Identification and isolation of kidney-derived stem cells from transgenic rats with diphtheria toxin-induced kidney damage

Adult stem cells have been well characterized in numerous organs, with the exception of the kidneys. Therefore, the present study aimed to identify and isolate kidney-derived stem cells. A total of 12 Fischer 344 transgenic rats expressing the human diphtheria toxin receptor in podocyte cells of the kidney, were used in the present study. The rats were administered 5-bromo-2′-deoxyuridine (BrdU) in order to detect cellular proliferation. After 60 days, the rats were treated with the diphtheria toxin (DT), in order to induce kidney injury. Immunohistochemical analysis indicated that the number of BrdU-positive cells were increased following DT treatment. In addition, the expression of octamer-binding transcription factor 4 (Oct-4), a stem cell marker, was detected and suggested that kidney-specific stem cells were present in the DT-treated tissue samples. Furthermore, tissue samples exhibited repair of the DT-induced injury. Further cellular culturing was conducted in order to isolate the kidney-specific stem cells. After 5 weeks of culture, the majority of the cells were non-viable, with the exception of certain specialized, unique cell types, which were monomorphic and spindle-shaped in appearance. The unique cells were isolated and subjected to immunostaining and reverse transcription-polymerase chain reaction analyses in order to reconfirm the expression of Oct-4 and to detect the expression of Paired box 2 (Pax-2), which is necessary for the formation of kidney structures. The unique cells were positive for Oct-4 and Pax-2; thus suggesting that the identified cells were kidney-derived stem cells. The results of the present study suggested that the unique cell type identified in the kidneys of the DT-treated rats were kidney-specific stem cells that may have been involved in the repair of DT-induced tissue injury. In addition, these cells may provide a useful cell line for studying the fundamental characteristics of kidney stem cells, as well as identifying kidney-specific stem cell markers.

Berberine improves kidney function in diabetic mice via AMPK activation

Diabetic nephropathy is a major cause of morbidity and mortality in diabetic patients. Effective therapies to prevent the development of this disease are required. Berberine (BBR) has several preventive effects on diabetes and its complications. However, the molecular mechanism of BBR on kidney function in diabetes is not well defined. Here, we reported that activation of AMP-activated protein kinase (AMPK) is required for BBR-induced improvement of kidney function in vivo. AMPK phosphorylation and activity, productions of reactive oxygen species (ROS), kidney function including serum blood urea nitrogen (BUN), creatinine clearance (Ccr), and urinary protein excretion, morphology of glomerulus were determined in vitro or in vivo. Exposure of cultured human glomerulus mesangial cells (HGMCs) to BBR time- or dose-dependently activates AMPK by increasing the thr172 phosphorylation and its activities. Inhibition of LKB1 by siRNA or mutant abolished BBR-induced AMPK activation. Incubation of cells with high glucose (HG, 30 mM) markedly induced the oxidative stress of HGMCs, which were abolished by 5-aminoimidazole-4-carboxamide ribonucleoside, AMPK gene overexpression or BBR. Importantly, the effects induced by BBR were bypassed by AMPK siRNA transfection in HG-treated HGMCs. In animal studies, streptozotocin-induced hyperglycemia dramatically promoted glomerulosclerosis and impaired kidney function by increasing serum BUN, urinary protein excretion, and decreasing Ccr, as well as increased oxidative stress. Administration of BBR remarkably improved kidney function in wildtype mice but not in AMPKα2-deficient mice. We conclude that AMPK activation is required for BBR to improve kidney function in diabetic mice.

