Mecanismo sensor y de adaptación a los niveles de oxígeno y su implicancia en las enfermedades cardiovasculares: a propósito del Premio Nobel de Fisiología-Medicina 2019 / Role of hypoxia-inducible factor-1 (HIF-1) in the adaptacion to oxygen levels: Nobel Prize in physiology-medicine 2019

RESUMEN: El Premio Nobel 2019 en Fisiología-Medicina se confirió a los Profesores Gregg Semenza, William Kaelin y Sir Peter Ratcliffe por sus investigaciones en la maquinaria molecular que regula la expresión de genes sensibles a los cambios en los niveles de oxígeno. La síntesis de eritropoyetina inducida por la disminución de los niveles sanguíneos de oxígeno condujo al estudio del gen de la eritropoyetina y descubrimiento de los elementos de respuesta a hipoxia (HRE) en la región promotora y posteriormente al factor transcripcional inducible por hipoxia tipo 1 (HIF-1). Este factor consta de dos subunidades: HIF-1α, sensible al oxígeno, y HIF-1β, expresada constitutivamente. HIF1 activa la transcripción de genes que codifican enzimas, transportadores y proteínas mitocondriales que disminuyen la utilización de oxígeno al cambiar el metabolismo oxidativo al metabolismo glicolítico y además aquellos involucrados en la angiogénesis y diferenciación celular. Las investigaciones paralelas en la enfermedad von Hippel-Lindau (VHL), un desorden autosómico dominante, permitieron descubrir el mecanismo de degradación de HIF1 en condiciones de normoxia y como se estabiliza bajo hipoxia. El impacto de HIF en clínica radica en el establecimiento de nuevas dianas terapéuticas para combatir la anemia y diversas enfermedades cardiovasculares. HIF promueve la angiogénesis a través de la expresión del factor de crecimiento vascular endotelial (VEGF), agente cardioprotector con potencial para tratar la isquemia/reperfusión, hipertrofia patológica e insuficiencia cardíaca.

ABSTRACT: The Nobel Prize in Physiology-Medicine was awarded to Drs. Gregg Semenza, William Kaelin and Sir Peter Ratcliffe for their research in the molecular machinery that regulates the expression of genes sensitive to the change in oxygen levels. The synthesis of erythropoietin induced by the decrease levels of oxygen in the blood led to investigate the promoter of the erythropoietin gene where the so-called hypoxia response elements (HRE) were described. Semenza et al. described a protein that binds to HREs and called it hypoxia-inducible transcriptional factor (HIF) that regulates gene expression among those involved in angiogenesis, cell differentiation and glycolytic enzymes. HIF presents two oxygen-sensitive subunits HIF-1α and HIF-1β constitutively expressed. In parallel, Kaelin et al. investigated von Hippel-Lindau disease (VHL), an autosomal dominant disorder, discovering a mutation of this protein generated a behavior similar to hypoxia. The impact of HIF-1α lies in the search for new strategies such as hydrolase inhibitors to combat prevalent diseases, including anemia and cardiovascular diseases These compounds promote the expression of vascular endothelial growth factor (VEGF), a cardioprotective agent with potential use in pre- and post-conditioning therapy, cardiac hypertrophy and heart failure.

Pathology of dogs in Campo Grande, MS, Brazil naturally co-infected with Leishmania infantum and Ehrlichia canis / Patologia de cães naturalmente coinfectados por Leishmania infantum e Ehrlichia canis em Campo Grande, MS, Brasil

Different parasites that commonly occur concomitantly can influence one another, sometimes with unpredictable effects. We evaluated pathological aspects of dogs naturally co-infected with Leishmania infantum and Ehrlichia canis. The health status of the dogs was investigated based on histopathological, hematological and biochemical analyses of 21 animals infected solely with L. infantum and 22 dogs co- infected with L. infantum and E. canis. The skin of both groups showed chronic, predominantly lymphohistioplasmacytic inflammatory reaction. The plasmacytosis in the lymphoid tissues was likely related with the hypergammaglobulinemia detected in all the dogs. The disorganization of extracellular matrix found in the reticular dermis of the inguinal region and ear, characterized by the substitution of thick collagen fibers for thin fibers, was attributed to the degree of inflammatory reaction, irrespective of the presence of parasites. In addition, the histopathological analysis revealed that twice as many dogs in the co-infected group presented Leishmania amastigotes in the ear skin than those infected solely with Leishmania, increasing the possibility of becoming infected through sand fly vectors. Our findings highlight the fact that the health of dogs infected concomitantly with L. infantum and E. canis is severely compromised due to their high levels of total plasma protein, globulins, alkaline phosphatase and creatine kinase, and severe anemia.

