Targeting Immunity in End-Stage Renal Disease

Regulation of renal lipid deposition in diabetic nephropathy on morroniside via inhibition of NF-KB/TNF-a/SREBP1c signaling pathway

Morroniside (MOR), a cyclic enol ether terpene glycoside isolated from Cornus officinalis, has been shown to inhibit lipid accumulation, although the mechanism of action is uncertain. The aim of this study was to investigate the potential pathways by which MOR affects renal lipid deposition in diabetic nephropathy (DN). In vitro and in vivo experiments were performed using the PA-induced HK-2 cell model and a KKAy animal model, respectively. Network pharmacological analysis was used to identify potential MOR signaling pathways for DN therapy, with results verified via Western blotting and immunofluorescence experiments. The effect of MOR on lipid metabolism was investigated using BODIPY 493/503 staining. Our results indicate that MOR significantly reduces lipid accumulation both in vitro and in vivo. According to network pharmacology studies, the NF-κB/TNF-α/SREBP1c signaling pathway may be the mechanism of action of MOR in DN. MOR was found to inhibit this pathway by reducing the phosphorylation of NF-κB p65 and the expression of TNF-α and SREBP1c, similar to the effects of Bay11-7082. Additionally, MOR significantly inhibited the expression of lipid factors such as ACC, FAS, and SCD1. In conclusion, MOR can regulate the disruption of lipid metabolism in DN and reduce renal lipid deposition via suppression of the NF-κB/TNF-α/SREBP1c signaling pathway.

The therapeutic potential of an allosteric non-competitive CXCR1/2 antagonist for diabetic nephropathy

AIMS

Diabetic nephropathy is a major consequence of inflammation developing in type 1 diabetes, with interleukin-8 (IL-8)-CXCR1/2 axis playing a key role in kidney disease progression. In this study, we investigated the therapeutic potential of a CXCR1/2 non-competitive allosteric antagonist (Ladarixin) in preventing high glucose-mediated injury in human podocytes and epithelial cells differentiated from renal stem/progenitor cells (RSC) cultured as nephrospheres.

MATERIALS AND METHODS

We used human RSCs cultured as nephrospheres through a sphere-forming functional assay to investigate hyperglycemia-mediated effects on IL-8 signalling in human podocytes and tubular epithelial cells.

RESULTS

High glucose impairs RSC self-renewal, induces an increase in IL-8 transcript expression and protein secretion and induces DNA damage in RSC-differentiated podocytes, while exerting no effect on RSC-differentiated epithelial cells. Accordingly, the supernatant from epithelial cells or podocytes cultured in high glucose was able to differentially activate leucocyte-mediated secretion of pro-inflammatory cytokines, suggesting that the crosstalk between immune and non-immune cells may be involved in disease progression in vivo.

CONCLUSIONS

Treatment with Ladarixin during RSC differentiation prevented high glucose-mediated effects on podocytes and modulated either podocyte or epithelial cell-dependent leucocyte secretion of pro-inflammatory cytokines, suggesting CXCR1/2 antagonists as possible pharmacological approaches for the treatment of diabetic nephropathy.

New Pandemic: Obesity and Associated Nephropathy

Incidence of obesity related renal disorders have increased 10-folds in recent years. One of the consequences of obesity is an increased glomerular filtration rate (GFR) that leads to the enlargement of the renal glomerulus, i.e., glomerulomegaly. This heightened hyper-filtration in the setting of type 2 diabetes irreparably damages the kidney and leads to progression of end stage renal disease (ESRD). The patients suffering from type 2 diabetes have progressive proteinuria, and eventually one third of them develop chronic kidney disease (CKD) and ESRD. For ameliorating the progression of CKD, inhibitors of renin angiotensin aldosterone system (RAAS) seemed to be effective, but on a short-term basis only. Long term and stable treatment strategies like weight loss via restricted or hypo-caloric diet or bariatric surgery have yielded better promising results in terms of amelioration of proteinuria and maintenance of normal GFR. Body mass index (BMI) is considered as a traditional marker for the onset of obesity, but apparently, it is not a reliable indicator, and thus there is a need for more precise evaluation of regional fat distribution and amount of muscle mass. With respect to the pathogenesis, recent investigations have suggested perturbation in fatty acid and cholesterol metabolism as the critical mediators in ectopic renal lipid accumulation associated with inflammation, increased generation of ROS, RAAS activation and consequential tubulo-interstitial injury. This review summarizes the renewed approaches for the obesity assessment and evaluation of the pathogenesis of CKD, altered renal hemodynamics and potential therapeutic targets.

