Treatment with Mesenchymal Stem Cells Improves Renovascular Hypertension and Preserves the Ability of the Contralateral Kidney to Excrete Sodium.

BACKGROUND: Mesenchymal stem cells (MSC) improve renal function and renovascular hypertension in the 2-kidney 1-clip model (2K-1C). While MSC play an immunomodulatory role, induce neoangiogenesis, and reduce fibrosis, they do not correct sodium loss by the contra-lateral kidney. OBJECTIVES: We investigated the tubular function of both stenotic and contralateral kidneys and the effect of MSC treatment by evaluating diuresis, natriuresis, and the expression of the main water and sodium transporters. METHOD: Adult Wistar rats were allocated into four groups: control (CT), CT+MSC, 2K-1C, and 2K-1C+MSC. MSC (2 × 105) were infused through the tail vein 3 and 5 weeks after clipping. Systolic blood pressure (SBP) was monitored weekly by plethysmography. Six weeks after clipping, 24-hour urine and blood samples were collected for biochemical analysis. Gene expression of the Na/H exchanger-3, epithelial sodium channel, Na/K-ATPase, Na/K/2Cl cotransporter, and aquaporins 1 and 2 (AQP1 and AQP2) were analyzed by RT-PCR. Intrarenal distribution of AQP1 and AQP2 was analyzed by immunohistochemistry. RESULTS: In hypertensive 2K-1C animals, MSC prevented additional increases in BP. AQP1, but not AQP2, was suppressed in the contralateral kidney, resulting in significant increase in urinary flow rate and sodium excretion. Gene expressions of sodium transporters were similar in both kidneys, suggesting that the high perfusing pressure in the contralateral kidney was responsible for increased natriuresis. Contralateral hypertensive kidney showed signs of renal deterioration with lower GFR in spite of normal RPF levels. CONCLUSIONS: MSC treatment improved renal function and enhanced the ability of the contralateral kidney to excrete sodium through a tubular independent mechanism contributing to reduce SBP.

Mesenchymal stem cells and chronic renal artery stenosis.

Renal artery stenosis is the main cause of renovascular hypertension and results in ischemic nephropathy characterized by inflammation, oxidative stress, microvascular loss, and fibrosis with consequent functional failure. Considering the limited number of strategies that effectively control renovascular hypertension and restore renal function, we propose that cell therapy may be a promising option based on the regenerative and immunosuppressive properties of stem cells. This review addresses the effects of mesenchymal stem cells (MSC) in an experimental animal model of renovascular hypertension known as 2 kidney-1 clip (2K-1C). Significant benefits of MSC treatment have been observed on blood pressure and renal structure of the stenotic kidney. The mechanisms involved are discussed.

Effects of mesenchymal stem cells in renovascular hypertension.

NEW FINDINGS: What is the topic of this review? The major topic of this review addresses the effects of mesenchymal stem cell treatment in renovascular hypertension. What advances does it highlight? This therapy may be a promising strategy to treat renovascular hypertension and its renal consequences in the near future. Renovascular hypertension induced by the two-kidney, one-clip technique is a renin-angiotensin system-dependent model that leads to renal vascular rarefaction, fibrosis and renal failure. Treatment of renovascular hypertension remains a challenge, and thus, new therapies are needed. In this report, we discuss the beneficial effects of mesenchymal stem cells on the reconstruction of the renal parenchyma of the stenotic kidney to improve vascular rarefaction and fibrosis. Mesenchymal stem cell therapy prevented the progressive increase in systolic arterial pressure, reduced sympathetic hyperactivity, improved renal morphology, induced neovascularization and reduced fibrosis in stenotic kidneys. Although this therapy may be a promising strategy to treat renovascular hypertension and its renal consequences, further studies are necessary to improve the efficiency of mesenchymal stem cells.

Effects of high glucose and high insulin concentrations on osteoblast function in vitro.

Bone disease as a consequence of diabetes mellitus (DM) is not fully understood. The effects of high glucose (30 mM), high insulin (50 nM), or mannitol (30 mM; osmotic control) were evaluated on MC3T3-E1 cells (osteoblasts) in vitro. The mRNA and protein levels of parathyroid hormone (PTH) receptor (PTH1R), collagen I, RANKL, osteoprotegerin (OPG), alkaline phosphatase (ALP), and glucose transporter (GLUT1) were estimated by real-time polymerase chain reaction or Western blotting. The mineralization capacity was analyzed by von Kossa staining. High glucose induced overexpression of RANKL (2×) and OPG (30×), suggesting that RANKL-induced osteoclast activity might not be a dominant mechanism of bone disease in DM, since this increase was followed by increased OPG. Collagen I increased by 12×, indicating an excess of organic matrix production. The expression of ALP decreased by 50%, indicating a deficit in mineralization capacity, confirmed by von Kossa staining. Mannitol induced similar effects as glucose suggesting that extracellular hyperosmolarity was able to stimulate organic matrix production. GLUT1 expression was not altered, and insulin did not reverse most of the effects of glucose, suggesting that glucose uptake by osteoblasts was not altered by high glucose. The data suggest that the bone fragility typical of DM is not a consequence of excessive bone reabsorption but is instead attributable to a defect in organic matrix mineralization. The heightened increase in OPG versus RANKL might cause a decrease in the bone-remodeling cycle. Osteoblasts appear to be more sensitive to extracellular hypertonicity than to the intracellular metabolic effects of hyperglycemia.

