Inflammatory Bowel Diseases Are Associated With an Increased Risk for Chronic Kidney Disease, Which Decreases With Age

Association of Inflammatory Bowel Disease with Incident IgA Nephropathy

Key Points

We analyzed a nationwide epidemiologic cohort including approximately 4,000,000 individuals. We found a potential association of inflammatory bowel disease with a greater risk of developing IgA nephropathy.

Background

There have been scarce epidemiologic data on the relationship between inflammatory bowel disease and the incidence of IgA nephropathy. In this study, we assessed whether inflammatory bowel disease was associated with a higher risk of developing IgA nephropathy using a large-scale epidemiologic cohort.

Methods

We retrospectively analyzed 4,311,393 adults enrolled in the JMDC Claims Database (previously known as the Japan Medical Data Center database), a nationwide epidemiologic database in Japan. The definitions of IgA nephropathy and inflammatory bowel disease (ulcerative colitis or Crohn disease) were based on International Classification of Diseases, 10th Revision codes. Individuals who had a history of IgA nephropathy were excluded. Study participants were categorized into two groups according to the presence of inflammatory bowel disease. Clinical outcomes were collected between January 2005 and May 2022. The primary outcome was incident IgA nephropathy.

Results

Median (interquartile range) age was 44 (36–53) years, and 2,497,313 (58%) were men. Inflammatory bowel disease was observed in 18,623 individuals (0.4%). Over a median follow-up of 1089 (532–1797) days, there were 2631 incidences of IgA nephropathy and 22 incidences in individuals without and with inflammatory bowel disease, yielding incident ratios with 95% confidence intervals of 1.74 (1.68–1.81) and 3.43 (2.26–5.21), respectively. Kaplan–Meier curves and the log-rank test showed that a cumulative incidence of IgA was higher in individuals with inflammatory bowel disease compared with those without (log-rank P = 0.0028). Multivariable Cox regression analysis demonstrated that individuals with inflammatory bowel disease were at higher risk of incident IgA nephropathy (hazard ratio, 1.96; 95% confidence interval, 1.29 to 2.99).

Conclusions

We demonstrated the potential association of inflammatory bowel disease with higher risk of developing IgA nephropathy in a general population.

Estimated Glomerular Filtration Rate and the Risk of Inflammatory Bowel Disease in Adults: A Swedish Population-Based Study

BACKGROUND

Kidney complications are common in patients with long-standing inflammatory bowel disease (IBD). Whether kidney complications, defined as low estimated glomerular filtration rate (eGFR), may predispose to later IBD is unknown.

METHODS

We analyzed the association between eGFR and the risk of being subsequently diagnosed with IBD among 1 612 160 adults from Stockholm. The exposure was categories of eGFR, with 90 to 104 mL/min/1.73 m2 as the reference. Cox regression models were used to investigate the association between eGFR, IBD, and IBD subtypes. Subgroup analyses included age strata, sex, education, and comorbidities. To explore the possibility of detection bias or reverse causation, we estimated IBD hazard ratios (HRs) after excluding cases and individuals censored during early years of follow-up.

RESULTS

During a median of 9 years of follow-up, we detected 9663 cases of IBD (3299 Crohn's disease, 5072 ulcerative colitis, 1292 IBD unclassified). Lower eGFR levels were associated with higher IBD risk (for eGFR 30-59 mL/min/1.73 m2: adjusted HR, 1.15; 95% confidence interval [CI], 1.01-1.33; and for eGFR <30 mL/min/1.73 m2: adjusted HR, 1.65; 95% CI, 1.16-2.37). This association was stronger in magnitude for Crohn's disease (for eGFR 30-59 mL/min/1.73 m2: HR, 1.33, 95% CI, 1.04-1.72; and for eGFR <30 mL/min/1.73 m2: HR, 2.25; 95% CI, 1.26-3.99). Results were consistent across strata of age, comorbidities, and attained education but suggested the association between eGFR and IBD to be stronger in women (P for interaction <.05). Results attenuated but were robust to exclusion of early IBD cases.

CONCLUSIONS

We observed an association between reduced eGFR and the risk of developing IBD, which was stronger in magnitude for Crohn's disease.

Causal relationship between gut microbiota and chronic renal failure: a two-sample Mendelian randomization study

Background

Observational studies and some experimental investigations have indicated that gut microbiota are closely associated with the incidence and progression of chronic renal failure. However, the causal relationship between gut microbiota and chronic renal failure remains unclear. The present study employs a two-sample Mendelian randomization approach to infer the causal relationship between gut microbiota and chronic renal failure at the genetic level. This research aims to determine whether there is a causal effect of gut microbiota on the risk of chronic renal failure, aiming to provide new evidence to support targeted gut therapy for the treatment of chronic renal failure.

Methods

Employing genome-wide association study (GWAS) data from the public MiBioGen and IEU OpenGWAS platform, a two-sample Mendelian randomization analysis was conducted. The causal relationship between gut microbiota and chronic renal failure was inferred using five different methods: Inverse Variance Weighted, MR-Egger, Weighted Median, Simple Mode, and Weighted Mode. The study incorporated sensitivity analyses that encompassed evaluations for pleiotropy and heterogeneity. Subsequently, the results of the Mendelian randomization analysis underwent a stringent correction for multiple testing, employing the False Discovery Rate method to enhance the validity of our findings.

