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5.
Am Health Drug Benefits ; 11(2): 65-73, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29915640

RESUMO

BACKGROUND: As healthcare costs rise and reimbursements decrease, healthcare organization leadership and clinical providers must collaborate to provide high-value healthcare. Medications are a key driver of the increasing cost of healthcare, largely as a result of the proliferation of expensive specialty drugs, including biologic agents. Such medications contribute significantly to the inpatient diagnosis-related group payment system, often with minimal or unproved benefit over less-expensive therapies. OBJECTIVE: To describe a systematic review process to reduce non-evidence-based inpatient use of high-cost medications across a large multihospital academic health system. METHODS: We created a Pharmacy & Therapeutics subcommittee consisting of clinicians, pharmacists, and an ethics representative. This committee developed a standardized process for a timely review (<48 hours) and approval of high-cost medications based on their clinical effectiveness, safety, and appropriateness. The engagement of clinical experts in the development of the consensus-based guidelines for the use of specific medications facilitated the clinicians' acceptance of the review process. RESULTS: Over a 2-year period, a total of 85 patient-specific requests underwent formal review. All reviews were conducted within 48 hours. This review process has reduced the non-evidence-based use of specialty medications and has resulted in a pharmacy savings of $491,000 in fiscal year 2016, with almost 80% of the savings occurring in the last 2 quarters, because our process has matured. CONCLUSION: The creation of a collaborative review process to ensure consistent, evidence-based utilization of high-cost medications provides value-based care, while minimizing unnecessary practice variation and reducing the cost of inpatient care.

6.
BMJ Qual Saf ; 24(12): 787-95, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26251506

RESUMO

BACKGROUND: Sepsis causes substantial morbidity and mortality in hospitalised patients. Although many studies describe the use of protocols in the management of patients with severe sepsis and septic shock, few have addressed emergency department (ED) screening and management for patients initially presenting with uncomplicated sepsis (ie, patients without organ failure or hypotension). OBJECTIVE: A quality improvement task force at a large, quaternary care referral hospital sought to develop a protocol focusing on early identification of patients with uncomplicated sepsis, in addition to severe sepsis and septic shock. INTERVENTION: The three-tiered intervention consisted of (1) a nurse-driven screening tool and management protocol to identify and initiate early treatment of patients with sepsis, (2) a computer-assisted screening algorithm that generated a 'Sepsis Alert' pop-up screen in the electronic medical record for treating clinical healthcare providers and (3) automated suggested sepsis-specific order sets for initial workup and resuscitation, antibiotic selection and goal-directed therapy. DESIGN: A before and after retrospective cohort study was undertaken to determine the intervention's impact on compliance with recommended sepsis management, including serum lactate measured in the ED, 2 L of intravenous fluid administered within 2 h of triage, antibiotics administered within 3 h of triage and blood cultures drawn before antibiotic administration. Mortality rates for patients in the ED with a sepsis-designated ICD-9 code present on admission were also analysed. RESULTS: Overall bundle compliance increased by 154%, from 28% at baseline to 71% in the last quarter of the study (p<0.001). Bundle, antibiotic and intravenous fluid compliance all increased significantly after launch of the sepsis initiative (eg, bundle and intravenous fluid compliance increased by 74% and 54%, respectively; p<0.001). Bundle and antibiotic compliance both showed further significant increases after implementation of suggested order sets (31% and 25% increases, respectively; p<0.001). The mortality rate for patients in the ED admitted with sepsis was 13.3% before implementation and fell to 11.1% after (p=0.230); mortality in the last two quarters of the study was 9.3% (p=0.107). CONCLUSIONS: The new protocol demonstrates that early screening interventions can lead to expedited delivery of care to patients with sepsis in the ED and could serve as a model for other facilities. Mortality was not significantly improved by our intervention, which included patients with uncomplicated sepsis.


