Treatment of BK Polyomavirus-Associated Nephropathy in Paediatric Kidney Transplant Recipients: Leflunomide Versus Cidofovir.

OBJECTIVES: BK polyomavirus-associated nephropathy is a clinicopathological entity that negatively affects graft function in kidney transplant recipients. We compared the efficacy of leflunomide and cidofovir to treat BK polyomavirus-associated nephropathy in pediatric kidney transplant recipients. MATERIALS AND METHODS: Medical records of pediatric recipients with BK viremia for the period 2004 through 2019 were reviewed retrospectively, and patients diagnosed with BK polyomavirusassociated nephro-pathy were included in the study. A serum BK virus level above 104 copies/mL was accepted as BK viremia. We defined BK polyomavirusassociated nephropathy as detection of BK virus SV40 antigen on immunochemistry staining of renal graft tissue accompanied by signs of tubulointerstitial nephritis or elevated serum creatinine in addition to BK viremia. RESULTS: Of 304 kidney transplant recipients, 53 had persistent BK viremia; 36 of these patients (61.1% male) were included in the study with the diagnosis of BK polyomavirus-associated nephropathy. Twelve patients (33.3%) received cidofovir, and 14 (38.8%) received leflunomide. Results were similar between the cidofovir and leflunomide groups for serum creatinine level at last follow-up (0.91 ± 0.29 vs 0.94 ± 0.37 mg/dL, respectively; P = .843) and graft failure rate (8.3% vs 14.2%, respectively; P = .632). Graft failure was observed in 8.3% of patients with BK polyomavirus-associated nephropathy. CONCLUSIONS: Leflunomide and cidofovir showed similar efficacy for treatment of BK polyomavirus-associated nephropathy.

Predictive Factors of BK Virus Development in Kidney Transplant Recipients and the Effect of Low-Dose Tacrolimus Plus Everolimus on Clinical Outcomes.

OBJECTIVES: This study aimed to determine the predictive factors of BK virus viremia/nephropathy in kidney transplant recipients and to evaluate the effects of low-dose tacrolimus plus everolimus. MATERIALS AND METHODS: This study included 3654 kidney transplant recipients. The patients were divided into 2 groups: group 1 were BK virus negative (n = 3525, 96.5%) and group 2 were BK virus positive (n = 129, viremia 3.5%, nephropathy 1%). Predictive factors were determined by receiver operating characteristic curve analysis and logistic regression models.We also divided and analyzed patients with BK virus viremia/nephropathy into 2 groups according to immunosuppressive changes. Group 2a had been switched to low-dose tacrolimus plus everolimus (n = 54, 41.9%), and group 2b had been switched to other immunosuppressive protocols (n = 75, 58.1%). RESULTS: We found that use of anti-T-cell lymphocyte globulin and tacrolimus, deceased donor transplant, and rejection were predictive factors for BK virus viremia/nephropathy. In addition, patients who had low-dose calcineurin inhibitor plus mammalian target of rapamycin inhibitor regimens showed a low rate of BK virus development(only 6.2% of all cases). In Group 2a, both the BK polyomavirus-associated nephropathy rate (n = 23 [42.6%] vs n = 12 [16%] in group 2b; P = .001) and viral load (DNA > 104 copies/mL) (n = 49 [90.7%] vs n = 27 [36%] in group 2b; P = .001) were increased versus group 2b. Graft function, graft survival, viral clearance, and rejection rate were similar between the groups after protocol change. CONCLUSIONS: BK virus viremia/nephropathy rate was lower in patients who received low-dose calcineurin inhibitor plus mammalian target of rapamycin inhibitor protocols; the low-dose tacrolimus plus everolimus switch protocol after BK virus was more effective and safe than other protocols.

Regulatory B Cells Profile in Kidney Transplant Recipients With Chronic-Active Antibody-Mediated Rejection.