A infecção simultânea por parasitas de diferentes espécies pode resultar em alterações imprevisíveis. O presente estudo avaliou a patologia de cães naturalmente coinfectados por Leishmania infantum e Ehrlichia canis. A saúde dos cães foi investigada pelas análises histopatológicas, hematológicas e bioquímicas de 21 cães infectados somente por L. infantum e 22 cães coinfectados por L. infantum e E. canis. Observou-se uma reação inflamatória crônica, predominantemente linfohistioplasmocítica, na pele dos dois grupos. A plasmocitose, encontrada nos tecidos linfóides, provavelmente estava relacionada com a hipergamaglobulinemia observada em todos os cães amostrados. A desorganização da matriz extracelular da derme da região inguinal e da orelha, demonstrada pela substituição das fibras de colágeno espessas por fibras finas, foi relacionada com o grau de reação inflamatória, independente da presença de parasitas. Ainda, observamos duas vezes mais animais do grupo coinfectado apresentando formas amastigotas na pele de orelha pela histopatologia comparado ao número de cães infectados apenas por Leishmania, tornando-os desta forma mais infectivos aos vetores. Nossos resultados ressaltam que a saúde de cães coinfectados estava severamente comprometida devido aos altos níveis de proteína plasmática total, globulinas, fosfatase alcalina, creatina quinase e anemia acentuada.

Novel three missense mutations observed in Von Hippel-Lindau gene in a patient reported with renal cell carcinoma.

Von Hippel‑Lindau (VHL) disease is an autosomal dominant hereditary cancer syndrome that predisposes to the development of a variety of benign and malignant tumors, especially cerebellar hemangioblastomas, retinal angiomas and clear‑cell renal cell carcinomas (RCC). We have identified of VHL gene using immunohistochemistry in a patient who was diagnosed for RCC. In order to understand the involvement of mutation in the VHL gene exon 1 was amplified and sequenced (accession number: JX 401534). The sequence analysis revealed the presence of novel missense mutations c.194 C>T, c.239 G>A, c.278 G>A, c.319 C>G, c. 337 C > G leading to the following variations p.Ala 65 Val, p.Gly 80 Asp, p.Gly 93 Glu, p.Gln 107 Glu, p.Gln 113 Glu in the protein.

Fundamentos moleculares de la enfermedad de von Hippel Lindau / Molecular bases of von Hipperl Lindau's disease

La enfermedad de von Hippel Lindau es una rara entidad genética que se caracteriza por la predisposición al cáncer, especialmente angiomas de la retina, hemangioblastomas del sistema nervioso central y carcinoma renal de células claras. Los productos del gen presentan un mecanismo de acción peculiar, pues está relacionado con los procesos de adaptación del organismo a la hipoxia. En este trabajo se presenta una panorámica actualizada de esta enfermedad, con énfasis en los aspectos moleculares

The von Hippel Lindau's disease is uncommon genetic entity characterized by a predisposition to cancer, specially the retina angiomas, hemangioblastomas of central nervous system and the clear cells renal carcinoma. Gene products have a typical action mechanism since it is related to organism adaptation processes to hypoxia. In present paper an updated panorama of this disease emphasizing in molecular processes

Enfermedad de von Hippel Lindau en una familia chilena: diagnóstico clínico y genético / Von Hippel Lindau disease: report of an affected family

Von Hippel Lindau disease is a hereditary syndrome characterized by the appearance of benign and malignant tumors in different organs. Its incidence is 1 case per 36000 born alive. We report a family with the disease. The index case was a male with a bilateral pheochromocytoma and cerebelar and retinal hemagioblastomas that had a sudden death due to a cerebrovascular accident at the age of 52 years. One sibling had central nervous system and retinal hemangioblastomas and other was operated for an unilateral pheochromocytoma. Both siblings had the R167Q VHL mutation of the syndrome. Other family members did not have the mutation.