Assuntos
Protocolos Clínicos , Serviço Hospitalar de Emergência/organização & administração , Melhoria de Qualidade/organização & administração , Sepse/diagnóstico , Sepse/terapia , Algoritmos , Diagnóstico por Computador/métodos , Fidelidade a Diretrizes , Humanos , Programas de Rastreamento/organização & administração , Pacotes de Assistência ao Paciente/métodos , Guias de Prática Clínica como Assunto , Ressuscitação/métodos , Estudos Retrospectivos , Sepse/mortalidade , Choque Séptico/diagnóstico , Choque Séptico/terapia
7.
Qual Manag Health Care ; 24(1): 45-51, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25539490

RESUMO

In an environment where there is increased demand for hospital beds, it is important that inpatient flow from admission to treatment to discharge is optimized. Among the many drivers that impact efficient patient throughput is an effective and timely discharge process. Early morning discharge helps align inpatient capacity with clinical demand, thereby avoiding gridlock that adversely affects scheduled surgical procedures, diagnostic procedures, and therapies. At our large, academic medical center, we hypothesized that an interdisciplinary approach to scheduled discharge order entry would increase the percentage of discharges occurring before 11:00 AM and improve overall discharge time. The pilot study involved moving rate-limiting steps to earlier in the discharge process, specifically medication reconciliation to the night before discharge and "discharge to home" order entry before 9:00 AM the morning of discharge. The baseline rate of discharges before 11:00 AM was 8% and significantly increased to 11% after the intervention (P = .02). Moreover, in the subset of patients (21%) for whom early medication reconciliation and discharge to home order entry were both executed, the percentage of patient discharges occurring before 11:00 AM increased to 29.7%, with an associated average discharge time of more than 3 hours earlier. No patient harm events were associated with this pilot project. There was no significant change in length of stay, and 30-day readmission rate improved significantly from 13.8% to 10.3% (P = .002). Our study demonstrates that a multidisciplinary approach using prescribed order entry and medication reconciliation is a low cost, safe, and effective way to increase early morning discharges and improve patient flow for large hospitals with high volumes of scheduled patient admissions.


Assuntos
Centros Médicos Acadêmicos/organização & administração , Continuidade da Assistência ao Paciente/organização & administração , Relações Interprofissionais , Alta do Paciente , Lista de Checagem , Eficiência Organizacional , Hospitais com 300 a 499 Leitos , Humanos , Tempo de Internação , Reconciliação de Medicamentos/organização & administração , Readmissão do Paciente , Projetos Piloto
8.
Am J Pathol ; 174(5): 1827-36, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-19342370

RESUMO

Podocytopenia characterizes many forms of glomerular disease, preceding the development of glomerulosclerosis. While detachment of viable podocytes from the underlying glomerular basement membrane is an important mechanism of podocyte loss, the underlying factors involved remain unclear. Secreted protein acidic and rich in cysteine (SPARC), a matricellular protein with counteradhesive properties, is normally expressed at low levels by the podocyte but is markedly increased following podocyte injury. Accordingly, we elucidate the role of SPARC in mediating experimental crescentic glomerulonephritis by inducing passive nephrotoxic nephritis in SPARC(+/+) and SPARC(-/-) mice. By days 4, 7, and 21 following disease induction, podocyte number is better preserved, glomerulosclerosis is ameliorated, and proteinuria is reduced in SPARC(-/-) mice as compared with SPARC(+/+) littermates. Moreover, the preserved podocyte number in SPARC(-/-) mice correlates with reduced urinary levels of both nephrin and podocin. To establish a causal role for SPARC in mediating detachment, cultured SPARC(+/+) and SPARC(-/-) podocytes were subjected to mechanical strain as well as trypsin digestion, and detachment assays were performed. While podocytes lacking SPARC were more resistant to stretch-induced detachment, stable re-expression of SPARC restored detachment rates to levels comparable with SPARC(+/+) podocytes. Taken together, this study proves that SPARC plays a causal role in mediating podocyte detachment and accelerating glomerulosclerosis in experimental crescentic glomerulonephritis.