Cyclosporine A combined with medium/low dose prednisone in progressive IgA nephropathy

The aim of the present study was to evaluate the efficacy of cyclosporine A (CsA) combined with medium/low dose prednisone in the treatment of progressive immunoglobulin A nephropathy (IgAN). Ninety-six patients who satisfied the inclusion criteria were enrolled in a prospective controlled clinical study. They were assigned into two groups and initially given either 0.6-0.8 mg/kg/day prednisone (maximum 40 mg/day) plus 3 mg/kg/day CsA (CsA group), or 1 mg/kg/day prednisone (maximum 60 mg/day) alone (steroid group). During therapy, the dose of prednisone was reduced in both groups and the dose of CsA was gradually tailed off over the first 3 months and maintained at 2 mg/kg/day in the CsA group. Urinary protein excretion, serum biochemical indexes, clinical efficacy and side effects of CsA were assayed. A significant decline in mean 24-hour urinary protein excretion (p < 0.05) was observed 1 month after treatment in patients in the CsA group, which was observed 2 months after treatment in the steroid group. The decline in mean 24-hour urinary protein excretion in the CsA group was more significant than in the steroid group. Serum albumin level increased significantly in the CsA group 2 months after therapy (p < 0.05). Moreover, at the end of the course, a higher remission rate was observed in patients with Lee's Grade III IgAN after combined treatment with prednisone and CsA (p < 0.05). No significant difference in clinical efficacy was observed in patients with Lee's Grade IV and Grade V IgAN between the two groups (p > 0.05). CsA at a dose of 2-3 mg/kg/day in combination with medium/low dose prednisone was effective in inducing remission of IgAN, especially for patients with Lee's Grade III IgAN, and is a safe and effective choice for short-term treatment of patients with progressive IgAN.

Mesenchymal stem cells transplantation ameliorates glomerular injury in streptozotocin-induced diabetic nephropathy in rats via inhibiting macrophage infiltration

Mesenchymal stem cells (MSCs) treatment has been shown to be effective in diabetic nephropathy (DN). However, the mechanisms involved in the renoprotective effects of MSCs have not been clearly demonstrated. Especially, there was no study on the relationship of MSCs and macrophages in diabetic kidney. To explore the effect of MSCs on macrophages in DN, streptozotocin-induced diabetes animals received no treatment or treatment with MSCs (2×10(6), via tail vein) for two continuous weeks. Eight weeks after treatment, physical, biochemical and morphological parameters were measured. Immunohistochemistry for fibronectin (FN), CollagenI, ED-1, monocyte chemoattractant protein-1 (MCP-1) was performed. Expressions of pro-inflammatory cytokines and hepatocyte growth factor (HGF) at gene level and protein level were determined by real-time reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. Blood glucose, urinary albumin excretion, creatinine clearance were significantly reduced after MSCs treatment. The glomerulosclerosis as revealed by periodic acid Schiff stain and expression of FN and CollagenI was also dramatically attenuated. Most importantly, the expression of MCP-1 and the number of infiltrated macrophages in kidney were effectively suppressed by MSCs treatment. The expression of HGF in MSCs group was up-regulated. Meanwhile, the expressions of IL-1β, IL-6 and TNFα were significantly down-regulated by MSCs treatment. Our study suggest that MSCs treatment ameliorates DN via inhibition of MCP-1 expression by secreting HGF, thus reducing macrophages infiltration, down-regulating IL-1β, IL-6, TNFα expression in renal tissue in diabetic rats.

Prevalence, awareness, treatment, and control of hypertension in the non-dialysis chronic kidney disease patients

BACKGROUND

Data on the epidemiology of hypertension in Chinese non-dialysis chronic kidney disease (CKD) patients are limited. The aim of the present study was to investigate the prevalence, awareness, treatment, and control of hypertension in the non-dialysis CKD patients through a nationwide, multicenter study in China.

METHODS

The survey was performed in 61 tertiary hospitals in 31 provinces, municipalities, and autonomous regions in China (except Hong Kong, Macao, and Taiwan). Trained physicians collected demographic and clinical data and measured blood pressure (BP) using a standardized protocol. Hypertension was defined as systolic BP ≥ 140 mmHg and/or diastolic BP ≥ 90 mmHg, and/or use of antihypertensive medications. BP < 140/90 mmHg and < 130/80 mmHg were used as the 2 thresholds of hypertension control. In multivariate logistic regression with adjustment for sex and age, we analyzed the association between CKD stages and uncontrolled hypertension in non-dialysis CKD patients.