Possible benefits of exogenous melatonin for individuals on dialysis: a narrative review on potential mechanisms and clinical implications

Prevention of oxidative stress and inflammation in chronic kidney disease patients (CKD) on dialysis may reduce dialysis-associated complications. Administration of powerful antioxidants may improve the consequences of peritoneal dialysis (PD) and hemodialysis (HD). This narrative review aimed to show the potential therapeutic effects of melatonin (MLT) on the consequences of CKD patients receiving HD or PD. The results of preclinical and clinical studies have proven that CKD and dialysis are accompanied by reduced endogenous MLT levels and related complications such as sleep disorders. Enhanced oxidative stress, inflammation, cellular damages, and renal fibrosis, along with dysregulation of the renin-angiotensin system (RAS), have been observed in CKD and patients on dialysis. Results of studies have revealed that the restoration of MLT via the exogenous source may regulate oxidative stress, inflammation, and RAS functions, inhibit fibrosis, and improve complications in patients with long-term dialysis patients. In summary, treatment of patients with CKD and dialysis with exogenous MLT is suggested as a practical approach in reducing the outcomes and improving the quality of life in patients via antioxidant, anti-inflammatory, and anti-fibrotic signaling pathways. Therefore, this hormone can be considered in clinical practice to manage dialysis-related complications.

Interleukin-8 is increased in chronic kidney disease in children, but not related to cardiovascular disease

Introduction:

In this study, we aimed to detect the cytokine that is involved in the early stage of chronic kidney disease and associated with cardiovascular disease.

Methods:

We included 50 patients who were diagnosed with predialytic chronic kidney disease and 30 healthy pediatric patients in Ege University Medical Faculty Pediatric Clinic, İzmir/Turkey. Interleukin-8 (IL-8), interleukin-10 (IL-10), interleukin-13 (IL-13), and transforming grow factor-β1 (TGF-β1) levels (pg/mL) were measured by ELISA. Carotid-femoral pulse wave velocity (PWV), augmentation index (Aix), carotid intima media thickness (cIMT), and left ventricular mass index (LVMI) were evaluated as markers of cardiovascular disease. The presence of a cardiovascular disease marker was defined as an abnormality in any of the parameters (cIMT, PWV, Aix, and left ventricular mass index (SVKI)). The patient group was divided into two groups as with and without cardiovascular disease.

Results:

Mean Aix and PWV values were higher in CKD patients than controls (Aix: CKD 32.8±11.11%, healthy subjects: 6.74±6.58%, PWV CKD: 7.31±4.34m/s, healthy subjects: 3.42±3.01m/s, respectively; p=0.02, p=0.03). The serum IL-8 levels of CKD were significantly higher than of healthy subjects 568.48±487.35pg/mL, 33.67±47.47pg/mL, respectively (p<0.001). There was no statistically significant difference between IL-8, IL-10, IL-13, TGF-1, in CKD patients with and without cardiovascular disease (p> 0.05).

Discussion:

IL-8 is the sole cytokine that increases in pediatric patients with chronic kidney disease among other cytokines (IL-10, IL-13 and TGF-β1). However, we did not show that IL-8 is related to the presence of cardiovascular disease.

The effects of dipeptidyl peptidase-4 inhibitors on kidney outcomes

AIMS

To summarize evidence from randomized controlled trials (RCTs) concerning the effects of dipeptidyl peptidase-4 (DPP-4) inhibitors on kidney outcomes in patients with type 2 diabetes mellitus (T2DM).

METHODS

The Medline, EMBASE and Cochrane databases were searched for RCTs comparing DPP-4 inhibitors with a placebo, active comparator or standard care, with at least 500 person-years follow-up in patients with T2DM and with reporting of kidney outcomes. Treatment effects were summarized using random-effects meta-analysis.

