on kidney transplantation. Any controversial findings are compiled to enable a clear overview of the role of gut microbiota and the outcome of kidney transplantation.

Microbiota, renal disease and renal transplantation

Aim of this frontier review has been to highlight the role of microbiota in healthy subjects and in patients affected by renal diseases with particular reference to renal transplantation. The microbiota has a relevant role in conditioning the healthy status and the diseases. In particular gut microbiota is essential in the metabolism of food and has a relevant role for its relationship with the immune system. The indigenous microbiota in patients with chronic renal failure is completely different than that of the healthy subjects and pathobionts appear. This abnormality in microbiota composition is called dysbiosis and may cause a rapid deterioration of the renal function both for activating the immune system and producing large quantity of uremic toxins. Similarly, after renal trans-plantation the microbiota changes with the appearance of pathobionts, principally in the first period because of the assumption of immunosuppressive drugs and antibiotics. These changes may deeply interfere with the graft outcome causing acute rejection, renal infections, diarrhea, and renal interstitial fibrosis. In addition, change in the microbiota may modify the metabolism of immuno-suppressive drugs causing in some patients the need of modifying the immunosuppressant dosing. The restoration of the indigenous microbiota after transplantation is important, either to avoiding the complications that impair the normal renal graft, and because recent studies have documented the role of an indigenous microbiota in inducing tolerance towards the graft. The use of prebiotics, probiotics, smart bacteria and diet modification may restore the indigenous microbiota, but these studies are just at their beginning and more data are needed to draw definitive conclusions.

Metabolome and microbiome in kidney diseases

Despite several decades of intensive research and hard work in nephrology, a void exists in the availability of markers for identifying at-risk individuals, diagnosing diseases at incipient stage, and predicting treatment response. Most of the current widely available diagnostic tools such as creatinine, urine analysis, and imaging studies are quite insensitive such that about half of the kidney function is lost before perceivable changes are observed with these tests. In addition, these parameters are affected by factors other than renal, questioning their specificity. Renal biopsy, though specific, is quite expensive, risky, and invasive. The recent surge in the knowledge of small molecules in the tissue and body fluids, "metabolomics," thanks to the Human Metabolome Database created by the Human Metabolome Project, has opened a new avenue for better understanding the disease pathogenesis and, in parallel, to identify novel biomarkers and druggable targets. Kidney, by virtue of its metabolic machinery and also being a major handler of metabolites generated by other tissues, is very much amenable to the metabolomic approach of studying its various perturbations. The gut microbiome, characterized by the Human Microbiome Project, is one of the principal players in metabolomics. Changes in metabolite profile due to alterations in gut microbiome can occur either as a cause or consequence of renal diseases. Unmasking the renal-metabolome-microbiome link has a great potential to script a new era in the diagnosis and management of renal diseases.

Acute Rejection and Infectious Complications in ABO- and HLA-Incompatible Kidney Transplantations

Background

Patients receiving ABO-incompatible (ABOi) or human leukocyte antigen (HLA)-incompatible (HLAi) kidney transplantation (KT) require potent immunosuppression and are thus at a higher risk of infectious complications. We evaluated the clinical outcomes of KT stratified by ABO and HLA incompatibilities and identified the factors associated with the clinical outcomes.

Material/Methods

Recipients who underwent living-related KT between 2012 and 2017 were included and classified into 4 groups: ABO-compatible and HLA-compatible (ABOc/HLAc), HLA-incompatible (ABOc/HLAi), ABO-incompatible (ABOi/HLAc), and ABO-incompatible and HLA-incompatible (ABOi/HLAi). Cox proportional hazards regression analyses were carried out to evaluate the risk factors of acute rejection. Out of the 1732 patients who underwent KT, 1190, 131, 358, and 53 were in the ABOc/HLAc, ABOi/HLAc, ABOc/HLAi, and ABOi/HLAi groups, respectively.

Results

The ABO/HLAi group showed the lowest 5-year graft survival rate (91.7%). Death-censored graft survival was not significantly different among the groups. The mortality rate from infections was significantly higher in the ABOi/HLAi group (7.5%) than the other groups. Antibody-mediated rejection-free graft survival was the lowest in the ABOi/HLAi group, with significant differences compared with the ABOi/HLAc group (P=0.02) and the ABOc/HLAi group (P=0.03). ABOi/HLAi (hazard ratio [HR], 2.63; 95% confidence interval [CI], 1.04–6.65; P<0.01) and combined infection (HR, 1.91; 95% CI, 1.45–2.51; P<0.01) were significant risk factors for acute rejection.

Conclusions

Patients with both ABO and HLA incompatibilities showed inferior rates of overall patient and graft survival due to infectious complications. Infection was a prominent risk factor of acute rejection following KT after adjusting for possible confounders including ABO and HLA incompatibility.

