Comparative effects of calcitriol and calcimimetic on bone health in renal insufficiency.

Calcitriol and calcimimetics are used to treat hyperparathyroidism secondary to chronic kidney disease (CKD). Calcitriol administration and the subsequent increase in serum calcium concentration decrease parathyroid hormone (PTH) levels, which should reduce bone remodeling. We have previously reported that, when maintaining a given concentration of PTH, the addition of calcimimetics is associated with an increased bone cell activity. Whether calcitriol administration affects bone cell activity while PTH is maintained constant should be evaluated in an animal model of renal osteodystrophy. The aim of the present study was to compare in CKD PTH-clamped rats the bone effects of calcitriol and calcimimetic administration. The results show that the administration of calcitriol and calcimimetic at doses that induced a similar reduction in PTH secretion produced dissimilar effects on osteoblast activity in 5/6 nephrectomized (Nx) rats with secondary hyperparathyroidism and in Nx rats with clamped PTH. Remarkably, in both rat models, the administration of calcitriol decreased osteoblastic activity, whereas calcimimetic increased bone cell activity. In vitro, calcitriol supplementation inhibited nuclear translocation of ß-catenin and reduced proliferation, osteogenesis, and mineralization in mesenchymal stem cells differentiated into osteoblasts. In conclusion, besides the action of calcitriol and calcimimetics at parathyroid level, these treatments have specific effects on bone cells that are independent of the PTH level.

Cognitive Impairment Related to Chronic Kidney Disease Is Associated with a Decreased Abundance of Membrane-Bound Klotho in the Cerebral Cortex.

Cognitive impairment (CI) is a complication of chronic kidney disease (CKD) that is frequently observed among patients. The aim of this study was to evaluate the potential crosstalk between changes in cognitive function and the levels of Klotho in the brain cortex in an experimental model of CKD. To induce renal damage, Wistar rats received a diet containing 0.25% adenine for six weeks, while the control group was fed a standard diet. The animals underwent different tests for the assessment of cognitive function. At sacrifice, changes in the parameters of mineral metabolism and the expression of Klotho in the kidney and frontal cortex were evaluated. The animals with CKD exhibited impaired behavior in the cognitive tests in comparison with the rats with normal renal function. At sacrifice, CKD-associated mineral disorder was confirmed by the presence of the expected disturbances in the plasma phosphorus, PTH, and both intact and c-terminal FGF23, along with a reduced abundance of renal Klotho. Interestingly, a marked and significant decrease in Klotho was observed in the cerebral cortex of the animals with renal dysfunction. In sum, the loss in cerebral Klotho observed in experimental CKD may contribute to the cognitive dysfunction frequently observed among patients. Although further studies are required, Klotho might have a relevant role in the development of CKD-associated CI and represent a potential target in the management of this complication.

Linfoma de Burkitt en paciente adulto inmunocompetente que se presenta como rotura esplénica espontánea / Burkitt's lymphoma in an immunocompetent adult patient presenting as spontaneous splenic rupture

RESUMEN El linfoma de Burkitt es un linfoma no Hodgkin de células B que ha sido denominado por la mayoría de los investigadores como el tumor humano de crecimiento más rápido, pues es capaz de lograr una tasa de duplicación celular entre 24 y 26 horas. Se presentó un paciente masculino de 48 años de edad, con diagnóstico de linfoma de Burkitt, inmunocompetente, con esplenomegalia gigante y rotura esplénica espontánea como complicación. El paciente tuvo una evolución desfavorable en un breve período de tiempo. El linfoma de Burkitt es una enfermedad altamente agresiva, donde la falta de sospecha clínica y diagnóstico no oportuno ensombrecen el pronóstico.

ABSTRACT Burkitt's lymphoma is a B-cell non-Hodgkin lymphoma that has been called by most researchers the fastest growing human tumor, as it is capable of achieving a cell doubling rate between 24 and 26 hours. We present a 48-year-old male patient with a diagnosis of Burkitt's lymphoma, immunocompetent, with giant splenomegaly and spontaneous splenic rupture as a complication. The patient had an unfavorable evolution in a short period of time. Burkitt's lymphoma is a highly aggressive disease, where lack of clinical suspicion and untimely diagnosis overshadow the prognosis.

