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A 27-year-old female at 20th week of pregnancy was admitted with edema, foamy urine, but normal blood pressure. Her blood count was normal, she had proteinuria of 3 g/day, creatinine 0.4 mg/dl, albumin 2.4 g/dl, and cholesterol 355 mg/dl. Antinuclear antibodies 1/160, but Anti-DNA, anticardiolipin antibodies and lupus anticoagulant were negative, with normal serum C3 and C4. A renal biopsy showed secondary membranous glomerulopathy, most likely lupus class V pure. Steroids, azathioprine, and aspirin were initiated, up to 28 weeks of pregnancy, when she developed severe hypertension, photopsia, headache, anasarca, extensive bruising of the extremities, severe anemia, thrombocytopenia, and creatinine rose to 2.09 mg/dl with preserved diuresis. A female infant, 1045 grams, was delivered by emergency caesarean section. Following the surgery, she experienced diplopia, dysarthria, bradypsychia, and sensory alterations in the lower extremities, necessitating emergency hemodialysis due to pulmonary congestion. Blood smear revealed schistocytes, LDH elevated at 1148 IU/L, while transaminases and liver function remained normal, suggesting thrombotic thrombocytopenic purpura. ADAMTS13 revealed 6% activity with the presence of inhibitor. Mycophenolate and daily plasmapheresis with fresh frozen plasma replacement yielded unsatisfactory response, unaffected by the addition of methylprednisolone pulses and rituximab. Eventually, intravenous cyclophosphamide was introduced, resulting in complete hematological remission and normalization of ADAMTS13, however dialysis-dependence persisted and four years later, right renal cancer prompted bilateral nephrectomy. After a total follow-up of six years, she remained free of neoplastic recurrence and lupus activity, receiving prednisone and hydroxychloroquine. The differential diagnosis of microangiopathic syndrome in a pregnant lupus patient is discussed., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Leiva, Navarro, Carpio and Ardiles.)

Background: Anemia exhibits complex causation mechanisms and genetic heterogeneity. Some cases result in poor outcomes with multisystemic dysfunction, including renal tubulopathy. Early diagnosis is crucial to improve management., Case-Diagnosis/treatment: A 21-month-old female patient was admitted with severe anemia. Persistent neutropenia and dysplastic signs suggested myelodysplastic syndrome, but targeted gene panel results were negative. After multiple transfusions, spontaneous hematologic recovery was observed. At 4 years old, she presented failure to thrive, renal Fanconi syndrome, and severe metabolic acidosis. Differential diagnosis included Pearson syndrome (PS), a life-threatening condition associated with mitochondrial DNA (mtDNA), featuring anemia and pancreatic insufficiency. Further analysis revealed a ~ 7.5 kb mtDNA deletion. Until the age of 5, supportive care has been provided, without pancreatic insufficiency., Conclusions: This PS case highlights the importance of genetic testing, even in the absence of typical features. Understanding the nature of mitochondrial disorders enables treatment tailoring and counseling about the prognosis., (© 2023. The Author(s), under exclusive licence to International Pediatric Nephrology Association.)