This study aims to reveal the relationship between regulatory B cell (Breg) subsets and chronic-active antibody-mediated rejection (c-aABMR) in renal transplant recipients. Our study involved 3 groups of participants: renal transplant recipients with biopsy-proven c-aABMR as the chronic rejection group (c-aABMR, n = 23), recipients with stable graft functions as the patient control group (PC; n = 11), and healthy volunteers (HV; n = 11). Breg subsets, immature/transitional B cells, plasmablastic cells, B10 cells, and BR1 cells were isolated from venous blood samples by flow cytometry. The median values of Breg frequencies in the total lymphocyte population were analyzed. There were no significant differences between the study groups for immature and/or transitional B cell frequencies. Plasmablastic cell frequencies of the c-aABMR group (7.80 [2.10-27.40]) and the PC group (6.00 [1.80-55.50]) were similar, but both of these values were significantly higher than the HVs' (3.40 [1.20-8.50]), (respectively, P = .005 and P = .039). B10 cell frequencies were also similar, comparing the c-aABMR (4.20 [0.10-7.40]) and the PC groups (4.10 [0.10-5.90]), whereas the HVs (5.90 [2.90-8.50]) had the highest B10 cell frequency with an only statistical significance against the PC group (respectively, P = .09 and P = .028). The c-aABMR and the PC groups were similar regarding BR1 cell frequencies. However, the HV group significantly had the highest frequency of BR1 cells (5.50 [2.80-10.80]) than the other groups (P < .001 for both). We demonstrated that frequencies of B10 and BR1 cells were higher in HVs than in transplant recipients, regardless of rejection state. However, there was no significant relation between Breg frequencies and the c-aABMR state.

Tacrolimus-Associated Pure Red Cell Aplasia in a Patient With Renal Transplant.

Pure red cell aplasia is a relatively rare disease characterized by suppression or absence of erythroid precursors while other cell lineages are normal in the bone marrow. The disease could be secondary to other diseases or an adverse side effect of certain drugs. Tacrolimus is widely used as an immunosuppressive agent in solid-organ transplant without significant myelosuppressive effects. However, several tacrolimus-related pure red cell aplasia cases have been reported to date. Here, we report a case of a renal transplant recipient who developed tacrolimus-associated pure red cell aplasia in the posttransplant period and recovered dramatically after switching from tacrolimus to cyclosporine. Early diagnosis of pure red cell aplasia, which generally requires multiple blood transfusions, is very important because an increased number of blood transfusions can cause immunogenic effects and increased risk for allograft survival. Tacrolimus is a prominent drug for immunosuppression and is suspected to cause pure red cell aplasia during the posttransplant period; therefore, clinicians should consider a switch from tacrolimus to another immunosuppressive agent.

Analysis of DUX4 Expression in Bone Marrow and Re-Discussion of DUX4 Function in the Health and Disease.

OBJECTIVE: DUX4 is an embryonic transcription factor (TF) later silenced in somatic tissues, while active in germline testis cells. Re-expression in somatic cells has been revealed to be present in pathologic conditions such as dystrophy, leukemia, and other cancer types. Embryonic cells, cancer cells and testis cells that show DUX4 expression are pluri-multipotent cells. This lead us to question "Could DUX4 be a TF that is active in certain types of potent somatic cells?" As a perfect reflection of the potent cell pool, we aimed to reveal DUX4 expression in the bone marrow. MATERIAL AND METHOD: Bone marrow aspiration materials of seven healthy donors aged between 3 and 32 (2 males/5 females) were investigated with qPCR analysis after RNA isolation for the presence of DUX4 full length mRNA expression. Samples have been investigated for protein existence of DUX4 via immunohistochemistry in two donors that had sufficient aspiration material. RESULTS: DUX4 mRNA expression was present in all donors, with higher expression compared to B-actin. DUX4 positive stained cells were also detected by immunohistochemistry. CONCLUSION: With these results, novel expression for DUX4 in hematopoietic tissue is described. Further studies on the function of DUX4 in hematopoietic cells can shed light on DUX4-related pathways, and contribute to the treatment of DUX4-related diseases such as B-ALL, other cancers, and facioscapulohumeral muscular dystrophy.

A UFLC-MS/MS Method for the Simultaneous Analysis of Urinary Podocin and Podocalyxin in Patients with Nephrotic Syndrome.

OBJECTIVE: To create an efficient and robust mass spectrometric method for the simultaneous quantitation of podocin and podocalyxin in urine samples and to evaluate urinary podocin and podocalyxin levels in patients with nephrotic syndrome (NS). METHODS: A mass spectrometric method was generated for the measurement of tryptic peptides in urine sediment. Separation of peptides was achieved via liquid chromatography, and mass spectrometric analyses were conducted by electrospray ionization triple-quadrupole mass spectrometry in the multiple reaction monitoring mode. RESULTS: Intra- and interassay precision values were below 12% and accuracies ranged from 87% to 111% for both of peptides. The validated method was successfully applied to detect these peptides in patients with NS. Urine podocin and podocalyxin levels were significantly higher in patients with NS compared to healthy controls. CONCLUSIONS: This proposed mass spectrometric method provides technological evidence that will benefit the clinical field in the early diagnosis and follow-up of NS.