Assuntos
Modelos Animais de Doenças , Glomerulonefrite/fisiopatologia , Osteonectina/fisiologia , Animais , Células Cultivadas , Progressão da Doença , Immunoblotting , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Knockout , Podócitos/metabolismo , Podócitos/patologia
9.
Nephrol Dial Transplant ; 24(2): 404-12, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18820279

RESUMO

BACKGROUND: Clinical studies suggest that statins reduce proteinuria and slow the decline in kidney function in chronic kidney disease. Given a rich literature identifying podocyte apoptosis as an early step in the pathophysiological progression to proteinuria and glomerulosclerosis, we hypothesized that rosuvastatin protects podocytes from undergoing apoptosis. Regarding a potential mechanism, our lab has shown that the cell cycle protein, p21, has a prosurvial role in podocytes and there is literature showing statins upregulate p21 in other renal cells. Therefore, we queried whether rosuvastatin is prosurvival in podocytes through a p21-dependent pathway. METHODS: Two independent apoptotic triggers, puromycin aminonucleoside (PA) and adriamycin (ADR), were used to induce apoptosis in p21 +/+ and p21 -/- conditionally immortalized mouse podocytes with or without pre-exposure to rosuvastatin. Apoptosis was measured by two methods: Hoechst 33342 staining and fluorescence-activated cell sorting (FACS). To establish a role for p21, p21 levels were measured by western blotting following rosuvastatin exposure and p21 was stably transduced into p21 -/- mouse podocytes. RESULTS: Rosuvastatin protects against ADR- and PA-induced apoptosis in podocytes. Further, exposure to rosuvastatin increases p21 levels in podocytes in vitro. ADR induces apoptosis in p21 -/- mouse podocytes, but rosuvastatin's protective effect is not seen in the absence of p21. Reconstituting p21 in p21 -/- podocytes restores rosuvastatin's prosurvival effect. CONCLUSION: Rosuvastatin is prosurvival in injured podocytes. Rosuvastatin exerts its protective effect through a p21-dependent antiapoptotic pathway. These findings suggest that statins decrease proteinuria by protecting against podocyte apoptosis and subsequent podocyte depopulation.


Assuntos
Apoptose/efeitos dos fármacos , Fluorbenzenos/farmacologia , Inibidores de Hidroximetilglutaril-CoA Redutases/farmacologia , Podócitos/citologia , Podócitos/efeitos dos fármacos , Pirimidinas/farmacologia , Sulfonamidas/farmacologia , Animais , Apoptose/fisiologia , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/fisiologia , Células Cultivadas , Inibidor de Quinase Dependente de Ciclina p21/deficiência , Inibidor de Quinase Dependente de Ciclina p21/genética , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Doxorrubicina/toxicidade , Humanos , Camundongos , Camundongos Knockout , Podócitos/metabolismo , Proteinúria/prevenção & controle , Puromicina Aminonucleosídeo/toxicidade , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Rosuvastatina Cálcica , Transdução Genética
10.
Am J Physiol Renal Physiol ; 296(2): F213-29, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18784259

RESUMO

Glomerular diseases remain the leading cause of chronic and end-stage kidney disease. Significant advances in our understanding of human glomerular diseases have been enabled by the development and better characterization of animal models. Diseases of the glomerular epithelial cells (podocytes) account for the majority of proteinuric diseases. Rodents have been extensively used experimentally to better define mechanisms of disease induction and progression, as well as to identify potential targets and therapies. The development of podocyte-specific genetically modified mice has energized the research field to better understand which animal models are appropriate to study acquired podocyte diseases. In this review we discuss inducible experimental models of acquired nondiabetic podocyte diseases in rodents, namely, passive Heymann nephritis, puromycin aminonucleoside nephrosis, adriamycin nephrosis, liopolysaccharide, crescentic glomerulonephritis, and protein overload nephropathy models. Details are given on the model backgrounds, how to induce each model, the interpretations of the data, and the benefits and shortcomings of each. Genetic rodent models of podocyte injury are excluded.