Results

According to the results from the Inverse Variance Weighted method, seven bacterial genera show a significant association with the outcome variable chronic renal failure. Of these, Ruminococcus (gauvreauii group) (OR = 0.82, 95% CI = 0.71-0.94, p = 0.004) may act as a protective factor against chronic renal failure, while the genera Escherichia-Shigella (OR = 1.22, 95% CI = 1.08-1.38, p = 0.001), Lactococcus (OR = 1.1, 95% CI = 1.02-1.19, p = 0.013), Odoribacter (OR = 1.23, 95% CI = 1.03-1.49, p = 0.026), Enterorhabdus (OR = 1.14, 95% CI = 1.00-1.29, p = 0.047), Eubacterium (eligens group) (OR = 1.18, 95% CI = 1.02-1.37, p = 0.024), and Howardella (OR = 1.18, 95% CI = 1.09-1.28, p < 0.001) may be risk factors for chronic renal failure. However, after correction for multiple comparisons using False Discovery Rate, only the associations with Escherichia-Shigella and Howardella remain significant, indicating that the other genera have suggestive associations. Sensitivity analyses did not reveal any pleiotropy or heterogeneity.

Conclusion

Our two-sample Mendelian randomization study suggests that the genera Escherichia-Shigella and Howardella are risk factors for chronic renal failure, and they may serve as potential targets for future therapeutic interventions. However, the exact mechanisms of action are not yet clear, necessitating further research to elucidate their precise roles fully.

Anti-Tumor Necrosis Factor Therapy and Risk of Kidney Function Decline and Mortality in Inflammatory Bowel Disease

Importance

Inflammatory bowel disease (IBD) is associated with adverse clinical outcomes, including chronic kidney disease and mortality, due in part to chronic inflammation. Little is known about the effects of anti-tumor necrosis factor (TNF) therapy on kidney disease progression and mortality among patients with new-onset IBD.

Objective

To examine the association of incident use of TNF inhibitors with subsequent decline in kidney function and risk of all-cause mortality.

Design, Setting, and Participants

This retrospective cohort study used data from the US Department of Veterans Affairs health care system. Participants were US veterans with new-onset IBD enrolled from October 1, 2004, through September 30, 2019. Data were analyzed from December 2022 to February 2024.

Exposures

Incident use of TNF inhibitors.

Main Outcomes and Measures

The main outcomes were at least 30% decline in estimated glomerular filtration rate (eGFR) and all-cause mortality.

Results

Among 10 689 patients (mean [SD] age, 67.4 [12.3] years; 9999 [93.5%] male) with incident IBD, 3353 (31.4%) had diabetes, the mean (SD) baseline eGFR was 77.2 (19.2) mL/min/1.73 m2, and 1515 (14.2%) were newly initiated on anti-TNF therapy. During a median (IQR) follow-up of 4.1 (1.9-7.0) years, 3367 patients experienced at least 30% decline in eGFR, and over a median (IQR) follow-up of 5.0 (2.5-8.0) years, 2502 patients died. After multivariable adjustments, incident use (vs nonuse) of TNF inhibitors was significantly associated with higher risk of decline in eGFR (adjusted hazard ratio [HR], 1.34 [95% CI, 1.18-1.52]) but was not associated with risk of all-cause mortality (adjusted HR, 1.02 [95% CI, 0.86-1.21]). Similar results were observed in sensitivity analyses.

Conclusions and Relevance

In this cohort study of US veterans with incident IBD, incident use (vs nonuse) of TNF inhibitors was independently associated with higher risk of progressive eGFR decline but was not associated with risk of all-cause mortality. Further studies are needed to elucidate potentially distinct pathophysiologic contributions of TNF inhibitor use to kidney and nonkidney outcomes in patients with IBD.

Altered gut mycobiome in patients with end-stage renal disease and its correlations with serum and fecal metabolomes

BACKGROUND

The relationship between the gut mycobiome and end-stage renal disease (ESRD) remains largely unexplored.

METHODS

In this study, we compared the gut fungal populations of 223 ESRD patients and 69 healthy controls (HCs) based on shotgun metagenomic sequencing data, and analyzed their associations with host serum and fecal metabolites.

RESULTS

Our findings revealed that ESRD patients had a higher diversity in the gut mycobiome compared to HCs. Dysbiosis of the gut mycobiome in ESRD patients was characterized by a decrease of Saccharomyces cerevisiae and an increase in various opportunistic pathogens, such as Aspergillus fumigatus, Cladophialophora immunda, Exophiala spinifera, Hortaea werneckii, Trichophyton rubrum, and others. Through multi-omics analysis, we observed a substantial contribution of the gut mycobiome to host serum and fecal metabolomes. The opportunistic pathogens enriched in ESRD patients were frequently and positively correlated with the levels of creatinine, homocysteine, and phenylacetylglycine in the serum. The populations of Saccharomyces, including the HC-enriched Saccharomyces cerevisiae, were frequently and negatively correlated with the levels of various toxic metabolites in the feces.

CONCLUSIONS

Our results provided a comprehensive understanding of the associations between the gut mycobiome and the development of ESRD, which had important implications for guiding future therapeutic studies in this field.

Absolute and Relative Risks of Kidney and Urological Complications in Patients With Inflammatory Bowel Disease

INTRODUCTION

The burden of kidney and urological complications in patients with inflammatory bowel disease (IBD) remains poorly characterized.

