Geographic variation of mutagenic exposures in kidney cancer genomes

International differences in the incidence of many cancer types indicate the existence of carcinogen exposures that have not yet been identified by conventional epidemiology make a substantial contribution to cancer burden1. In clear cell renal cell carcinoma, obesity, hypertension and tobacco smoking are risk factors, but they do not explain the geographical variation in its incidence2. Underlying causes can be inferred by sequencing the genomes of cancers from populations with different incidence rates and detecting differences in patterns of somatic mutations. Here we sequenced 962 clear cell renal cell carcinomas from 11 countries with varying incidence. The somatic mutation profiles differed between countries. In Romania, Serbia and Thailand, mutational signatures characteristic of aristolochic acid compounds were present in most cases and but these were rare elsewhere. In Japan, a mutational signature of unknown cause was found in more than 70% of cases but in less than 2% elsewhere. A further mutational signature of unknown cause was ubiquitous but exhibited higher mutation loads in countries with higher incidence rates of kidney cancer. Known signatures of tobacco smoking correlated with tobacco consumption, but no signature was associated with obesity or hypertension, suggesting that non-mutagenic mechanisms of action underlie these risk factors. The results of this study indicate the existence of multiple, geographically variable, mutagenic exposures that potentially affect tens of millions of people and illustrate the opportunities for new insights into cancer causation through large-scale global cancer genomics.

Multi-ancestry genome-wide association study of kidney cancer identifies 63 susceptibility regions

Here, in a multi-ancestry genome-wide association study meta-analysis of kidney cancer (29,020 cases and 835,670 controls), we identified 63 susceptibility regions (50 novel) containing 108 independent risk loci. In analyses stratified by subtype, 52 regions (78 loci) were associated with clear cell renal cell carcinoma (RCC) and 6 regions (7 loci) with papillary RCC. Notably, we report a variant common in African ancestry individuals ( rs7629500 ) in the 3' untranslated region of VHL, nearly tripling clear cell RCC risk (odds ratio 2.72, 95% confidence interval 2.23-3.30). In cis-expression quantitative trait locus analyses, 48 variants from 34 regions point toward 83 candidate genes. Enrichment of hypoxia-inducible factor-binding sites underscores the importance of hypoxia-related mechanisms in kidney cancer. Our results advance understanding of the genetic architecture of kidney cancer, provide clues for functional investigation and enable generation of a validated polygenic risk score with an estimated area under the curve of 0.65 (0.74 including risk factors) among European ancestry individuals.

Zinc Deficiency, Plasma Fatty Acid Profile and Desaturase Activities in Hemodialysis Patients: Is Supplementation Necessary?

Background: Desaturation and elongation are critical processes in endogenous metabolic fatty acid pathways. Zinc (Zn) is a cofactor for desaturases and elongases enzymes. There is limited evidence regarding the relationships between biomarkers of Zn status, nutritional intake, plasma phospholipid fatty acid profile and clinical outcomes among patients undergoing hemodialysis (HD). Objective: To examine the relationships between dietary and serum levels of Zn and Cu/Zn ratio and to explore associations of these micronutrients with PUFA profile and estimated desaturase and elongase enzyme activities in serum phospholipids among HD patients. Methods: This study included 40 adult patients undergoing hemodialysis treatment. Repeated 24-h recalls were applied for dietary intake assessment. Serum concentration of Zn and Cu were determined using inductively coupled plasma mass spectrometry and fatty acid composition by gas-liquid chromatography. Desaturase and elongase activities were calculated from product-precursor fatty acid ratios. Results: Inadequate dietary Zn intake was found in 55% of HD patients. They all had serum Zn concentration below the reference value of 60 μg/dL (mean 38.8 ± 7.72 μg/dL). Adequate zinc intake was accompanied with significantly higher intake of energy, total fats, SFA, MUFA and proteins. There was no correlation between Zn serum status and Zn intake estimates. Serum Cu/Zn ratio was high, (2.76 ± 0.68), directly and significantly associated with HD period, CRP, BMI, VFA, and inversely with Kt/V, albumin, iron, and iPTH. The n-6/n-3 ratio in plasma phospholipids was elevated (12.25 ± 3.45) and patients with inadequate Zn intake had lower n-3 PUFA intake and status compared to those with adequate intake. Serum Zn concentrations were inversely correlated with linoleic/dihomo-γ-linolenic acid ratio (LA/DGLA) (p = 0.037), related to D6-desaturase activity (p = 0.033) and directly with DGLA relative abundances (p = 0.024). Cu status was inversely associated with EPA level (p = 0.03) and estimates of elongase activity (p = 0.001). Furthermore, positive relationship was found between the Cu/Zn ratio and determined elongase value (p = 0.01). Conclusion: Findings of this study underpin the high prevalence of Zn deficiency and inadequate n-3 PUFA intake and status among subjects undergoing HD. The results obtained indicate that the assessment of Zn status should be a standard parameter of nutritional status screening in HD patients while emphasizing the importance of Cu/Zn determination. Although further research is warranted, Zn and-n-3 PUFA supplementation in HD patients might be beneficial for the prevention and attenuation of adverse health outcomes.

