Anti-C5 monoclonal antibody treatment showing pathological resolution of complement-mediated atypical hemolytic uremic syndrome: a case report.

BACKGROUND: No reports have shown histological changes before and after anti-C5 monoclonal antibody treatment in patients with atypical hemolytic uremic syndrome (aHUS). Here, we report a rare case of complement-mediated aHUS with a complement factor H (CFH) mutation and anti-CFH antibodies who underwent multiple kidney biopsies. CASE PRESENTATION: A 53-year-old woman developed aHUS with CFH gene mutation [c.3572C > T (p. Ser1191 Leu)] and anti-CFH antibodies. Her father had succumbed to acute kidney injury (AKI) in his 30 s. She exhibited AKI, thrombocytopenia, and hemolytic anemia with schistocytes. After improving the platelet count with one session of plasma exchange, a kidney biopsy was performed one month after the onset of symptoms. Blood vessel thrombosis, obvious endothelial swelling, endocapillary hypercellularity, and subendothelial exudative lesions in the glomeruli and arterioles were detected. Anti-C5 monoclonal antibody treatment with eculizumab immediately improved disease activity. A second biopsy 3 months later revealed marked improvement of endothelial injuries with residual membrane double contours and exudative lesions. A third biopsy at 17 months after gradual improvement of kidney function showed a further decrease of double contours along with alterations of the exudative lesions to fibrous intimal thickening. CONCLUSIONS: This is the first report showing the pathophysiology of aHUS in the kidneys and the efficacy of anti-C5 monoclonal antibody treatment by presenting serial kidney pathological features before and after anti-C5 monoclonal antibody treatment. Since her CFH mutation was considered the most important pathological condition, treatment centered on eculizumab was administered, resulting in a good long-term prognosis. In addition, kidney pathological resolution in aHUS occurred over 1 year after anti-C5 monoclonal antibody treatment.

Investigation of Clinical Features and Association between Vascular Endothelial Injury Markers and Cytomegalovirus Infection Associated with Thrombotic Microangiopathy in Patients with Anti-Neutrophil Cytoplasmic Antibody (ANCA)-Associated Vasculitis: Case-Based Research.

Anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV) can occasionally trigger thrombotic microangiopathy (TMA). Cytomegalovirus (CMV) may be reactivated during intensive immunosuppressive therapy for AAV and cause TMA. Therefore, we aimed to evaluate the clinical features of and the association between vascular endothelial injury markers and TMA due to CMV in patients with AAV. A 61-year-old female was diagnosed with AAV and severe kidney injury. Immunosuppressive therapy gradually improved her symptoms and laboratory findings. However, 2 weeks after induction therapy initiation, she exhibited altered consciousness, a significant decrease in platelet count, and hemolytic anemia, resulting in a TMA diagnosis. Plasma exchange did not improve TMA findings and routine screening test revealed CMV infection. Ganciclovir injection improved the infection and TMA findings. Consequently, we diagnosed her with CMV-induced TMA. Both AAV and CMV may induce severe vascular endothelial injury, potentially leading to TMA development. CMV-induced TMA should be considered when TMA develops during induction therapy against AAV. Moreover, of the three serum markers of vascular injury-serum sulfatides, soluble thrombomodulin, and pentraxin 3-serum sulfatides may be associated with the development of TMA, and a high level of soluble thrombomodulin may be associated with the development of CMV viremia during the clinical course of AAV.

Anti-SARS-CoV-2 IgG antibody titer after BNT162b2 mRNA COVID-19 vaccination in Japanese patients who underwent renal replacement therapy, hemodialysis, peritoneal dialysis, and kidney transplantation.

