Prognostic factors for the evolution and reversibility of chronic rejection in pediatric liver transplantation

OBJECTIVE: Chronic rejection remains a major cause of graft failure with indication for re-transplantation. The incidence of chronic rejection remains high in the pediatric population. Although several risk factors have been implicated in adults, the prognostic factors for the evolution and reversibility of chronic rejection in pediatric liver transplantation are not known. Hence, the current study aimed to determine the factors involved in the progression or reversibility of pediatric chronic rejection by evaluating a series of chronic rejection cases following liver transplantation. METHODS: Chronic rejection cases were identified by performing liver biopsies on patients based on clinical suspicion. Treatment included maintaining high levels of tacrolimus and the introduction of mofetil mycophenolate. The children were divided into 2 groups: those with favorable outcomes and those with adverse outcomes. Multivariate analysis was performed to identify potential risk factors in these groups. RESULTS: Among 537 children subjected to liver transplantation, chronic rejection occurred in 29 patients (5.4%). In 10 patients (10/29, 34.5%), remission of chronic rejection was achieved with immunosuppression (favorable outcomes group). In the remaining 19 patients (19/29, 65.5%), rejection could not be controlled (adverse outcomes group) and resulted in re-transplantation (7 patients, 24.1%) or death (12 patients, 41.4%). Statistical analysis showed that the presence of ductopenia was associated with worse outcomes (risk ratio=2.08, p=0.01). CONCLUSION: The presence of ductopenia is associated with poor prognosis in pediatric patients with chronic graft rejection.

Persistent hypertension and progressive renal injury induced by salt overload after short term nitric oxide inhibition

INTRODUCTION: Administration of the NO inhibitor Nwð-nitro-L-arginine methyl ester (NAME) and a high-salt diet (HS) promotes severe albuminuria and renal injury, which regresses upon discontinuation of treatments. OBJECTIVE: We investigated whether these changes reappear after reinstitution of HS, and whether they are prevented by treatment with the antilymphocyte agent mycophenolate mofetil (MMF) or the AT-1 receptor blocker losartan (L). Adult male Munich-Wistar rats received NAME and HS. A control Group (C) received only HS. After 20 days, rats receiving HS and NAME exhibited severe hypertension and albuminuria. After a 30-day recovery period, hypertension was attenuated and albuminuria had virtually disappeared. MATERIAL AND METHODS: Rats were then distributed among the following groups: HS, receiving HS; NS, receiving a normal salt (NS) diet; HS-MMF, receiving HS and MMF; HS-LOS, receiving HS and L; HS-HDZ, receiving HS and hydralazine (HDZ). Sixty days later, NS rats showed only slight albuminuria and renal damage or inflammation. In contrast, HS rats developed severe hypertension, marked glomerulosclerosis with interstitial expansion and renal infiltration by macrophages and angiotensin II-positive cells. The group treated with losartan had lowered blood pressure and a lack of albuminuria or renal injury. MMF provided similar protection without altering blood pressure, suggesting a nonhemodynamic effect, a hypothesis reinforced by the finding that HDZ lowered blood pressure without preventing renal injury. RESULTS: These results indicate that treatment with HS and NAME predisposes to the development of hypertension and renal injury upon salt overload, characterizing a new model of chronic nephropathy. CONCLUSION: The response to MMF or L, but not HDZ, suggests a key role for inflammatory rather than hemodynamic factors.

INTRODUÇÃO: A administração de Nômega-nitro-L-arginina metiléster (NAME), um inibidor da produção de NO, com dieta rica em sal (HS) promove albuminúria e dano renal graves, reversíveis ao interromperem-se os tratamentos. OBJETIVO: Investigamos se tais alterações recrudescem ao reinstituir-se a HS e se são prevenidas pelo micofenolato mofetil (MMF), um agente antilinfócito, ou losartan, um bloqueador do receptor AT-1. MATERIAL E MÉTODOS: Ratos Münich-Wistar machos adultos receberam NAME e HS. Um grupo controle (C) recebeu apenas HS. Após 20 dias, os ratos que receberam HS e NAME exibiam hipertensão e albuminúria graves. Após recuperação de 30 dias, a hipertensão atenuou-se e a albuminúria praticamente desapareceu. Formaram-se então os grupos: HS, recebendo HS; NS, recebendo dieta normal em sal (NS); HS-MMF, recebendo HS e MMF; HS-LOS, recebendo HS e losartan; HS-HDZ, recebendo HS e hidralazina. Após sessenta dias os ratos NS tinham albuminúria e dano/inflamação renal apenas discretos. Já os ratos HS desenvolveram hipertensão e glomerulosclerose acentuadas, expansão intersticial e infiltração renal por macrófagos e células positivas para angiotensina II. Losartan baixou a pressão arterial e preveniu albuminúria e lesão renal. MMF proporcionou proteção semelhante sem alteração pressórica, sugerindo a ação de mecanismos não hemodinâmicos, hipótese reforçada pelo achado de que a HDZ baixou a pressão arterial sem prevenir a nefropatia. RESULTADOS: Esses resultados indicam que o tratamento com HS e NAME predispõe ao desenvolvimento de hipertensão e lesão renal induzidos por excesso de sal, caracterizando um novo modelo de nefropatia crônica. CONCLUSÃO: A resposta ao MMF ou losartan, mas não à hidralazina, sugere o predomínio de fatores inflamatórios.

Use of non-absorbable polypropylene mesh for the treatment of spontaneous renal graft rupture / Uso de una malla no absorbible de polipropileno para el tratamiento de la ruptura espontánea de injerto renal

Renal graft rupture (RGR) is a life-threatening complication of kidney transplantation (KT), frequently associated with rejection and acute tubular necrosis. RGR repair with the use of suture, and corsetage with various materials (including synthetic glue, polyglactin absorbable hemostatic mesh, and lyophilized human dura), is indicated in non-severe cases. However, the employment of non-absorbable synthetic mesh had not been previously reported. Here, a case of a KT from cadaveric donor with RGR associated with acute rejection is reported. The graft was salvaged with the employment of a non-absorbable polypropylene mesh. Six months after KT, the patient remains asymptomatic with normal renal function. To the best of our knowledge, this is the first report of the use of a non-absorbable polypropylene mesh to repair a RGR. In a setting in which economical restrictions are important, the use of non-absorbable synthetic mesh may represent a good option of treatment.

La ruptura del injerto renal (RIR) es una complicación del trasplante renal (TR) que amenaza la vida, y frecuentemente está asociada a rechazo y necrosis tubular aguda. La reparación de la RIR con el uso de sutura y ferulización con varios materiales (incluyendo pegamento sintético, mallas hemostáticas absorbibles de poliglactina y duramadre liofilizada humana) está indicada en los casos no graves. Sin embargo, el empleo de mallas no absorbibles no había sido informado previamente. Aquí se informa el caso de un TR proveniente de donador cadavérico con RIR asociada a rechazo agudo. El injerto fue rescatado con el empleo de una malla no absorbible de polipropileno. Seis meses después del TR el paciente se encuentra asintomático con función renal normal. Hasta donde tenemos conocimiento, éste es el primer informe del uso de una malla no absorbible de polipropileno para reparar una RIR. En un medio con importantes restricciones económicas, el uso de mallas sintéticas no absorbibles puede representar una buena opción de tratamiento.