Introduction: Severe acute respiratory syndrome virus 2 (SARS-CoV-2) has caused over million deaths worldwide, with more than 61,000 deaths in Chile. The Chilean government has implemented a vaccination program against SARS-CoV-2, with over 17.7 million people receiving a complete vaccination scheme. The final target is 18 million individuals. The most common vaccines used in Chile are CoronaVac (Sinovac) and BNT162b2 (Pfizer-Biotech). Given the global need for vaccine boosters to combat the impact of emerging virus variants, studying the immune response to SARS-CoV-2 is crucial. In this study, we characterize the humoral immune response in inoculated volunteers from Chile who received vaccination schemes consisting of two doses of CoronaVac [CoronaVac (2x)], two doses of CoronaVac plus one dose of BNT162b2 [CoronaVac (2x) + BNT162b2 (1x)], and three doses of BNT162b2 [BNT162b2 (3x)]., Methods: We recruited 469 participants from Clínica Dávila in Santiago and the Health Center Víctor Manuel Fernández in the city of Concepción, Chile. Additionally, we included participants who had recovered from COVID-19 but were not vaccinated (RCN). We analyzed antibodies, including anti-N, anti-S1-RBD, and neutralizing antibodies against SARS-CoV-2., Results: We found that antibodies against the SARS-CoV-2 nucleoprotein were significantly higher in the CoronaVac (2x) and RCN groups compared to the CoronaVac (2x) + BNT162b2 (1x) or BNT162b2 (3x) groups. However, the CoronaVac (2x) + BNT162b2 (1x) and BNT162b2 (3x) groups exhibited a higher concentration of S1-RBD antibodies than the CoronaVac (2x) group and RCN group. There were no significant differences in S1-RBD antibody titers between the CoronaVac (2x) + BNT162b2 (1x) and BNT162b2 (3x) groups. Finally, the group immunized with BNT162b2 (3x) had higher levels of neutralizing antibodies compared to the RCN group, as well as the CoronaVac (2x) and CoronaVac (2x) + BNT162b2 (1x) groups., Discussion: These findings suggest that vaccination induces the secretion of antibodies against SARS-CoV-2, and a booster dose of BNT162b2 is necessary to generate a protective immune response. In the current state of the pandemic, these data support the Ministry of Health of the Government of Chile's decision to promote heterologous vaccination as they indicate that a significant portion of the Chilean population has neutralizing antibodies against SARS-CoV-2., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Díaz-Dinamarca, Díaz, Barra, Puentes, Arata, Grossolli, Riveros-Rodriguez, Ardiles, Santelises, Vasquez-Saez, Escobar, Soto, Canales, Díaz, Lamperti, Castillo, Urra, Zuñiga, Ormazabal, Nova-Lamperti, Benítez, Rivera, Cortes, Valenzuela, García-Escorza and Vasquez.)

This article reviews the pulmonary manifestations of anti-neutrophil cytoplasmic antibody associated vasculitis (AAV). Its frequency in the different phenotypes of the disease, clinical manifestations and updated therapeutic recommendations are reviewed, aiming to alert the medical community about the existence of these diseases. We pretend to stimulate a timely suspicion, diagnostic precision, and the implementation of effective therapies, to reduce the eventual sequelae derived from a diagnostic omission or an inappropriate treatment for the different clinical scenarios in which these diseases appear.

Cyclosporine (CsA) and tacrolimus (TAC) are immunosuppressant drugs characterized by a narrow therapeutic range and high pharmacokinetic variability. The effect of polymorphisms in genes related to the metabolism and transport of these drugs, namely CYP3A4 , CYP3A5 , MDR1 and POR genes, has been evaluated in diverse populations. However, the impact of these polymorphisms on drug disposition is not well established in Latin American populations. Using TaqMan ® probes, we determined the allelic frequency of seven variants in CYP3A4 , CYP3A5 , MDR1 and POR in 139 Chilean renal transplant recipients, of which 89 were treated with CsA and 50 with TAC. We tested associations between variants and trough and/or 2-hour concentrations, normalized by dose (C 0 /D and C 2 /D) at specific time points post-transplant. We found that CYP3A5*3/*3 carriers required lower doses of TAC. In TAC treated patients, most CYP3A5*3/*3 carriers presented higher C 0 /D and a high proportion of patients with C 0 levels outside the therapeutic range relative to other genotypes. These results reinforce the value of considering CYP3A5 genotypes alongside therapeutic drug monitoring for TAC treated Chilean kidney recipients., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Contreras-Castillo, Plaza, Stojanova, Navarro, Carmona, Corvalán, Cerpa, Sandoval, Muñoz, Leiva, Castañeda, Farias, Alvarez, Llull, Mezzano, Ardiles, Varela, Rodríguez, Flores, Cayún, Krall and Quiñones.)

Renal papillary necrosis is an infrequent cause of hematuria characterized by ischemic necrosis of the renal medulla, especially the papilla. Its most common cause is analgesic abuse. Despite being oligo-symptomatic, in many cases its presence is associated with serious functional sequelae. Imaging, especially computed tomography, is essential to make the diagnosis. We report a 63-year-old female studied for an asymptomatic microscopic hematuria whose tomographic study showed a bilateral renal papillary necrosis. No etiology was found, and she evolved with a spontaneous complete remission.