BACKGROUND: Coronavirus disease (COVID-19) vaccination is recommended for patients undergoing renal replacement therapy (RRT), including hemodialysis (HD), peritoneal dialysis (PD), and kidney transplantation (KT). However, the difference in the immune response between RRT patients and healthy individuals after mRNA vaccines remains uncertain. METHODS: This retrospective observational study evaluated the anti-severe-acute-respiratory-syndrome-coronavirus-2 (anti-SARS-CoV-2) IgG antibody acquisition, titers and their changes, normal response rate (reaching titers of healthy individuals), factors associated with a normal response, and effectiveness of booster vaccination in Japanese RRT patients. RESULTS: Most HD and PD patients acquired anti-SARS-CoV-2 IgG antibodies after the second vaccination; however, their antibody titers and normal response rates (62-75%) were low compared with those of healthy subjects. Approximately 62% of KT recipients acquired antibodies, but the normal response rate was low (23%). Anti-SARS-CoV-2 IgG antibody waning occurred in the control, HD, and PD groups, while negative or very low titers remained in KT recipients. Third booster vaccination was effective in most HD and PD patients. However, the effect was mild in KT recipients - only 58% reached a normal response level. Multivariate logistic regression analyses demonstrated that younger age, higher serum albumin level, and RRT other than KT were significantly associated with a normal response after the second vaccination. CONCLUSIONS: RRT patients, particularly KT recipients, exhibited poor vaccine responses. Booster vaccination would be beneficial for HD and PD patients; however, its effect in KT recipients was mild. Further COVID-19 vaccinations using the latest vaccine or alternative procedures should be considered in RRT patients.

Immunological risk and complement genetic evaluations in early onset de novo thrombotic microangiopathy after living donor kidney transplantation: A Japanese multicenter registry.

BACKGROUND: Thrombotic microangiopathy (TMA) after kidney transplantation (KTx), particularly early onset de novo (dn) TMA, requires immediate interventions to prevent irreversible organ damage. This multicenter study was performed to investigate the allogeneic clinical factors and complement genetic background of dnTMA after KTx. METHODS: Perioperative dnTMA after KTx within 1 week after KTx were diagnosed based on pathological or/and hematological criteria at each center, and their immunological backgrounds were researched. Twelve aHUS-related gene variants were examined in dnTMA cases. RESULTS: Seventeen recipients (15 donors) were enrolled, and all dnTMA cases were onset within 72-h of KTx, and 16 of 17 cases were ABO incompatible. The implementation rate of pre-transplant plasmaphereses therapies were low, including cases with high titers of anti-A/anti-B antibodies. Examination of aHUS-related gene variants revealed some deletions and variants with minor allele frequency (MAF) in Japan or East Asian genome databases in genes encoding alternative pathways and complement regulatory factors. These variants was positive in 8 cases, 6 of which were positive in both recipient and donor, but only in one graft loss case. CONCLUSIONS: Although some immunological risks were found for dnTMA after KTx, only a few cases developed into TMA. The characteristic variations revealed in the present study may be novel candidates related to dnTMA in Japanese or Asian patients, but not pathogenic variants of aHUS. Future studies on genetic and antigenic factors are needed to identify factors contributing to dnTMA after KTx.

Comparison of the factors associated with the short-term prognosis between elderly and non-elderly patients with anti-neutrophil cytoplasmic antibody-associated vasculitis: a retrospective observational study.

OBJECTIVES: The difference in factors associated with the prognosis between elderly and non-elderly patients with anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV) is uncertain. We aimed to elucidate the clinical factors associated with the short-term prognosis (within 6 months from the start of the treatment) and investigate the differences in the associated factors between elderly and non-elderly individuals. METHODS: We performed a dual centre retrospective observational study of patients newly treated with AAV (eosinophilic granulomatous with polyangiitis was excluded). The primary outcome was all-cause death, and the secondary outcome was end-stage renal disease (ESRD) and infectious complications within 6 months after the start of treatment. We analysed factors associated with these outcomes using logistic regression analyses. RESULTS: Of the 79 patients, patients aged ≥75 years were defined as elderly (n=41), whereas those aged <75 years were de¬fined as non-elderly (n=38). In elderly patients, age was significantly associated with all-cause mortality. In the non-elderly patients, the geriatric nutritional risk index was significantly associated with all-cause death. The estimated glomerular filtration rate (eGFR) before the start of treatment was significantly associated with ESRD in elderly and non-elderly patients. In elderly patients, the Birmingham vasculitis score 3, eGFR, methylprednisolone pulse use, and cyclophosphamide use were significantly associated with infectious complications. Factors other than the serum albumin level were not significantly associated with infectious complications in the non-elderly population. CONCLUSIONS: The factors associated with all-cause death and infectious complications differed between elderly and non-elderly patients. Awareness of these differences may contribute to better management of AAV.

