Does the correlation between EBNA-1 and p63 expression in breast carcinomas provide a clue to tumorigenesis in Epstein-Barr virus-related breast malignancies?

Several investigators have identified Epstein-Barr virus (EBV) particles in breast carcinomas, a fact that supports a role for EBV in mammary tumorigenesis. The possible mechanism involved in this process is not clear. The present study was carried out in an attempt to determine whether there is a relationship between latent infection with EBV and p53 and p63 expression in breast carcinomas. Immunohistochemistry developed with 3.3-diaminobenzidine tetrahydrochloride was performed in 85 formalin-fixed paraffin-embedded breast carcinomas using anti-EBV EBNA-1, anti-p63, anti-p53, anti-estrogen receptor (ER) and anti-progesterone receptor (PR) antibodies. The cases were selected to represent each of the various histologic types: intraductal carcinoma (N = 12), grade I invasive ductal carcinoma (N = 15), grade II invasive ductal carcinoma (N = 15), grade III invasive ductal carcinoma (N = 15), tubular carcinoma (N = 8), lobular carcinoma (N = 10), and medullary carcinoma (N = 10). The ductal breast carcinomas were graded I, II and III based on the Scarff-Bloom and Richardson grading system modified by Elston and Ellis. One slide containing at least 1000 neoplastic cells was examined in each case. ER, PR, p63, p53 and EBNA-1 were positive in 60, 40, 11.8, 21.2 and 37.6% of carcinomas, respectively. There was a correlation between EBNA-1 and p63 expression (P < 0.001), but not between EBNA-1 and p53 (P = 0.10). These data suggest a possible role for p63 in the mammary tumorigenesis associated with Epstein-Barr virus infection.

Thalidomide and pentoxifylline block the renal effects of supernatants of macrophages activated with Crotalus durissus cascavella venom

Because thalidomide and pentoxifylline inhibit the synthesis and release of tumor necrosis factor-alpha (TNF-alpha), we determined the effect of these drugs on the renal damage induced by supernatants of macrophages activated with Crotalus durissus cascavella venom in order to identify the role of TNF-alpha in the process. Rat peritoneal macrophages were collected with RPMI medium and stimulated in vitro with C.d. cascavella venom (10 µg/ml) in the absence and presence of thalidomide (15 µM) or pentoxifylline (500 µM) for 1 h and washed and kept in culture for 2 h. Supernatant (1 ml) was tested on an isolated perfused rat kidney (N = 6 for each group). The first 30 min of each experiment were used as control. The supernatant was added to the perfusion system. All experiments lasted 120 min. The toxic effect of the preparation of venom-stimulated macrophages on renal parameters was determined. At 120 min, thalidomide (Thalid) and pentoxifylline (Ptx) inhibited (P < 0.05) the increase in perfusion pressure caused by the venom (control = 114.0 ± 1.3; venom = 137.1 ± 1.5; Thalid = 121.0 ± 2.5; Ptx = 121.4 ± 4.0 mmHg), renal vascular resistance (control = 4.5 ± 0.2; venom = 7.3 ± 0.6; Thalid = 4.5 ± 0.9; Ptx = 4.8 ± 0.6 mmHg/ml g-1 min-1), urinary flow (control = 0.23 ± 0.001; venom = 0.44 ± 0.01; Thalid = 0.22 ± 0.007; Ptx = 0.21 ± 0.009 ml g-1 min-1), glomerular filtration rate (control = 0.72 ± 0.06; venom = 1.91 ± 0.11; Thalid = 0.75 ± 0.04; Ptx = 0.77 ± 0.05 ml g-1 min-1) and the decrease in percent tubular sodium transport (control = 77.0 ± 0.9; venom = 73.9 ± 0.66; Thalid = 76.6 ± 1.1; Ptx = 81.8 ± 2.0%), percent tubular chloride transport (control = 77.1 ± 1.2; venom = 71.4 ± 1.1; Thalid = 77.6 ± 1.7; Ptx = 76.8 ± 1.2%), and percent tubular potassium transport (control = 72.7 ± 1.1; venom = 63.0 ± 1.1; Thalid = 72.6 ± 1.0; Ptx = 74.8 ± 1.0%), 30 min before and during the stimulation of macrophages with C.d. cascavella venom. These data suggest the participation of TNF-alpha in the renal effects induced by supernatant of macrophages activated with C.d. cascavella venom.

