Tuberous Sclerosis Complex and the kidneys: what nephrologists need to know.

Tuberous sclerosis complex (TSC) is an autosomal dominant disease characterized by the development of hamartomas in the central nervous system, heart, skin, lungs, and kidneys and other manifestations including seizures, cortical tubers, radial migration lines, autism and cognitive disability. The disease is associated with pathogenic variants in the TSC1 or TSC2 genes, resulting in the hyperactivation of the mTOR pathway, a key regulator of cell growth and metabolism. Consequently, the hyperactivation of the mTOR pathway leads to abnormal tissue proliferation and the development of solid tumors. Kidney involvement in TSC is characterized by the development of cystic lesions, renal cell carcinoma and renal angiomyolipomas, which may progress and cause pain, bleeding, and loss of kidney function. Over the past years, there has been a notable shift in the therapeutic approach to TSC, particularly in addressing renal manifestations. mTOR inhibitors have emerged as the primary therapeutic option, whereas surgical interventions like nephrectomy and embolization being reserved primarily for complications unresponsive to clinical treatment, such as severe renal hemorrhage. This review focuses on the main clinical characteristics of TSC, the mechanisms underlying kidney involvement, the recent advances in therapy for kidney lesions, and the future perspectives.

Acteoside Attenuates Recognition Memory Impairment in CUMS Rats via Regulating Synaptic Plasticity and mTOR Signaling Pathway / El Acteoside Atenúa el Deterioro de la Memoria de Reconocimiento en Ratas ELCI Mediante la Regulación de la Plasticidad Sináptica y la Vía de Señalización mTOR

SUMMARY: We evaluated the role and mechanism of acteoside in the regulation of memory impairment induced by chronic unpredictable mild stress (CUMS). CUMS was used to induce depression in rats and the successful establishment of CUMS model were verified by forced swimming test and sucrose preference test. The Y-maze test and novel object recognition test assessed memory functions. The structural changes in the cortex and hippocampus were observed by hematoxylin and eosin (HE) staining. Immunofluorescence staining and western blotting determined the protein levels. Y-maze test and novel object recognition test showed that there was memory performance impairment in rats of CUMS group, which was improved by the acteoside treatment. HE staining showed that CUMS exposure damaged the structure in the cortex and hippocampus, while the acteoside treatment alleviated the structural changes. Compared with the control group, the levels of BNDF and CREB in the cortex and hippocampus of the CUMS group were significantly decreased. Acteoside significantly reversed the expressions of these proteins in CUMS rats. Meanwhile, compared with the control group, the levels of p-mTOR and p- P70S6K in the cortex and hippocampus of the CUMS group were significantly increased, and these changes were significantly reversed by acteoside. Nevertheless, the effect of acteoside on mTOR signaling was markedly blocked by rapamycin, a specific inhibitor of mTOR signaling. Acteoside can attenuate memory impairment and ameliorate neuronal damage and synaptic plasticity in depression rats probably via inhibiting the mTOR signaling pathway. Acteoside may serve as a novel reagent for the prevention of depression.

Evaluamos el papel y el mecanismo del acteoside en la regulación del deterioro de la memoria inducido por estrés leve crónico impredecible (ELCI). Se utilizó ELCI para inducir depresión en ratas y el establecimiento exitoso del modelo ELCI se verificó mediante una prueba de natación forzada y una prueba de preferencia de sacarosa. La prueba del laberinto en Y y la prueba de reconocimiento de objetos novedosos evaluaron las funciones de la memoria. Los cambios estructurales en la corteza y el hipocampo se observaron mediante tinción con hematoxilina y eosina (HE). La tinción por inmunofluorescencia y la transferencia Western determinaron los niveles de proteína. La prueba del laberinto en Y y la prueba de reconocimiento de objetos novedosos mostraron que había un deterioro del rendimiento de la memoria en ratas del grupo ELCI, que mejoró con el tratamiento con acteósidos. La tinción con HE mostró que la exposición a ELCI dañó la estructura de la corteza y el hipocampo, mientras que el tratamiento con actósidos alivió los cambios estructurales. En comparación con el grupo de control, los niveles de BNDF y CREB en la corteza y el hipocampo del grupo ELCI disminuyeron significativamente. Acteoside revirtió significativamente las expresiones de estas proteínas en ratas ELCI. Mientras tanto, en comparación con el grupo control, los niveles de p-mTOR y p-P70S6K en la corteza y el hipocampo del grupo ELCI aumentaron significativamente, y estos cambios fueron revertidos significativamente ELCI por el acteoside. Sin embargo, el efecto del acteoside sobre la señalización de mTOR fue notablemente bloqueado por la rapamicina, un inhibidor específico de la señalización de mTOR. El acteoside puede atenuar el deterioro de la memoria y mejorar el daño neuronal y la plasticidad sináptica en ratas con depresión, probablemente mediante la inhibición de la vía de señalización mTOR. Acteoside puede servir como un reactivo novedoso para la prevención de la depresión.