Background: To reduce the progression of chronic kidney disease (CKD) and cardiovascular risk, the guidelines recommend the blockade of the renin-angiotensin-aldosterone system (RAAS) in patients with proteinuria., Aim: To assess the frequency of enalapril or losartan use in diabetics or hypertensive patients with stage 3 CKD., Material and Methods: Review of clinical records of patients with CKD in an urban primary care clinic., Results: We identified 408 subjects aged 40 to 98 years (66% women) with stage 3 CKD. Sixty six percent had only hypertension and 34% were diabetic with or without hypertension. Seventy four percent received RAAS blockers (52% used enalapril, 45% losartan and 2% both medications). RAAS blockers were used in 70% of hypertensive and 78% of diabetic patients. The prescription in hypertensive diabetics with microalbuminuria was lower than in those without microalbuminuria (72% vs 87%, p < 0.05), but the opposite occurred in pure hypertensive patients with and without microalbuminuria (88% vs 69%, p < 0.05). There were no significant differences in blood pressure levels, microalbuminuria or serum potassium levels between RAAS blocker users and non-users. No differences were observed either between enalapril and losartan users., Conclusions: The adherence to clinical guidelines is insufficient and users of the recommended drugs did not achieve the expected goals.

Background: The existence and type of renal involvement influences the prognosis of systemic lupus erythematosus and this information may be critical when it comes to taking appropriate therapeutic decisions., Objective: To evaluate statistical correlations between clinical and histological data in patients with biopsied lupus nephropathy., Methods: Review of clinical information in adult kidney biopsy requests reported between 2002 and 2014 with a definitive clinical and histopathological diagnosis of renal involvement in systemic lupus erythematosus., Results: 134 cases (86% women), aged 15-59 years. Indication for renal biopsy: asymptomatic urinary abnormalities (30%), nephrotic proteinuria without hypoalbuminaemia (9%), nephrotic syndrome (19%), renal failure (40%) and two cases without clinical renal manifestations. The most common lesions were purely proliferative (68%). In patients with asymptomatic urinary abnormalities, 35% were class IV, 30% class III, 23% mixed, 10% class V and 2% class II. In subjects with nephrotic proteinuria, 75% were class IV, 17% mixed and 8% class III. In nephrotic syndrome patients, 46% were class IV, 27% class V, 19% mixed and 8% class III. In renal failure subjects, 67% were class IV, 22% mixed, 7% class III and 4% class V. These proportions were not statistically different. Although class IV showed the worst renal function, almost half (44%) of those without renal failure belonged to this class., Conclusion: We could not demonstrate a consistent clinical-pathological relationship that predicts patterns or severity of histological findings based on the clinical profile in patients with systemic lupus erythematosus and renal manifestations. These results highlight the importance of biopsy as a key diagnostic tool in this disease., (Copyright © 2018 Sociedad Española de Nefrología. Published by Elsevier España, S.L.U. All rights reserved.)

We report a 19 years old male presenting with knee pain, elevated liver enzymes and proteinuria. Further investigation found positive antinuclear and anti-smooth muscle antibodies and a liver biopsy revealed the presence of an autoimmune hepatitis. Treatment with corticosteroids and azathioprine was started, resulting in normalization of liver enzymes but proteinuria persisted and a kidney biopsy disclosed a focal segmental glomerulosclerosis. The use of lisinopril resulted in a significative reduction of proteinuria and, after 30 months of follow up, he continues with azathioprine, lisinopril and a low prednisone dose without evidence of liver or kidney disease activity.

Renal involvement is a frequent complication in antineutrophil cytoplasmic antibodies (ANCA)associated vasculitides, adding morbidity and mortality, such as chronic kidney disease and the need for renal replacement therapy. With the aim of reaching a consensus on relevant issues regarding the diagnosis, treatment and follow-up of patients with these diseases, the Chilean Societies of Nephrology and Rheumatology formed a working group that, based on a critical review of the available literature and their experience, raised and answered consensually a set of questions relevant to the subject. This document includes aspects related to the clinical diagnosis, the histological characteristics, the therapeutic alternatives to induce and maintain the remission of the disease, relapse surveillance strategies and complementary therapies.

The case of a male patient under hemodialytic therapy, who developed right heart failure is presented. Echocardiography revealed pericardial effusion, constrictive pattem in the right cavities, septation, without valvular damage and preserved systolic and diastolic function. Pericardial drainage and extensive pericardiectomy was performed obtaining cultures of pericardial tissue positive for an HACEK group organism, Cardiobacterium hominis, with repeatedly negative blood cultures. This is a rare clinical presentation of isolated bacterial pericarditis by an atypical microorganism, without associated endocarditis. The infection mechanisms are presented and the scarce available scientific literature is discussed in this study.