In vivo growth-inhibition of Sarcoma 180 by piplartine and piperine, two alkaloid amides from Piper

Piplartine {5,6-dihydro-1-[1-oxo-3-(3,4,5-trimethoxyphenyl)-2-propenyl]-2(1H)pyridinone} and piperine {1-5-(1,3)-benzodioxol-5-yl)-1-oxo-2,4-pentadienyl]piperidine} are alkaloid amides isolated from Piper. Both have been reported to show cytotoxic activity towards several tumor cell lines. In the present study, the in vivo antitumor activity of these compounds was evaluated in 60 female Swiss mice (N = 10 per group) transplanted with Sarcoma 180. Histopathological and morphological analyses of the tumor and the organs, including liver, spleen, and kidney, were performed in order to evaluate the toxicological aspects of the treatment with these amides. Administration of piplartine or piperine (50 or 100 mg kg-1 day-1 intraperitoneally for 7 days starting 1 day after inoculation) inhibited solid tumor development in mice transplanted with Sarcoma 180 cells. The inhibition rates were 28.7 and 52.3% for piplartine and 55.1 and 56.8% for piperine, after 7 days of treatment, at the lower and higher doses, respectively. The antitumor activity of piplartine was related to inhibition of the tumor proliferation rate, as observed by reduction of Ki67 staining, a nuclear antigen associated with G1, S, G2, and M cell cycle phases, in tumors from treated animals. However, piperine did not inhibit cell proliferation as observed in Ki67 immunohistochemical analysis. Histopathological analysis of liver and kidney showed that both organs were reversibly affected by piplartine and piperine treatment, but in a different way. Piperine was more toxic to the liver, leading to ballooning degeneration of hepatocytes, accompanied by microvesicular steatosis in some areas, than piplartine which, in turn, was more toxic to the kidney, leading to discrete hydropic changes of the proximal tubular and glomerular epithelium and tubular hemorrhage in treated animals.

Increased expression of p38 mitogen- activated protein kinase is related to the acute renal lesions induced by gentamicin

Mitogen-activated protein kinases (MAPK) may be involved in the pathogenesis of acute renal failure. This study investigated the expression of p-p38 MAPK and nuclear factor kappa B (NF-kappaB) in the renal cortex of rats treated with gentamicin. Twenty rats were injected with gentamicin, 40 mg/kg, im, twice a day for 9 days, 20 with gentamicin + pyrrolidine dithiocarbamate (PDTC, an NF-kappaB inhibitor), 14 with 0.15 M NaCl, im, twice a day for 9 days, and 14 with 0.15 M NaCl , im, twice a day for 9 days and PDTC, 50 mg kg-1 day-1, ip, twice a day for 15 days. The animals were killed 5 and 30 days after the last of the injections and the kidneys were removed for histological, immunohistochemical and Western blot analysis and for nitrate determination. The results of the immunohistochemical study were evaluated by counting the p-p38 MAPK-positive cells per area of renal cortex measuring 0.05 mm². Creatinine was measured by the Jaffé method in blood samples collected 5 and 30 days after the end of the treatments. Gentamicin-treated rats presented a transitory increase in plasma creatinine levels. In addition, animals killed 5 days after the end of gentamicin treatment presented acute tubular necrosis and increased nitrate levels in the renal cortex. Increased expression of p-p38 MAPK and NF-kappaB was also observed in the kidneys from these animals. The animals killed 30 days after gentamicin treatment showed residual areas of interstitial fibrosis in the renal cortex, although the expression of p-p38 MAPK in their kidneys did not differ from control. Treatment with PDTC reduced the functional and structural changes induced by gentamicin as well as the expression of p-p38 MAPK and NF-kappaB. The increased expression of p-p38 MAPK and NF-kappaB observed in these rats suggests that these signaling molecules may be involved in the pathogenesis of tubulointerstitial nephritis induced by gentamicin.