Genome engineering and disease modeling via programmable nucleases for insulin gene therapy; promises of CRISPR/Cas9 technology.

Targeted genome editing is a continually evolving technology employing programmable nucleases to specifically change, insert, or remove a genomic sequence of interest. These advanced molecular tools include meganucleases, zinc finger nucleases, transcription activator-like effector nucleases and RNA-guided engineered nucleases (RGENs), which create double-strand breaks at specific target sites in the genome, and repair DNA either by homologous recombination in the presence of donor DNA or via the error-prone non-homologous end-joining mechanism. A recently discovered group of RGENs known as CRISPR/Cas9 gene-editing systems allowed precise genome manipulation revealing a causal association between disease genotype and phenotype, without the need for the reengineering of the specific enzyme when targeting different sequences. CRISPR/Cas9 has been successfully employed as an ex vivo gene-editing tool in embryonic stem cells and patient-derived stem cells to understand pancreatic beta-cell development and function. RNA-guided nucleases also open the way for the generation of novel animal models for diabetes and allow testing the efficiency of various therapeutic approaches in diabetes, as summarized and exemplified in this manuscript.

Organ function, sphingolipid levels and inflammation in tunicamycin induced endoplasmic reticulum stress in male rats.

Disorders of the endoplasmic reticulum (ER) lead to cellular damage but can cause cell death if ER dysfunction is prolonged. We aimed to examine liver/kidney functions, neutral sphingomyelinase (N-SMase) activity, sphingolipid levels, cytosolic phospholipase A2 (cPLA2) and cyclooxygenase-2 (COX-2) protein expression in rats under ER stress. ER stress was induced by tunicamycin (TM) and the ER stress inhibitor taurodeoxycholic acid (TUDCA) was injected before induction of ER stress. ER stress was confirmed by increased tissue levels of GRP78. Hematological and biochemical profiles were measured by autoanalyzers while hepatic and renal injury was evaluated via microscopy and histopathological scoring. Tissue levels of C16-C24 sphingomyelins (SM), C16-C24 ceramides (CERs) and sphingosine-1-phosphate (S1P) were determined by LC-MS/MS. Tissue cPLA2 and COX-2 were measured by western blot and activity assays. Tunicamycin treatment caused kidney and liver function test abnormalities, increased hematocrit and hemoglobin levels but decreased white blood cell counts. Histopathological findings showed hepatic necroinflammation and renal tubular damage in rats treated with TM. TUDCA administration attenuated WBC abnormalities and TM- induced hepatic/renal functional impairment in ER stress, as evident by significantly restored serum ALT, AST, creatinine, and total bilirubin levels. A significant increase was observed in N-SMase activity, tissue levels of C16-C24 CERs, cPLA2 and COX-2 expression in liver and kidney tissue under ER stress. TUDCA administration decreased tissue CER levels, cPLA2 and COX-2 expression as well as prostaglandin E2 (PGE2) formation. These results signify that ER stress causes hepatic and renal toxicity as well as CER-induced PGE2 formation in liver and kidney.

The role of COL6A1and PD-1 expressions in renal cell carcinoma.

OBJECTIVE: The COL6A1 is a gene encoding the alpha 1 polypeptide subunit of collagen 6 (COL6A1), an extracellular matrix protein subunit. Programmed cell death receptor-1 (PD-1) and its ligand, programmed cell death receptor ligand-1 (PD-L1) have been shown to have a prognostic significance in clear cell renal cell carcinomas (RCCs). In this study, we evaluated the expressions of COL6A1 and PD-1 in four different RCC subtypes. MATERIALS AND METHODS: A total of 161 radical nephrectomy and nephron-sparing surgery cases with RCCs from five different health care centers were included in this study. Clinical data of the cases were taken from electronic records of the institutions. The pathological data were collected by an expert uropathologist and re-evaluated with slides obtained from paraffin blocks of the cases. The correlation of COL6A1 and PD-1 expression with sex, age, tumor type, lymphovascular invasion (LVI), World Health Organization/International Society of Urological Pathology (WHO/ISUP) grade, and tumor stage (pT) was analyzed with the Pearson chi-squared test. RESULTS: Patients with sarcomatoid RCC and clear cell RCC had significantly higher COL6A1 scores and intensities than in other types of RCC (p=0.004 and p=0.002, respectively). WHO/ISUP grade and, COL6A1 and PD-1 staining scores also showed positive correlation (r=0.230, p=0.004 and r=0.277, p=0.001, respectively for COL6A1 and r=0.191, p=0.018 and r=0.166, p=0.041, respectively for PD-1). The staining scores and intensities of COL6A1 and PD-1 were not different between the patients with positive and negative LVI (p>0.05). CONCLUSION: In high-grade RCCs, we found the relationship between immunohistochemical staining scores of COL6A1 and PD-1 proteins and clinical, demographic, and histopathological parameters. Our results proved that COL6A1 and PD-1 are really promising proteins as prognostic parameters and for targeted immunotherapy.