RESULTS

Ten trials including 47 955 patients (mean estimated glomerular filtration rate [eGFR] 71 mL/min/1.73m² , mean follow-up 10 762 patient-years per trial) were eligible for inclusion. DPP-4 inhibitors were compared with placebo (five trials), active comparator (three trials), and standard care (two trials). Overall, treatment with DPP-4 inhibitors was associated with a greater decline in eGFR than treatment with the comparators (weighted mean difference -1.12 mL/min/1.73m² , 95% confidence interval [CI] -1.61, -0.62; high-certainty evidence). There were no detectable effects of DPP-4 inhibitors on rates of doubling serum creatinine (risk ratio [RR] 1.10, 95% CI 0.90, 1.34; high-certainty evidence), end-stage kidney disease (RR 0.97, 95% CI 0.77, 1.23; high-certainty evidence), death from kidney causes (RR 1.81, 95% CI 0.67, 4.93; low-certainty evidence), or all-cause mortality (RR 1.01, 95% CI 0.95, 1.09; high-certainty evidence). DPP-4 inhibitors significantly reduced the risks of the surrogate kidney outcome of new albuminuria (RR 0.88, 95% CI 0.8, 0.98; moderate-certainty evidence) and worsening albuminuria (RR 0.88, 95% CI 0.82, 0.94; moderate-certainty evidence). There was no difference in the safety outcome of acute kidney injury (RR 1.04, 95% CI 0.57, 1.87; high-certainty evidence).

CONCLUSIONS

Dipeptidyl peptidase-4 inhibitors are associated with a greater decline in eGFR, despite reducing the development and progression of albuminuria, and have no clear effect on other key kidney outcomes.

Herbal antioxidants in dialysis patients: a review of potential mechanisms and medical implications

The consumption of exogenous antioxidants isolated from herbal extracts has shown beneficial effects on ameliorating dialysis-related complications through debilitating oxidative stress and inflammatory process. Many clinical studies available in public databases have reported the improved consequences of dialysis in patients supplemented with herbal antioxidants. Exploration of such data offers great possibilities for gaining insights into the potential mechanisms and medical implications of herbal antioxidants. In this work, the mechanisms and implications of some famous bioactive substances including silymarin, curcumin, resveratrol, emodin, and quercetin on the consequences of dialysis in chronic kidney disease (CKD) patients were explored. The protective features of silymarin are due to the flavonoid complex silybin. Curcumin is an active element from the root of curcuma longa with extensive beneficial properties, including antioxidant, anti-inflammatory activity, and inhibitory effects on cell apoptosis. Resveratrol can reduce the oxidative stress by neutralization of free radicals. Emodin is known as a natural anthraquinone derivative isolated from Chinese herbs. Finally, quercetin has been reported to exhibit several properties including antioxidant, anti-diabetic, analgesic, antihistaminic, antiviral, cholesterol reducer, and renal hemodynamic modulator. However, potential mechanisms and medical implications of the aforementioned herbal antioxidants seem to be more complicated, that is, more studies are required in this field.

Association between dynapenic abdominal obesity and inflammatory profile in diabetic older community-dwelling patients with end-stage renal disease

BACKGROUND

Obesity and poor strength impose higher risk factor for end-stage renal disease (ESRD) patients. It is expected that the combination of both conditions might be critically associated with the inflammatory profile in this population, especially in community-dwelling elderly. So, diagnosis of dynapenic obesity and inflammation is an important tool in the management of chronic kidney disease patients at imminent risk of hospitalization.

PURPOSE

To investigate the association between dynapenic abdominal obesity and inflammatory markers in community-swelling elderly with ESRD.

METHODS

Two hundred and forty-seven community-dwelling older patients (66.74 ± 3.20 years; n = 150, 60.73%, males) undergoing maintenance phase hemodialysis volunteered for this study. The study sample was categorized into four groups according to handgrip strength and waist circumference as follows: control, dynapenia (low strength alone), abdominal obesity (high waist circumference alone), and dynapenic obesity (D/AO) (the combination of low strength and high waist circumference). Blood samples were collected for tumor necrosis factor alpha (TNF-α), interleukin (IL)- 6 and IL- 10. Results were considered significant at P < 0.05.

RESULTS

Proportions for control, abdominal obesity, dynapenic, and D/AO were 38.5%, 15.8%, 25.9%, and 19.8%, respectively. Higher concentrations of TNF-α were found in the D/AO group (P < 0.0001). This group also displayed lower levels of IL-10 (P < 0.0001). Further, the D/AO traits were strongly associated with TNF-α and IL-10 (P < 0.0001).

CONCLUSION

The closely relation between D/AO and inflammatory profile provides evidence that the pooled information of low muscle strength and abdominal obesity may be clinically relevant for the management of ESRD patients.