Abundance of Multidrug Resistance Efflux Pumps in the Urinary Metagenome of Kidney Transplant Patients

Antibiotic resistance including the emergence of multidrug resistant microbes has become a public health crisis. In this study, we analyzed the antibiotic resistance genes (ARGs) in the urinary metagenome of the kidney transplant and healthy subjects using metagenomic shotgun sequencing. Our data suggest an increased abundance of antibiotic resistance genes in the kidney transplant subjects. In addition, the antibiotic resistance genes identified in the transplant subjects were predominantly composed of multidrug efflux pumps (MDEPs) which are evolutionarily ancient, commonly encoded on chromosomes rather than plasmids, and have a low rate of mutation. Since the MDEPs had a low abundance in the healthy subjects, we speculate that the MDEPs may enhance the fitness of bacteria to survive in the high stress environment of transplantation that includes multiple stressors including surgery, antibiotics, and immunosuppressive agents.

Gut microbiota in surgical and critically ill patients

Microbiota-defined as a collection of microbial organisms colonising different parts of the human body-is now recognised as a pivotal element of human health, and explains a large part of the variance in the phenotypic expression of many diseases. A reduction in microbiota diversity, and replacement of normal microbes with non-commensal, pathogenic or more virulent microbes in the gastrointestinal tract-also known as gut dysbiosis-is now considered to play a causal role in the pathogenesis of many acute and chronic diseases. Results from animal and human studies suggest that dysbiosis is linked to cardiovascular and metabolic disease through changes to microbiota-derived metabolites, including trimethylamine-N-oxide and short-chain fatty acids. Dysbiosis can occur within hours of surgery or the onset of critical illness, even without the administration of antibiotics. These pathological changes in microbiota may contribute to important clinical outcomes, including surgical infection, bowel anastomotic leaks, acute kidney injury, respiratory failure and brain injury. As a strategy to reduce dysbiosis, the use of probiotics (live bacterial cultures that confer health benefits) or synbiotics (probiotic in combination with food that encourages the growth of gut commensal bacteria) in surgical and critically ill patients has been increasingly reported to confer important clinical benefits, including a reduction in ventilator-associated pneumonia, bacteraemia and length of hospital stay, in small randomised controlled trials. However, the best strategy to modulate dysbiosis or counteract its potential harms remains uncertain and requires investigation by a well-designed, adequately powered, randomised controlled trial.

Infectious Complications Following Kidney Transplantation-A Focus on Hepatitis C Infection, Cytomegalovirus Infection and Novel Developments in the Gut Microbiota

The incidence of infectious complications, compared with the general population and the pre-transplant status of the recipient, increases substantially following kidney transplantation, causing significant morbidity and mortality. The potent immunosuppressive therapy given to prevent graft rejection in kidney transplant recipients results in an increased susceptibility to a wide range of opportunistic infections including bacterial, viral and fungal infections. Over the last five years, several advances have occurred that may have changed the burden of infectious complications in kidney transplant recipients. Due to the availability of direct-acting antivirals to manage donor-derived hepatitis C infection, this has opened the way for donors with hepatitis C infection to be considered in the donation process. In addition, there have been the development of medications targeting the growing burden of resistant cytomegalovirus, as well as the discovery of the potentially important role of the gastrointestinal microbiota in the pathogenesis of post-transplant infection. In this narrative review, we will discuss these three advances and their potential implications for clinical practice.

[Gut microbiota in renal transplant recipients, patients with chronic kidney disease and healthy subjects]

OBJECTIVE

Recent studies have shown that gut microbiota is associated with immunomodulation in transplant recipients, but the composition and function of gut microbiota in renal transplant recipients have not been understood.

METHODS

We analyzed the composition and function of gut microbiota in the fecal samples from 16 renal transplant (RT) recipients by deep sequencing of the 16S rRNA V3 variable region. The gut microbiota of RT recipients was compared to that of 84 patients with chronic kidney disease (CKD) and 53 healthy subjects.

RESULTS

The overall microbial structure of RT recipients was similar to that of CKD. The abundance of Firmicutes, Lachnospiraceae, Ruminococcaceae and Faecalibacterium was decreased and that of Bacteroidetes, Proteobacteria, Clostridiales, and Enterobacteriaceae was increased significantly in RT recipients and CKD patients compared with the healthy control subjects. Functional comparison revealed significantly enhanced carbohydrate metabolism and decreased metabolism of cofactors, vitamins, cell motility and genetic information processing in RT recipients and CKD patients. RT recipients and CKD patients also showed slight differences in that the abundance of Proteobacteria and Enterobacteriaceae and the pathways involving transport system members and carbohydrate metabolism were much greater in the former. We found that several beneficial genera in the Lachnospiraceae and Veillonellaceae were negatively correlated with such clinical markers as serum creatinine and blood urea nitrogen.

CONCLUSIONS

Our results suggested that alterations in the composition and function of gut microbiota are significantly correlated with the clinical conditions of in RT recipients, and future prospective studies of these correlations may provide evidence for predicting the clinical outcomes of RT recipients.