Urothelial carcinoma of bladder in a pediatric patient case report of a rare disease.

Urothelial carcinoma is a very rare malignancy in the pediatric population. In spite of the extremely low amount of published cases, the incidence rate is between 0.4 and 0.1% before the age of 20. Insomuch that only less than 30 cases have been reported in the first decade. Those tumors were mostly solitary, non-invasive, with low-risk of progression and recurrence rate compared to adult-onset form. In this case report, we aim to discuss the diagnosis and treatment of a 10-year-old male patient with urothelial carcinoma of bladder who admitted to our clinic.

Mesalazine induced focal segmental glomerulosclerosis in a patient with ulcerative colitis.

Focal segmental glomerulosclerosis (FSGS) and other glomerulonephritis due to the use of 5-aminosalicylic acid derivatives have been reported in the literature. A 38-year-old male who had been using mesalazine for four years because of ulcerative colitis applied to doctor due to swelling in the lower extremities. The patient was diagnosed with nephrotic syndrome (NS). Renal biopsy was performed, and FSGS was diagnosed. Antiproteinuric treatments were initiated with steroid therapy. The patient has been followed with the normal renal function of the after treatment. 5-aminosalicylic acid derivatives affect renal functions at different levels and caused in NS.

Tacrolimus Variability: A Cause of Donor-Specific Anti-HLA Antibody Formation in Children.

BACKGROUND AND OBJECTIVES: The most important determinant of long-term graft survival in renal transplantation is adequate immunosuppression. Inadequate immunosuppression may lead to graft loss due to the presence of anti-HLA antibody. The aim of this study was to investigate the effect of variability in tacrolimus blood concentration on anti-HLA antibody development in pediatric recipients of living-donor renal transplants. METHODS: Pediatric recipients of living-donor renal transplants were retrospectively evaluated. Patients with a minimum of two years of follow-up who were administered tacrolimus were included in the study. Patients who had pretransplant anti-HLA antibody were excluded. Variability in tacrolimus blood concentration was assessed using the coefficient of variation ("tacrolimus CV") method. Tacrolimus CV was calculated separately for the first 6 months post-transplant, between 6 and 12 months post-transplant, and from the end of the first year post-transplant to the last follow-up. We constructed receiver operating characteristic (ROC) curves of the tacrolimus CV for each group to find the best cutoff value. RESULTS: A total of 67 patients (including 48 males; 72%) with a mean age of 15.16 ± 4.43 years were included in the study. Anti-HLA antibody positivity was detected in 12 patients (18%). More than three HLA mismatches and the presence of acute cellular rejection correlated with the development of anti-HLA antibody (p = 0.056, 0.009). Tacrolimus CVs for the three periods were 0.37 ± 0.11, 0.31 ± 0.18, and 0.35 ± 0.12, respectively. The cutoff value of tacrolimus CV for anti-HLA antibody development was calculated as 0.32 with a sensitivity of 90.91% and specificity of 50.94% [AUC (area under the curve) 0.713, p = 0.023]. During the second 6-month period and after a  year post-transplant, the percentage of patients with tacrolimus CV > 0.32 was significantly higher in the anti-HLA antibody positive group than in the antibody negative group (67% vs 31%, p = 0.027; 83% vs 47%, p = 0.033). The eGFR (estimated glomerular filtration rate) was similar for the anti-HLA antibody negative and positive groups (78.72 ± 2.86 vs 77.45 ± 8.08, p > 0.05). CONCLUSION: High tacrolimus concentration variability appears to be associated with anti-HLA antibody formation in pediatric recipients of living-donor renal transplants.

Diclofenac induced gastrointestinal and renal toxicity is alleviated by thymoquinone treatment.