METHODS

We analyzed association between developing IBD (as a time-varying exposure) and relative risks of receiving diagnoses of chronic kidney disease (CKD), acute kidney injury (AKI), or kidney stones, and experiencing a clinically-relevant decline in estimated glomerular filtration rate (eGFR) (CKD progression; composite of kidney failure or an eGFR decline ≥30%) in 1,682,795 individuals seeking healthcare in Stockholm, Sweden, during 2006-2018. We quantified 5- and 10-year absolute risks of these complications in a parallel matched cohort of IBD cases and random controls matched (1:5) on sex, age, and eGFR.

RESULTS

During median 9 years, 10,117 participants developed IBD. Incident IBD was associated with higher risks of kidney-related complications compared with non-IBD periods: hazard ratio (HR) (95% confidence interval) was 1.24 (1.10-1.40) for receiving a CKD diagnosis and 1.11 (1.00-1.24) for CKD progression. For absolute risks, 11.8% IBD cases had a CKD event within 10-year. Of these, 6.4% received a CKD diagnosis, and 7.9% reached CKD progression. The risks of AKI (HR 1.97 [1.70-2.29]; 10-year absolute risk 3.6%) and kidney stones (HR 1.69 [1.48-1.93]; 10-year absolute risk 5.6%) were also elevated. Risks were similar in Crohn's disease and ulcerative colitis.

DISCUSSION

More than 10% of patients with IBD developed CKD within 10-year from diagnosis, with many not being identified through diagnostic codes. This, together with their elevated AKI and kidney stone risks, highlights the need of established protocols for kidney function monitoring and referral to nephrological/urological care for patients with IBD.

Inflammatory Bowel Disease With Chronic Kidney Disease and Acute Kidney Injury

INTRODUCTION

It remains unclear whether inflammatory bowel disease is associated with long-term risk of chronic kidney disease (CKD) and acute kidney injury (AKI) in the general population.

METHODS

A total of 417,302 participants, including 2,940 patients with ulcerative colitis and 1,261 patients with Crohn's disease, without previous CKD and AKI at baseline (2006-2010) from the UK Biobank were included. The study outcomes included incident CKD and AKI, ascertained by self-report data and data linkage with primary care, hospital admissions, and death registry records. Analysis was conducted in 2022.

RESULTS

During a median follow-up of 12.5 years, 13,564 and 14,331 participants developed CKD and AKI, respectively. Compared with the hazard ratio for non-inflammatory bowel diseases, the hazard ratios for CKD and AKI related to inflammatory bowel diseases were 1.57 (95% CI=1.37, 1.79) and 1.96 (95% CI=1.74, 2.20) after adjustments for age, sex, and race and were 1.32 (95% CI=1.15, 1.51) and 1.70 (95% CI=1.51, 1.91) after further adjustments for biological, behavioral, and socioeconomic factors in addition to mental health and self-rated health. Similar results were found for patients with Crohn's disease (adjusted hazard ratio=1.38 (95% CI=1.09, 1.75) for CKD and 1.62 [95% CI=1.30, 2.02] for AKI) and those with ulcerative colitis (adjusted hazard ratio=1.29 (95% CI=1.09, 1.51) for CKD and 1.71 [95% CI=1.49, 1.97] for AKI) in the fully adjusted models. Genetic risks of kidney diseases did not significantly affect the association of inflammatory bowel disease with incident CKD and AKI (both p-interactions>0.05). The association between inflammatory bowel disease and the risk of incident CKD (p-interaction=0.010) and AKI (p-interaction<0.001) were stronger in younger participants than in older participants.

CONCLUSIONS

Inflammatory bowel disease was associated with higher risks for CKD and AKI, independent of genetic risks of kidney diseases.

Upadacitinib in end stage renal disease: A case of acute severe ulcerative colitis

Recent data, indicating that inflammatory bowel disease (IBD) may be a risk factor for future chronic kidney disease, highlight the need to study the safety and clinical effectiveness of advanced IBD therapies in patients with end stage renal disease (ESRD), defined as an eGFR <15 mL/min/1.73m2. Upadacitinib, a selective oral Janus kinase (JAK) 1 inhibitor, has demonstrated efficacy in the management of moderate to severe ulcerative colitis. There is also emerging data indicating that JAK inhibition may be clinically effective in the setting of steroid-refractory acute severe ulcerative colitis (ASUC). There is, however, a lack of "real-world" data documenting the use of JAK inhibitors in patients with ESRD. Here, we report the use of upadacitinib in a patient with ESRD for the management of steroid-refractory ASUC, demonstrating, for the first time, the safe and clinically effective use of upadacitinib in this population.

Association between inflammatory bowel disease, nephrolithiasis, tubulointerstitial nephritis, and chronic kidney disease: A propensity score-matched analysis of US nationwide inpatient sample 2016-2018

OBJECTIVES

The incidence and prevalence of inflammatory bowel disease (IBD), mainly including ulcerative colitis (UC) and Crohn's disease (CD), are increasing globally. We aimed to evaluate the potential association between IBD and nephrolithiasis, tubulointerstitial nephritis, and chronic kidney disease (CKD).

METHODS

Data of hospitalized adults ≥20 years of age were extracted from the U.S. National Inpatient Sample (NIS) during 2016-2018. Patients with UC, CD, or CKD were identified through the International Classification of Diseases, Tenth Revision (ICD-10) codes. Propensity score matching (PSM) analysis (1:1) was conducted to balance the characteristics between groups. Logistic regression analyses were performed to determine the relationships between UC or CD and kidney conditions.