Renal involvement affects over one half of patients with Systemic Lupus Erythematosus increasing their mortality and morbidity, including chronic renal disease and the need of renal replacement therapies. Aiming to achieve a consensus in the most relevant topics on diagnosis, therapy and follow-up of patients with lupus renal disease, the Chilean Societies of Nephrology and Rheumatology constituted a workgroup that, based on a critical review of the available literature and their experience, raised and answered by consensus a set of relevant questions. This document includes aspects related to the clinical diagnosis, the importance of a suitable histological classification, therapeutic alternatives to induce and maintain disease remission, strategies for follow-up, additional therapies and gynecological-obstetric issues.

The presence of high protein levels in the glomerular filtrate plays an important role in renal fibrosis, a disorder that justifies the use of animal models of experimental proteinuria. Such models have proved useful as tools in the study of the pathogenesis of chronic, progressive renal disease. Since bradykinin and the kinin B2 receptor (B2R) belong to a renoprotective system with mechanisms still unclarified, we investigated its anti-fibrotic role in the in vivo rat model of overload proteinuria. Upon up-regulating the kinin system by a high potassium diet we observed reduction of tubulointerstitial fibrosis, decreased renal expression of α-smooth muscle actin (α-SMA) and vimentin, reduced Smad3 phosphorylation and increase of Smad7. These cellular and molecular effects were reversed by HOE-140, a specific B2R antagonist. In vitro experiments, performed on a cell line of proximal tubular epithelial cells, showed that high concentrations of albumin induced expression of mesenchymal biomarkers, in concomitance with increases in TGF-β1 mRNA and its functionally active peptide, TGF-β1. Stimulation of the tubule cells by bradykinin inhibited the albumin-induced changes, namely α-SMA and vimentin were reduced, and cytokeratin recovered together with increase in Smad7 levels and decrease in type II TGF-β1 receptor, TGF-β1 mRNA and its active fragment. The protective changes produced by bradykinin in vitro were blocked by HOE-140. The development of stable bradykinin analogues and/or up-regulation of the B2R signaling pathway may prove value in the management of chronic renal fibrosis in progressive proteinuric renal diseases., (Copyright © 2015 Elsevier Inc. All rights reserved.)

A higher frequency of chronic renal disease is observed in obese patients, suggesting a pathogenic association between both conditions. Obesity unmasks clinical manifestations of chronic kidney disease such as high blood pressure, which may accelerate its progression. Obesity also promotes hyper filtration and the appearance of microalbuminuria, activates the renin-angiotensin-aldosterone system and is associated with high levels of pro-inflammatory cytokines. Therefore weight reduction may slow the progression of chronic renal disease and reduce its associated cardiovascular risk factors.

Antineoplastic treatment with cisplatin is frequently complicated by nephrotoxicity. Although oxidative stress may be involved, the pathogenic mechanisms responsible for renal damage have not been completely clarified. In order to investigate the role of the renal kinin system in this condition, a group of rats was submitted to high potassium diet to stimulate the synthesis and excretion of tissue kallikrein 1 (rKLK1) previous to an intraperitoneal injection of 7 mg/kg cisplatin. A significant reduction in lipoperoxidation, evidenced by urinary excretion of malondialdehyde and renal immunostaining of hidroxy-nonenal, was accompanied by a decline in apoptosis. Coincident with these findings we observed a reduction in the expression of renal KIM-1 suggesting that renoprotection may be occurring. Stimulation or indemnity of the renal kinin system deserves to be evaluated as a complementary pharmacological measure to diminish cisplatin nephrotoxicity., (Copyright © 2014 Elsevier Inc. All rights reserved.)