Relationship between glomerular number in fresh kidney biopsy samples and light microscopy samples.

BACKGROUND: On-site evaluation of fresh kidney biopsy (FKB) samples at the time of biopsy is useful to verify that adequate specimens are acquired. However, some cases present poor correlation between glomerular number in FKB samples and light microscopy (LM) samples. We examined the usefulness of such on-site evaluation. METHODS: We conducted a retrospective cross-sectional observational study (n = 129) to assess the correlation between glomerular number in FKB samples and LM samples and the associated factors hindering the evaluation. RESULTS: There was a significant positive correlation between glomerular number in FKB samples and LM samples. The median ratio of glomerular number (LM samples/FKB samples) was 0.74. According to this ratio, cases were divided into three groups: reasonable estimation (65 cases), underestimation (32 cases), and overestimation (32 cases). Comparing the reasonable and underestimation groups, significant differences were detected in the extent of interstitial fibrosis and tubular atrophy (IFTA) and interstitial inflammation. Logistic regression analysis demonstrated that IFTA and interstitial inflammation were significantly associated with the underestimation. Moreover, the cortex length of FKB samples correlated with glomerular number in LM samples regardless of tubulointerstitial lesions. CONCLUSIONS: Glomerular number determined during on-site evaluation can be a reference for the actual number of glomeruli in LM samples. Since tubulointerstitial lesions make it difficult to recognize glomeruli in FKB samples, the possibility of underestimation for cases with possibly severe tubulointerstitial lesions should be considered. In such cases, evaluation of cortex length of FKB samples may substitute for evaluating glomeruli on-site.

A nationwide analysis of renal and patient outcomes for adults with lupus nephritis in Japan.

BACKGROUND: The prognosis of lupus nephritis (LN) has improved following the introduction of effective immunosuppressive therapy and progress in supportive care. This study examined recent renal and patient prognosis for adults with LN in Japan. METHODS: We conducted a nationwide retrospective cohort study of LN patients who received a renal biopsy between 2007 and 2012 that were registered in the Japan Renal Biopsy Registry. Of 623 registered adults with LN from 25 institutions and their affiliated or community hospitals, 489 were eligible for this study. RESULTS: The median age at renal biopsy was 39 years, and 82.2% of patients were female. Renal biopsies were performed in 348 patients with new-onset LN, 106 with relapse LN, and 35 with refractory LN. The distribution of ISN/RPS 2003 Classes was as follows: I 1.6%; II 5.3%; III (± V) 27.0%; IV (± V) 47.0%; V 18.4%; VI 0.6%. During the median observation period of 63.8 months, 36 patients (7.3%) reached a doubling of serum creatinine or end-stage kidney disease (ESKD), and 28 patients (5.7%) died. The 5 year renal and patient survival rates were 93.9% and 94.7%, respectively. Multivariate analysis revealed body mass index (BMI) and estimated glomerular filtration rate (eGFR) were independent risk factors for a doubling of serum creatinine in ESKD. Age and eGFR were independent risk factors for death. CONCLUSION: Recent prognosis for adults with LN are relatively good in Japan. Risk factors for impaired renal function are BMI and eGFR at renal biopsy, while age and eGFR are risk factors for death.

Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis Developing Pancreatic Lesion and Diabetes Mellitus: A Case Report and Review of the Literature.