Determination of renal function in long-term heart transplant patients by measurement of urinary retinol-binding protein levels

Significant improvements have been noted in heart transplantation with the advent of cyclosporine. However, cyclosporine use is associated with significant side effects, such as chronic renal failure. We were interested in evaluating the incidence of long-term renal dysfunction in heart transplant recipients. Fifty-three heart transplant recipients were enrolled in the study. Forty-three patients completed the entire evaluation and follow-up. Glomerular (serum creatinine, creatinine clearance measured, and creatinine clearance calculated) and tubular functions (urinary retinol-binding protein, uRBP) were re-analyzed after 18 months. At the enrollment time, the prevalence of renal failure ranged from 37.7 to 54% according to criteria used to define it (serum creatinine > or = 1.5 mg/dL and creatinine clearance <60 mL/min). Mean serum creatinine was 1.61 ± 1.31 mg/dL (range 0.7 to 9.8 mg/dL) and calculated and measured creatinine clearances were 67.7 ± 25.9 and 61.18 ± 25.04 mL min-1 (1.73 m²)-1, respectively. Sixteen of the 43 patients who completed the follow-up (37.2%) had tubular dysfunction detected by increased levels of uRBP (median 1.06, 0.412-6.396 mg/dL). Eleven of the 16 patients (68.7%) with elevated uRBP had poorer renal function after 18 months of follow-up, compared with only eight of the 27 patients (29.6%) with normal uRBP (RR = 3.47, P = 0.0095). Interestingly, cyclosporine trough levels were not different between patients with or without tubular and glomerular dysfunction. Renal function impairment is common after heart transplantation. Tubular dysfunction, assessed by uRBP, correlates with a worsening of glomerular filtration and can be a useful tool for early detection of renal dysfunction.

Molecular and cellular pathogenesis of autosomal recessive polycystic kidney disease

Autosomal recessive polycystic kidney disease (ARPKD) is an inherited disease characterized by a malformation complex which includes cystically dilated tubules in the kidneys and ductal plate malformation in the liver. The disorder is observed primarily in infancy and childhood, being responsible for significant pediatric morbidity and mortality. All typical forms of ARPKD are caused by mutations in a single gene, PKHD1 (polycystic kidney and hepatic disease 1). This gene has a minimum of 86 exons, assembled into multiple differentially spliced transcripts and has its highest level of expression in kidney, pancreas and liver. Mutational analyses revealed that all patients with both mutations associated with truncation of the longest open reading frame-encoded protein displayed the severe phenotype. This product, polyductin, is a 4,074-amino acid protein expressed in the cytoplasm, plasma membrane and primary apical cilia, a structure that has been implicated in the pathogenesis of different polycystic kidney diseases. In fact, cholangiocytes isolated from an ARPKD rat model develop shorter and dysmorphic cilia, suggesting polyductin to be important for normal ciliary morphology. Polyductin seems also to participate in tubule morphogenesis and cell mitotic orientation along the tubular axis. The recent advances in the understanding of in vitro and animal models of polycystic kidney diseases have shed light on the molecular and cellular mechanisms of cyst formation and progression, allowing the initiation of therapeutic strategy designing and promising perspectives for ARPKD patients. It is notable that vasopressin V2 receptor antagonists can inhibit/halt the renal cystic disease progression in an orthologous rat model of human ARPKD.

Contribution of CD4+ T cells to the early mechanisms of ischemia- reperfusion injury in a mouse model of acute renal failure