Assuntos
Modelos Animais de Doenças , Nefropatias/patologia , Podócitos/patologia , Animais , Camundongos , Ratos
11.
Am J Physiol Renal Physiol ; 294(4): F830-9, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18216149

RESUMO

ANG II is a critical mediator of diabetic nephropathy. Pharmacologic inhibition of ANG II slows disease progression beyond what could be predicted by the blood pressure lowering effects alone, suggesting the importance of nonhemodynamic pathways of ANG II in mediating disease. Podocyte injury and loss are cardinal features of diabetic nephropathy. Mounting evidence suggests that the podocyte is a direct target of ANG II-mediated signaling in diabetic renal disease. We have tested the hypothesis that high glucose leads to the activation of a local angiotensin system in podocytes and delineated the underlying pathways involved. Cultured podocytes were exposed to standard glucose (5 mM), high glucose (40 mM), or mannitol as an osmotic control. ANG II levels in cell lysates were measured in the presence or absence of inhibitors of angiotensin-converting enzyme (captopril), chymase (chymostatin), and renin (aliskiren) activity. The effects of glucose on renin and angiotensin subtype 1 receptor expression and protein levels were determined. Exposure to high glucose resulted in a 2.1-fold increase ANG II levels mediated through increased renin activity, as exposure to high glucose increased renin levels and preincubation with Aliskiren abrogated glucose-induced ANG II production. Relevance to the in vivo setting was demonstrated by showing glomerular upregulation of the prorenin receptor in a podocyte distribution early in the course of experimental diabetic nephropathy. Furthermore, high glucose increased angiotensin subtype 1 receptor levels by immunofluorescence and Western blot. Taken together, the resultant activation of a local renin angiotensin system by high glucose may promote progressive podocyte injury and loss in diabetic nephropathy.


Assuntos
Angiotensina II/genética , Nefropatias Diabéticas/etiologia , Glucose/farmacologia , Rim/fisiologia , Podócitos/fisiologia , Sistema Renina-Angiotensina/fisiologia , Renina/genética , Angiotensina II/farmacologia , Angiotensina II/fisiologia , Animais , Células Cultivadas , Primers do DNA , Nefropatias Diabéticas/fisiopatologia , Rim/efeitos dos fármacos , Rim/fisiopatologia , Camundongos , Podócitos/citologia , Podócitos/efeitos dos fármacos , Reação em Cadeia da Polimerase , RNA Mensageiro/genética , Sistema Renina-Angiotensina/efeitos dos fármacos
12.
Curr Hypertens Rep ; 8(2): 132-8, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-16672146

RESUMO

The renoprotective effects of pharmacologic inhibition of angiotensin II extend beyond the blood pressure-lowering effects alone, consistent with the observation that angiotensin II is produced locally within the kidney and mediates tissue injury through a series of nonhemodynamic effects. Podocytes are terminally differentiated epithelial cells that contribute to the filtration barrier of the kidney, but also safeguard against the development of glomerulosclerosis. Mounting evidence demonstrates that podocytes are not only a local source of angiotensin II production, but are also vulnerable to its deleterious effects, thus fueling the future development of glomerular scarring. In this review article, we explore the role of a local angiotensin system as a mediator of podocyte injury and discuss its potential link to hypertensive renal disease.


Assuntos
Angiotensina II/metabolismo , Glomerulonefrite/etiologia , Glomerulosclerose Segmentar e Focal/metabolismo , Hipertensão Renal/etiologia , Podócitos/metabolismo , Glomerulonefrite/metabolismo , Glomerulosclerose Segmentar e Focal/complicações , Glomerulosclerose Segmentar e Focal/patologia , Humanos , Hipertensão Renal/metabolismo , Glomérulos Renais/metabolismo , Glomérulos Renais/patologia , Podócitos/patologia , Sistema Renina-Angiotensina
13.
Curr Opin Nephrol Hypertens ; 15(1): 1-7, 2006 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16340659