P1037EFFECT OF VITAMIN D SUPPLEMENTATION ON PROTEINURIA, LIPID STATUS, GLICOREGULATION, C-REACTIVE PROTEIN, VEGF-A, TGF-BETA1 AND NEPHRIN IN PATIENTS WITH TYPE 2 DIABETES MELLITUS

Background and Aims: Vitamin D insufficiency/deficiency is often present in patients with Type-2 diabetes mellitus and could present a risk factor for rapid progression of diabetic nephropathy and higher incidence of cardiovascular events. The aim of this study was to examine the influence of vitamin D supplementation on glucoregulation, inflammation, cholesterol, triglycerides, albuminuria and biomarkers of renal injury – nephrin, VEGF-A and TGF- β1 in patients with Type-2 diabetes mellitus and vitamin D insufficiency/deficiency. Method: We included 90 patients with Type-2 diabetes mellitus and vitamin D insufficiency/deficiency in this prospective, cohort study. Patients are divided in 3 equal groups: 30 patients with normal albuminuria, 30 with microalbuminuria and 30 with macroalbuminuria. Therapy included 6 months of supplementation with cholecalciferol drops: first 2 months with 20000 IU twice weekly, than if vitamin D level remained below normal range, we procedeed with same dose next 4 months. If the level of vitamin D normalized, we proceeded with 5000 IU twice weekly. At the beginning and at the end of the study we measured levels of albumin, hemoglobin, serum iron, urea, creatinine, fasting blood glucose, hemoglobin A1c, calcium, phosphorus, total cholesterol, triglycerides, C-reactive protein, intact parathyroid hormone, and urine analysis: 24-hour urine protein, albumin/creatinine ratio and creatinine clearance. Biomarkers are measured in serum and urine. Levels of calcium, phosphorus and vitamin D are also checked 2 months after beginning of therapy due to possible correction of cholecalciferol dose. Results are analysed according to the vitamin D level at the beginning and at the end of the study. Results: The lowest level of vitamin D, before therapy, is found in patients with macroalbuminuria, while at the end of the study we found significantly higher level of vitamin D in all three groups. After 6 months of therapy we found significant decrease of 24-hour urine protein, total cholesterol, triglycerides, hemoglobin A1c and VEGF-A in urine, in all three groups, and C-reactive protein in patients with normal albuminuria and microalbuminuria, nephrin in urine in patients with microalbuminuria and TGF- β1 in urine in patients with macroalbuminuria. Conclusion: vitamin D supplementation with high-dose cholecalciferol in patients with Type-2 diabetes mellitus (with or without albuminuria) decreases C-reactive protein, hemoglobin A1c, total cholesterol, triglycerides in serum, and albumin/creatinine ratio, 24-hour urine protein, VEGF-A, TGF- β1 and nephrin in urine.

P1789DE NOVO INFLAMMATORY BOWEL DISEASE AFTER KIDNEY TRANSPLANTATION - REPORT OF THREE CASES

Background and Aims

Inflammatory bowel disease (IBD) are not common after kidney transplantation. Development of IBD in the patient on immunosuppression is unexpected, because IBD is believed to be the result of inappropriate and ongoing activation of the mucosal immune system and immunosuppressive drugs are used in the treatment of IBD. The aim of our study was to evaluate the occurrence of de novo IBD, ulcerative colitis and Crohn’s disease, in the patients who received kidney transplant in our hospital, the time after transplantation and the immunosuppression therapy when diagnosis was made.

