rAAV6-mediated miR-29b delivery suppresses renal fibrosis.

BACKGROUND: Previous studies showed that microRNA-29b (miR-29b) inhibits renal fibrosis. Therefore, miR-29b replacement therapy represents a promising approach for treating renal fibrosis. However, an efficient method of kidney-targeted miRNA delivery has yet to be established. Recombinant adeno-associated virus (rAAV) vectors have great potential for clinical application. For kidney-targeted gene delivery, the most suitable AAV serotype has yet to be established. Here, we identified the most suitable AAV serotype for kidney-targeted gene delivery and determined that AAV-mediated miR-29b delivery can suppress renal fibrosis in vivo. METHOD: To determine which AAV serotype is suitable for kidney cells, GFP-positive cells were identified by flow cytometry after the infection of rAAV serotype 1-9 vectors containing the EGFP gene. Next, we injected rAAV vectors into the renal pelvis to determine transduction efficiency in vivo. GFP expression was measured seven days after injecting rAAV serotype 1-9 vectors carrying the EGFP gene. Finally, we investigated whether rAAV6-mediated miR-29b delivery can suppress renal fibrosis in UUO mouse model. RESULTS: We found that rAAV6 vector is the most suitable for targeting kidney cells regardless of animal species in vitro and rAAV6 is the most suitable vector for kidney-targeted in vivo gene delivery in mice. Intra-renal pelvic injection of rAAV vectors can transduce genes into kidney TECs. Furthermore, rAAV6-mediated miR-29b delivery attenuated renal fibrosis in UUO model by suppressing Snail1 expression. CONCLUSION: Our study has revealed that rAAV6 is the most suitable serotype for kidney-targeted gene delivery and rAAV6-mediated miR-29b delivery into kidney TECs can suppress established renal fibrosis.

[Two cases of incidentally detected renal arteriovenous fistula over ten years after renal biopsy].

CASE 1: The case was a 66-year-old Japanese woman. A renal biopsy had been carried out at 53 years of age, and she was diagnosed as IgA nephropathy. Her renal function had been stable at around 0.7 mg/dL of serum creatinine. At 66 years of age, macrohematuria was found and she was admitted to hospital. Enhanced abdominal computed tomography showed left renal arteriovenous fistula (AVF) (21 mm x 10 mm), and hydronephrosis. Her renal AVF was successfully treated with coil embolization, and hydronephrosis was improved with stable renal function. Her AVF was cirsoid type, which is usually congenital, although it was not recognized before the renal biopsy. CASE 2: A 48-year-old Japanese woman was referred to a nephrologist for proteinuria and an elevated serum creatinine level. She had undergone two renal biopsies when she was 14 and 18 years of age and her condition had been diagnosed as chronic glomerulonephritis. However, she had not received any special treatment. Upon abdominal ultrasonography, a right renal AVF (18 mm x 23 mm) was detected. Her aneurysmal type AVF was successfully treated with coil embolization. In these 2 cases, renal biopsy might be a cause of renal AVF. Regular screening test using ultrasonography is recommended to avoid missing remote complications of renal biopsy.

Relationship between dietary protein intake and the changes in creatinine clearance and glomerular cross-sectional area in patients with IgA nephropathy.

BACKGROUND: Dietary protein intake (PI) induces glomerular hyperfiltration and reduced dietary PI can be effective in preserving kidney function. However, there is limited information regarding the relationship between dietary PI and glomerular histological changes in chronic kidney disease. We investigated the relationship between changes in dietary PI and both the changes in creatinine clearance and glomerular histomorphometry in adult patients with IgA nephropathy (IgAN). METHODS: A total of 24 consecutive adult patients with biopsy-confirmed IgAN were enrolled and glomerular histomorphometric variables and clinical variables were investigated. The main clinical variables were differences in creatinine clearance (Ccr) (dCcr) and in PI (dPI) which were calculated by subtracting PI and Ccr values in patients on a controlled diet during hospitalization for kidney biopsy from the respective values in patients on daily diets as outpatients. These values of PI were estimated from urinary urea excretion measured by 24-h urine collection. The main renal histomorphometric variable was glomerular tuft area (GTA) (µm(2)). RESULTS: dCcr positively correlated with dPI (r = 0.726, P < 0.001). GTA correlated positively with dPI (r = 0.556, P = 0.013). Multiple regression analysis showed that dPI was independently associated with both dCcr and GTA. Additionally, GTA positively correlated with dietary PI as outpatients (r = 0.457, P = 0.043). CONCLUSION: Changes in dietary PI were associated with the changes in glomerular filtration rate. Furthermore, histomorphometric findings suggested that a greater dietary PI can affect the glomerular size at the time of the initial diagnostic biopsy for IgAN.