RESULTS

Three cohorts were included for analysis after PSM analysis. Cohorts 1, 2 and 3 contained 235 262 subjects (117 631 with CD or without IBD), 140 856 subjects (70 428 with UC or without IBD), and 139 098 subjects (69 549 with CD or UC), respectively. Multivariate analysis revealed that compared to non-IBD individuals, CD patients were significantly associated with greater odds for nephrolithiasis (adjusted odds ratio [aOR] 2.25, 95% confidence interval [CI] 2.08-2.43), tubulointerstitial nephritis (aOR 1.31, 95% CI 1.24-1.38), CKD at any stage (aOR 1.28, 95% CI 1.24-1.32), and moderate-to-severe CKD (aOR 1.22, 95% CI 1.17-1.26), while UC was associated with a higher rate of nephrolithiasis. Compared to UC, CD was associated with higher odds for all such kidney conditions.

CONCLUSIONS

Patients with CD are more likely to have nephrolithiasis, tubulointerstitial nephritis, CKD at any stage, and moderate-to-severe CKD compared to non-IBD individuals.

Influence of nonalcoholic fatty liver disease on inflammatory bowel disease hospitalizations in the United States

Background

The reported prevalence of nonalcoholic fatty liver disease (NAFLD) in patients with inflammatory bowel disease (IBD) is 32%. We assessed the influence of NAFLD on IBD hospitalizations in the United States (US).

Methods

We utilized the National Inpatient Sample database, from 2016-2019, to identify the total IBD hospitalizations in the US and we further subdivided them according to the presence or absence of NAFLD. Hospitalization characteristics, comorbidities and outcomes were compared. Statistical significance was set at P<0.05.

Results

There were 1,272,260 IBD hospitalizations in the US, of which 5.04% involved NAFLD. For IBD hospitalizations with NAFLD, the mean age was 50-64 years, and the proportion of males was 46.97%. IBD hospitalizations with NAFLD had a lower proportion of African Americans (8.7% vs. 11.38%, P<0.001). Comorbidities such as hypertension (50.34% vs. 44.04%, P<0.001) and obesity (18.77% vs. 11.81%, P<0.001) were significantly higher in the NAFLD cohort. Overall, based on the Charlson Comorbidity Index, patients with NAFLD had a higher number of comorbidities (52.77% vs. 20.66%, P<0.001). Mortality was higher in the NAFLD compared to the non-NAFLD cohort (3.14% vs. 1.44%, P<0.001). Patients with NAFLD also incurred significantly higher hospital charges ($69,536 vs. $55,467, p<0.001) and had a longer mean length of stay (6.10 vs. 5.27 days, P<0.001) compared to the cohort without NAFLD. Complications and inpatient procedure requirements were also higher in the NAFLD cohort.

Conclusion

Our study revealed greater mortality, morbidity, and healthcare resource utilization in patients with IBD who were hospitalized with a concomitant diagnosis of NAFLD.

Enteroendocrine cells and gut hormones as potential targets in the crossroad of the gut-kidney axis communication

Recent studies suggest that disruptions in intestinal homeostasis, such as changes in gut microbiota composition, infection, and inflammatory-related gut diseases, can be associated with kidney diseases. For instance, genomic investigations highlight how susceptibility genes linked to IgA nephropathy are also correlated with the risk of inflammatory bowel disease. Conversely, investigations demonstrate that the use of short-chain fatty acids, produced through fermentation by intestinal bacteria, protects kidney function in models of acute and chronic kidney diseases. Thus, the dialogue between the gut and kidney seems to be crucial in maintaining their proper function, although the factors governing this crosstalk are still emerging as the field evolves. In recent years, a series of studies have highlighted the significance of enteroendocrine cells (EECs) which are part of the secretory lineage of the gut epithelial cells, as important components in gut-kidney crosstalk. EECs are distributed throughout the epithelial layer and release more than 20 hormones in response to microenvironment stimuli. Interestingly, some of these hormones and/or their pathways such as Glucagon-Like Peptide 1 (GLP-1), GLP-2, gastrin, and somatostatin have been shown to exert renoprotective effects. Therefore, the present review explores the role of EECs and their hormones as regulators of gut-kidney crosstalk and their potential impact on kidney diseases. This comprehensive exploration underscores the substantial contribution of EEC hormones in mediating gut-kidney communication and their promising potential for the treatment of kidney diseases.

Does inflammatory bowel disease promote kidney diseases: a mendelian randomization study with populations of European ancestry

BACKGROUND

This study aimed to investigate a causal relationship between IBD and multiple kidney diseases using two-sample Mendelian randomization (MR) analyses.

METHODS

We selected a group of single nucleotide polymorphisms (SNPs) specific to IBD as instrumental variables from a published genome-wide association study (GWAS) with 86,640 individuals of European ancestry. Summary statistics for multiple kidney diseases were obtained from the publicly available GWAS. Genetic data from one GWAS involving 210 extensive T-cell traits was used to estimate the mediating effect on specific kidney disease. Inverse-variance weighted method were used to evaluate the MR estimates for primary analysis.