A growing number of patients are recognized worldwide to have chronic kidney disease. Glomerular and interstitial fibrosis are hallmarks of renal progression. However, fibrosis of the kidney remains an unresolved challenge, and its molecular mechanisms are still not fully understood. Gremlin is an embryogenic gene that has been shown to play a key role in nephrogenesis, and its expression is generally low in the normal adult kidney. However, gremlin expression is elevated in many human renal diseases, including diabetic nephropathy, pauci-immune glomerulonephritis and chronic allograft nephropathy. Several studies have proposed that gremlin may be involved in renal damage by acting as a downstream mediator of TGF-β. To examine the in vivo role of gremlin in kidney pathophysiology, we generated seven viable transgenic mouse lines expressing human gremlin (GREM1) specifically in renal proximal tubular epithelial cells under the control of an androgen-regulated promoter. These lines demonstrated 1.2- to 200-fold increased GREM1 expression. GREM1 transgenic mice presented a normal phenotype and were without proteinuria and renal function involvement. In response to the acute renal damage cause by folic acid nephrotoxicity, tubule-specific GREM1 transgenic mice developed increased proteinuria after 7 and 14 days compared with wild-type treated mice. At 14 days tubular lesions, such as dilatation, epithelium flattening and hyaline casts, with interstitial cell infiltration and mild fibrosis were significantly more prominent in transgenic mice than wild-type mice. Tubular GREM1 overexpression was correlated with the renal upregulation of profibrotic factors, such as TGF-β and αSMA, and with increased numbers of monocytes/macrophages and lymphocytes compared to wild-type mice. Taken together, our results suggest that GREM1-overexpressing mice have an increased susceptibility to renal damage, supporting the involvement of gremlin in renal damage progression. This transgenic mouse model could be used as a new tool for enhancing the knowledge of renal disease progression.

The albumin overload model induces proteinuria and tubulointersitial damage, followed by hypertension when rats are exposed to a hypersodic diet. To understand the effect of kinin system stimulation on salt-sensitive hypertension and to explore its potential renoprotective effects, the model was induced in Sprague-Dawley rats that had previously received a high-potassium diet to enhance activity of the kinin pathway, followed with/without administration of icatibant to block the kinin B₂ receptor (B₂R). A disease control group received albumin but not potassium or icatibant, and all groups were exposed to a hypersodic diet to induce salt-sensitive hypertension. Potassium treatment increased the synthesis and excretion of tissue kallikrein (Klk1/rKLK1) accompanied by a significant reduction in blood pressure and renal fibrosis and with downregulation of renal transforming growth factor-β (TGF-β) mRNA and protein compared with rats that did not receive potassium. Participation of the B₂R was evidenced by the fact that all beneficial effects were lost in the presence of the B₂R antagonist. In vitro experiments using the HK-2 proximal tubule cell line showed that treatment of tubular cells with 10 nM bradykinin reduced the epithelial-mesenchymal transdifferentiation and albumin-induced production of TGF-β, and the effects produced by bradykinin were prevented by pretreatment with the B₂R antagonist. These experiments support not only the pathogenic role of the kinin pathway in salt sensitivity but also sustain its role as a renoprotective, antifibrotic paracrine system that modulates renal levels of TGF-β.

An important proportion of patients with essential hypertension are salt sensitive, defined as those who experience significant blood pressure changes according to the amount of salt intake. They have a disturbance in the pressure induced natriuresis mechanism and their kidneys have functional and morphological alterations consistent with an acquired tubulointerstitial alteration, afferent arteriole damage and alteration of peritubular capillaries. All these alterations lead to disturbances in sodium load excretion under normal pressures. There is also an associated activation of kidney vasoconstrictor/salt retaining systems and a reduction in the vasodilator/salt eliminating mechanisms. These alterations, that originate early in life, generate a new blood pressure level, that corrects natriuresis at the expense of a sustained hypertension.

The prevalence of 20 diseases was studied in a representative sample of 3619 individuals in Chile. Twelve percent of the participants were younger than 25, 63% were 25-64 years old, and 25% were at least 65 years old. Thirty-four percent had high blood pressure, 60% were aware of their condition, 36% received treatment, and 12% reached their goal blood pressure. Renal function was assessed by serum creatinine and glomerular filtration rate, as estimated by the Cockroft-Gault formula. In all, 6.7% had elevated creatinine, 14% showed proteinuria, and 0.2% showed advanced renal damage. The results of this study will contribute to the prevention of renal diseases in Chile.