Sustained down-regulation of ß-dystroglycan and associated dysfunctions of astrocytic endfeet in epileptic cerebral cortex.

Epilepsy is characterized by the abnormal activation of neurons in the cerebral cortex, but the molecular and cellular mechanisms contributing to the development of recurrent seizures are largely unknown. Recently, the critical involvement of astrocytes in the pathophysiology of epilepsy has been proposed. However, the nature of plastic modulations of astrocytic proteins in the epileptic cortex remains poorly understood. In this study, we utilized the zero magnesium in vitro model of epilepsy and examined the potential molecular changes of cortical astrocytes, focusing specifically on endfeet, where specialized biochemical compartments exist. We find that the continuous epileptic activation of neurons for 1 h decreases the expression level of ß-dystroglycan (ßDG) in acute cortical brain slices prepared from mice. This change is completely abolished by the pharmacological blockade of NMDA-type glutamate receptors as well as by matrix metalloproteinase inhibitors. Consistent with the highly specialized localization of ßDG at astrocytic endfeet, where it plays a pivotal role in anchoring endfeet-enriched proteins in astrocytes, the down-regulation of ßDG is accompanied by a decrease in the expression of AQP4 but not laminin. Importantly, this down-regulation of ßDG persists for at least 1 h, even after the apparent recovery of neuronal activation. Finally, we show that the down-regulation of ßDG is associated with the dysfunction of the endfeet at the blood-brain interface as a diffusion barrier. These results suggest that the sustained down-regulation of ßDG leads to dysfunctions of astrocytic endfeet in the epileptic cerebral cortex and may contribute to the pathogenesis of epilepsy.

[Validity of the assessment of urinary protein excretion by spot urine in patients with chronic kidney disease].

AIM: We investigate the validity of the assessment of urinary protein excretion by spot urine samples collected by different methods in outpatients with chronic kidney disease (CKD). SUBJECTS AND METHODS We obtained 24-hour urine and two spot urine samples, including the first morning urine and daytime urine in 159 CKD patients. Urinary protein excretion was assessed by the protein/creatinine ratio from spot urine samples (morning: m-UP (g/gCr), daytime: d-UP (g/gCr) ]. We examined the correlations and the differences among m-UP, d-UP and the actual urinary protein excretion obtained by 24-hour urine (a-UP(g/day) . RESULTS: Significant correlations were found between m-UP and a-UP, and between d-UP and a-UP (r = 0.88, 0.85; p < 0.001). Correlations between m-UP and a-UP were greater relative to those between d-UP and a-UP in patients with less than 3.5 g/day of a-UP and in patients with CKD stages 1 to approximately 3. The percent difference between m-UP and a-UP was--16.0 +/- 40.5%, and that between d-UP and a-UP was 27.1 +/- 72.9%. The absolute value of the percent difference between d-UP and a-UP tended to be greater than that between m-UP and a-UP (34.9 +/- 25.9% vs. 49.9 +/- 59.9%, p = 0.06). CONCLUSION: Urinary protein/creatinie ratio of the first morning urine is better approximate the urinary protein excretion obtained by 24-hour urine compared with that of spot urine in the daytime.

Triple therapy with single daily dose of cyclosporine in Japanese patients with idiopathic membranous nephropathy.

OBJECTIVE: The optimal therapeutic approach to patients with idiopathic membranous nephropathy (IMN) remains controversial. In this study, we assessed the efficacy of single daily dose cyclosporine (CsA) combined with low-dose prednisolone (PSL) and an angiotensin II receptor blocker (ARB) in patients with IMN. METHODS: We studied 13 nephrotic patients (8 men, 5 women) with IMN diagnosed on biopsy. An initial single daily dose of 2 mg/kg, but not exceeding 150 mg, CsA was given for 12 months, tapered by a 25 mg reduction every 2 months. An initial twice-daily dose of 0.5 mg/kg PSL was given for 2 months and was also tapered. An ARB was given to all patients and the same dosage was used throughout the study. Patients were followed up for 6 to 66 months. RESULTS: Nine patients achieved complete remission at 6.7±2.9 months, and incomplete remission was obtained in the remaining patients. After a follow-up period of 32.7±20.0 months, their serum creatinine and estimated glomerular filtration rate values were similar to baseline levels. The 9 patients who completed the treatment course have not relapsed. Moreover, there were no adverse effects requiring discontinuation of this triple therapy. CONCLUSION: A single daily dose of CsA combined with a low dose of PSL and an ARB in new-onset nephrotic patients with IMN induced a high remission rate of nephrotic syndrome, with a low incidence of relapse and a low risk of adverse effects. The triple therapy and prospective follow-up shows potential as a treatment approach for patients with IMN.