CKIP-1 acts downstream to Cx43 on the activation of Nrf2 signaling pathway to protect from renal fibrosis in diabetes

We previously reported that both Cx43 and CKIP-1 attenuated diabetic renal fibrosis via the activation of Nrf2 signaling pathway. However, whether CKIP-1, a scaffold protein, participates in regulating the activation of Nrf2 signaling pathway by Cx43 remains to be elucidated. In this study, the effect of adenovirus-mediated Cx43 overexpression on renal fibrosis in CKIP-1-/- diabetic mice was investigated. We found that overexpression of Cx43 could significantly alleviate renal fibrosis by activating the Nrf2 pathway in diabetic mice, but have no obvious effect in CKIP-1-/- diabetic mice. Cx43 overexpressed plasmid and CKIP-1 small interfering RNA were simultaneously transfected into glomerular mesangial cells and the result demonstrated that the effect of activation of Nrf2 signaling pathway by Cx43 was blocked by CKIP-1 depletion. The interaction between Cx43 and CKIP-1 was analyzed by immunofluorescence and immunoprecipitation assays. We found that Cx43 interacted with CKIP-1, and the interaction was weakened by high glucose treatment. Moreover, Cx43 regulated the expression of CKIP-1 and the interaction of CKIP-1 with Nrf2 via Cx43 carboxyl terminus (CT) domain, thereby activating Nrf2 signaling pathway. According to the results, we preliminary infer that CKIP-1 acts downstream to CX43 on the activation of Nrf2 signaling pathway to protect from renal fibrosis in diabetes, the mechanism of which might be related to the interaction of CKIP-1 with Nrf2 through Cx43 CT. Our study provides further experimental basis for targeting the Cx43-CKIP-1-Nrf2 axis to resist diabetic renal fibrosis.

Associations between Cell-Free Mitochondrial DNA and Inflammation, and Their Clinical Implications for Patients on Hemodialysis: A Prospective Multicenter Cohort Study

BACKGROUND

Cell-free mitochondrial DNA (cf-mtDNA) has recently been in the spotlight as an endogenously produced danger molecule that can potentially elicit inflammation. However, its clinical and prognostic implications are uncertain in patients undergoing hemodialysis.

METHODS

We examined the association of baseline cf-mtDNA categorized as tertiles with health-related quality of life (HRQOL), inflammatory cytokines, and mortality in a multicenter prospective cohort of 334 patients on hemodialysis. To better understand cf-mtDNA-mediated inflammation, we measured cytokine production after in vitro stimulation of bone marrow-derived macrophages (BMDMs) with mtDNA.

RESULTS

The higher cf-mtDNA tertile had a longer dialysis vintage, a greater comorbidity burden, and increased levels of inflammatory markers, including high-sensitivity-C-reactive protein, tumor necrosis factor-alpha, CXCL16, and osteoprotegerin. In particular, mtDNA augmented inflammatory cytokine release from BMDMs by lipopolysaccharide, the levels of which are reported to be increased in hemodialysis patients. Although the patients with higher levels of cf-mtDNA generally had lower (poorer) scores for HRQOL, cf-mtDNA was not associated with all-cause mortality in hemodialysis patients.

CONCLUSION

cf-mtDNA was correlated with poor clinical status and modestly associated with impaired quality of life in patients on hemodialysis. In proinflammatory milieu in end-stage renal disease, these associations may be attributed to the boosting effects of cf-mtDNA on inflammation.

Propionate supplementation promotes the expansion of peripheral regulatory T-Cells in patients with end-stage renal disease

Patients with end-stage renal disease (ESRD) suffer from a progressively increasing low-grade systemic inflammation, which is associated with higher morbidity and mortality. Regulatory T cells (Tregs) play an important role in regulation of the inflammatory process. Previously, it has been demonstrated that short-chain fatty acids reduce inflammation in the central nervous system in a murine model of multiple sclerosis through an increase in tissue infiltrating Tregs. Here, we evaluated the effect of the short-chain fatty acid propionate on the chronic inflammatory state and T-cell composition in ESRD patients. Analyzing ESRD patients and healthy blood donors before, during, and 60 days after the propionate supplementation by multiparametric flow cytometry we observed a gradual and significant expansion in the frequencies of CD25^highCD127^- Tregs in both groups. Phenotypic characterization suggests that polarization of naïve T cells towards Tregs is responsible for the observed expansion. In line with this, we observed a significant reduction of inflammatory marker CRP under propionate supplementation. Of interest, the observed anti-inflammatory surroundings did not affect the protective pathogen-specific immunity as demonstrated by the stable frequencies of effector/memory T cells specific for tetanus/diphtheria recall antigens. Collectively, our data suggest that dietary supplements with propionate have a beneficial effect on the elevated systemic inflammation of ESRD patients. The effect can be achieved through an expansion of circulating Tregs without affecting the protective pathogen-reactive immunity.

