T cell subpopulations and cytokine levels in hemodialysis patients

The causal effect of inflammatory proteins and immune cell populations on diabetic nephropathy: evidence from Mendelian randomization

BACKGROUND

Diabetic nephropathy (DN) is one of the diabetic microvascular complications with complex pathophysiology, and exploring the landscape of immune dysregulation in DN is valuable for pathogenesis and disease treatment. We crystallized possible inflammatory exposures into 91 circulating inflammatory proteins and 109 blood immune cells; and assessed the causal relationship between inflammation and DN using Mendelian randomization (MR).

METHODS

Based on publicly available genetic data, we explored causal associations between inflammation and DN risk by two-sample MR analysis. Genome-wide association study (GWAS) summary statistics for 91 circulating inflammatory proteins, 109 immune cells absolute counts, and DN were acquired from the GWAS Catalog. Inverse Variance Weighted (IVW) was the main MR method, while MR-Egger and MR-pleiotropy residuals and outliers (MR-PRESSO) were utilized for sensitivity analysis. Cochrane's Q was used to test for heterogeneity. The leave-one-out method ensured the stability of the MR results.

RESULTS

This study revealed that higher levels of TNF-related activation-induced cytokine and tumor necrosis factor ligand superfamily member 14 were possibly associated with the increased risk of DN according to the IVW approach, with estimated odds ratios (OR) of 1.287 (95% confidence interval [CI] 1.051 to 1.577, P = 0.015) and 1.249 (95% CI 1.018 to 1.532, P = 0.033). Five immune cell traits were identified that might be linked to increased DN risk, including the higher absolute counts of HLA DR+ natural killer cell (OR = 1.248, 95% CI 1.055 to 1.476, P = 0.010), IgD+ CD38+ B cell (OR = 1.148, 95% CI 1.033 to 1.276, P = 0.010), CD25++ CD8+ T cell (OR = 1.159, 95% CI 1.032 to 1.302, P = 0.013), CD4- CD8- T cell (OR = 1.226, 95% CI 1.032 to 1.457, P = 0.020), and IgD- CD38- B cell (OR = 1.182, 95% CI 1.009 to 1.386, P = 0.039). In addition, elevated levels of interleukin-1 alpha (OR = 0.712, 95% CI 0.514 to 0.984, P = 0.040) and unswitched memory B cell (OR = 0.797, 95% CI 0.651 to 0.974, P = 0.027) may reduce the risk of developing DN.

CONCLUSION

We identified inflammation-related exposures that may be associated with the risk of DN at the level of genetic prediction, which contributes to a better understanding of the etiologic of DN and facilitates the development of targeted therapies for DN.

IL-6 and IL-17 as potential links between pre-existing hypertension and long-term COVID sequelae in patients undergoing hemodialysis: a multicenter cross-sectional study

Long COVID, characterized by persistent symptoms following acute infection, poses a significant health challenge, particularly for patients with pre-existing chronic conditions such as hypertension. We hypothesized that an increase in the production of interleukins (IL)-6 and IL-17 could serve as a potential mechanism linking pre-existing uncontrolled blood pressure (BP) to the occurrence of long-term COVID sequelae in patients undergoing hemodialysis (HD). This cross-sectional study examined serum IL-6 and IL-17 levels in 80 patients undergoing HD, considering preinfection BP, the presence of long-term COVID sequelae, and the time interval after acute COVID-19 infection, which was either 5 or 10 months. Controlled BP was defined as a 3-month average pre-dialysis BP < 140/90 mmHg and post-dialysis < 130/80 mmHg. The findings suggest that the prevalence of long-term COVID sequelae was significantly higher in patients with uncontrolled BP than in the BP-controlled group. Both IL-6 and IL-17 concentrations were also significantly higher in patients with uncontrolled BP compared with the BP-controlled group. The patients with long-term COVID sequelae had higher IL-6 and IL-17 values than the fully recovered patients at both time points, but their concentrations decreased significantly over time. Further research and prospective studies are warranted to validate these findings.

The Interplay between Immune and Metabolic Pathways in Kidney Disease

Kidney disease is a significant health problem worldwide, affecting an estimated 10% of the global population. Kidney disease encompasses a diverse group of disorders that vary in their underlying pathophysiology, clinical presentation, and outcomes. These disorders include acute kidney injury (AKI), chronic kidney disease (CKD), glomerulonephritis, nephrotic syndrome, polycystic kidney disease, diabetic kidney disease, and many others. Despite their distinct etiologies, these disorders share a common feature of immune system dysregulation and metabolic disturbances. The immune system and metabolic pathways are intimately connected and interact to modulate the pathogenesis of kidney diseases. The dysregulation of immune responses in kidney diseases includes a complex interplay between various immune cell types, including resident and infiltrating immune cells, cytokines, chemokines, and complement factors. These immune factors can trigger and perpetuate kidney inflammation, causing renal tissue injury and progressive fibrosis. In addition, metabolic pathways play critical roles in the pathogenesis of kidney diseases, including glucose and lipid metabolism, oxidative stress, mitochondrial dysfunction, and altered nutrient sensing. Dysregulation of these metabolic pathways contributes to the progression of kidney disease by inducing renal tubular injury, apoptosis, and fibrosis. Recent studies have provided insights into the intricate interplay between immune and metabolic pathways in kidney diseases, revealing novel therapeutic targets for the prevention and treatment of kidney diseases. Potential therapeutic strategies include modulating immune responses through targeting key immune factors or inhibiting pro-inflammatory signaling pathways, improving mitochondrial function, and targeting nutrient-sensing pathways, such as mTOR, AMPK, and SIRT1. This review highlights the importance of the interplay between immune and metabolic pathways in kidney diseases and the potential therapeutic implications of targeting these pathways.