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) affects small blood vessels and causes severe systemic organ injury commonly affecting the lungs and kidney. However, gastrointestinal, especially pancreatic, lesions are rare. We report the case of a 67-year-old Japanese man diagnosed with myeloperoxidase (MPO) AAV who developed pancreatic lesions and diabetes mellitus. The patient was admitted to our hospital due to fever, cough, and weight loss. He developed progressive glomerulonephritis, lung nodules, and pancreatic swelling and mass. Additionally, laboratory examination revealed positive MPO-ANCA and elevated glycated hemoglobin A1c, which were suggestive of diabetes mellitus. Renal biopsy revealed necrotizing crescentic glomerulonephritis and vasculitis in the small arteries. Endoscopic ultrasound-guided fine needle aspiration of the pancreas was performed, and histological findings suggested the possibility of pancreatic vasculitis and parenchymal injury. The patient was diagnosed with AAV, which was managed with glucocorticoids. This improved the renal function and pancreatic lesions. Furthermore, blood glucose levels improved despite treatment with glucocorticoids. These findings suggest that AAV-related pancreatic lesions worsened glycemic control. However, glucocorticoid therapy improved vasculitis and pancreatic lesions, which resulted in improved glycemic control.

Polyunsaturated fatty acid deficiency affects sulfatides and other sulfated glycans in lysosomes through autophagy-mediated degradation.

Metabolic changes in sulfatides and other sulfated glycans have been related to various diseases, including Alzheimer's disease (AD). However, the importance of polyunsaturated fatty acids (PUFA) in sulfated lysosomal substrate metabolism and its related disorders is currently unknown. We investigated the effects of deficiency or supplementation of PUFA on the metabolism of sulfatides and sulfated glycosaminoglycans (sGAGs) in sulfatide-rich organs (brain and kidney) of mice. A PUFA-deficient diet for over 5 weeks significantly reduced the sulfatide expression by increasing the sulfatide degradative enzymes arylsulfatase A and galactosylceramidase in brain and kidney. This sulfatide degradation was clearly associated with the activation of autophagy and lysosomal hyperfunction, the former of which was induced by suppression of the Erk/mTOR pathway. A PUFA-deficient diet also activated the degradation of sGAGs in the brain and kidney and that of amyloid precursor proteins in the brain, indicating an involvement in general lysosomal function and the early developmental process of AD. PUFA supplementation prevented all of the above abnormalities. Taken together, a PUFA deficiency might lead to sulfatide and sGAG degradation associated with autophagy activation and general lysosomal hyperfunction and play a role in many types of disease development, suggesting a possible benefit of prophylactic PUFA supplementation.

Prevalence of latent tuberculosis infection and its risk factors in Japanese hemodialysis patients.

BACKGROUND: The majority of active tuberculosis (TB) cases develop from latent tuberculosis infection (LTBI). Since the risk of TB in hemodialysis (HD) patients is particularly high, interferon-gamma release assay (IGRA) for LTBI screening in HD patients is considered important. However, the prevalence and characteristics of LTBI in Japanese HD patients remain obscure. METHODS: We performed an observational cross-sectional study of LTBI using IGRA QFT-3G tests in 118 HD outpatients enrolled at 3 hospitals of varying location and function. RESULTS: Of the 118 patients, 96 were QFT negative, 7 were QFT indeterminate, 14 were QFT positive, and 1 was QFT judgment impossible. No patient had active TB. Confirmed (QFT positive) and possible (QFT positive + indeterminate) LTBI patients totaled 14 (11.9%) and 21 (17.8%), respectively. The LTBI possible group was significantly older and had a significantly higher rate of nephrosclerosis versus the QFT-negative group. The indeterminate group had a significantly longer HD period. The QFT results were not remarkably affected by other clinical data, including hospital characteristics. The possible LTBI rate increased age-dependently, with higher values from 60 years of age. CONCLUSIONS: The prevalence of LTBI is high in Japanese HD patients, especially from the age of 60 years. Older age was a significant risk factor for LTBI, with prediction difficult using other clinical data. Extended HD may mask IGRA results. Therefore, aggressive screening for LTBI is advised in all HD patients regardless of hospital region or type, especially in patients over 60 years of age or newly commencing HD.