Renal ischemia-reperfusion (IR) injury is the major cause of acute renal failure in native and transplanted kidneys. Mononuclear leukocytes have been reported in renal tissue as part of the innate and adaptive responses triggered by IR. We investigated the participation of CD4+ T lymphocytes in the pathogenesis of renal IR injury. Male mice (C57BL/6, 8 to 12 weeks old) were submitted to 45 min of ischemia by renal pedicle clamping followed by reperfusion. We evaluated the role of CD4+ T cells using a monoclonal depleting antibody against CD4 (GK1.5, 50 µ, ip), and class II-major histocompatibility complex molecule knockout mice. Both CD4-depleted groups showed a marked improvement in renal function compared to the ischemic group, despite the fact that GK1.5 mAb treatment promoted a profound CD4 depletion (to less than 5% compared to normal controls) only within the first 24 h after IR. CD4-depleted groups presented a significant improvement in 5-day survival (84 vs 80 vs 39%; antibody treated, knockout mice and non-depleted groups, respectively) and also a significant reduction in the tubular necrosis area with an early tubular regeneration pattern. The peak of CD4-positive cell infiltration occurred on day 2, coinciding with the high expression of ßC mRNA and increased urea levels. CD4 depletion did not alter the CD11b infiltrate or the IFN-g and granzyme-B mRNA expression in renal tissue. These data indicate that a CD4+ subset of T lymphocytes may be implicated as key mediators of very early inflammatory responses after renal IR injury and that targeting CD4+ T lymphocytes may yield novel therapies.

Are the current chronic allograft nephropathy grading systems sufficient to predict renal allograft survival?

A major problem in renal transplantation is identifying a grading system that can predict long-term graft survival. The present study determined the extent to which the two existing grading systems (Banff 97 and chronic allograft damage index, CADI) correlate with each other and with graft loss. A total of 161 transplant patient biopsies with chronic allograft nephropathy (CAN) were studied. The samples were coded and evaluated blindly by two pathologists using the two grading systems. Logistic regression analyses were used to evaluate the best predictor index for renal allograft loss. Patients with higher Banff 97 and CADI scores had higher rates of graft loss. Moreover, these measures also correlated with worse renal function and higher proteinuria levels at the time of CAN diagnosis. Logistic regression analyses showed that the use of angiotensin-converting enzyme inhibitor (ACEI), hepatitis C virus (HCV), tubular atrophy, and the use of mycophenolate mofetil (MMF) were associated with graft loss in the CADI, while the use of ACEI, HCV, moderate interstitial fibrosis and tubular atrophy and the use of MMF were associated in the Banff 97 index. Although Banff 97 and CADI analyze different parameters in different renal compartments, only some isolated parameters correlated with graft loss. This suggests that we need to review the CAN grading systems in order to devise a system that includes all parameters able to predict long-term graft survival, including chronic glomerulopathy, glomerular sclerosis, vascular changes, and severity of chronic interstitial fibrosis and tubular atrophy.

Roles of mitogen-activated protein kinases and angiotensin II in renal development

Experimental and clinical evidence suggests that angiotensin II (AII) participates in renal development. Renal AII content is several-fold higher in newborn rats and mice than in adult animals. AII receptors are also expressed in higher amounts in the kidneys of newborn rats. The kidneys of fetuses whose mother received a type 1 AII receptor (AT1) antagonist during gestation present several morphological alterations. Mutations in genes that encode components of the renin-angiotensin system are associated with autosomal recessive renal tubular dysgenesis. Morphological changes were detected in the kidneys of 3-week-old angiotensin-deficient mice. Mitogen-activated protein kinases (MAPKs) are important mediators that transduce extracellular stimuli to intracellular responses. The MAPK family comprises three major subgroups, namely extracellular signal-regulated protein kinase (ERK), c-jun N-terminal kinases (JNK), and p38 MAPK (p38). Important events in renal growth during nephrogenesis such as cellular proliferation and differentiation accompanied by apoptosis on a large scale can be mediated by MAPK pathways. A decrease in glomerulus number was observed in embryos cultured for 48 and 120 h with ERK or p38 inhibitors. Many effects of AII are mediated by MAPK pathways. Treatment with losartan during lactation provoked changes in renal function and structure associated with alterations in AT1 and type 2 AII (AT2) receptors and p-JNK and p-p38 expression in the kidney. Several studies have shown that AII and MAPKs play an important role in renal development. However, the relationship between the effects of AII and MAPK activation on renal development is still unclear.