Cytochrome-P450 enzymes metabolize cyclosporine both in the liver and in the intestinal wall. Diltiazem, by competitive inhibition of these enzymes, may increase the absorption and the bioavailability of cyclosporine. Some evidence points to a higher activity of some specific enzymes in women, such as CYP3A, that may influence differences in cyclosporine pharmacokinetics. We examined possible gender-associated differences in pharmacokinetic profiles of cyclosporine in 19 stable renal transplant recipients cotreated with diltiazem. Ten women and nine men, chronically using diltiazem associated with cyclosporine, azathioprine, and prednisone were randomly assigned to an 8-week period of continued controlled treatment with diltiazem (10 patients) or a wash-out period discontinuing diltiazem (nine patients). At the end of this period, the time-concentration curves of cyclosporine in the first 4 hours were performed after a single dose of cyclosporine. Thereafter, a cross-over between groups was performed, and time-concentration curves repeated. A specific RIA was used to measure cyclosporine concentrations. Comparisons between male and female patients in doses of cyclosporine and other pharmacokinetics parameters (C(0), C(2), AUC(0-4)), with or without diltiazem, did not show any difference related to gender. The association of diltiazem allowed a similar degree of reduction in Neoral dosage in male and female patients (21%). No changes in serum creatinine, blood urea nitrogen, potassium, uric acid, or blood pressure, or other adverse event were observed during the study. In these groups of patients, gender was not an important factor to be considered when diltiazem is added to cyclosporine therapy.

Background: Angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor type 1 blockers (ARB) are frequently prescribed for renal transplant patients. The main reasons for their use are that their antihypertensive and antifibrogenic effects may prevent chronic renal allograft dysfunction, potentially improving transplant survival. Furthermore, ACE and ARB have been used to reduce the hematocrit in patients with posttransplant erythrocytosis. We evaluated the effects of the ARB valsartan on the evolution of hematocrit in stable renal transplant patients treated with cyclosporine (CsA), azathioprine (Aza), and prednisone., Patients and Methods: Twenty-six stable renal transplant patients treated with valsartan 80 mg/d orally were followed for 6 months. Evaluations were performed prior to as well as at 3 and 6 months following the initiation of valsartan., Results: The hematocrit levels decreased significantly at 3 months (46.1 +/- 7.3 vs 39.9 +/- 5.8 ; P < .0001) in patients with a normal hematocrit, namely a level over 38%, with no further reduction at 6 months. In recipients with an hematocrit less than 38%, there was no significant reduction, either at 3 or 6 months follow-up. Valsartan was well tolerated without significant side effects., Conclusion: We postulate that inhibition of the proerythropoietic effects of angiotensin II and/or the reduction in hypoxia within the renal tubulointerstitium as well as the vasodilator effects on the efferent arterioles, represent possible mechanisms for the reduction and stabilization of the hematocrit in stable renal transplant patients.

Background: The area-under-the-curve (AUC) of cyclosporine (CsA) reflects exposure to the drug, but this monitoring strategy is time-consuming and not cost-effective. Recently, it has been suggested that the concentration at 2 hours after dosing (C2) shows the best correlation with AUC. The C2 has been replacing the trough measurement (C0) to monitor CsA therapy, but in patients receiving diltiazem there is not much information about this issue. We investigated the correlations between C2 and C0 with absorption AUC over the first 4 hours (AUC(0-4)) in renal stable transplant patients receiving CsA therapy with or without diltiazem., Patients and Methods: Ten patients (five men) of ages 23 to 68 years and 6 to 84 months after transplantation, were randomly assigned to an 8-week initial period of either diltiazem washout or controlled treatment with diltiazem. Time-concentration curves of cyclosporine were performed at the end of this period using a specific RIA measurement of blood samples. Thereafter, a crossover of the groups was performed and after another 8 weeks, a second curve was obtained. Drugs that change the pharmacokinetics of cyclosporine or diltiazem were not allowed., Results: The cyclosporine daily dose was lower with diltiazem (173 +/- 4 mg vs 213 +/- 4 mg, P = .002), but despite a dose reduction of only 19% +/- 1.5%, there was a trend to a larger AUC/dose (28 +/- 5 ng x h/mL x mg vs 17 +/- 2 ng x h/mL x mg, P = .1) and a trend to an increased C2 when treatment included diltiazem (1035 +/- 156 ng/mL vs 652 +/- 126 ng/mL, P = NS). Moreover, we confirmed that C2 showed the best correlation with AUC(0-4), (r = 0.7, P = .04), a correlation that improved with diltiazem (r = 0.9, P < .002)., Conclusion: C2 is the point that correlates best with AUC(0-4) with or without diltiazem. C2 in the presence of diltiazem was associated with a stronger, more significant correlation with AUC(0-4).