Temsirolimus (Torisel®) en tumor desmoplásico de células redondas avanzado / Temsirolimus (Torisel®) in desmoplastic tumor of advanced round cells

INTRODUCCIÓN: El tumor desmoplásico de células redondas es un tumor mesenquimal que surge de la superficie peritoneal. 1 Es considerado un sarcoma de partes blandas que suele afectar principalmente al sexo masculino con una elevada prevalencia en niños y adultos jóvenes. 1,2 En Argentina se desconoce su incidencia, pero es considerado una neoplasia poco frecuente. La tasa de incidencia ajustada por edad en los Estados Unidos se estima en 0,3 casos/millón de habitantes.3 Su principal característica diagnóstica es una traslocación recíproca del gen t(11;22) (p13;q11 o q12), que provoca la fusión del gen del sarcoma de Ewing y el cromosoma 22 del tumor de Wilms. 1 Las manifestaciones clínicas iniciales suelen ser inespecíficas y están relacionadas con el tamaño, la ubicación y la velocidad de progresión de la enfermedad.1,2 Suele presentarse como una masa abdominal palpable con dolor y otros síntomas gastrointestinales asociados. Las masas tumorales pueden causar síntomas de compresión, como obstrucción intestinal y uronefrosis. En casos avanzados puede existir carcinomatosis peritoneal con o sin ascitis, o compromiso metastásico en ganglios linfáticos, hígado y pulmones. TECNOLOGÍA: El temsirolimus es un inhibidor selectivo de la molécula denominada mTOR (diana de la rapamicina en las células de mamífero).6,7 Además de regular las proteínas del ciclo celular, mTOR regula la traducción de los factores inducibles por la hipoxia, HIF-1 y HIF-2 alfa. Estos factores regulan la capacidad de los tumores de adaptarse a entornos hipóxicos y de producir el factor de crecimiento del endotelio vascular (VEGF). Por tanto, el efecto antitumoral del temsirolimus podría derivar también en parte de su capacidad de deprimir los niveles de HIF y VEGF en el tumor o en el microentorno tumoral y reducir así el desarrollo de vasos. OBJETIVO: El objetivo del presente informe es evaluar rápidamente los parámetros de eficacia, seguridad, costos y recomendaciones disponibles acerca del empleo de temsirolimus (Torisel®) en personas con diagnóstico de tumor desmoplásico de células redondas avanzado. MÉTODOS: Se realizó una búsqueda bibliográfica en las principales bases de datos tales como PUBMED, LILACS, BRISA, COCHRANE, SCIELO, EMBASE, TRIPDATABASE como así también en sociedades científicas, agencias reguladoras, financiadores de salud y agencias de evaluación de tecnologías sanitarias. Se priorizó la inclusión de revisiones sistemáticas, ensayos clínicos controlados aleatorizados, evaluación de tecnología sanitaria y guías de práctica clínica de alta calidad metodológica. RECOMENDACIONES No se hallaron guías de práctica clínica actualizadas en Argentina y en el Mundo que recomienden la tecnología en la indicación evaluada. Las guías actualizadas de la Red Nacional de Centros para el Tratamiento Integral del cáncer de los Estados Unidos (NCCN, su sigla del inglés National Comprehensive Cáncer Network) no mencionan el uso de temsirolimus dentro de las opciones terapéuticas para el tratamiento de los tumores desmoplásicos de células redondas avanzados.4 Un consenso de expertos estadounidenses sobre la temática publicado en 2020 no menciona el uso de temsirolimus dentro de las opciones de tratamento. CONCLUSIONES No se hallaron ensayos clínicos publicados que hayan evaluado la eficacia y seguridad de la utilización de temsirolimus (Torisel®) en personas con diagnóstico de tumor desmoplásico de células redondas avanzado. La evidencia que sustentaría el uso del fármaco en la indicación mencionada proviene de una series de casos retrospectiva. El mismo incluyo cinco personas progresadas a distintos tratamientos y cirugías, que utilizaron temsirolimus asociada a vinorelbina y ciclofosfamida. El estudio reportó una mediana de libre de progresión de 8,5 meses sobre tres personas, y eventos adversos serios como la fatiga, neutropenia grado 3-4, mucositis y fallo renal. Un estudio en curso, sin resultados publicados y que incluye la tecnología en la indicación evaluada, ha detenido la inclusión de personas debido a que no se cumplió su objetivo de eficacia pre-especificado. Su comercialización en la indicación evaluada no se encuentra autorizada por la agencia regulatoria de los Estados Unidos y de Europa. No se hallaron guías de práctica clínica actualizadas en Argentina y en el Mundo que recomienden la tecnología en la indicación evaluada. No se hallaron evaluaciones económicas publicadas para Argentina y el Mundo, donde el precio de adquisición internacional de referencia relevado para un vial de 25mg/ml es de USD 1.213 (ARS 443.352 noviembre/23).