RESUMO

PURPOSE OF REVIEW: Podocyte injury is a central event in the development of glomerulosclerosis. This review highlights contributions from the past year to our understanding of mechanisms of podocyte injury and implications for potential treatment strategies of glomerular disease. RECENT FINDINGS: Rearrangement of the actin cytoskeleton, the backbone linking the slit diaphragm, apical domain and sole plate, serves as a common denominator during foot process effacement. Reports on the role of synaptopodin and CDK5 on actin dynamics as well as cathepsin L and B7.1 in subsequent cell migration have expanded our understanding of the podocyte response to injury. Mounting evidence supports an expanding role of the slit diaphragm in signal transduction to mediate downstream cellular responses, including prosurvival effects of the integral proteins nephrin and CD2AP. The discovery that TRPC6 localizes to the slit diaphragm and identification of specific mutations of the transport channel in kindreds of familial focal segmental glomerulosclerosis implicate a causal role for aberrant calcium signaling in podocyte injury. Disruption of the dystroglycan complex, which anchors the podocyte to the underlying basement membrane, in states of foot process effacement may have implications for the recent finding of viable podocytes in the urine in glomerular disease. SUMMARY: The resurgence of research in podocyte biology over the past decade underscores the importance of this unique cell in preserving glomerular structure and function. A greater understanding of the complex signaling mechanisms governing podocyte biology in health and disease will ultimately lead to novel therapeutic avenues for treating disorders of the podocyte.


Assuntos
Membrana Basal Glomerular/patologia , Nefropatias/tratamento farmacológico , Podócitos/patologia , Inibidores da Enzima Conversora de Angiotensina/farmacologia , Citoesqueleto/patologia , Humanos , Nefropatias/patologia , Podócitos/efeitos dos fármacos , Podócitos/metabolismo , Sialoglicoproteínas/metabolismo
14.
Am J Physiol Renal Physiol ; 289(3): F577-84, 2005 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16093428

RESUMO

Glomerular capillary hypertension is a final common pathway to glomerulosclerosis. Because podocyte loss is an early event in the development of glomerulosclerosis, it is logical that the deleterious effects of glomerular capillary hypertension involve podocyte injury. Yet, the mechanisms by which elevated intraglomerular pressure is translated into a maladaptive podocyte response remain poorly understood. Secreted protein acidic and rich in cysteine (SPARC) is a matricellular protein activated in various disease states of the podocyte and accelerates renal injury, as evidenced by the milder course of experimental diabetic nephropathy in SPARC-null mice compared with diabetic SPARC wild-type mice. Accordingly, we tested the hypothesis that mechanical strain activates SPARC in podocytes and thus is a putative mediator of podocyte injury in states of intraglomerular capillary hypertension. Conditionally immortalized mouse podocytes were subjected to 10% cyclical stretch while nonstretched cells served as controls. SPARC levels were measured in whole cell lysate and cell media. Immunostaining was performed for SPARC in an experimental model of glomerular capillary hypertension. Our results demonstrate cyclical stretch of podocytes markedly increased SPARC levels in cell lysate, through activation of p38, as well as secreted SPARC. Relevance was shown by demonstrating increased podocyte staining for SPARC in the uninephrectomized spontaneously hypertensive rat. In conclusion, we have made the novel observation that mechanical forces characteristic of states of glomerular capillary hypertension lead to increased levels of SPARC in podocytes. We speculate that the increase in SPARC may be maladaptive and lead to a progressive reduction in podocyte number, thus fueling the future development of glomerulosclerosis.


Assuntos
Glomerulosclerose Segmentar e Focal/fisiopatologia , Hipertensão Renal/fisiopatologia , Glomérulos Renais/fisiologia , Osteonectina/genética , Estresse Mecânico , Animais , Capilares/fisiologia , Linhagem Celular Transformada , Expressão Gênica/fisiologia , Glomerulosclerose Segmentar e Focal/metabolismo , Hipertensão Renal/metabolismo , Glomérulos Renais/irrigação sanguínea , Glomérulos Renais/citologia , Camundongos , Osteonectina/metabolismo , Ratos , Ratos Endogâmicos SHR , Transdução de Sinais/fisiologia , Regulação para Cima/fisiologia , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
15.
Kidney Int ; 67(1): 157-66, 2005 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-15610239