Ratio of urinary potassium to urinary sodium and the potassium and edema status in nephrotic syndrome.

OBJECTIVE: This study aimed to evaluate the relevance of ratios of urinary potassium to urinary sodium + potassium (U(K)/U(Na + K)) to edema status in minimal-change nephrotic syndrome (MCNS). METHODS: We retrospectively studied 26 adults with newly diagnosed MCNS with significant pitting edema. On the basis of mean value (0.46±0.21) of U(K)/U(Na + K) determined from spot urine samples on admission, patients were classified into 2 groups. RESULTS: On admission, 12 of 26 patients had U(K)/U(Na + K) >0.46 (0.65±0.16, Group H), 14 patients had U(K)/U(Na + K) <0.46 (0.29±0.08, Group L). The level of serum albumin was similarly decreased in these 2 groups. Noteworthy were lower urine volume, fractional excretion of sodium (FENa), serum sodium, and higher hematocrit in the group H as compared with the group L. The group H had a shorter mean time required from onset of edema to hospitalization, and tended to have a longer mean time to complete remission than group L. High U(K)/U(Na + K) levels in group H decreased significantly after remission, eventually becoming equal to those of group L (0.24±0.05 vs. 0.25±0.05). CONCLUSION: U(K)/U(Na + K) determined from spot urine sample on admission relates to laboratory or clinical indices to distinguish edema status in adult patients with MCNS.

Benefits of staple food restriction for Japanese obese patients with chronic kidney disease: a pilot study.

OBJECTIVE: We conducted a pilot study to assess the effects of dietary intervention on metabolic risk factors and renal parameters in obese patients with chronic kidney disease (CKD). METHODS: We studied 19 obese patients with CKD at our outpatient clinic. The diet selected for this study restricted only their staple food intake, with no change in the side dish component of their meals. We studied neither the lifestyles of the patients nor the activities that they were involved in. We examined changes in clinical and laboratory parameters at baseline and after consumption of the diet. RESULTS: After 2 and 6 months of staple food restriction, changes in body weight were found to be -3.6% ± 3.9% and -3.4% ± 4.7%, respectively. Of the 19 patients, the body weights of 9 decreased by >3% (range: 3.4% to 17.1%) from baseline to follow-up at 6 months. After 6 months of following the diet, these 9 patients showed marked reductions in blood pressure, homeostasis model assessment insulin resistance, and triglycerides, when compared with the remaining 10 patients with stable body weights; however, for proteinuria and estimated glomerular filtration rate they reported having values similar to the 10 patients with stable body weights. CONCLUSIONS: Weight reduction associated with a lowered insulin resistance was reported in obese patients with CKD after 6 months of staple food restriction; however, further studies need to be conducted to confirm the presence of other possible renal benefits.

Benefits of first-half intensive haemodiafiltration for the removal of uraemic solutes.

AIM: Haemodiafiltration (HDF) is the most efficient blood purification method and can remove a wide spectrum of solutes of different molecular weights (MW). The purpose of this study was to investigate whether the removed amounts of solutes, especially the larger molecules, could be increased by changing the HDF filtration procedure. METHODS: A new first-half intensive HDF treatment (F-HDF) was designed, whereby convective clearance is intensively forced during the first half of a HDF session. We compared the removed amounts of solutes in the same group of nine patients treated by F-HDF, constant rate-replacing HDF (C-HDF) and a high-flux haemodialysis (HD). RESULTS: F-HDF can remove significantly larger amounts of α(1) -microglobulin (MG), molecular weight (MW) 33,000, compared with HD and C-HDF (30.1 ± 15.1 vs 12.4 ± 0.3, 15.0 ± 3.1 mg, P < 0.01). Regarding the removal amounts and clear space of ß(2) MG, MW 11,800, there were no significant differences between the three treatment modalities. Regarding amounts of creatinine, urea nitrogen and phosphorus, there were no significant differences between the three treatment modalities. CONCLUSION: In post-replacement HDF with a high-flux membrane dialyzer, the method used in the present study in which replacement is completed during the first half of the process, is associated with a greater rate of larger molecule removal than the conventional uniform replacement method.