Conversion to mTOR Inhibitor to Reduce the Incidence of Cytomegalovirus Recurrence in Kidney Transplant Recipients Receiving Preemptive Treatment: A Prospective, Randomized Trial.

BACKGROUND: Although mammalian target of rapamycin inhibitors (mTORi) are associated with a lower incidence of the first episode of cytomegalovirus (CMV) infection/disease in kidney transplant recipients receiving calcineurin inhibitors (CNIs), the efficacy and safety of the conversion from the antimetabolite to an mTORi for the prevention of CMV recurrence are unknown. METHODS: In this single-center prospective randomized trial, low-immunological-risk, CMV-positive kidney transplant recipients receiving preemptive therapy were randomized to be converted (sirolimus [SRL]) or not (control [CTR]) immediately after the treatment of the first episode of CMV infection/disease and were followed for 12 mo. A sample size of 72 patients was calculated to demonstrate a 75% reduction in the incidence of CMV recurrence (80% power, 95% confidence level). RESULTS: Of 3247 adult kidney transplants performed between September 13, 2015, and May 7, 2019, 1309 (40%) were treated for the first CMV infection/disease, and 72 were randomized (35 SRL and 37 CTR). In the SRL group, there were no episodes of CMV recurrence, compared with 16 patients in the CTR group (0% versus 43%; P < 0.0001). Four patients had a second and 1 a third recurrent CMV event. Three of them were converted to SRL and did not develop any further CMV events. There were no differences in the incidence of acute rejection, drug discontinuation, kidney function, and patient and graft survival at 12 mo. CONCLUSIONS: These data suggest that, in CMV-positive kidney transplant recipients, the conversion from an antiproliferative drug to SRL after the first CMV episode is an effective and safe strategy for recurrent episodes.

The use of mTOR inhibitors for the treatment of kaposiform hemangioendothelioma. A systematic review.