RESULTS

The analysis included 8927 non-dialysis CKD patients. The prevalence, awareness, and treatment of hypertension in non-dialysis CKD patients were 67.3%, 85.8%, and 81.0%, respectively. Of hypertensive CKD patients, 33.1% and 14.1% had controlled BP to < 140/90 mmHg and < 130/80 mmHg, respectively. With successive CKD stages, the prevalence of hypertension in non-dialysis CKD patients increased, but the control of hypertension decreased (P < 0.001). When the threshold of BP < 130/80 mmHg was considered, the risk of uncontrolled hypertension in CKD 2, 3a, 3b, 4, and 5 stages increased 1.3, 1.4, 1.4, 2.5, and 4.0 times compared with CKD 1 stage, respectively (P < 0.05). Using the threshold of < 140/90 mmHg, the risk of uncontrolled hypertension increased in advanced stages (P < 0.05).

CONCLUSIONS

The prevalence of hypertension Chinese non-dialysis CKD patients was high, and the hypertension control was suboptimal. With successive CKD stages, the risk of uncontrolled hypertension increased.

[Effects of valsartan, mycophenolate mofetil and their combined application on TRAIL and nuclear factor-kappaB expression in the kidneys of diabetic rats]

OBJECTIVE

To evaluate the expression of TNF-related apoptosis inducing ligand (TRAIL) and nuclear factor (NF)-kappaB in the kidney tissues of diabetic rats and the effects of valsartan, mycophenolate mofetil (MMF), and their combined application on the renal TRAIL and NF-kappaB expression.

METHODS

Eighty uninephrectomized male Wistar rats were randomly divided into 2 groups: normal control (NC) group (n = 28), undergoing intraperitoneal injection of citric acid buffer, and diabetes mellitus (DM) group, undergoing intraperitoneal injection of streptozotocin (STZ) to establish DM models. The 52 DM rats were randomly divided into 7 equal subgroups: DM without treatment for 4 weeks (DM4), DM without treatment for 8 weeks (DM8) DM without treatment for 12 weeks (DM12) , and DM without treatment for 16 weeks (DM16), valsartan treatment (DM + V), MMF treatment (DM + M), and combined treatment (DM + V + M). The treatment subgroups were treated for 8 weeks immediately after the diabetic models ere established. Twenty-four hour urine was collected to measure the amount of protein 4, 8, 12, and 16 weeks after the induction of DM respectively. The rats were sacrificed. Blood samples were collected from the abdominal aorta to detect the blood urea nitrogen (BUN), serum creatinine (sCr), albumin, and glucose. The kidneys were taken out. Hypertrophy index (left kidney weight/body weight) was determined. Quantitative real time RT-PCR was performed to detect the expression of TRAIL and NF-kappaB mRNA. Immunohistochemistry was used to detect the protein expression of TRAIL and NF-kappaB.