RESULTS

Genetic predisposition to IBD was associated with higher risk of IgA nephropathy (IgAN) (OR, 1.78; 95% CI, 1.45-2.19), but not membranous nephropathy, diabetic nephropathy, glomerulonephritis, nephrotic syndrome, chronic kidney disease, and urolithiasis. CD4 expression on CD4 + T cell had a significant genetic association with the risk of IgAN (OR, 2.72; 95% CI, 1.10-6.72). Additionally, consistent results were also observed when IBD was subclassified as ulcerative colitis (OR, 1.38; 95% CI, 1.10-1.71) and Crohn's disease (OR, 1.37; 95% CI, 1.12-1.68). MR-PRESSO and the MR-Egger intercept did not identify pleiotropic SNPs.

CONCLUSIONS

This study provides genetic evidence supporting a positive casual association between IBD, including its subclassification as ulcerative colitis and Crohn's disease, and the risk of IgAN. However, no casual association was found between IBD and other types of kidney diseases. Further exploration of IBD interventions as potential preventive measures for IgAN is warranted.

Inflammatory bowel disease increases the levels of albuminuria and the risk of urolithiasis: a two-sample Mendelian randomization study

BACKGROUND

Alterations in kidney function and increased risk of kidney diseases in patients with inflammatory bowel disease (IBD) have been reported, but the causal relationship remains unclear. Herein, Mendelian randomization was employed to identify the causal effect of inflammatory bowel disease on kidney function and the risk of chronic kidney disease (CKD), urolithiasis, and IgA nephropathy.

METHODS

The International Inflammatory Bowel Disease Genetics Consortium provided the summary-level genome-wide association study (GWAS) data that correlates with Crohn's disease (CD) and ulcerative colitis (UC). GWAS data for estimated glomerular filtration rate from serum creatinine (eGFRcrea), urine albumin-creatinine ratio (uACR), and CKD were obtained from the CKDGen Consortium, and GWAS data for urolithiasis were obtained from the FinnGen consortium. The summary-level GWAS data for IgA nephropathy were obtained from the meta-analysis of UK-biobank, FinnGen, and Biobank Japan. Inverse-variance weighted was used as the primary estimate. Furthermore, the Steiger test was used to validate the direction of causality.

RESULTS

The inverse-variance weighted data revealed that genetically predicted UC significantly increased uACR levels, while genetically predicted CD significantly increased the risk of urolithiasis.

CONCLUSIONS

UC increases the levels of uACR, and CD increases the risk of urolithiasis.

Sustained effect of leukocytapheresis/granulocytapheresis versus anti-human TNF-α monoclonal antibody on ulcerative colitis: A 2-year retrospective study

Although anti-tumor necrosis factor-α monoclonal antibody biological preparations (BP) agents are widely used as an established treatment tool for refractory ulcerative colitis (UC), whether leukocytapheresis/granulocytapheresis (L/G-CAP) has similar beneficial impact on the disease activity remains undetermined. Furthermore, the costs defrayed for the treatment with these 2 modalities have not been compared. We retrospectively evaluated whether L/G-CAP offered sustained beneficial effects over 2-year period. The patients who had moderately to severely active UC (Rachmilewitz clinical activity index (CAI) ≧ 5) and were treated with a series (10 sessions) of L/G-CAP (n = 19) or BP (n = 7) as an add-on therapy to conventional medications were followed. Furthermore, the cost-effectiveness pertaining to the treatment with L/G-CAP and BP was assessed over 12 months. At baseline, L/G-CAP and BP groups manifested similar disease activity (CAI, L/G-CAP; 7.0 [6.0-10.0], BP; 10.0 [6.0-10.0], P = .207). The L/G-CAP and BP treatment suppressed the activity, with CAI 1 or less attained on day 180. When the L/G-CAP group was dichotomized into L/G-CAP-high and L/G-CAP-low group based on CAI values (≥3 or < 3) on day 365, CAI was gradually elevated in L/G-CAP-high group but remained suppressed in L/G-CAP-low group without additional apheresis for 2 years. Anemia was corrected more rapidly and hemoglobin levels were higher in BP group. The cost of the treatment with L/G-CAP over 12 months was curtailed to 76% of that with BP (1.79 [1.73-1.92] vs 2.35 [2.29-3.19] million yen, P = .028). L/G-CAP is as effective as BP in a substantial number of patients over 2 years. The cost for the treatment of UC favors L/G-CAP although the correction of anemia may prefer BP. Thus, L/G-CAP can effectively manage the disease activity with no additional implementation for 2 years although further therapeutic modalities might be required in a certain population with high CAI observed on day 365.

Prevalence and Etiologies of Renal and Urinary Manifestations in a Large Cohort of Children With Inflammatory Bowel Disease

BACKGROUND AND OBJECTIVES

Renal and/or urinary manifestations (RUM) have been reported in pediatric patients with inflammatory bowel disease (IBD) but their incidence is unknown. The aims of this study were to assess the prevalence and causes of these manifestations in children with IBD and determine the causal link with 5-aminosalicylic acid (5-ASA) treatment.

METHODS

A retrospective observational study was performed with children with diagnosis of IBD. All children with RUM during follow-up and/or impaired renal function [estimated glomerular filtration rate (eGFR) < 90 mL/min/1.73 m 2 ] were identified.

RESULTS

Of 228 included patients, 9 (3.9%) had a RUM during follow-up [follow-up: 5 years (1-12 years)] at a median age of 16 years (8-17 years). It concerned 7 of 171 patients with Crohn disease and 2 of 57 with ulcerative colitis. Seven patients were taking 5-ASA at the time of the RUM. Only 1 of them had an iatrogenic renal complication related to this treatment. Patients with RUM had a more severe disease with increased anti-tumor necrosis factor-α use ( P = 0.031), more abscesses ( P = 0.003), and a higher rate of digestive surgery ( P = 0.04). For the whole cohort, a significant decrease in eGFR was found during follow-up (121 vs 107 mL/min/1.73 m 2 , P < 0.001). At the end of follow-up, 38 of 202 (19%) patients had an eGFR < 90 mL/min/1.73 m 2 .