Inflammatory markers in end-stage renal disease patients on haemodialysis

Background

CXC chemokine ligand 16 (CXCL16) is an inflammatory chemokine that mediates renal infiltration of macrophages and activated T cells. Aim: To investigate serum levels of CXCL16 in patients undergoing hemodialysis and their correlation with other inflammatory markers such as C-reactive protein (CRP) and intact parathyroid hormone (iPTH).

Methods

The study included 40 hemodialysis patients (22 males) and 40 age and gender-matched controls (24 males). Fasting blood sugar (FBS), urea, creatinine, calcium and inorganic phosphorous were assayed in participants using routine methods, glycosylated hemoglobin (HbA1c) by quantitative chromatographic spectrophotometry, iPTH by chemiluminescent microparticle immunoassay, CRP by nephelometry and CXCL16 by ELISA technique.

Results

Serum CXCL16, CRP, PTH, FBS, HbA1c, phosphorus, urea, and creatinine levels were significantly higher in hemodialysis patients compared to controls (p<0.00001). No statistically significant differences were observed between patients and controls for calcium. Serum CXCL16 levels correlated positively with CRP (r=0.956, p<0.00001) and iPTH (r=-0.403, p<0.001). Hemodialysis patients (diabetics or hypertensives) had significantly higher CXCL16 levels compared to non-diabetics or non-hypertensives.

Conclusions

High levels of serum CXCL16, CRP and iPTH reflect the inflammatory status of hemodialysis patients and help avoid complications. Serum CXCL16 could be used as a biomarker together with CRP in these patients.

A Systematic Review and Meta-Analysis of Depression and Protein-Energy Wasting in Kidney Disease

Introduction

Depression comorbid with chronic disease may be mediated by inflammation. We sought to characterize relationships between inflammatory biomarkers and depressive symptoms in patients with chronic kidney disease and end-stage kidney disease.

Methods

A systematic literature search was conducted by 2 authors up to March 19, 2019, for studies of patients with chronic kidney disease or end-stage kidney disease evaluating circulating inflammatory biomarkers associated with depression of chronic disease: albumin, C-reactive protein (CRP), high-sensitivity CRP, interleukin-6 (IL-6), tumor necrosis factor-α, and interleukin-1. Standardized mean differences in biomarkers between individuals with and without depression were computed and analyzed using mixed effects models. Correlations between biomarkers and the severity of depressive symptoms were computed.

Results

Thirty-four studies (5652 participants) compared biomarkers between depressed and nondepressed individuals. Individuals with depression had lower albumin levels (standardized mean difference, −0.37; 95% confidence interval [CI], −0.61 to −0.13), higher CRP levels (standardized mean difference, 0.76; 95% CI, 0.16–1.37), and higher IL-6 levels (standardized mean difference, 0.42; 95% CI, 0.21–0.63). Studies were heterogeneous for albumin, CRP, high-sensitivity CRP, and tumor necrosis factor-α. Twenty-three studies (3047 participants) investigated correlations between biomarkers and depressive symptoms. The severity of depressive symptoms correlated with albumin (Z = −0.25; 95% CI, −0.36 to −0.14), high-sensitivity CRP (Z = 0.28; 95% CI, 0.13–0.43), and IL-6 (Z = 0.34; 95% CI, 0.18–0.49). There was heterogeneity across studies of IL-6. Only 6 studies (321 participants) investigated the effect of antidepressant treatment on inflammatory biomarkers, which was insufficient to combine in meta-analysis.

Conclusion

Lower albumin and higher IL-6 were associated with both the presence and severity of depression, CRP with the presence of depression, and high-sensitivity CRP with the severity of depressive symptoms. The effect of interventions to lower inflammation in patients with kidney disease and depression deserves investigation.