Monitoring renal function: measured and estimated glomerular filtration rates - a review

Chronic kidney disease (CKD) is a world-wide public health problem, with adverse outcomes of kidney failure, cardiovascular disease, and premature death. This finding has led to the hypothesis that earlier recognition of kidney disease and successful intervention may improve outcome. The National Kidney Foundation, through its Kidney Disease Outcomes Quality Initiative (K/DOQI), and other National institutions recommend glomerular filtration rate (GFR) for the definition, classification, screening, and monitoring of CKD. Blood creatinine clearance, the most widely used clinical marker of kidney function, is now recognized as an unreliable measure of GFR because serum creatinine is affected by age, weight, muscle mass, race, various medications, and extra-glomerular elimination. Cystatin C concentration is a new and promising marker for kidney dysfunction in both native and transplanted kidneys. Because of its low molecular weight, cystatin C is freely filtered at the glomerulus and is almost completely reabsorbed and catabolized, but not secreted, by tubular cells. Given these characteristics, cystatin C concentration may be superior to creatinine concentration in detecting chronic kidney disease. This review aims to evaluate from recent literature the clinical efficiency and relevance of these GFR markers in terms of screening CKD.

Glomerular damage as a predictor of renal allograft loss

Interstitial fibrosis and tubular atrophy (IF/TA) are the most common cause of renal graft failure. Chronic transplant glomerulopathy (CTG) is present in approximately 1.5-3.0% of all renal grafts. We retrospectively studied the contribution of CTG and recurrent post-transplant glomerulopathies (RGN) to graft loss. We analyzed 123 patients with chronic renal allograft dysfunction and divided them into three groups: CTG (N = 37), RGN (N = 21), and IF/TA (N = 65). Demographic data were analyzed and the variables related to graft function identified by statistical methods. CTG had a significantly lower allograft survival than IF/TA. In a multivariate analysis, protective factors for allograft outcomes were: use of angiotensin-converting enzyme inhibitor (ACEI; hazard ratio (HR) = 0.12, P = 0.001), mycophenolate mofetil (MMF; HR = 0.17, P = 0.026), hepatitis C virus (HR = 7.29, P = 0.003), delayed graft function (HR = 5.32, P = 0.016), serum creatinine ≥1.5 mg/dL at the 1st year post-transplant (HR = 0.20, P = 0.011), and proteinuria ≥0.5 g/24 h at the 1st year post-transplant (HR = 0.14, P = 0.004). The presence of glomerular damage is a risk factor for allograft loss (HR = 4.55, P = 0.015). The presence of some degree of chronic glomerular damage in addition to the diagnosis of IF/TA was the most important risk factor associated with allograft loss since it could indicate chronic active antibody-mediated rejection. ACEI and MMF were associated with better outcomes, indicating that they might improve graft survival.

Effects of sirolimus alone or in combination with cyclosporine A on renal ischemia/reperfusion injury

Calcineurin inhibitors exacerbate ischemic injury in transplanted kidneys, but it is not known if sirolimus protects or exacerbates the transplanted kidney from ischemic injury. We determined the effects of sirolimus alone or in combination with cyclosporin A (CsA) on oxygenated and hypoxic/reoxygenated rat proximal tubules in the following in vitro groups containing 6-9 rats per group: sirolimus (10, 50, 100, 250, 500, and 1000 ηg/mL); CsA (100 µg/mL); sirolimus (50 and 250 ηg/mL) + CsA (100 µg/mL); control; vehicle (20% ethanol). For in vivo studies, 3-week-old Wistar rats (150-250 g) were submitted to left nephrectomy and 30-min renal artery clamping. Renal function and histological evaluation were performed 24 h and 7 days after ischemia (I) in five groups: sham, I, I + SRL (3 mg·kg-1·day-1, po), I + CsA (3 mg·kg-1·day-1, sc), I + SRL + CsA. Sirolimus did not injure oxygenated or hypoxic/reoxygenated proximal tubules and did not potentiate the tubular toxic effects of CsA. Neither drug affected the glomerular filtration rate (GFR) at 24 h. GFR was reduced in CsA-treated rats on day 7 (0.5 ± 0.1 mL/min) but not in rats receiving sirolimus + CsA (0.8 ± 0.1 mL/min) despite the reduction in renal blood flow (3.9 ± 0.5 mL/min). Acute tubular necrosis regeneration was similar for all groups. Sirolimus alone was not toxic and did not enhance hypoxia/reoxygenation injury or CsA toxicity to proximal tubules. Despite its hemodynamic effects, sirolimus protected post-ischemic kidneys against CsA toxicity.