Mesangial cells cultured from pregnant rats display reduced reactivity to angiotensin II: the role of relaxin, nitric oxide and AT2 receptor.

BACKGROUND/AIMS: Pregnancy is characterized by vasodilatation and increased glomerular filtration rate (GFR), despite overstimulation of the renin angiotensin system (RAS). The mesangial cells (MCs) influences GFR and when cultured from pregnant rats displays refractoriness to Ang II. We evaluated the role of relaxin (RLX) and its receptor (RXFP1), nitric oxide (NO) and the AT2 receptor in this response. METHODS: MCs cultured from kidneys of virgin (V) and pregnant (P) Wistar rats were treated with RLX or AT2 receptor blocker PD123319 or NO synthase inhibitor L-NAME. After 24 hr, intracellular calcium concentration ([Ca]i) was recorded before and after the addition of Ang II. RESULTS: MCs from V group expressed AT2, RLX and RXFP1, whose levels were increased in P cells. Ang II induced a 150% increase in [Ca] i in the V cells and 85% (p<0.05) in the P cells. V cells treated with RLX displayed a similar response to that observed in P cells, suggesting that RLX can modulate the reactivity of the MCs to Ang II. L-NAME and PD123319 did not interfere in this response. CONCLUSION: Results suggest that RLX is a mediator of the refractoriness of the MCs to Ang II during pregnancy.

Effect of hydroalcoholic extract from Copaifera langsdorffii leaves on urolithiasis induced in rats.

Copaifera langsdorffii Desf. commonly known as "copaíba", produce a commercially valuable oil-resin that is extensively used in folk medicine for anti-inflammatory, antimicrobial and antiseptic purposes. We have found the hydroalcoholic extract of this plant leaf has the potential to treat urolithiasis, a problem affecting ~7% of the population. To isolate the functional compounds C. langsdorffii leaves were dried, ground, and macerated in a hydroalcoholic solution 7:3 to produce a 16.8% crude extract after solvent elimination. Urolithiasis was induced by introduction of a calcium oxalate pellet (CaOx) into the bladders of adult male Wistar rats. The treated groups received the crude extract by oral gavage at 20 mg/kg body weight daily for 18 days. Extract treatment started 30 days after CaOx seed implantation. To monitor renal function sodium, potassium and creatinine concentrations were analyzed in urine and plasma, and were found to be in the normal range. Analyses of pH, magnesium, phosphate, calcium, uric acid, oxalate and citrate levels were evaluated to determine whether the C. langsdorffii extract may function as a stone formation prevention agent. The HPLC analysis of the extract identified flavonoids quercitrin and afzelin as the major components. Animals treated with C. langsdorffii have increased levels of magnesium and decreased levels of uric acid in urinary excretions. Treated animals have a significant decrease in the mean number of calculi and a reduction in calculi mass. Calculi taken from extract treated animals were more brittle and fragile than calculi from untreated animals. Moreover, breaking calculi from untreated animals required twice the amount of pressure as calculi from treated animals (6.90 ± 3.45 vs. 3.00 ± 1.51). The extract is rich in flavonoid heterosides and other phenolic compounds. Therefore, we hypothesize this class of compounds might contribute significantly to the observed activity.

The role of oxidative stress in renovascular hypertension.

1. There is mounting evidence that increased oxidative stress and sympathetic nerve activity play important roles in renovascular hypertension. In the present review, we focus on the importance of oxidative stress in two distinct populations of neurons involved with cardiovascular regulation: those of the rostral ventrolateral medulla (RVLM) and those of the paraventricular nucleus of the hypothalamus (PVN) in the maintenance of sympathoexcitation and hypertension in two kidney-one clip (2K1C) hypertensive rats. Furthermore, the role of oxidative stress in the clipped kidney is also discussed. 2. In the studies reviewed in this article, it was found that hypertension and renal sympathoexcitation in 2K1C rats were associated with an increase in Angiotensin II type one receptor (AT(1) ) expression and in oxidative markers within the RVLM, PVN and in the clipped kidneys of 2K1C rats. Furthermore, acute or chronic anti-oxidant treatment decreased blood pressure and sympathetic activity, and improved the baroreflex control of heart rate and renal sympathetic nerve activity in 2K1C rats. Tempol or vitamin C administration in the RVLM, PVN or systemically all reduced blood pressure and renal sympathetic activity. Cardiovascular improvement in response to chronic anti-oxidant treatment was associated with a downregulation of AT(1) receptors, as well as oxidative markers in the central nuclei and clipped kidney. 3. The data discussed in the present review support the idea that an increase in oxidative stress within the RVLM, PVN and in the ischaemic kidney plays a major role in the maintenance of sympathoexcitation and hypertension in 2K1C rats.