RESUMO

BACKGROUND: Increased intraglomerular pressure is a final pathway toward glomerulosclerosis in systemic hypertension, diabetes, and focal segmental glomerulosclerosis (FSGS). Increased intraglomerular pressure causes stress-tension, or stretch, on resident glomerular cells. However, the effects of stretch on podocyte growth, and the mechanisms that underlie this, have not been elucidated. METHODS: To test the hypothesis that stretch alters podocyte growth, cultured mouse podocytes were exposed to cyclic mechanical stretch created by vacuum; control cells were grown under similar conditions, but not exposed to stretch. Proliferation (cell cycle phases) and hypertrophy (forward light scatter) were measured in stretched and control podocytes by flow cytometry. The role of the cyclin-dependent kinase (CDK) inhibitors, p21 and p27, was examined by stretching podocytes isolated from p21 and p27 knockout (-/-) mice, and the role of specific signaling pathways was assessed by Western blot analysis and blocking studies. RESULTS: Our results showed that stretch reduced cell cycle progression in wild-type and single p27-/- podocytes and induced hypertrophy in these cells in all phases of the cell cycle at 24, 48, and 72 hours. In contrast, stretch did not induce hypertrophy in single p21-/- and double p21/p27-/- podocytes. Stretch-induced hypertrophy required cell cycle entry, and was prevented by specifically blocking extracellular signal-regulated kinase 1/2 (Erk1/2) or Akt. Although stretch increased p38 activation, inhibition of this pathway had no effect on hypertrophy. CONCLUSION: Mechanical stretch induces hypertrophy in podocytes in vitro in all phases of the cell cycle. This effect is cell cycle dependent, and requires p21, Erk1/2, and Akt. Stretch may play a role in podocyte injury when intraglomerular pressure is increased.


Assuntos
Crescimento Celular , Glomérulos Renais/citologia , Animais , Ciclo Celular , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/fisiologia , Células Cultivadas , Meios de Cultura , Inibidor de Quinase Dependente de Ciclina p21 , Inibidor de Quinase Dependente de Ciclina p27 , Técnicas In Vitro , Glomérulos Renais/fisiologia , Sistema de Sinalização das MAP Quinases , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mitógenos , Modelos Biológicos , Estresse Mecânico , Proteínas Supressoras de Tumor/deficiência , Proteínas Supressoras de Tumor/genética
16.
Kidney Int ; 65(1): 30-9, 2004 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-14675034

RESUMO

BACKGROUND: Glomerular capillary hypertension, a common denominator in various forms of progressive glomerular disease, results in mechanical distention of the capillary tuft, and subsequent injury of the overlying podocyte layer. The mechanisms by which elevated intraglomerular pressure is translated into a maladaptive podocyte response remain poorly understood. Angiotensin II plays a central role in the pathogenesis of chronic renal injury, largely through its actions on the subtype 1 receptor. Accordingly, we have tested the hypothesis that mechanical strain up-regulates local angiotensin II in podocytes, thereby resulting in a progressive reduction in podocyte number. METHODS: Conditionally immortalized mouse podocytes were subjected to cyclical stretch of 10% amplitude. Nonstretched podocytes served as controls. Angiotensin II levels were measured in whole cell lysate by competitive enzyme-linked immunosorbent assay (ELISA). Expression of angiotensin II receptors (AT1R, AT2R) was measured by quantitative polymerase chain reaction (PCR) and Western blot analysis. Apoptosis was measured by Hoechst staining. Immunostaining for AT1R was performed in tissue sections from rats with 5/6 remnant kidney disease, a model of glomerular hypertension. RESULTS: Mechanical strain increased angiotensin II production in podocytes at 24, 48, and 72 hours (P < 0.05 vs. nonstretched controls). Stretching podocytes resulted in a fivefold increase in AT1R mRNA expression at 24 hours and a twofold increase in protein levels vs. controls (P < 0.05), and also an increase in transforming growth hormone-beta (TGF-beta) mRNA expression. AT1R staining was increased in a podocyte distribution in the 5/6 remnant kidney, consistent with our in vitro findings. Mechanical strain resulted in a 2.5-fold increase in apoptosis (P < 0.001 vs. nonstretched controls) in an angiotensin II-dependent fashion. CONCLUSION: Mechanical strain leads to up-regulation of the AT1R and increased angiotensin II production in conditionally immortalized podocytes. The resulting activation of a local tissue angiotensin system leads to an increase in podocyte apoptosis, mainly in an AT1R-mediated fashion.


