Role of High-sensitivity C-reactive Protein in Future Cardiovascular Events in Hemodialysis Patients.

BACKGROUND/AIM: The pathogenesis of cardio-vascular disease (CVD) in hemodialysis (HD) patients involves inflammation and oxidative stress. High-sensitivity C-reactive protein (hs-CRP) is an established inflammatory biomarker associated with CVD. Several studies have suggested that the inflammatory biomarker pentraxin-3 (PTX-3) and the oxidative stress-related biomarker soluble lectin-like low-density lipoprotein receptor-1 (sLOX-1) are novel biomarkers for CVD in non-HD populations. This study aimed to clarify the association of these established and novel biomarkers with future cardiovascular (CV) events in HD patients. PATIENTS AND METHODS: This was a single-center prospective cohort study that included 255 HD patients. The primary outcome was the composite of nonfatal and fatal CV events. The event-free survival rate between the two groups according to the median plasma level of each biomarker at baseline was evaluated using the Kaplan-Meier method. The risk for CV events at elevated levels of each biomarker was estimated using Cox proportional hazard model. RESULTS: We observed 44 CV events during the median follow-up period of 743 days. The event-free survival rate significantly differed between the two groups in hs-CRP but not in PTX-3 or sLOX-1. The unadjusted hazard ratio (HR) for CV events in patients with hs-CRP levels above the median was 2.63 [95% confidence interval (CI)=1.37-5.02]. The HR remained significant after adjusting for age, sex, history of CVD, and diabetes (HR=2.30; 95%CI=1.20-4.43). CONCLUSION: In HD patients, hs-CRP may have a predictable role for future CV events, whereas PTX-3 and sLOX-1 do not.

Hypoxia-inducible Factor-1α Suppresses the Innate Immune Response in Cultured Human Proximal Tubular Cells.

BACKGROUND/AIM: Retinoic acid-inducible gene (RIG)-I like receptors (RLRs) are expressed on renal proximal tubular epithelial cells (RPTECs) in viral nephropathy, indicating the presence of RLR-mediated innate immune responses in RPTECs. Hypoxia is also known to affect innate immunity. This study investigated the effects of hypoxia, and hypoxia-inducible factor (HIF) on innate immunity in RPTECs. MATERIALS AND METHODS: Primary human RPTECs were cultured under normoxic or hypoxic conditions and treated with a synthetic analog of double-stranded RNA (polyIC). The expression levels of RIG-I and MDA5, as RLRs, and IFNß, IL6, and TNFα, as inflammatory mediators were evaluated using quantitative reverse transcription-polymerase chain reaction, western blotting, and lactate dehydrogenase activity (LDH) assays. To further investigate the role of hypoxia, a small interfering RNA was used to knockdown HIF1α. RESULTS: Under normoxic conditions, polyIC increased RIG-I, MDA5, and IFNß mRNA expression in RPTECs by, 9.4±0.4-, 10.8±0.5-, and 4.0±0.1-fold, respectively, compared to control, and by 5.4±0.1-, 7.4±0.1-, and 2.4±0.3-fold, respectively, under hypoxic conditions, the rate of increase was lower than that under normoxic conditions (p<0.01). Protein expression showed a similar trend. Under hypoxic conditions, polyIC treatment with HIF1α knockdown in RPTECs increased RIG-I, MDA5, and IFNß mRNA expression by 3.1±0.5-, 2.9±0.4-, and 6.1±0.4-fold, respectively, and cytotoxicity, demonstrated by LDH assay, was increased compared to that without knockdown (all p<0.01). CONCLUSION: Hypoxia suppresses polyIC-induced RLRs mediated innate immune responses in RPTECs via HIF1α.

Dietary Intake of Polyunsaturated Fatty Acids and Diabetic Nephropathy: Cohort Analysis of the Tsugaru Study.

BACKGROUND/AIM: Diabetic nephropathy (DN) is the leading cause of end-stage renal failure and its incidence continues to increase. To decrease this, a countermeasure from an early stage is required. This is a DN stage 2 observation study that analyzed the results of a concurrent dietary survey in the Tsugaru study and discussed the relationship between dietary intake of n-3 fatty acid and DN. PATIENTS AND METHODS: Patients with stage 2 DN and aged 20 years or older in the Tsugaru region of Aomori Prefecture were enrolled. We examined the association between urinary albumin excretion (UAE) at enrollment and 36 months later and n-3PUFA intake obtained from a dietary survey. RESULTS: Of the 317 subjects at enrollment, 234 were followed for 36 months, of whom 123 were able to complete the dietary survey. After 36 months of follow-up of these 123 subjects, 28 were in remission and 18 had progressed. Correlations between UAE at 36 months and each of the parameters were examined and UAE at enrollment showed a positive correlation (r=0.4224, p<0.001); correlations between eicosapentaenoic acid (EPA)/arachidonic acid (AA), EPA+docosahexaenoic acid/AA, and n-6/n-3 and UAE at 36 months were weak. As shown by multiple regression analysis, the factor influencing UAE after 36 months was UAE at enrollment. CONCLUSION: Concerning the relationship between fatty acid intake balance and UAE, the previously reported renoprotective effect of n-3 fatty acids could not be demonstrated.

Relationship Between Cardiovascular Events and Serum Lipid and Plasma Fatty Acid Profile in Maintenance Hemodialysis Patients With Diabetic Mellitus.