BACKGROUND: Kaposiform hemangioendothelioma (KHE) is a locally aggressive and potentially lethal vascular tumor of infancy. Current consensus recommendations include the use of vincristine and/or systemic steroids as first-line treatment. Mammalian target of rapamycin (mTOR) inhibitors represent a promising therapy for patients with KHE. The goal of our study is to critically assess the existing literature on outcomes of patients with KHE treated with mTOR inhibitors. METHODS: We conducted a literature search from 1 January 2000, to 30 April 2022. Articles reporting outcomes of patients treated with mTOR inhibitors for KHE were included. Descriptive statistics were used to describe and summarize the outcomes of the treatment. RESULTS: We included 327 patients with a mean age at diagnosis of 9.1 months (SD ± 9). Patients were treated with an mTOR inhibitor for a mean of 15.2 months (SD ± 4.1). A total of 315 (96.3%) patients had positive outcomes including improvement of the tumor size, symptoms and/or laboratory parameters in 227 (85%) and complete remission in 38 (12%). Seven (2%) patients did not respond to treatment and seven (2%) died of sepsis (4), Kasabach-Merritt phenomenon complications (1), cardiac and liver failure due to ductus arteriosus (1), or metastatic disease (1). CONCLUSION: This systematic review supports the efficacy and safety of mTOR inhibitors for KHE. Their use resulted in positive outcomes in terms of decreased symptoms, reduction in tumor size and improvement in biochemical parameters with a mortality rate of 2%. According to these findings, we suggest revised consensus treatment guidelines for KHE with mTOR inhibitors potentially considered first-line therapy.

The impact of mTOR inhibitors in the regression of left ventricular hypertrophy in elderly kidney transplant recipients.

End-stage kidney disease is frequently associated with left ventricular hypertrophy (LVH), a condition more prevalent in the elderly, that may increase mortality after renal transplantation (RTx). Previous studies suggested that mTOR inhibitors (mTORi) can improve LVH, but this has never been tested in elderly kidney transplant recipients. In this prospective randomized clinical trial, we analyzed the impact of Everolimus (EVL) on the reversal of LVH after RTx in elderly recipients (≥60 years) submitted to different immunosuppressive regimens: EVL/lowTacrolimus (EVL group, n = 53) or mycophenolate sodium/regularTacrolimus (MPS group, n = 47). Patients performed echocardiograms (Echo) up to 3 months after RTx and then annually. At baseline, mean age was 65±3 years in both groups and LVH was observed in 63.6% of patients in EVL group and in 61.8% of MPS group. Last Echo was performed at mean time of 47 and 49 months after RTx in EVL and MPS groups, respectively (P = .34). LVH regression was observed in 23.8% (EVL group) and 19% (MPS group) of patients (P = 1.00). Mean eGFR, blood pressure, and use of RAS blockers were similar between groups throughout follow-up. EVL did not improve LVH in this cohort, and this lack of benefit may be attributed to concomitant use of TAC, senescence, or both.

Temsirolimus combined with cyclophosphamide and etoposide for pediatric patients with relapsed/refractory acute lymphoblastic leukemia: a Therapeutic Advances in Childhood Leukemia Consortium trial (TACL 2014-001).

Phosphatidylinositol 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) signaling is commonly dysregulated in acute lymphoblastic leukemia (ALL). The TACL2014-001 phase I trial of the mTOR inhibitor temsirolimus in combination with cyclophosphamide and etoposide was performed in children and adolescents with relapsed/refractory ALL. Temsirolimus was administered intravenously (IV) on days 1 and 8 with cyclophosphamide 440 mg/m2 and etoposide 100 mg/m2 IV daily on days 1-5. The starting dose of temsirolimus was 7.5 mg/m2 (DL1) with escalation to 10 mg/m2 (DL2), 15 mg/m2 (DL3), and 25 mg/m2 (DL4). PI3K/mTOR pathway inhibition was measured by phosphoflow cytometry analysis of peripheral blood specimens from treated patients. Sixteen heavily-pretreated patients were enrolled with 15 evaluable for toxicity. One dose-limiting toxicity of grade 4 pleural and pericardial effusions occurred in a patient treated at DL3. Additional dose-limiting toxicities were not seen in the DL3 expansion or DL4 cohort. Grade 3/4 non-hematologic toxicities occurring in three or more patients included febrile neutropenia, elevated alanine aminotransferase, hypokalemia, mucositis, and tumor lysis syndrome and occurred across all doses. Response and complete were observed at all dose levels with a 47% overall response rate and 27% complete response rate. Pharmacodynamic correlative studies demonstrated dose-dependent inhibition of PI3K/mTOR pathway phosphoproteins in all studied patients. Temsirolimus at doses up to 25 mg/m2 with cyclophosphamide and etoposide had an acceptable safety profile in children with relapsed/refractory ALL. Pharmacodynamic mTOR target inhibition was achieved and appeared to correlate with temsirolimus dose. Future testing of next-generation PI3K/mTOR pathway inhibitors with chemotherapy may be warranted to increase response rates in children with relapsed/refractory ALL.