Assuntos
Angiotensina II/metabolismo , Glomérulos Renais/fisiologia , Mecanotransdução Celular/fisiologia , Vasoconstritores/metabolismo , Angiotensina II/farmacologia , Animais , Apoptose/fisiologia , Capilares/fisiologia , Linhagem Celular Transformada , Expressão Gênica/fisiologia , Hipertensão Renal/fisiopatologia , Glomérulos Renais/irrigação sanguínea , Glomérulos Renais/efeitos dos fármacos , Camundongos , RNA Mensageiro/análise , Ratos , Receptor Tipo 1 de Angiotensina/genética , Receptor Tipo 1 de Angiotensina/metabolismo , Receptor Tipo 2 de Angiotensina/genética , Receptor Tipo 2 de Angiotensina/metabolismo , Circulação Renal/efeitos dos fármacos , Circulação Renal/fisiologia , Estresse Mecânico , Fator de Crescimento Transformador beta/genética , Regulação para Cima , Vasoconstritores/farmacologia
17.
Nephron Exp Nephrol ; 98(4): e114-23, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15627794

RESUMO

BACKGROUND: A decrease in podocyte number contributes to the development of glomerulosclerosis in diabetic nephropathy. Although podocytes have been detected in the urine in certain glomerular diseases, their viability is poorly understood. METHODS: Diabetes was induced in rats with streptozotocin. Urine was collected from control rats (given citrate), and rats with diabetic nephropathy, and cells obtained by centrifugation were resuspended in tissue culture media, and seeded onto collagen-coated tissue culture plates. Cells were grown under standard cell culture conditions ex vivo. Cell number was measured, the cell type in the urine was identified by immunostaining with specific antibodies, and morphology was assessed by light and electron microscopy. RESULTS: Within 24 h, cells obtained from the urine of diabetic rats attached to tissue culture plates ex vivo. Cells were not detected in the urine from control rats. All cells from diabetic rats stained positive for the podocyte-specific proteins synaptopodin, nephrin, podocin and Glepp-1 and negative for mesangial (OX-7), tubular (Tamm-Horsfall protein) and endothelial (RECA) cell antigens. The cell number increased daily, which is consistent with cell growth ex vivo. CONCLUSIONS: Rats with diabetic nephropathy shed podocytes into the urine that attach and grow ex vivo. These results are consistent with the detachment of viable podocytes in diabetes and add new perspectives into our understanding of development of glomerulosclerosis in diabetes mellitus.


Assuntos
Nefropatias Diabéticas/etiologia , Podócitos/citologia , Animais , Apoptose , Adesão Celular , Sobrevivência Celular , Células Cultivadas , Diabetes Mellitus Experimental/etiologia , Diabetes Mellitus Experimental/patologia , Nefropatias Diabéticas/patologia , Masculino , Podócitos/patologia , Podócitos/ultraestrutura , Ratos , Ratos Sprague-Dawley , Urina/citologia
18.
Semin Nephrol ; 23(6): 569-82, 2003 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-14631565

RESUMO

Although initially identified and characterized as regulators of the cell cycle and hence proliferation, an extended role for cell cycle proteins has been appreciated more recently in a number of physiologic and pathologic processes, including development, differentiation, hypertrophy, and apoptosis. Their precise contribution to the cellular response to injury appears to be dependent on both the cell type and the nature of the initiating injury. The glomerulus offers a remarkable situation in which to study the cell cycle proteins, as each of the 3 major resident cell types (the mesangial cell, podocyte, and glomerular endothelial cell) has a specific pattern of cell cycle protein expression when quiescent and responds uniquely after injury. Defining their roles may lead to potential therapeutic strategies in glomerular disease.