Cholesterol Emboli Co-Existing with Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis in a 76-Year-Old Woman.

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis injures small vessels and causes severe systemic organ injury. Main target antigens of ANCA are myeloperoxidase and proteinase 3. ANCA strongly associates with the development and progression of the vasculitis. Its manifestations include rapidly progressive glomerulonephritis, interstitial pneumonitis, alveolar hemorrhage, purpura, and neurological disorder. Most patients with ANCA-associated vasculitis in Japan are elderly and have atherosclerotic risk factors. Cholesterol emboli are systemic vascular inflammation triggered by cholesterol crystals. Cholesterol emboli cause kidney dysfunction and ischemia of the intestines, brain, heart, skin, and peripheral nerves. Diabetes mellitus, hypertension, hyperlipidemia, and history of cardiovascular diseases are risk factors of the development of cholesterol emboli. We report a case of ANCA-associated vasculitis coexisting with cholesterol emboli. A 76-year-old woman was diagnosed with ANCA-associated interstitial pneumonitis. She rapidly developed progressive glomerulonephritis, purpura, and peripheral sensory nerve disorder. A kidney biopsy revealed that renal dysfunction was caused by vasculitis of the interlobular arteries and cholesterol emboli. A skin biopsy revealed that purpura was caused by cholesterol emboli. Glucocorticoid and statin therapies were administered. Thereafter, the renal function and other symptoms improved and stabilized. The representative symptoms of ANCA-associated vasculitis and cholesterol emboli are closely similar, and it is difficult to distinguish between these diseases when they coexist. Because the background characteristics of patients with ANCA-associated vasculitis and risk factors of cholesterol emboli overlap, at the time of diagnosing ANCA-associated vasculitis, clinicians should consider the possibility of cholesterol emboli coexistence.

Impact of chronic kidney dysfunction on serum Sulfatides and its metabolic pathway in mice.

Serum sulfatides are critical glycosphingolipids that are present in lipoproteins and exert anticoagulant effects. A previous study reported decreased levels of serum sulfatides in hemodialysis patients and suggested an association with cardiovascular disease. However, the mechanism of changes in serum sulfatides in chronic kidney dysfunction has not been well investigated. The current study examined whether a chronic kidney disease (CKD) state could decrease serum sulfatide levels using 5/6 nephrectomy (5/6NCKD) mice, an established CKD murine model, and studied the mechanisms contributing to diminished sulfatides. 5/6NCKD mice and sham operation control mice were sacrificed at the 4th or 12th postoperative week (POW) for measurement of serum sulfatide levels. Hepatic sulfatide content, which is the origin of serum sulfatides, and the expression of sulfatide metabolic enzymes in liver tissue were assessed as well. The 5/6NCKD mice developed CKD and showed increased serum creatinine and indoxyl sulfate. The serum levels and hepatic amounts of sulfatides were significantly decreased in 5/6NCKD mice at both 4 and 12 POW, while the degradative enzymes of sulfatides arylsulfatase A and galactosylceramidase were significantly increased. In a Hepa1-6 murine liver cell line, indoxyl sulfate addition caused intracellular levels of sulfatides to decrease and degradative enzymes of sulfatides to increase in a manner comparable to the changes in 5/6NCKD mice liver tissue. In conclusion, chronic kidney dysfunction causes degradation of sulfatides in the liver to decrease serum sulfatide levels. One explanation of these results is that indoxyl sulfate, a uremic toxin, accelerates the degradation of sulfatides in liver tissue.

Peroxisome proliferator-activated receptor α attenuates high-cholesterol diet-induced toxicity and pro-thrombotic effects in mice.