Linfohistiocitosis hemofagocítica, un síndrome potencialmente fatal. Presentación de tres casos / Hemophagocytic lymphohistiocytosis, a potentially fatal syndrome. Presentation of three cases

Introducción: La evidencia actual sobre el síndrome de linfohistiocitosis hemofagocítica se basa en series de casos y, por tanto, las decisiones clínicas se fundamentan en el criterio de expertos. En Cuba son escasos los informes publicados, lo cual valida los esfuerzos que incrementen la comprensión de esta entidad en nuestro medio. Objetivo: Describir tres casos de síndrome de linfohistiocitosis hemofagocítica secundaria, una complicación extremadamente infrecuente y poco sospechada. Casos clínicos: De los tres pacientes estudiados, dos presentaron linfoma como enfermedad subyacente. A uno de ellos se le diagnosticó un linfoma no Hodgkin de células T anaplásico en la necropsia; mientras el otro paciente fue diagnosticado y tratado precozmente por linfoma no Hodgkin de células grandes B, el cual evolucionó satisfactoriamente. El tercer paciente presentó endocarditis de valva tricúspide y alcanzó la remisión luego de tratamiento antibiótico, inmunomodulador y quirúrgico. Conclusiones: Los casos presentados destacan la complejidad del síndrome de linfohistiocitosis hemofagocítica y refuerzan la necesidad crítica de su diagnóstico y tratamiento oportuno en nuestro medio(AU)

Introduction: The current evidence about hemophagocytic lymphohistiocytosis syndrome is based on case series and, therefore, clinical decisions are based on expert criteria. In Cuba, there are few published reports, which validates the efforts that may increase understanding of this entity in our environment. Objective: To describe three cases of secondary hemophagocytic lymphohistiocytosis syndrome, an extremely rare and little suspected complication. Clinical cases: Of the three patients studied, two presented lymphoma as subjacent disease. One of them was diagnosed with anaplastic T-cell non-Hodgkin lymphoma at autopsy. The other was diagnosed and treated early for large B-cell non-Hodgkin lymphoma, and evolved satisfactorily. The third patient presented tricuspid valve endocarditis and achieved remission after antibiotic, immunomodulatory and surgical treatment. Conclusions: The cases presented highlight the complexity of hemophagocytic lymphohistiocytosis syndrome and reinforce the critical need for diagnosis and timely treatment of this condition in our setting(AU)

Enfermedad linfoproliferativa asociada a artritis reumatoide: reporte de tres casos / Lymphoproliferative disease associated with rheumatoid arthritis: report of three cases

Las investigaciones en la última década han demostrado que el riesgo de desarrollar linfoma en pacientes con artritis reumatoide es el doble que el riesgo de la población general. Sin embargo, no se cuenta con datos de la magnitud de este problema en Cuba. Se presentan los casos de tres pacientes con diagnóstico de artritis reumatoide seropositiva tratadas con metotrexate, que durante su evolución desarrollaron linfoma no Hodgkin. Las pacientes recibieron quimioterapia de primera línea y alcanzaron remisión total con supervivencia de tres años hasta el momento. El diagnóstico de las enfermedades linfoproliferativas en pacientes con artritis reumatoide es un desafío; por lo que es necesario un elevado índice de sospecha que, en ausencia de marcadores fiables de linfomagénesis, permita el manejo oportuno de estos pacientes(AU)

Research in the last decade has shown that the risk of developing lymphoma in patients with rheumatoid arthritis is twice the risk of the general population. However, there is not data on the magnitude of this problem in Cuba.We present the cases of three patients with a diagnosis of seropositive rheumatoid arthritis treated with methotrexate who during their evolution developed non-Hodgkin's lymphoma.The patients received first-line chemotherapy and they achieved total remission with three-year survival so far.The diagnosis of lymphoproliferative diseases in patients with rheumatoid arthritis is a challenge; therefore, a high index of suspicion is necessary that, in the absence of reliable markers of lymphomagenesis, allows the timely management of these patients(AU)