Background: Antiphospholipid antibodies have been found in the sera from patients with idiopathic and secondary glomerulopathies, mainly related to lupus. No special attention has been devoted to idiopathic membranous nephropathy, a glomerular disease with a high frequency of thrombotic complications, particularly of the renal vein., Aim: To study the presence and significance of antiphospholipid antibodies in idiopathic membranous nephropathy., Material and Methods: Anticardiolipin and anti-ss2-glycoprotein-I IgG antibodies were measured in serum samples from 21 patients with idiopathic membranous nephropathy (age range 11-75 years, 5 female). The medical records of 20 of these patients were reviewed, looking for vascular complications and nephrological evolution during a follow-up period that ranged from two to 277 months., Results: Five patients had anticardiolipin antibody titers over the cutoff for normal values, and two others were positive for anti-ss2-glycoprotein-I, without cross-reactivity. There was no difference in the incidence of thrombotic complications in the renal vein, or other locations, between these seven patients and the remaining patients. No differences in the clinical course of the nephropathy were detected either., Conclusions: Antiphospholipid antibodies may be found in patients with primary membranous nephropathy. They are not related to thrombosis or a worse evolution.

Background: Nuclear factor-kappaB (NF-kappaB) regulates genes involved in renal disease progression, such as the chemokines monocyte chemoattractant protein-1 (MCP-1) and RANTES. NF-kappaB is activated in experimental models of renal injury, and in vitro studies also suggest that proteinuria and angiotensin II could be important NF-kappaB activators. It has been proposed that locally produced MCP-1 may be involved in the development of diabetic nephropathy (DN). We examined the hypothesis that NF-kappaB could be an indicator of renal damage progression in DN., Methods: Biopsy specimens from 11 patients with type 2 diabeties and overt nephropathy were studied by southwestern histochemistry for the in situ detection of activated NF-kappaB. In addition, by immunohistochemistry and/or in situ hybridization, we studied the expression of MCP-1 and RANTES, whose genes are regulated by NF-kappaB., Results: NF-kappaB was detected mainly in cortical tubular epithelial cells and, to a lesser extent, in some glomerular and interstitial cells. A strong upregulation of MCP-1 and RANTES was observed in all the cases, mainly in tubular cells, and there was a strong correlation between the expression of these chemokines and NF-kappaB activation in the same cells, as observed in serial sections (r = 0.7; P = 0.01). In addition, the tubular expression of these chemokines was correlated mainly with the magnitude of the proteinuria (P = 0.002) and with interstitial cell infiltration (P<0.05)., Conclusions: The activation of NF-kappaB and the transcription of certain pro-inflammatory chemokines in tubular epithelial cells are markers of progressive DN. Proteinuria might be one of the main factors inducing the observed pro-inflammatory phenotype.

Background: Activation of the renin angiotensin system has been described in pathologic conditions, including kidney damage. Angiotensin II (Ang II) acts through two receptors, AT1 and AT2. Most of the known actions of Ang II, including vasoconstriction and fibrosis, are due to AT1 activation. Recent data suggest that AT2 participates in the regulation of cell growth and renal inflammatory infiltration. Therefore, we investigated the renal expression of AT2 receptors in several models of renal injury., Methods: Investigations were done in the following experimental models of kidney damage: systemic infusion of Ang II (inflammation), folic acid nephropathy (tubular cell death), and protein overload proteinuria. AT2 expression was determined by immunohistochemistry (protein) and reverse transcription-polymerase chain reaction (RT-PCR) (gene)., Results: In control animals, low levels of renal expression of AT2 were found. Ang II infusion resulted in an up-regulation of AT2 in tubular cells and de novo AT2 expression in glomeruli and vessels, associated with the presence of inflammatory cells. Acute tubular injury induced by folic acid was characterized by AT2 overexpression and apoptosis in tubular cells. Protein overload caused heavy proteinuria and tubular AT2 up-regulation., Conclusion: AT2 is re-expressed in pathologic conditions of kidney damage, such as inflammation, apoptosis, and proteinuria, suggesting a potential role of this receptor during renal injury.