Peroxisome proliferator-activated receptor α (PPARα) is involved in the regulation of fatty acid and cholesterol metabolism. A high-cholesterol (HC) diet increases the risk of developing cardiovascular diseases (CVD); however, it is unclear whether the toxic effects of cholesterol involve changes in thrombotic factor expression, and whether PPARα is necessary for such effects. To investigate this possibility, we fed a HC diet to wild-type (WT) and Ppara-null mice and measured cholesterol and triglyceride contents, liver histology, serum/plasma levels of coagulation factors, hepatic expression of the coagulation factors, liver/serum sulfatide levels, hepatic sulfatide metabolism, hepatic expression of lipid transporters, and hepatic oxidative stress and its relating enzymes. In Ppara-null mice, the HC diet caused triglyceride accumulation and exacerbated inflammation and oxidative stress in liver, increased levels of coagulation factors, including tissue factor, plasminogen activator inhibitor-1 and carboxypeptidase B2 in blood and liver, and decreased levels of anti-thrombotic sulfatides in serum and liver. These changes were much less marked in WT mice. These findings imply that cholesterol overload exerts its toxic effects at least in part by enhancing thrombosis, secondary to abnormal hepatic lipid metabolism, inflammation, and oxidative stress. Moreover, we reveal for the first time that PPARα can attenuate these toxic effects by transcriptional regulation of coagulation factors and sulfatides, in addition to its known effects of controlling lipid homeostasis and suppressing inflammation and oxidative stress. Therapies aimed at activating PPARα might prevent HC diet-induced CVD through modulating various pro- and anti-thrombotic factors.

Influence of arteriovenous fistula on daily living behaviors involving the upper limbs in hemodialysis patients: a cross-sectional questionnaire study.

BACKGROUND: Arteriovenous fistulae can restrict daily living behaviors involving the upper limbs in hemodialysis patients, but no studies have investigated the detailed effects of an arteriovenous fistula on routine life activities. Accordingly, many medical caregivers are unable to explain the effects of an arteriovenous fistula on daily life, particularly during non-dialysis periods, because they cannot observe them directly. METHODS: Thirty outpatients undergoing hemodialysis at 2 facilities scored the difficulty due to an arteriovenous fistula in performing 48 living behaviors during non-dialysis and 10 behaviors during dialysis into 5 grades in a comprehensive questionnaire survey. These behaviors were selected based on an open-answer pre-questionnaire administered to the 30 patients beforehand. The scores were also compared between dominant arm and non-dominant arm arteriovenous fistula groups. RESULTS: During non-dialysis, the difficulty scores of behaviors restricted out of concern for arteriovenous fistula obstruction (wear a wristwatch, hang a bag on the arm, carry a baby or a dog in the arms, wear a short-sleeved shirt, etc.) increased. The difficulties of "wear a wristwatch" and "hang a bag on the arm" were significantly higher in the non-dominant arm arteriovenous fistula group (both P < 0.05). In contrast, scores related to motor function (write, eat or drink, scratch an itch, etc.) increased remarkably during dialysis because of connection of the arteriovenous fistula to the dialysis machine. The difficulties of "write" and "eat or drink" were significantly higher in the dominant arm arteriovenous fistula group (both P < 0.05). CONCLUSIONS: Several key daily living behaviors restricted by an arteriovenous fistula were identified in this questionnaire survey. These results will be useful for pre-operative explanation of arteriovenous fistula surgery and arm selection in end-stage renal disease patients.

Technical Performance and Clinical Effectiveness of Drop Type With Adjustable Concentrator-Cell Free and Concentrated Ascites Reinfusion Therapy.