Impact of Single Hemodialysis Treatment on immune Cell Subpopulations

Hemodialysis (HD) is known to trigger a chronic inflammatory status, affecting the innate and acquired immune response. This study was aimed at a comparative analysis of immune cell subsets, proliferation, and apoptosis in subjects receiving chronic HD treatment with respect to a healthy control. Regardless of the dialysis filter used, we observed a reshaping of the acquired immune component both with respect to healthy patients and between the various sessions of dialysis treatment, with an impairment of CD3 cells, along with an increase in CD4 and CD8 cell populations producing pro-inflammatory factors such as IL-17 and IFN-gamma. The population of B cells, monocytes and NK cells were not impaired by the dialysis procedure. These results confirmed the high impact of the HD treatment on the patient's immune system, underlying the imbalance of T cell counterparts.

Meta-analysis of cancer risk among end stage renal disease undergoing maintenance dialysis

Currently, there is no consensus on whether maintenance dialysis increases cancer risk in patients with end-stage renal disease (ESRD). Therefore, this study was to systematically evaluate the risk of cancer among ESRD patients undergoing maintenance dialysis. Related studies on the impact of maintenance dialysis on cancer risk were retrieved from PubMed, Embase, Cochrane Library, and other databases from their respective inceptions to 19 February 2021. ESRD patients receiving maintenance dialysis were classified into cancer including non-melanoma skin cancer (NMSC) and cancer excluding NMSC. Standardized incidence ratio (SIR) with its 95% confidence interval (95% CI) was calculated to assess cancer risk. Fourteen studies were included in the meta-analysis. The risk of cancer in patients undergoing maintenance dialysis (with or without NMSC) was significantly higher than controls both in cancer including NMSC (SIR = 1.38, 95% CI: 1.27-1.49, P < 0.001) and cancer excluding NMSC (SIR = 1.34, 95% CI: 1.23-1.47, P < 0.001). Subgroup results identified the higher risk of cancer incidence in both men and women receiving maintenance dialysis. Meanwhile, elevated excess risks were observed among patients with younger age and shorter follow-up time (P < 0.001). Meanwhile, the combined SIR of bladder, cervix, colorectum, kidney, liver, thyroid, tongue, and other cancers were all increased (P < 0.05). ESRD patients undergoing dialysis has higher risk of cancer.

Effects of Standardized Brazilian Green Propolis Extract (EPP-AF®) on Inflammation in Haemodialysis Patients: A Clinical Trial

BACKGROUND

Patients on haemodialysis (HD) present a significant inflammatory status, which has a pronounced negative impact on their outcomes. Propolis is a natural resin with anti-inflammatory and immunomodulatory properties. We assessed the safety and impact of a standardized Brazilian green propolis extract (EPP-AF®) on the inflammatory status in patients under conventional HD.

METHODS

Patients were assigned to receive 200 mg/day of EPP-AF® for 4 weeks followed by 4 weeks without the drug, and changes in plasma levels of interleukins (ILs), interferon gamma (IFN-γ), tumour necrosis factor-alpha (TNF-α), and high-sensitivityc-reactive protein (HsCRP) were measured. A heatmap was used to illustrate trends in data variation.

RESULTS

In total, 37 patients were included in the final analysis. Patients presented an exacerbated inflammatory state at baseline. During EPP-AF® use, there was a significant reduction in IFN-γ (p=0.005), IL-13 (p=0.04 2), IL-17 (p=0.039), IL-1ra (p=0.008), IL-8 (p=0.009), and TNF-α (p  <  0.001) levels compared to baseline, and significant changes were found in Hs-CRP levels. The heatmap demonstrated a pattern of pronounced proinflammatory status at baseline, especially in patients with primary glomerulopathies, and a clear reduction in this pattern during the use of EPP-AF®. There was a tendency to maintain this reduction after suspension of EPP-AF®. No significant side effects were observed.

CONCLUSION

Patients under haemodialysis presented a pronounced inflammatory status, and EPP-AF® was demonstrated to be safe and associated with a significant and maintained reduction in proinflammatory cytokines in this population. This trial is registered with Clinicaltrials.gov NCT04072341.

Immune System Dysfunction and Inflammation in Hemodialysis Patients: Two Sides of the Same Coin

Biocompatibility in hemodialysis (HD) has considerably improved in recent decades, but remains an open issue to be solved, appearing essential to reduce systemic inflammation and enhance patients’ clinical outcomes. Clotting prevention, reduction in complement and leukocyte activation, and improvement of antioxidant effect represent the main goals. This review aims to analyze the different pathways involved in HD patients, leading to immune system dysfunction and inflammation. In particular, we mostly review the evidence about thrombogenicity, which probably represents the most important characteristic of bio-incompatibility. Platelet activation is one of the first steps occurring in HD patients, determining several events causing chronic sub-clinical inflammation and immune dysfunction involvement. Moreover, oxidative stress processes, resulting from a loss of balance between pro-oxidant factors and antioxidant mechanisms, have been described, highlighting the link with inflammation. We updated both innate and acquired immune system dysfunctions and their close link with uremic toxins occurring in HD patients, with several consequences leading to increased mortality. The elucidation of the role of immune dysfunction and inflammation in HD patients would enhance not only the understanding of disease physiopathology, but also has the potential to provide new insights into the development of therapeutic strategies.