[Premature immune senescence and chronic kidney disease: Update and perspectives]

Immune senescence is associated with age-related diseases (i.e. infectious disease, cardiovascular diseases and cancers). Chronic kidney disease patients die prematurely when compared with general population, because of a higher occurrence of infections, cardiovascular events and cancer. These diseases are commonly observed in the elderly population and frequently associated with immune senescence. Indeed, chronic kidney disease causes a premature aging of the T lymphocyte compartment, widely related to a decrease in thymic function, a phenomenon that plays a key role in the onset of age-related diseases in chronic kidney disease patients. The degree of immune senescence also influences patients' outcome after renal transplantation, particularly the risk of acute rejection and infections. Partial reversion of pre-transplant immune senescence is observed for some renal transplant patients. In conclusion, to reduce the increasing incidence of morbidity and mortality of chronic kidney disease patients, a better knowledge of uremia-induced immune senescence would help to pave the way to build clinical studies and promote innovative therapeutic approaches. We believe that therapeutic reversion and immune senescence prevention approaches will be part of the management of chronic kidney disease patients in the future.

Renal Lipid Metabolism and Lipotoxicity in Diabetes

The pathogenesis of diabetic kidney disease is a complex process caused by both glucotoxicity and lipotoxicity due to lipid accumulation. In cases of diabetic animals, lipid deposition is found in both tubular and glomerular portions of the kidneys, which are the major sites of diabetic nephropathy lesions. The aim of this review was to provide insights into the mechanisms that lead to the development of renal lipid accumulation and the effects of renal lipotoxicity in the diabetic condition. An increased number of lipogenic genes and a decreased number of lipid oxidation genes are also detected in diabetic kidneys, both of which lead to lipid accumulation. The induction of oxidative stress, inflammation, fibrosis and apoptosis caused by lipid accumulation and lipid metabolites is called lipotoxicity. Renal lipotoxicity due to derangement in lipid metabolism may be a pathogenic mechanism leading to diabetic nephropathy and renal dysfunction.

Diabetic nephropathy: The regulatory interplay between epigenetics and microRNAs

Diabetic nephropathy (DN) is still one of the leading causes of end-stage renal disease despite the emergence of different therapies to counter the metabolic, hemodynamic and fibrotic pathways, implicating a prominent role of genetic and epigenetic factors in its progression. Epigenetics is the study of changes in the expression of genes which may be inheritable and does not involve a change in the genome sequence. Thrust areas of epigenetic research are DNA methylation and histone modifications. Noncoding RNAs (ncRNAs), particularly microRNAs (miRNAs) control the expression of genes via post-transcriptional mechanisms. However, the regulation by epigenetic mechanisms and miRNAs are not completely distinct. A number of emerging reports have revealed the interplay between epigenetic machinery and miRNA expression, particularly in cancer. Further research has proved that a feedback loop exists between miRNA expression and epigenetic regulation in disorders including DN. Studies showed that different miRNAs (miR-200, miR-29 etc.) were found to be regulated by epigenetic mechanisms viz. DNA methylation and histone modifications. Conversely, miRNAs (miR-301, miR-449 etc.) themselves modulated levels of DNA methyltranferases (DNMTs) and Histone deacetylases (HDACs), enzymes vital to epigenetic modifications. With already few FDA approved epigenetic -modulating drugs (Vorinostat, Decitabine) in the market and miRNA therapeutic drugs under clinical trial it becomes imperative to analyze the possible interaction between the two classes of drugs in the modulation of a disease process. The purpose of this review is to articulate the interplay between miRNA expression and epigenetic modifications with a particular focus on its impact on the development and progression of DN.

Advances in understanding the genetic basis of diabetic kidney disease

Diabetic kidney disease (DKD) is a devastating complication of Type 1 and Type 2 diabetes and leads to increased morbidity and mortality. Earlier work in families has provided strong evidence that heredity is a major determinant of DKD. Previous linkage analyses and candidate gene studies have identified potential DKD genes; however, such approaches have largely been unsuccessful. Genome-wide association studies (GWAS) have made significant contribution in identifying SNPs associated with common complex diseases. Thanks to advanced technology, new analytical approaches, and international research collaborations, many DKD GWASs have reported unique genes, highlighted novel biological pathways and suggested new disease mechanisms. This review summarizes the current state of GWAS technology; findings from GWASs of DKD and its related traits conducted over the past 15 years and discuss the future of this field.