Ppia is the most stable housekeeping gene for qRT-PCR normalization in kidneys of three Pkd1-deficient mouse models.

Autosomal Dominant Polycystic Kidney Disease (ADPKD) is the most common inherited renal disorder, characterized by renal cyst development leading to end-stage renal disease. Although the appropriate choice of suitable reference is critical for quantitative RNA analysis, no comparison of frequently used "housekeeping" genes is available. Here, we determined the validity of 7 candidate housekeeping genes (Actb, Actg1, B2m, Gapdh, Hprt, Pgam1 and Ppia) in kidney tissues from mouse models orthologous to ADPKD, including a cystic mice (CY) 10-12 weeks old (Pkd1flox/flox:Nestincre/Pkd1flox/-:Nestincre, n = 10) and non-cystic (NC) controls (Pkd1flox/flox/Pkd1flox/-, n = 10), Pkd1-haploinsufficient (HT) mice (Pkd1+/-, n = 6) and wild-type (WT) controls (Pkd1+/+, n = 6) and a severely cystic (SC) mice 15 days old (Pkd1V/V, n = 7) and their controls (CO, n = 5). Gene expression data were analyzed using six distinct statistical softwares. The estimation of the ideal number of genes suggested the use of Ppia alone as sufficient, although not ideal, to analyze groups altogether. Actb, Hprt and Ppia expression profiles were correlated in all samples. Ppia was identified as the most stable housekeeping gene, while Gapdh was the least stable for all kidney samples. Stat3 expression level was consistent with upregulation in SC compared to CO when normalized by Ppia expression. In conclusion, present findings identified Ppia as the best housekeeping gene for CY + NC and SC + CO groups, while Hprt was the best for the HT + WT group.

Phyllanthus niruri as a promising alternative treatment for nephrolithiasis.

In spite of considerable efforts to identify effective treatments for urolithiasis, this is a goal yet to be achieved. This review summarizes experimental and clinical data evaluating the effect of the plant Phyllanthus niruri, a plant with worldwide distribution, as a potential agent to prevent and/or to treat urolithiasis The review is based on data from the literature and on the results obtained by our group from either in vivo/in vitro experiments or clinical studies. Phyllanthus niruri has been shown to interfere with many stages of stone formation, reducing crystals aggregation, modifying their structure and composition as well as altering the interaction of the crystals with tubular cells leading to reduced subsequent endocytosis. The clinical beneficial effects of Phyllanthus niruri may be related to ureteral relaxation, helping to eliminate calculi or to clear fragments following lithotripsy, or also to a putative reduction of the excretion of urinary crystallization promoters such as calcium. No adverse renal, cardiovascular, neurological or toxic effects have been detected in either of these studies. Altogether, these studies suggest a preventive effect of Phyllanthus niruri in stone formation or elimination, but still longer-term randomized clinical trials are necessary to confirm its therapeutic properties.

904 nm Low-Level Laser Irradiation Decreases Expression of Catabolism-Related Genes in White Adipose Tissue of Wistar Rats: Possible Roles of Laser on Metabolism.

Background: Adipose tissue is the main energy storage tissue in the body. Its catabolic and anabolic responses depend on several factors, such as nutritional status, metabolic profile, and hormonal signaling. There are few studies addressing the effects of laser photobiomodulation (PBM) on adipose tissue and results are controversial. Objective: Our purpose was to investigate the metabolic effects of PBM on adipose tissue from Wistar rats supplemented or not with caffeine. Materials and methods: Wistar rats were divided into four groups: control (CTL), laser-treated [CTL (L)], caffeine (CAF), and caffeine+PBM [CAF (L)]. Blood was extracted for quantification of triglyceride and cholesterol levels and white adipose tissues were collected for analysis. We evaluated gene expression in the adipose tissue for the leptin receptor, lipase-sensitive hormone, tumor necrosis factor alpha, and beta adrenergic receptor. Results: We demonstrated that the low-level laser irradiation was able to increase the feed intake of the animals and the relative mass of the adipose tissue in the CTL (L) group compared with CTL. Laser treatment also increases serum triglycerides [CTL = 46.99 ± 5.87; CTL (L) = 57.46 ± 14.38; CAF = 43.98 ± 5.17; and CAF (L) = 56.9 ± 6.12; p = 0.007] and total cholesterol (CTL = 70.62 ± 6.80; CTL (L) = 79.41 ± 13.07; CAF = 71.01 ± 5.52; and CAF (L) = 79.23 ± 6.881; p = 0.003). Conclusions: Laser PBM decreased gene expression of the studied genes in the adipose tissue, indicating that PBM is able to block the catabolic responses of this tissue. Interestingly, the CAF (L) and CAF animals presented the same CLT (L) phenotype, however, without increasing the feed intake and the relative weight of the adipose tissue. The description of these phenomena opens a new perspective for the study of the action of low-level laser in adipose tissue.