Method

We used an electronic medical archival system to identify the patients with IBD. Between 1996 and 2018 a total of 462 kidney transplantations were done in Military Medical Academy. Analysis in this study included 400 patients who were regulary controlled in our hospital. Demographic data and clinical findings including age, sex, primary renal disease, type of kidney donor, and immunosuppressive therapy were evaluated. The time of the occurrance of the IBD after transplantation, the colonoscopy and pathologic findings were also noted.

Results

de novo IBD was observed in three patients 19, 11 and 7 years after kidney transplantation respectively. In all patients end-stage renal disease was due to chronic glomerulonephritis without histology verification. Family history was negative in all. They were male, age 40, 42 i 47 years respectively when diagnosis was made. Their immunosuppressive regimen included prednisone, mycophenolate mofetil (MMF) and tacrolimus with a trough level between 5 and 7 ng/ml. They all developed constitutional symptoms with significant weight loss and fever, abdominal pain and cramps, diarrhoea which was in one case bloody. Infectious and other etiology was excluded. Colonoscopy showed ulcerative colitis in two patients and Crohn’s disease in one. The patients with ulcerative colitis responded on maintenance therapy combined with 5-aminosalicylic acid, but one of them had common flare-ups with mild clinical picture. The patient with Crohn’s disease was successfully treated with azathioprine instead of MMF with high-dose steroids.

Conclusion

We concluded that new onset of IBD can develop after kidney transplantation despite use of immunosuppressive therapy. It should be considered in all transplanted patients who develop gastrointestinal complaints. The future studies could answer why the immunosuppressive therapy is not effective for IBD in these group of patients.

P0258EVALUATION OF ACUTE - PHASE REACTANTS IN MONITORING DISEASE ACTIVITY AND RESPONSE TO IMMUNOSUPPRESSIVE THERAPY IN IDIOPATHIC RETROPERITONEAL FIBROSIS

Background and Aims

Idiopathic retroperitoneal fibrosis (IRF) is a rare disease characterized by fibroinflammatory periaortic tissue that affects the ureters, causing obstructive nephropathy and impairment of renal function. Findings strongly suggest an autoimmune etiology. Medical treatment includes immunosuppressive drugs, but the optimal treatment has not been established. Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) represent markers of active inflammation in the early phase of the disease, and hence could be sensitive predictors of the treatment response.

Method

This retrospective case series study includes patients with IRF treated with two different protocols: corticosteroids in combination with mycophenolate mofetil (MMF) and corticosteroids combined with azathioprine (AZA). The total number of 28 patients (13 in the first group and 15 in the second group) were treated and followed in the Clinic of nephrology in Military Medical Academy.

Results

At presentation 92.3% of patients had elevated levels of ESR and CRP, and 67.8% of them had acute renal insufficiency. Systemic symptoms resolved after four weeks in all patients. The kidney function improved significantly in both groups after first moth of treatment, although the creatinine level was higher in the MMF group because of the disease recurrence in 23% of the patients. In MMF group was observed faster reduction in the periaortic mass after six months and 53.8% of patients achieve 100% of the mass reduction at the end of the treatment while 33.3% in AZA group. The levels of ESR and CRP after one month of treatment in AZA group correlated with the fibrotic mass reduction after six months and after one year. In MMF group, only the CRP level after one month correlated with the fibrotic mass reduction achieved after one year.

Conclusion

MMF had more rapid and complete effect in hydrnephrosis withdrawal and total reduction of the fibrotic tissue, comparing with AZA whose effect was slower and without complete mass reduction. CRP strongly correlated with the remission of the disease in both therapeutic protocols.

Genetic Variants Related to Longer Telomere Length are Associated with Increased Risk of Renal Cell Carcinoma

BACKGROUND

Relative telomere length in peripheral blood leukocytes has been evaluated as a potential biomarker for renal cell carcinoma (RCC) risk in several studies, with conflicting findings.

OBJECTIVE

We performed an analysis of genetic variants associated with leukocyte telomere length to assess the relationship between telomere length and RCC risk using Mendelian randomization, an approach unaffected by biases from temporal variability and reverse causation that might have affected earlier investigations.