CONCLUSION

In children with IBD, RUM can occur, independently of treatment with 5-ASA. During follow-up, a significant decrease in eGFR was observed. We suggest monitoring renal function in all patients with IBD.

Kidney Biopsy Findings and Clinical Outcomes of US Veterans with Inflammatory Bowel Disease

Introduction

Patients with inflammatory bowel disease (IBD; ulcerative colitis [UC] and Crohn's disease [CD]) may have unique patterns of kidney injury related to their underlying or coexisting disease or to medications. We present the kidney biopsy findings and clinical outcomes of veterans with UC or CD from the US Department of Veteran's Affairs (VA) health system.

Methods

Histopathologic and clinical data were extracted by retrospective review of the VA electronic health record of patients with IBD and a kidney biopsy between 2000 and 2018. Incident end-stage kidney disease (ESKD) was defined as requirement of kidney replacement therapy. Statistical analyses were performed using SAS.

Results

A total of 140 patients (UC: 91 and CD: 49) underwent kidney biopsy. The three most common diagnoses were IgA nephropathy (17.1%), diabetic nephropathy (14.3%), and acute interstitial nephritis (9.3%). Significant interstitial fibrosis, tubular atrophy, and arteriosclerosis were present in 45% of biopsies. Twenty-six percent of patients with UC and 20% of those with CD progressed to ESKD, with a mean time from kidney biopsy of 3.1 and 1.9 years, respectively. Forty-five percent of patients with UC and 34% of those with CD died, with a mean time from kidney biopsy of 4.3 and 4.6 years, respectively.

Conclusion

Among US veterans with IBD who underwent a kidney biopsy, IgA nephropathy, diabetic nephropathy, and interstitial nephritis were among the most common findings. Additionally, features of advanced kidney disease with rapid clinical progression to ESKD or death were observed. These findings suggest a delay and possibly a low rate of diagnosis.

Identification of shared gene signatures and molecular mechanisms between chronic kidney disease and ulcerative colitis

Background

There is a complex interaction between chronic kidney disease (CKD) and ulcerative colitis (UC), but the pathophysiological mechanisms underlying the coexistence of CKD and UC are unclear. This study aimed to investigate the key molecules and pathways that may mediate the co-occurrence of CKD and UC through quantitative bioinformatics analysis based on a public RNA-sequencing database.

Methods

The discovery datasets of CKD (GSE66494) and UC (GSE4183), as well as validation datasets of CKD (GSE115857) and UC (GSE10616), were downloaded from the Gene Expression Omnibus (GEO) database. After identifying differentially expressed genes (DEGs) with GEO2R online tool, the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses for the DEGs were performed. Next, protein-protein interaction network was constructed with Search Tool for the Retrieval of Interacting Genes (STRING) and visualized by Cytoscape. Gene modules were identified by the plug-in MCODE and hub genes were screened using the plug-in CytoHubba. Then, correlation between immune cell infiltration and hub genes was analyzed, and the receiver operating characteristic curves were used to assess the predictive value of hub genes. Finally, immunostaining of human specimens was used to validate the relevant findings.

Results

A total of 462 common DEGs were identified and selected for further analyses. GO and KEGG enrichment analyses indicated that these DEGs were primarily enriched in immune- and inflammation-related pathways. Among them, the PI3K-Akt signaling pathway ranked top in both discovery and validation cohorts, and the key signal molecule phosphorylated Akt (p-Akt) was shown to be significantly overexpressed in human CKD kidneys and UC colons, and further elevated in CKD-UC comorbidity specimens. Moreover, nine candidate hub genes, including CXCL8, CCL2, CD44, ICAM1, IL1A, CXCR2, PTPRC, ITGAX, and CSF3, were identified, of which ICAM1 was validated as a common hub gene. Besides, immune infiltration analysis revealed that neutrophils, macrophages, and CD4⁺ T memory cells significantly accumulated in both diseases, and ICAM1 was remarkably associated with neutrophil infiltration. Furthermore, intercellular adhesion molecule1 (ICAM1)-mediated neutrophil infiltration was validated to be upregulated in kidney and colon biopsies of CKD and UC patients, and further increased in patients diagnosed with both CKD and UC. Finally, ICAM1 had shown critical value as a diagnostic marker for the co-occurrence of CKD and UC.

Conclusions

Our study elucidated that immune response, PI3K-Akt signaling pathway, and ICAM1-mediated neutrophil infiltration might be the common pathogenesis of CKD and UC, and identified ICAM1 as a key potential biomarker and therapeutic target for the comorbidity of these two diseases.

Renal manifestations in inflammatory bowel disease: a systematic review

As extra-intestinal manifestations (EIMs) are frequent in inflammatory bowel disease (IBD) and affect morbidity and sometimes even mortality, vigilance in the surveillance of EIMs and installing the appropriate treatment are essential. Data on renal manifestations in patients with IBD are however rare. Nevertheless, up to 5-15% of adult patients with IBD will develop chronic kidney disease over time. The pathophysiology of renal involvement in patients with IBD is complex and poorly understood, with a wide range of renal disorders affecting the glomeruli and/or the tubular structure. Furthermore, medication used to treat IBD can be potentially nephrotoxic and metabolic complication due to the disease itself can furthermore cause renal damage. The aim of this systematic review is to provide an overview of the existing data in literature on these renal manifestations and complications in patients with IBD.