BACKGROUND/AIM: Cardiovascular disease (CVD) is a frequent complication in hemodialysis (HD) patients, especially when the underlying disease is diabetes mellitus (DM). In this study, we investigated cardiovascular events and lipid and fatty acid profile in maintenance HD patients with diabetic kidney disease (DKD). PATIENTS AND METHODS: The subjects were 123 patients undergoing HD at Oyokyo Kidney Research Institute Hirosaki Hospital, who were considered to have DKD as the underlying cause of dialysis induction. Among these patients, the lipid and fatty acid profile were examined in two groups, CVD group (n=53) and non-CVD group (n=70), according to the presence or absence of a history of cardiovascular events (coronary artery disease, stroke, arteriosclerosis obliterans, valvular disease, and aortic disease). For serum lipid profile, the levels of total-cholesterol (T-C), triglycerides (TG), high density lipoprotein-cholesterol (HDL-C), and low density lipoprotein-cholesterol (LDL-C) were measured, and for fatty acid balance, 24 fractions of fatty acid composition in plasma total lipids were measured. These markers were compared between the CVD and non-CVD groups. RESULTS: The levels of T-C and TG were significantly lower in the CVD group compared with the non-CVD group (147.7±36.9 mg/dl vs. 159.2±35.6 mg/dl, p<0.05, 120.2±65.7 mg/dl vs. 143.8±124.4 mg/dl, p<0.05). In the plasma fatty acid composition, alpha-linolenic acid (ALA) and docosapentaenoic acid (DPA) were significantly lower in the CVD group compared with the non-CVD group (0.74±0.26 wt% vs. 0.84±0.31 wt%, p<0.05; 0.61±0.21 wt% vs. 0.70±0.30 wt%, p<0.05). CONCLUSION: Abnormal fatty acid balance, especially low levels of ALA and DPA, rather than serum lipids, are more likely the factors associated with cardiovascular events in maintenance HD patients with underlying DKD.

Valacyclovir-associated acute kidney injury and encephalopathy in an elderly woman with normal kidney function: a case report.

A 72-year-old Japanese woman was treated by 3000 mg/day of valacyclovir for the herpes zoster in her left back. She had been treated as hypertension with no renal insufficiency. In two days, she visited an emergency room of a regional stroke care center with dysarthria, dexterity disorder and gait disturbance. Neither head CT nor MRI found intracranial lesions, then, laboratory tests revealed that her serum creatinine level was 4.63 mg/dL. She was transferred and admitted to our hospital on the following day and received hemodialysis under the diagnosis of AKI due to acyclovir accompanied with encephalopathy. Afterward, her serum concentration of acyclovir revealed as 44 µg/mL, which is extremely high. Her neurological symptom disappeared in parallel with the decrease of serum concentration of acyclovir. She received 3 sessions of hemodialysis and discharged on the 8th day of admission with almost normal renal function and no neurological sequela.

Nintedanib-Induced Renal Thrombotic Microangiopathy.

Nintedanib is a unique tyrosine kinase inhibitor used to suppress fibrosis in patients with idiopathic pulmonary fibrosis (IPF). Nintedanib has been shown to suppress multiple processes of fibrosis, thereby reducing the rate of lung function decline in patients with IPF. Since vascular endothelial growth factor is one of this agent's targets, nephrotoxicity, including renal thrombotic microangiopathy (TMA), is a possible major adverse effect. However, only 2 previous cases of nintedanib-induced renal TMA have been published. Our patient was an 83-year-old man with IPF. As adverse effects including liver enzyme level elevation, diarrhoea, anorexia, and nephrotoxicity developed, the nintedanib dosage was reduced after 9 months. The digestive symptoms resolved promptly, but the proteinuria and reduced kidney function remained. Although the kidney injury had improved to some extent, we performed a percutaneous renal biopsy. The biopsy revealed typical TMA findings such as microaneurysms filled with pale material, segmental double contours of glomerular basement membranes, and intracapillary foam cells. After discontinuation of nintedanib, the patient's nephrotoxicity improved. Nintedanib-induced renal TMA is reversible and is possibly dose-dependent. Here, we report the clinical course of our case and review the characteristics of nintedanib-induced renal TMA.

PolyIC Induces Retinoic Acid-inducible Gene-I and Melanoma Differentiation-associated Gene 5 and Modulates Inflammation in Podocytes.

BACKGROUND/AIM: Viral infection often exacerbates proteinuria, which has been suggested to be due to antiviral responses of podocytes. We examined the effect of polyinosinic-polycytidylic acid (polyIC) on the expression of retinoic acid-inducible gene-I (RIG-I) and melanoma differentiation-associated gene 5 (MDA5) in differentiated human podocytes in culture. MATERIALS AND METHODS: The podocytes were treated with 2 ng/ml to 500 µg/ml of polyIC for 3 to 36 h, and also transfected with siRNA against RIG-I and MDA5. F-actin staining was performed to assess actin reorganization. RESULTS: PolyIC induced the expression of RIG-I and MDA5 in dose- and time-dependent manner, accompanied with interferon-ß (IFN-ß) and interleukin-6 (IL-6) up-regulation and actin reorganization. Temporal knockdown of RIG-I by siRNA decreased IFN-ß expression, while MDA5 siRNA inhibited IFN-ß and IL-6 expression. Actin reorganization was attenuated by RIG-I and MDA5 knockdown. CONCLUSION: RIG-I and MDA5 may play a role in the antiviral responses of podocytes.