RESULTS

1) The 24 h urine protein levels and hypertrophy indexes of all DM subgroups were significantly higher than those of the NC groups (all P <0.05). 24 h urine protein and hypertrophy index increased gradually and peaked in the l2th week; blood albumin gradually decreased since the 8th week(P <0.01), and BUN and sCr began to decrease only since the 16th week (both P <0.01). Compared with the DM 8 subgroup, the hypertrophy index and 24 h urine protein of the different treatment subgroups, especially the DM + V + M subgroup, were significantly lower (all P <0.05). 2) Quantitative real time RT-PCR showed that compared with the NC group, the TRAIL expression levels of the DM subgroups were significantly lower before the 12th week after induction of DM model (all P < 0.01), and then significantly higher in the 16th week (all P < 0.01). The TRAIL expression of the treatment groups, especially that of the DM + M subgroup, were significantly higher than that of the DM8 group (all P <0.05). Compared with the NC group, the NF-kappaB expression levels of the DM subgroups were significantly higher time-dependently (all P <0.01). Compared with the DM8 group, the NF-kappaB expression levels of the treatment subgroups, especially that of the DM + V + M subgroup were significantly lower (all P <0.05). 3) The expression of TRAIL was mainly located in the convoluted tubule of kidney, and no TRAIL protein expression was detected in the glomeruli or renal vasculature. The levels of NF-kappaB protein expression, shown in glomeruli and convoluted tubules, of all DM subgroups were all higher than that of the NC group. The NF-kappaB protein expression level of the DM + V + M subgroup was significantly lower. The number of NF-kappaB positive cells was significantly related to the mononuclear macrophage infiltration , kidney function, and structural lesion.

CONCLUSION

An important monitoring factor in the autoimmune system, TRAIL closely participates in the pathogenesis of diabetic nephropathy, possibly controlled by NF-kappaB. In the early stage combination of valsartan and MMF may upregulate the expression of TRAIL, thus protecting the kidney function.

[Protective effects of Salvia miltiorrhiza on rats with streptozotocin diabetes and its mechanism]

OBJECTIVE

To explore the effects of Salvia miltiorrhiza on renal morphology and renal function of rats with streptozotocin diabetes.

METHODS

Thirty male Wistar rats were randomly divided into three groups, which were normal control group, untreated group and Salvia miltiorrhiza-treated group. Diabetic nephropathy was induced in rats of the last two groups by intraperitoneal injection of streptozotocin after unilateral nephrectomy. Then the rats in the normal control and untreated groups were fed with normal saline while those in the Salvia miltiorrhiza-treated group were fed Salvia miltiorrhiza preparation for 8 weeks. The glomerular volume (VG), kidney-to-body weight ratio (KW/BW), urinary albumin excretion rate (UAER) and creatinine clearance (Ccr) were observed. The expression levels of transforming growth factor-beta1 (TGF-beta1), connective tissue growth factor (CTGF), fibronectin (FN) and plasminogen activator inhibitor-1 (PAI-1) were detected by real-time quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) at the end of the experiment.

RESULTS

UAER, Ccr, VG and KW/BW ratio were significantly higher in the untreated group than those in the normal control group (P<0.05). The expression levels of TGF-beta1, CTGF, PAI-1 and FN in the untreated group were also significantly higher as compared with those in the normal control group (P<0.05). UAER, Ccr, VG, KW/BW ratio and the levels of TGF-beta1, CTGF, PAI-1 and FN in the Salvia miltiorrhiza-treated group were obviously lower than those in the untreated group (P<0.05).

CONCLUSION

Salvia miltiorrhiza can protect rats with streptozotocin diabetes from diabetic nephropathy by suppressing the over-expressions of TGF-beta1, CTGF, PAI-1 and FN in renal cortex.

Downregulation of alpha-fetoprotein siRNA inhibits proliferation of SMMC-7721 cells

AIM: To study the function of a-fetoprotein (AFP) in SMMC-7721 hepatoma cells.

METHODS: A hairpin siRNA expressing plasmid pSilencer3.0-H1-afp was constructed andtransfected into SMMC-7721 cells with Lipofectamine 2000. The expression of AFP was monitored by real-time RT-PCR and immunoassays, its effect on SMMC-7721 cell proliferation and cell death was detected by MTT and fluorescence- activated cell sorter (FACS).

RESULTS: The AFP-siRNA expressing plasmid downregulated the expression of AFP obviously (about 34%), and inhibited SMMC-7721 cell proliferation, but did not induce apoptosis.

CONCLUSION: Downregulation of AFP siRNA inhibits proliferation of SMMC-7721 cells, but cannot cause apoptosis.