Cell-free and concentrated ascites reinfusion therapy (CART) is a very useful treatment method for refractory ascites but is difficult for many hospitals to employ due to its need for specialized equipment. We have therefore developed drop-type with adjustable concentrator CART (DC-CART) that uses a drop-type filtration mechanism and requires only a simple pump and pressure monitor for its concentration process. Easy adjustment of ascites concentration is possible through a recirculation loop, and filter membrane washing is aided by DC-CART's external pressure-type filtration to enable the processing of any quality or quantity of ascites. Moreover, the absence of a roller pump before filtration avoids inflammatory substance release from compressed cells. A total of 268 sessions of DC-CART using ascites from 98 patients were performed with good clinical results at our hospitals between January 2012 and June 2016. This report presents the detailed methods of DC-CART and summarizes its clinical effectiveness using patient ascites and blood data obtained from 59 sessions between March 2015 and February 2016. This novel technique successfully processed refractory ascites in numerous diseases with no serious adverse events. DC-CART could concentrate large amounts of ascites (from median weight: 4900 g [max: 20 200 g] to median weight: 695 g; median concentration ratio: 7.4), and a high amount of protein (median weight: 73 g [max: 294 g]) could be reinfused. Serum albumin levels were significantly increased (P = 0.010) and kidney function and systemic hemodynamics were well maintained in treated subjects. Additional concentration of ascites and adjustment of ascites volume were easily performed by recirculation (from median weight: 615 g to median weight: 360 g; median concentration ratio: 1.5). Time was needed during DC-CART for filter membrane cleaning, especially for viscous ascites. Overall, DC-CART represents a safe and useful treatment method for various forms of refractory ascites that can be performed at a wide range of health care institutions.

Identification of chronic kidney disease patient characteristics influencing the renoprotective effects of febuxostat therapy: a retrospective follow-up study.

BACKGROUND: The ability of antihyperuricemic therapy to exert renoprotective effects in patients with chronic kidney disease (CKD) is controversial. In the present study, we studied patient characteristics that may mask favorable impact of antihyperuricemic therapy on the progression of CKD. METHODS: This was a single-center, retrospective, follow-up study. One-hundred and seventy-eight CKD patients with hyperuricemia who received febuxostat therapy were included in this study. Mean serum uric acid (mUA) level after treatment and changes in estimated glomerular filtration rate (ΔeGFR) over 6 months were measured and their correlation was examined. Patients were divided into two groups based on mUA, and their ΔeGFR were compared. These analyses were evaluated in various subgroups. RESULTS: Febuxostat therapy markedly decreased UA level in any CKD stage patients without resulting in serious adverse events. eGFRs of CKD patients in the mUA < 6.0 mg/dl group were maintained, whereas those in the mUA ≥ 6.0 mg/dl group decreased. A significant inverse correlation was observed between mUA and ΔeGFR (r = -0.16, p = 0.019). The renoprotective effects of febuxostat were significant in the following subgroups: male patients, age < 70 years, systolic blood pressure < 130 mmHg, normal cholesterol levels, and absence of diabetes. Coexisting vascular risk factors appear to exert additive masking effects against febuxostat renoprotection. CONCLUSIONS: The results of this study suggest that various vascular risk factors markedly attenuate the renoprotective effects of febuxostat.

Decreased Fatty Acid ß-Oxidation Is the Main Cause of Fatty Liver Induced by Polyunsaturated Fatty Acid Deficiency in Mice.

Insufficient intake of polyunsaturated fatty acids (PUFA) causes fatty liver. The mechanism responsible is primarily related to increased lipogenesis and decreased FA degradation based on rodent studies. However, these studies were limited by the fact that the typical PUFA-deficient diets contained insufficient amounts of long-chain FA, the PUFA-containing diets were primarily composed of n-3 PUFA-enriched oil, and the intake of PUFA was excessive compared with the physiological requirement. To address these issues, mice were fed a PUFA-deficient diet containing long-chain FA at a standard fed level and then were orally fed a n-3/n-6-balanced PUFA-containing oil [PUFA (+)] or a PUFA-deficient oil [PUFA (-)] at physiological relevant levels (0.1 mL/mouse/2d). We compared these groups and examined whether fatty liver in PUFA deficiency was attributable to both the effects of increased lipogenesis and decreased FA catabolism. Compared with the PUFA (+) group, the PUFA (-) group showed increases in liver triglyceride and serum FA content. Hepatic gene expression of several mitochondrial ß-oxidation enzymes, the serum 3-hydroxybutyrate level, and DNA-binding ability of peroxisome proliferator-activated receptor α (PPARα) were increased in the PUFA (+) group, whereas these adaptive responses were significantly attenuated in the PUFA (-) group. The hepatic expression of typical lipogenesis genes did not differ between the groups. Therefore, fatty liver in PUFA deficiency is attributable to suppression of the FA-degrading system probably from decreased PPARα adaptive responsiveness, and PUFA may be an essential factor for PPARα functioning. This finding is helpful for managing clinical situations having a risk of PUFA deficiency.