Effect of endogenous hydrogen sulfide inhibition on structural and functional renal disturbances induced by gentamicin

Animal models of gentamicin nephrotoxicity present acute tubular necrosis associated with inflammation, which can contribute to intensify the renal damage. Hydrogen sulfide (H2S) is a signaling molecule involved in inflammation. We evaluated the effect of DL-propargylglycine (PAG), an inhibitor of endogenous H2S formation, on the renal damage induced by gentamicin. Male Wistar rats (N = 8) were injected with 40 mg/kg gentamicin (im) twice a day for 9 days, some of them also received PAG (N = 8, 10 mg·kg-1·day-1, ip). Control rats (N = 6) were treated with saline or PAG only (N = 4). Twenty-four-hour urine samples were collected one day after the end of these treatments, blood samples were collected, the animals were sacrificed, and the kidneys were removed for quantification of H2S formation and histological and immunohistochemical studies. Gentamicin-treated rats presented higher sodium and potassium fractional excretion, increased plasma creatinine [4.06 (3.00; 5.87) mg%] and urea levels, a greater number of macrophages/monocytes, and a higher score for tubular interstitial lesions [3.50 (3.00; 4.00)] in the renal cortex. These changes were associated with increased H2S formation in the kidneys from gentamicin-treated rats (230.60 ± 38.62 µg·mg protein-1·h-1) compared to control (21.12 ± 1.63) and PAG (11.44 ± 3.08). Treatment with PAG reduced this increase (171.60 ± 18.34), the disturbances in plasma creatinine levels [2.20 (1.92; 4.60) mg%], macrophage infiltration, and score for tubular interstitial lesions [2.00 (2.00; 3.00)]. However, PAG did not interfere with the increase in fractional sodium excretion provoked by gentamicin. The protective effect of PAG on gentamicin nephrotoxicity was related, at least in part, to decreased H2S formation.

Mechanisms of endothelial dysfunction in obesity-associated hypertension

Obesity is strongly associated with high blood pressure, dyslipidemia, and type 2 diabetes. These conditions synergistically increase the risk of cardiovascular events. A number of central and peripheral abnormalities can explain the development or maintenance of high blood pressure in obesity. Of great interest is endothelial dysfunction, considered to be a primary risk factor in the development of hypertension. Additional mechanisms also related to endothelial dysfunction have been proposed to mediate the development of hypertension in obese individuals. These include: increase in both peripheral vasoconstriction and renal tubular sodium reabsorption, increased sympathetic activity and overactivation of both the renin-angiotensin system and the endocannabinoid system and insulin resistance. The discovery of new mechanisms regulating metabolic and vascular function and a better understanding of how vascular function can be influenced by these systems would facilitate the development of new therapies for treatment of obesity-associated hypertension.

Salt-induced epithelial-to-mesenchymal transition in Dahl salt-sensitive rats is dependent on elevated blood pressure

Dietary salt intake has been linked to hypertension and cardiovascular disease. Accumulating evidence has indicated that salt-sensitive individuals on high salt intake are more likely to develop renal fibrosis. Epithelial-to-mesenchymal transition (EMT) participates in the development and progression of renal fibrosis in humans and animals. The objective of this study was to investigate the impact of a high-salt diet on EMT in Dahl salt-sensitive (SS) rats. Twenty-four male SS and consomic SS-13BN rats were randomized to a normal diet or a high-salt diet. After 4 weeks, systolic blood pressure (SBP) and albuminuria were analyzed, and renal fibrosis was histopathologically evaluated. Tubular EMT was evaluated using immunohistochemistry and real-time PCR with E-cadherin and alpha smooth muscle actin (α-SMA). After 4 weeks, SBP and albuminuria were significantly increased in the SS high-salt group compared with the normal diet group. Dietary salt intake induced renal fibrosis and tubular EMT as identified by reduced expression of E-cadherin and enhanced expression of α-SMA in SS rats. Both blood pressure and renal interstitial fibrosis were negatively correlated with E-cadherin but positively correlated with α-SMA. Salt intake induced tubular EMT and renal injury in SS rats, and this relationship might depend on the increase in blood pressure.