Assuntos
Apoptose/fisiologia , Proteínas de Ciclo Celular/metabolismo , Glomerulonefrite/etiologia , Glomerulonefrite/fisiopatologia , Glomérulos Renais/metabolismo , Animais , Proteínas de Ciclo Celular/fisiologia , Divisão Celular , Células Cultivadas , Quinases Ciclina-Dependentes/metabolismo , Mesângio Glomerular/citologia , Mesângio Glomerular/metabolismo , Humanos , Glomérulos Renais/fisiologia , Prognóstico , Sensibilidade e Especificidade
19.
Kidney Int ; 64(4): 1222-31, 2003 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-12969140

RESUMO

BACKGROUND: Podocyte loss contributes to the development of glomerulosclerosis. Although podocytes have been detected in the urine in certain glomerular diseases, the viability of detached cells is not known. METHODS: Urine was collected from rats with experimental membranous nephropathy [passive Heymann nephritis (PHN) model], centrifuged, and following resuspension in tissue culture media, cells were seeded onto collagen-coated tissue culture plates. Cells were grown under typical cell culture conditions. Cell number was measured, the cell type was identified by immunostaining with specific antibodies, and cell morphology was assessed by light and electron microscopy. RESULTS: Cells obtained in the urine from PHN rats were positive for synaptopodin, nephrin, podocin, WT-1, and GLEPP1 (podocyte-specific antigens). When grown ex vivo under cell culture conditions, cells obtained in the urine from PHN rats adhered to tissue culture plates, and expressed podocyte-specific proteins at the mRNA [reverse transcription-polymerase chain reaction (RT-PCR)] and protein (immunostaining) level. Cells did not stain with antibodies to mesangial (OX-7), tubular (Tamm-Horsfall protein) and endothelial (RECA) cells. Electron microscopy showed the presence of foot processes, and podocytes from PHN rats stained positive for C5b-9. Although podocyte number increased transiently during the first 5 days ex vivo, apoptosis increased significantly thereafter, reducing overall cell number. CONCLUSION: Rats with experimental membranous nephropathy shed podocytes into the urine that attach to tissue culture plates ex-vivo, and proliferate. These results suggest that detached podocytes are viable. These results add new perspectives into our understanding of podocyte loss in the development of glomerulosclerosis.


Assuntos
Glomerulonefrite Membranosa/patologia , Glomerulonefrite Membranosa/fisiopatologia , Rim/patologia , Rim/fisiopatologia , Animais , Adesão Celular , Contagem de Células , Divisão Celular , Sobrevivência Celular , Células Cultivadas , Complexo de Ataque à Membrana do Sistema Complemento/metabolismo , Imunofluorescência , Glomerulonefrite Membranosa/urina , Rim/metabolismo , Rim/ultraestrutura , Masculino , Microscopia Eletrônica , Ratos , Ratos Sprague-Dawley , Coloração e Rotulagem , Urina/citologia
20.
Nephrol Dial Transplant ; 18 Suppl 6: vi8-13, 2003 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12953035

RESUMO

Injury to the podocyte underlies many forms of glomerular disease. In contrast to mesangial and endothelial cells, podocytes do not typically proliferate. Moreover, the lack of proliferation is thought to underlie the development of glomerulosclerosis. Studies have recently shown that the lack of podocyte proliferation is due to an increase in cyclin-dependent kinase inhibitors, which arrest the cell cycle. Current work is aimed at further delineating the mechanisms regulating podocyte proliferation.


Assuntos
Proteínas de Ciclo Celular/fisiologia , Ciclo Celular/fisiologia , Diferenciação Celular/fisiologia , Células Epiteliais/fisiologia , Glomerulosclerose Segmentar e Focal/fisiopatologia , Glomérulos Renais/fisiopatologia , Humanos
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