Peroxisome proliferator-activated receptor α-dependent renoprotection of murine kidney by irbesartan.

Activation of renal peroxisome proliferator-activated receptor α (PPARα) is renoprotective, but there is no safe PPARα activator for patients with chronic kidney disease (CKD). Studies have reported that irbesartan (Irbe), an angiotensin II receptor blocker (ARB) widely prescribed for CKD, activates hepatic PPARα. However, Irbe's renal PPARα-activating effects and the role of PPARα signalling in the renoprotective effects of Irbe are unknown. Herein, these aspects were investigated in healthy kidneys of wild-type (WT) and Ppara-null (KO) mice and in the murine protein-overload nephropathy (PON) model respectively. The results were compared with those of losartan (Los), another ARB that does not activate PPARα. PPARα and its target gene expression were significantly increased only in the kidneys of Irbe-treated WT mice and not in KO or Los-treated mice, suggesting that the renal PPARα-activating effect was Irbe-specific. Irbe-treated-PON-WT mice exhibited decreased urine protein excretion, tubular injury, oxidative stress (OS), and pro-inflammatory and apoptosis-stimulating responses, and they exhibited maintenance of fatty acid metabolism. Furthermore, the expression of PPARα and that of its target mRNAs encoding proteins involved in OS, pro-inflammatory responses, apoptosis and fatty acid metabolism was maintained upon Irbe treatment. These renoprotective effects of Irbe were reversed by the PPARα antagonist MK886 and were not detected in Irbe-treated-PON-KO mice. These results suggest that Irbe activates renal PPARα and that the resultant increased PPARα signalling mediates its renoprotective effects.

Age-dependent PPARα activation induces hepatic sulfatide accumulation in transgenic mice carrying the hepatitis C virus core gene.

Sulfatides, a type of glycosphingolipid, are associated with carcinogenesis. Peroxisome proliferator-activated receptor α (PPARα) is involved in the regulation of sulfatide metabolism as well as in cancer development. We previously reported that transgenic (Tg) mice expressing hepatitis C virus core protein (HCVcp) exhibited age-dependent PPARα activation and carcinogenesis in liver. However, the metabolism of sulfatides in hepatocellular carcinoma is unknown. To examine the relationship between sulfatide metabolism, carcinogenesis, HCVcp, and PPARα, age-dependent changes of these factors were examined in HCVcpTg, PPARα inhibitor-treated HCVcpTg, and non-Tg mice. The sulfatide content in liver, the hepatic expression of two key enzymes catalyzing the initial and last reactions in sulfatide synthesis, the hepatic expression of known sulfatide-transferring protein, oxidative stress, and hepatic PPARα expression and its activation were age-dependently increased in HCVcpTg mice. The increased synthesis and accumulation of sulfatides and PPARα activation were significantly enhanced in liver cancer lesions. These changes were attenuated by PPARα inhibitor treatment and not observed in non-Tg mice. These results suggest that HCVcp-induced age-dependent PPARα activation increases synthesis of sulfatides and the resulting sulfatide accumulation affects HCV-related liver cancer. The monitoring of hepatic sulfatide content and the modulation of sulfatide generation by intervention using a PPARα inhibitor might be useful for the prediction and prevention of HCV-related hepatocarcinogenesis, respectively.