In silico development of new PET radiopharmaceuticals from mTOR inhibitors.

Rapamycin (or sirolimus) is a macrolide that has shown to be useful as an immunosuppressant and that was studied in metabolic, neurological, or genetic disorders. Rapamycin is a specific natural inhibitor of the mechanistic target of rapamycin (mTOR) that is a kinase protein playing a pivotal role in cell growth and proliferation by activation of several metabolic processes. This work aimed to evaluate the utility of several compounds obtained from rapamycin and its semi-synthetic analogs everolimus and temsirolimus as possible radiopharmaceuticals oriented to this protein. Density Functional Theory calculations of these molecules were made and further analysis of the dual descriptor, charges populations, and of the electrostatic potential surfaces were performed. Molecular docking simulations were used to evaluate the interactions of the rapamycin with the studied candidates. They allowed us to propose two strategies for the synthesis of novel compounds based on electrophilic reactions. Molecular docking results also helped us to eliminate molecules that did not interact correctly with the target. Finally, we found for the first time, that the novel compounds synthesized through the electrophilic addition reaction that employed 18F-selectfluor, should maintain the biological activity of original compounds and could be suitable as Positron Emission Tomography radiopharmaceuticals targeting mTOR Complex1 system.

Mammalian Target of Rapamycin Inhibitors Vs Calcineurin Inhibitors in Chronic Graft Rejection After Lung Transplantation: A Systematic Review and Meta-Analysis.

BACKGROUND: The number of lung transplantations has been rising constantly. However, use of this therapeutic resource is limited by several issues that are difficult to resolve, such as chronic graft rejection and complications secondary to immunosuppression. METHODS: This systematic review compared mammalian target of rapamycin (mTOR) inhibitor immunosuppression associated with low-dose calcineurin inhibitors with isolated calcineurin inhibitor immunosuppression on the new-onset chronic rejection development and mortality 12 months after lung transplantation. Three controlled randomized clinical trials (SHITRIT, NOCTET, and 4EVERLUNG) were selected from electronic databases. RESULTS: Meta-analysis of the data at 12 months postintervention showed that only 4EVERLUNG assessed chronic graft rejection, with a higher incidence in the control group; however, the difference was not statistically significant (P = .197). Significant data were related to an increase in the number of adverse events (P = .0064) and improved renal function (P < .0001) in the mTOR inhibitor-based scheme. The other outcomes indicated a trend toward greater risk of death and acute graft rejection with the use of mTORs. CONCLUSIONS: The researchers suggest considering the use of mTOR inhibitors, whose greatest benefit is felt by patients with renal dysfunction, in association with the use of calcineurin inhibitors, because of the imminent risk of death among patients with renal failure.

Everolimus as a possible prenatal treatment of in utero diagnosed subependymal lesions in tuberous sclerosis complex: a case report.

INTRODUCTION: The association between cardiac rhabdomyoma and intraventricular tumors and/or subcortical nodules is characteristic of tuberous sclerosis complex (TSC). Patients with TSC may have refractory seizures, autistic behavior, and cognitive decline. CASE REPORT: The patient received the fetal diagnosis of TSC at the age of 19 weeks of gestations, where presented at prenatal ultrasound cardiac and brain tumors. Fetal MRI showed a lesion in the right and left lateral ventricles near the foramen of Monro associated with subependymal lesions along the entire ependyma of the lateral ventricles and several subcortical tubercles, and the fetal Doppler echocardiogram revealed three cardiac lesions. The fetus underwent intrauterine treatment with everolimus and presented regression and subsequent stabilization of the cardiac and brain lesions; additionally, the patient did not develop seizures or autism and presented good neuropsychomotor development. CONCLUSION: It is the first evidence that mTOR inhibitors may help to prevent neurological complications associated with TSC.