The aim of this study was to investigate whether thymoquinone (TQ) could alleviate diclofenac (DCLF)-induced gastrointestinal and renal toxicity in rats. Diclofenac was administered via intramuscular injection twice daily for 5 days and TQ was given by gavage for the same period. Hematological and biochemical profiles were measured with autoanalyzers while reactive oxygen/nitrogen species (ROS/RNS) generation and total antioxidant capacity (TAC) were assayed by standard kits. Tissue injuries were evaluated by microscopy and histopathological scoring. Diclofenac treatment caused kidney and liver function test abnormalities, reduced hematocrit and hemoglobin levels but increased WBC and platelet counts. Histopathological findings showed renal tubular damage, gastrointestinal lesions and increased fibrosis in DCLF treated rats. Thymoquinone administration, along with DCLF treatment, attenuated hematological test abnormalities and DCLF induced renal functional impairment as evident by significantly restored serum creatinine and blood urea nitrogen levels. Similarly, TQ treatment significantly alleviated liver function test abnormalities and decreased tissue injury in the stomach and duodenum. Diclofenac treatment caused increased ROS/RNS formation and decreased TAC in the kidney, stomach and duodenal tissue. Thymoquinone administration increased gastrointestinal and renal TAC in DCLF treated rats. These results indicate that TQ could ameliorate gastrointestinal and renal toxicity induced by high dose DCLF treatment.

Efficacy of 18F-2-fluoro-2-deoxy-D-glucose Positron Emission Tomography/Computerized Tomography for Bone Marrow Infiltration Assessment in the Initial Staging of Lymphoma.

OBJECTIVE: Currently 18F-2-fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography/computerized tomography (PET/CT) is being successfully used for staging and follow-up of Hodgkin's lymphoma (HL) and non-Hodgkin's lymphoma (NHL). Various studies have demonstrated that PET/CT effectively detects bone marrow involvement (BMI) and is concordant with bone marrow biopsy (BMB) findings, thus it is deemed as a complementary method. This study was aimed to evaluate18F-FDG-PET/CT efficiency for detection of BMI in HL and NHL. METHODS: The study included 172 lymphoma cases who were admitted to Akdeniz University Medical School Department of Nuclear Medicine for initial staging with PET/CT. Visual and semiquantitative assessments were performed for PET/CT scan findings of the cases. The maximum standard uptake (SUVmax) value was the quantitative parameter used for 18F-FDG-PET scan. In visual assessment, bone marrow metabolic activity that is greater than the liver was considered as pathologic. For semiquantitative assessment, regions of interest were drawn for SUVmax estimation, which included iliac crest in cases with diffusely increased metabolic activity and the highest activity area in cases with focal involvement. BMB was considered as the reference test. RESULTS: On visual assessment of all the cases, PET/CT was found to yield 31% sensitivity and 85% specificity rate for detection of BMI. On visual assessment of HL cases, sensitivity rate was determined as 80%, and specificity as 78%, while in NHL cases the corresponding values were 24% and 90%, respectively. On semiquantitative assessment of HL cases, considering SUVmax≥4, sensitivity was found as 80% and specificity as 68%. In NHL patients, considering SUVmax≥3.2, sensitivity rate was detected as 65% and specificity as 58%. CONCLUSION: In this study, a moderately high concordance was observed between PET/CT and BMB findings. PET/CT appears to be a significant method for detecting BMI. Although PET/CT is not a substitute for BMB, we suggest it can be used as a guide to biopsy site and a complementary imaging technique for BMB.

Analysis of TNF-related apoptosis-inducing ligand and receptors and implications in thymus biology and myasthenia gravis.

Myasthenia Gravis is an autoantibody-mediated, neuromuscular junction disease, and is usually associated with thymic abnormalities presented as thymic tumors (~10%) or hyperplastic thymus (~65%). The exact role of thymus in Myasthenia Gravis development is not clear, yet many patients benefit from thymectomy. The apoptotic ligand TNF-Related Apoptosis-Inducing Ligand is thought to be involved in the regulation of thymocyte counts, although conflicting results are reported. We investigated differential expression profiles of TNF-Related Apoptosis-Inducing Ligand and its transmembrane receptors, Nuclear Factor-kB activation status, and apoptotic cell counts in healthy thymic tissue and pathological thymus from Myasthenia Gravis patients. All tissues expressed TNF-Related Apoptosis-Inducing Ligand and its receptors, with hyperplastic tissue having the highest expression levels of death receptors DR4 and DR5. No detectable Nuclear Factor-kB activation, at least via the canonical Protein Kinase A-mediated p65 Ser276 phosphorylation, was evident in any of the tissues studied. Apoptotic cell counts were higher in MG-associated tissue compared to the normal thymus. Possible use of the TNF-Related Apoptosis-Inducing Ligand within the concept of an apoptotic ligand-mediated medical thymectomy in thymoma- or thymic hyperplasia-associated Myasthenia Gravis is also discussed.