Crohn's Disease of the Elderly: Unique Biology and Therapeutic Efficacy and Safety

The incidence and prevalence of inflammatory bowel disease (IBD) is increasing in the elderly population. Compared with patients with onset during younger years, patients with elderly-onset IBD have a distinct clinical presentation, disease phenotype, and natural history. Genetics contribute less to pathogenesis of disease, whereas aging-related biological changes, such as immunosenescence and dysbiosis, are associated with elderly-onset IBD. Frailty is an increasingly recognized predictor of adverse outcomes. As an increasingly wider array of biologic and small molecule therapeutic options becomes available, data regarding efficacy and safety of these agents in patients are paramount given the unique characteristics of this population.

Lack of Monitoring Is Associated with Risk of Acute Kidney Events among Patients with Inflammatory Bowel Disease

Background: Although the iatrogenic risk of kidney failure is infrequent with treatment for inflammatory bowel disease (IBD), the repercussions for the patient could be major. The aim of this study was to assess the incidence of kidney events in IBD and to examine the protective effect of kidney function monitoring. Methods: In the French National Health Insurance database, 94,363 patients had a diagnosis of IBD between January 2010 and December 2016. By using a survival model with time-dependent covariates, we analyzed the time from inclusion in this IBD cohort to the first hospitalization for acute kidney impairment (AKI) according to patient characteristics, comorbidities, IBD phenotype and presence of monitoring. Results: A total of 693 patients were hospitalized for AKI, with an incidence of 1.36/1000 person−years (95% confidence interval [CI] 1.26−1.47). The incidence of AKI was lower than those without 5-aminosalicylic acid (5-ASA) use. Patients with 5-ASA use rarely had any lack of monitoring as compared with those not under 5-ASA use (3% vs. 17%). On multivariate analysis, lack of monitoring was associated with a substantial risk of AKI (hazard ratio 3.96, 95% CI [3.20−4.90], p < 0.0001). Conclusions: Increased frequency of monitoring is essential to identify nephropathy at an early stage and avoid the progression to chronic kidney disease.

Linagliptin ameliorates acetic acid-induced colitis via modulating AMPK/SIRT1/PGC-1α and JAK2/STAT3 signaling pathway in rats

Ulcerative colitis is a chronic inflammatory disease, profoundly affecting the patient's quality of life and is associated with various complications. Linagliptin, a potent DPP- IV inhibitor, shows favorable anti-inflammatory effects in several animal model pathologies. To this end, the present study aimed to investigate the anti-inflammatory effect of linagliptin in a rat model of acetic acid-induced colitis. Moreover, the molecular mechanisms behind this effect were addressed. Accordingly, colitis was established by the administration of a 2 ml 6% acetic acid intrarectally and treatment with linagliptin (5 mg/kg) started 24 h after colitis induction and continued for 7 days. On one hand, the DPP-IV inhibitor alleviated the severity of colitis as evidenced by a decrease of disease activity index (DAI) scores, colon weight/length ratio, macroscopic damage, and histopathological deteriorations. Additionally, linagliptin diminished colon inflammation via attenuation of TNF-α, IL-6, and NF-κB p65 besides restoration of anti-inflammatory cytokine IL-10. On the other hand, linagliptin increased levels of p-AMPK, SIRT1, and PGC-1α while abolishing the increment in p-JAK2 and p-STAT3. In parallel linagliptin reduced mTOR levels and upregulated expression levels of SHP and MKP-1 which is postulated to mediate AMPK-driven JAK2/STAT3 inhibition. Based on these findings, linagliptin showed promising anti-inflammatory activity against acetic acid-induced colitis that is mainly attributed to the activation of the AMPK-SIRT1-PGC-1α pathway as well as suppression of the JAK2/STAT3 signaling pathway that might be partly mediated through AMPK activation.

Role of gut-kidney axis in renal diseases and IgA nephropathy

PURPOSE OF REVIEW

Growing evidence show the importance of gut/kidney axis in renal diseases. Advances in gut microbiome sequencing, associated metabolites, detection of gut permeability and inflammation provide new therapeutic strategies targeting gut for kidney diseases and particularly for Immunoglobulin A (IgA) nephropathy (IgAN).

RECENT FINDINGS

The diversity and composition of gut flora have been recently deeply explored in kidney diseases. Modulation and depletion of microbiota in animal models allowed the understanding of molecular mechanisms involved in the crosstalk between gut, immune system and kidney. New clinical trials in order to positively modulate microbiota result in improvement of gastrointestinal disorders and inflammation in patients suffering with kidney diseases.

SUMMARY

The investigation of gut alterations in kidney diseases open new therapeutic strategies. In IgAN, targeted treatments for intestinal inflammation and modifications of gut microbiota seem promising.