Background: Nuclear factor-kappaB (NF-kappaB) and activated protein-1 (AP-1) are transcription factors that regulate many genes involved in the progression of renal disease. Recent data have shown that NF-kappaB is activated in tubules and glomeruli in various experimental models of renal injury. In vitro studies also suggest that proteinuria could be an important NF-kappaB activator. We therefore approached the idea that NF-kappaB may be an indicator of renal damage progression., Methods: Paraffin-embedded renal biopsy specimens from 34 patients with intense proteinuria [14 with minimal change disease (MCD) and 20 with idiopathic membranous nephropathy (MN)] and from 7 patients with minimal or no proteinuria (IgA nephropathy) were studied by Southwestern histochemistry for the in situ detection of activated transcription factors NF-kappaB and AP-1. In addition, by immunohistochemistry, we performed staining for the NF-kappaB subunits (p50 and p65) and AP-1 subunits (c-fos, c-jun). By immunohistochemistry and/or in situ hybridization, the expression of some chemokines [monocyte chemoattractant protein-1 (MCP-1), RANTES, osteopontin (OPN)] and profibrogenic cytokines [transforming growth factor-beta (TGF-beta)], whose genes are regulated by NF-kappaB and/or AP-1, were studied further., Results: NF-kappaB was detected mainly in the tubules of proteinuric patients, but rarely in nonproteinuric IgA nephropathy (IgAN) patients. In addition, there was a significant relationship between the intensity of proteinuria and NF-kappaB activation in MCD (r = 0.64, P = 0.01) and MN patients (r = 0.64, P < 0.01). Unexpectedly, patients with MCD had a significantly higher NF-kappaB tubular activation than those with MN (P < 0.01). To assess whether there was a different composition of NF-kappaB protein components, immunostaining was performed for the NF-kappaB subunits p50 and p65. However, no differences were noted between MCD and MN patients. In those patients, there was a lower tubular activation of AP-1 compared with NF-kappaB. Moreover, a strong correlation in the expression of both transcription factors was observed only in MN (r = 0.7, P = 0.004). Patients with progressive MN had an overexpression of MCP-1, RANTES, OPN, and TGF-beta, mainly in the proximal tubules, while no significant expression was found in MCD patients., Conclusions: On the whole, our results show that a tubular overactivation of NF-kappaB and AP-1 and a simultaneous up-regulation of certain proinflammatory and profibrogenic genes are markers of progressive renal disease in humans. Increased activation of solely NF-kappaB and/or AP-1 may merely indicate the response of tubular renal cells to injury.

Unlabelled: Overexpression of chemokines, fibrogenic cytokines, and myofibroblasts in human membranous nephropathy., Background: Proteinuria plays a central role in the progression of glomerular disease, and there is growing evidence suggesting that it may determine tubular cell activation with release of chemokines and fibrogenic factors, leading to interstitial inflammatory reaction. However, most studies on this subject have been performed in experimental models, and the experience in human kidney biopsies has been scarce. We analyzed the tissue sections of patients with idiopathic membranous nephropathy (IMN), a noninflammatory glomerular disease that may follow a progressive disease with heavy persistent proteinuria, interstitial cell infiltration, and decline of renal function., Methods: Paraffin-embedded biopsy specimens from 25 patients with IMN (13 progressive and 12 nonprogressive) were retrospectively studied by immunohistochemistry [monocyte chemoattractant protein-1 (MCP-1), regulated on activation normal T-cell expressed and secreted chemokine (RANTES), osteopontin (OPN), platelet-derived growth factor-BB (PD-GF-BB)] and in situ hybridization [MCP-1, RANTES, PDGF-BB, transforming growth factor-beta1 (TGF-beta1)]. Moreover, we studied the presence of myofibroblasts, which were identified by the expression of alpha-smooth muscle actin (alpha-SMA), the monocytes/macrophages (CD68-positive cells), and T-cell infiltration (CD4+ and CD8+ cells). All of the patients were nephrotic and without treatment at time of the biopsy., Results: A strong up-regulation of MCP-1, RANTES, and OPN expression was observed, mainly in tubular epithelial cells, with a significant major intensity in the progressive IMN patients. A strong correlation between the mRNA expression and the corresponding protein was noted. The presence of these chemokines and OPN was associated with interstitial cell infiltration. TGF-beta and PDGF were also up-regulated, mainly in tubular epithelial cells, with a stronger expression in the progressive IMN, and an association with the presence of myofibroblasts was found., Conclusions: Patients with severe proteinuria and progressive IMN have an overexpression in tubular epithelial cells of the chemokines MCP-1, RANTES, and OPN and the profibrogenic cytokines PDGF-BB and TGF-beta. Because this up-regulation was associated with an interstitial accumulation of mononuclear cells and an increase in myofibroblastic activity, it is suggested that those mediators are potential predictors of progression in IMN. Finally, based on experimental data and the findings of this article, we speculate that severe proteinuria is the main factor responsible for the up-regulation of these factors in tubular epithelial cells.