Effects of Probiotics on Inflammation and Uremic Toxins Among Patients on Dialysis: A Systematic Review and Meta-Analysis

BACKGROUND/OBJECTIVES

We performed this systematic review and meta-analysis to evaluate effects of probiotics on inflammation, uremic toxins, and gastrointestinal (GI) symptoms in end-stage renal disease (ESRD) patients.

METHODS

A literature search was conducted utilizing MEDLINE, EMBASE, and Cochrane Database from inception through October 2017. We included studies that assessed assessing effects of probiotics on inflammatory markers, protein-bound uremic toxins (PBUTs), and GI symptoms in ESRD patients on dialysis. Effect estimates from the individual study were extracted and combined utilizing random effect, generic inverse variance method of DerSimonian and Laird. The protocol for this meta-analysis is registered with PROSPERO; No. CRD42017082137.

RESULTS

Seven clinical trials with 178 ESRD patients were enrolled. There was a significant reduction in serum C-reactive protein (CRP) from baseline to post-probiotic course (≥ 2 months after treatment) with standardized mean difference (SMD) of - 0.42 (95% CI - 0.68 to - 0.16, p = 0.002). When compared to control, patients who received probiotics also had a significant higher degree of reduction in CRP level with SMDs of - 0.37 (95% CI - 0.72 to 0.03, p = 0.04). However, there were no significant changes in serum TNF-alpha or albumin with SMDs of - 0.32 (95% CI - 0.92 to 0.28, p = 0.29) and 0.16 (95% CI - 0.20 to 0.53, p = 0.39), respectively. After probiotic course, there were also significant decrease in PBUTs and improvement in overall GI symptoms (reduction in GI symptom scores) with SMDs of - 0.61 (95% CI - 1.16 to - 0.07, p = 0.03) and - 1.04 (95% CI - 1.70 to - 0.38, p = 0.002), respectively.

CONCLUSION

Our study demonstrates potential beneficial effects of probiotics on inflammation, uremic toxins, and GI Symptoms in ESRD patients. Future large-scale clinical studies are required to assess its benefits on other important clinical outcomes including patient mortality.

Urinary microbiome associated with chronic allograft dysfunction in kidney transplant recipients

BACKGROUND

We performed a study to identify differences in the urinary microbiome associated with chronic allograft dysfunction (CAD) and compared the urinary microbiome of male and female transplant recipients with CAD.

METHODS

This case-control study enrolled 67 patients within the Deterioration of Kidney Allograft Function (DeKAF) Genomics cohort at two transplant centers. CAD was defined as a greater than 25% rise in serum creatinine relative to a 3 month post-transplant baseline. Urine samples from patients with and without CAD were analyzed using 16S V4 bacterial ribosomal DNA sequences.

RESULTS

Corynebacterium was more prevalent in female and male patients with CAD compared to non-CAD female patients (P = 0.0005). A total 21 distinct Operational Taxonomic Unit (OTUs) were identified as significantly different when comparing CAD and non-CAD patients using Kruskal-Wallis (P < 0.01). A subset analysis of female patients with CAD compared to non-CAD females identified similar differentially abundant OTUs, including the genera Corynebacterium and Staphylococcus (Kruskal-Wallis; P = 0.01; P = 0.004, respectively). Male CAD vs female CAD analysis showed greater abundance of phylum Proteobacteria in males.

CONCLUSION

There were differences in the urinary microbiome when comparing female and male CAD patients with their female non-CAD counterparts and these differences persisted in the subset analysis limited to female patients only.

Organ transplantation and gut microbiota: current reviews and future challenges

Organ transplantation is often the only effective treatment for patients with end-stage diseases, such as heart, liver, kidney and small bowel failure and is carried out frequently worldwide. Still the post-transplantation complications remain health- and life-threatening outcome that needed to be resolved. With the rapid development of molecular technologies in recent years, more and more researchers realize that the gut microbiota may play a critical role in human diseases. The intestinal microbiome has been proved to provide a lot of functions to the host, such as digesting food, modulating metabolism, promoting angiogenesis and regulating the immune system. Several studies have investigated the alteration of intestinal microbiota in post-transplantation patients and observed significant changes in the intestinal microbiome compared to the pre-transplant condition. Due to the abovementioned features that the gut microbiota may be used in the prognosis of clinical outcome of organ transplantation. In addition, the FMT (fecal microbiota transplantation), probiotics and prebiotics as the newest therapy methods, effectiveness of which has been verified in some diseases, such as Clostridium difficile infection, inflammatory bowel disease and other chronic disorders, might be used as the prognosis tool in organ transplantation as well. The purpose of this present review is to elucidate the relationship between gut microbiota and organ transplantation as well as the potential use of new therapies like fecal microbiota transplantation, probiotic and prebiotic administration after the transplantation, and provide some ideas for future researches in field of organ transplantation.