Changes in expressions of ADAM9, 10, and 17 as well as α-secretase activity in renal cell carcinoma.

BACKGROUND: ADAM9, 10, and 17 are a class of disintegrins and metallproteinases with α-secretase activity. There are conflicting results regarding the role(s) of ADAM9, 10, and 17 in carcinogenesis, and only a few studies have examined their levels and cellular localization in renal cell carcinoma (RCC). Studies examining changes in α-secretase activity in RCC compared to enzymatic activity of the uninvolved kidney are lacking. METHOD: A cross-sectional study was conducted in 56 patients undergoing radical nephrectomy after the diagnosis of RCC. α-Secretase activity was determined using flourogenic substrate in freshly frozen tumor tissues as well as similarly treated tissues from the neighboring kidney. Immunohistochemical analyses of ADAM9, 10, and 17 were also performed. RESULTS: α-Secretase activity decreased markedly in all types of RCC as compared to neighboring uninvolved kidney tissue having 5 to 10 times higher levels of α-secretase activity. Although type-dependent variations were observed, tumoral expressions of ADAMs, except for ADAM17, were lower in the tumors compared to that of neighboring tissues, but the changes in α-secretase activity were greater. In RCC tissue, ADAM9 expressions were localized in nuclear and cytoplasmic compartments, whereas ADAM10 and 17 were present predominately in the cytoplasm potentially explaining the markedly decreased enzyme activity. Membranous localization of ADAMs was noted in uninvolved kidney tissue. CONCLUSIONS: The loss of α-secretase activity observed here in conjunction with previous findings argue against tumorigenic effects of ADAM9, 10, and 17 supporting that increased nuclear and cytoplasmic expression may be an attempt to compensate for loss of function.

Neuropeptide Levels as well as Neprilysin Activity Decrease in Renal Cell Carcinoma.

Calcitonin Gene-related Peptide (CGRP), Vasoactive Intestinal Peptide (VIP) and Substance P (SP) are sensory neuropeptides which may alter cancer growth through modulation of chronic inflammation. We recently reported that SP suppresses breast cancer growth and metastasis through neuroimmune modulation. These neuropeptides are hydrolyzed by Neprilysin (NEP) to bioactive fragments. Decreased activity of NEP was reported in clear cell and chromophobe type renal cell carcinoma (RCC). It is however not known how the levels of neuropeptides hydrolyzed with NEP changes in RCC. Decrease activity of SP and CGRP containing sensory nerve endings was previously reported to increase cancer metastasis in animal models. It is however not known how peptidergic nerve endings are altered in RCC. Hence we here evaluated the levels of neuronal and non-neuronal neuropeptides and NEP activity in RCC including papillary type as well as neighboring uninvolved kidney. A cross-sectional study was conducted in 57 patients undergoing radical nephrectomy and diagnosed with RCC. NEP activity, levels and expression were determined using flourogenic substrate, western blot and qPCR respectively in freshly-frozen tissues. Immunohistochemical analyses were also performed. Neuronal and non-neuronal levels of CGRP, SP and VIP levels were determined using two-step acetic acid extraction. Levels and activity of NEP were markedly decreased in RCC regardless of subtype. Similar levels of VIP were detected in first and second extractions. VIP levels were higher in clear cell and papillary RCC compared to nearby kidney tissue. VIP levels of neighboring kidney tissue of papillary type RCC was significantly lower compared to kidney samples from clear cell RCC. CGRP levels were higher in second extraction. Similar to VIP levels, CGRP levels of neighboring kidney tissue from clear cell and chromophobe type RCC was significantly lower compared to corresponding tumor samples, an effect observed in the second extraction. VIP and CGRP levels of nearby kidney tissue varied subtype dependently demonstrating that different subtypes of RCC alter their local environment differently. Furthermore NEP-induce hydrolysis of VIP creates selective VPAC-1 receptor agonist which has anti-proliferative and anti-inflammatory effects. Hence loss of NEP activity may prevent anti-tumoral effects of VIP on RCC.