DESIGN, SETTING, AND PARTICIPANTS

Genotypes from nine telomere length-associated variants for 10 784 cases and 20 406 cancer-free controls from six genome-wide association studies (GWAS) of RCC were aggregated into a weighted genetic risk score (GRS) predictive of leukocyte telomere length.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Odds ratios (ORs) relating the GRS and RCC risk were computed in individual GWAS datasets and combined by meta-analysis.

RESULTS AND LIMITATIONS

Longer genetically inferred telomere length was associated with an increased risk of RCC (OR=2.07 per predicted kilobase increase, 95% confidence interval [CI]:=1.70-2.53, p<0.0001). As a sensitivity analysis, we excluded two telomere length variants in linkage disequilibrium (R2>0.5) with GWAS-identified RCC risk variants (rs10936599 and rs9420907) from the telomere length GRS; despite this exclusion, a statistically significant association between the GRS and RCC risk persisted (OR=1.73, 95% CI=1.36-2.21, p<0.0001). Exploratory analyses for individual histologic subtypes suggested comparable associations with the telomere length GRS for clear cell (N=5573, OR=1.93, 95% CI=1.50-2.49, p<0.0001), papillary (N=573, OR=1.96, 95% CI=1.01-3.81, p=0.046), and chromophobe RCC (N=203, OR=2.37, 95% CI=0.78-7.17, p=0.13).

CONCLUSIONS

Our investigation adds to the growing body of evidence indicating some aspect of longer telomere length is important for RCC risk.

PATIENT SUMMARY

Telomeres are segments of DNA at chromosome ends that maintain chromosomal stability. Our study investigated the relationship between genetic variants associated with telomere length and renal cell carcinoma risk. We found evidence suggesting individuals with inherited predisposition to longer telomere length are at increased risk of developing renal cell carcinoma.

Tissue and urinary KIM-1 relate to tumor characteristics in patients with clear renal cell carcinoma

The objective of this prospective follow-up trial was to ascertain whether the urinary kidney injury molecule-1 (uKIM-1) associates with tumor tissue (tKIM-1) expression and with the pathological characteristics of clear renal cell carcinoma (cRCC) in radically nephrectomized (RN) and/or in partially nephrectomized (PN) patients with cRCC, pre- and postoperatively. This clinical study included 40 patients subjected to RN/PN (cRCC group) and 30 healthy volunteers (control group). Urinary KIM-1 was determined by ELISA TIM-1/KIM-1 kit and normalized by urinary creatinine. Immunohistochemical staining (monoclonal anti-human anti-TIM-1/KIM-1/HAVCR antibody) was used for semiquantitative analysis of the tKIM-1 expression and expressed as a score (% KIM-1 positively stained tubules). Both markers were interpreted in terms of the tumor characteristics comprising tumor size, Fuhrman grade, pathological (pT) stage, tumor/nodes/metastasis (TNM) stage, lymphovascular invasion and type of surgery RN/PN. Preoperative uKIM-1 was significantly higher in the cRCC group compared to controls, such as uKIM-1 was statistically higher in RN than in PN patients. Postoperatively, uKIM-1 decreased to control values. Expression of tKIM-1 was documented in all nephrectomized patients. Significant associations were achieved between uKIM-1 and tKIM-1 and with considered tumor characteristics, especially with tumor size and grade. Based on the accomplished associations, we found uKIM-1 as a highly sensitive marker for cRCC diagnosis. The clinical trial registration number: 1110-2012.

Retroperitoneal fibrosis and constrictive pericarditis-IgG4 related diseases: A case report

Retroperitoneal fibrosis (RPF) is a rare disease characterized by infiltration of inflammatory cells and deposition of thickened fibrous tissues. The present study presents the case of a 53-year-old patient treated for generalized weakness and fatigue for 1 year prior to hospitalization. A cardiac ultrasound revealed pericardial effusion that required pericardiocentesis, during which 1,400 ml serous fluid with the characteristics of an exudate was aspirated. A pericardiectomy was performed due to persistent effusion and histological examination indicated pericardial fibrosis. A thoracic-abdominal computed tomography scan revealed the presence of retroperitoneal fibrosis. The patient was treated with corticosteroids and azathioprine. Follow-up examinations showed a significant reduction in the amount of abdominal fibrous tissue and no increase in pericardial effusion 1 year following the end of treatment. The patient continues to have regular follow-up control examinations with a cardiologist and nephrologist.