Extracellular Matrix Components as Diagnostic Tools in Inflammatory Bowel Disease

Simple Summary

For decades, the extracellular matrix (ECM) has been defined as a structure component playing a rather neglected role in the human body. In recent years, research has shed light on the role of ECM within cellular processes, including proliferation, migration and differentiation, as well as in inflammation. In inflammation, ECM composition is constantly being remodeled and undergoes dynamic and rapid changes. Tracking these changes could serve as a novel diagnostic tool. Inflammatory bowel disease is accompanied by complications such as fibrosis, stenosis and fistulas. All of these structural complications involve excessive synthesis or degradation of ECM. With this review, we explored whether the analysis of ECM composition can be of support in diagnosing inflammatory bowel disease and whether changes within ECM can help to predict a complicated disease course early on.

Abstract

Work from the last years indicates that the extracellular matrix (ECM) plays a direct role in various cellular processes, including proliferation, migration and differentiation. Besides homeostatic processes, its regulatory function in inflammation becomes more and more evident. In inflammation, such as inflammatory bowel disease, the ECM composition is constantly remodeled, and this can result in a structuring of fistulizing disease course. Thus, tracking early ECM changes might bear the potential to predict the disease course. In this review, we provide an overview of relevant diagnostic methods, focusing on ECM changes.

The elderly IBD patient in the modern era: changing paradigms in risk stratification and therapeutic management

The incidence and prevalence of inflammatory bowel disease (IBD) is rising in the elderly population. Compared with patients with onset during their younger years, patients with elderly onset IBD have a distinct clinical presentation, disease phenotype, and natural history. Genetics contribute less to pathogenesis of disease, whereas biological changes associated with aging including immunosenescence, dysbiosis, and frailty have a greater impact on disease outcomes. With the advent of an increasingly wider array of biologic and small-molecule therapeutic options, data regarding efficacy and safety of these agents in elderly IBD patients specifically are paramount, given the unique characteristics of this population.

Inflammatory Bowel Disease Is More Common in Patients with IgA Nephropathy and Predicts Progression of ESKD: A Swedish Population-Based Cohort Study

BACKGROUND

Case reports suggest an association between inflammatory bowel disease, a chronic autoimmune condition linked to increased circulating IgA levels, and IgA nephropathy, the most common form of primary GN and a leading cause of ESKD.

METHODS

In a Swedish population-based cohort study, we compared 3963 biopsy-verified IgA nephropathy patients with 19,978 matched controls between 1974 and 2011, following up participants until 2015. Inflammatory bowel disease data and ESKD status were obtained through national medical registers. We applied Cox regression to estimate hazard ratios (HRs) for future inflammatory bowel disease in IgA nephropathy and conditional logistic regression to assess risk of earlier inflammatory bowel disease in IgA nephropathy. We also explored whether inflammatory bowel disease affects development of ESKD in IgA nephropathy.

RESULTS

During a median follow-up of 12.6 years, 196 (4.95%) patients with IgA nephropathy and 330 (1.65%) matched controls developed inflammatory bowel disease (adjusted HR, 3.29; 95% confidence interval [95% CI], 2.73 to 3.96). Inflammatory bowel disease also was more common before a confirmed IgA nephropathy diagnosis. Some 103 (2.53%) IgA nephropathy patients had an earlier inflammatory bowel disease diagnosis compared with 220 (1.09%) controls (odds ratio [OR], 2.37; 95% CI, 1.87 to 3.01). Both logistic regression (OR, 2.60; 95% CI, 2.02 to 3.35) and time-varying Cox regression (HR, 1.84; 95% CI, 1.33 to 2.55) demonstrated that inflammatory bowel disease was associated with increased ESKD risk in patients with IgA nephropathy.

CONCLUSIONS

Patients with IgA nephropathy have an increased risk of inflammatory bowel disease both before and after their nephropathy diagnosis. In addition, among patients with IgA nephropathy, comorbid inflammatory bowel disease elevates the risk of progression to ESKD.

Intestinal SIRT1 Deficiency-Related Intestinal Inflammation and Dysbiosis Aggravate TNFα-Mediated Renal Dysfunction in Cirrhotic Ascitic Mice

In advanced cirrhosis, the TNFα-mediated intestinal inflammation and bacteria dysbiosis are involved in the development of inflammation and vasoconstriction-related renal dysfunction. In colitis and acute kidney injury models, activation of SIRT1 attenuates the TNFα-mediated intestinal and renal abnormalities. This study explores the impacts of intestinal SIRT1 deficiency and TNFα-mediated intestinal abnormalities on the development of cirrhosis-related renal dysfunction. Systemic and renal hemodynamics, intestinal dysbiosis [cirrhosis dysbiosis ratio (CDR) as marker of dysbiosis], and direct renal vasoconstrictive response (renal vascular resistance (RVR) and glomerular filtration rate (GFR)) to cumulative doses of TNFα were measured in bile duct ligated (BDL)-cirrhotic ascitic mice. In SIRT1^IEC-KO-BDL-ascitic mice, the worsening of intestinal dysbiosis exacerbates intestinal inflammation/barrier dysfunction, the upregulation of the expressions of intestinal/renal TNFα-related pathogenic signals, higher TNFα-induced increase in RVR, and decrease in GFR in perfused kidney. In intestinal SIRT1 knockout groups, the positive correlations were identified between intestinal SIRT1 activity and CDR. Particularly, the negative correlations were identified between CDR and RVR, with the positive correlation between CDR and GFR. In mice with advanced cirrhosis, the expression of intestinal SIRT1 is involved in the linkage between intestinal dysbiosis and vasoconstriction/hypoperfusion-related renal dysfunction through the crosstalk between intestinal/renal TNFα-related pathogenic inflammatory signals.