Disseminated Hemangioblastomatosis of the Central Nervous System without von Hippel-Lindau Disease: A Case Report

We report a very rare case of hemangioblastomatosis that developed after surgical removal of a solitary cerebellar hemangioblastoma (HB). A 51-yr-old man presented with back pain 10 yr after undergoing surgery for cerebellar HB. Magnetic resonance imaging showed numerous mass lesions along the entire neuraxis accompanied by prominent leptomeningeal enhancement. Genomic DNA analysis showed no mutation in the von Hippel-Lindau (VHL) genes. A surgical specimen obtained from a lesion in the cauda equina showed pathological findings identical to those of the cerebellar HB that had been resected 10 yr earlier. External beam radiation therapy and radiosurgery were subsequently performed; however, the patient succumbed one year after receiving the diagnosis of hemangioblastomatosis. The reduction of tumor cell spillage during surgery and regular long-term follow-up are recommended for patients with HBs.

[Von Hippel Lindau disease: about one case]

Von Hippel Lindau disease is an autosomal dominant inherited disorder secondary to a mutation of the VHL gene, localisated on the chromosome 3, which is a tumor suppressor gene. Tumoral manifestations include hemangioblastomas, renal cysts and/or tumors, pancreatic cysts and/or neuroendocrine tumors, pheochromocytomas and endolymphatic sac tumors. Early diagnosis is necessary to allow for a regular follow up of the patient and his descendants

Molecular analysis of the Von Hippel-Lindau (VHL) gene in a family with non-syndromic pheochromocytoma: the importance of genetic testing

The two index patients of the family analyzed in this study had undergone bilateral adrenalectomy for pheochromocytomas. This prompted genetic analyses of the probands and seven first-degree relatives. The two pheochromocytoma patients and two additional asymptomatic family members were found to harbor a mutation c496G>T in exon 3 of the VHL gene. The family was then lost to systematic follow-up. Three years after performing the initial genetic evaluation, the sister of the probands, who was known to carry the same VHL germline mutation, was referred to our service after a pregnancy that was complicated by preeclampsia. She reported paroxysms suggestive for pheochromocytoma, but her urinary metanephrines were negative. However, computerized tomography of the abdomen showed an adrenal mass that was also positive on metaiodobenzylguanidine (MIBG) scintigraphy. This study illustrates that molecular analysis of the index patient(s) can lead to the identification of presymptomatic relatives carrying the mutation. Moreover, despite negative urinary metanephrines, the identification of a specific mutation has led to an increased suspicion and detection of a pheochromocytoma in the sister of the probands.

Dois pacientes índices da família analisada neste estudo foram submetidos a adrenalectomia bilateral devido a feocromocitoma. Foi, então, realizado o estudo genético dos pacientes e de sete parentes de primeiro grau. Os dois pacientes com feocromocitoma e dois outros membros assintomáticos da família apresentaram a mutação c496G>T no exon 3 do gene VHL. A família perdeu seguimento médico. Três anos após a realização da avaliação genética, a irmã dos pacientes, portadora da mutação, foi encaminhada para o nosso serviço após uma gestação complicada por pré-eclampsia. Ela referia paroxismos sugestivos de feocromocitoma, mas as metanefrinas urinárias eram negativas. Entretanto, a tomografia computadorizada de abdômen evidenciou uma massa adrenal que também se contrastou na cintilografia com metaiodobenzilguanidina (MIBG). Esse estudo mostra que a análise molecular do paciente índice pode levar à identificação de parentes assintomáticos portadores da mutação. Além disso, mesmo com as metanefrinas urinárias negativas, a identificação de uma mutação específica levou a um aumento da suspeita e detecção de feocromocitoma na irmã dos afetados pela doença.

maladie de von Hippel-Lindau: stude moleculaire de deux familles Libanaises et analyse de la correlation genotype-phenotype

The von Hippel-Lindau syndrome [VHL] is a dominantly transmitted hereditary disorder associating multisystemic tumors affecting mainly the central nervous system, the kidneys, the pancreas, as well as pheochromocytomas. Mutations of the tumor suppressor gene VHL on chromosome 3 are responsible for the disease. This article reports for the first time the study of two Lebanese VHL affected families, presenting particularly hemangioblastomas of the central nervous system. Two different mutations of the VHL gene, S65W and F76S, respectively identified in the two families, confirmed the clinical diagnosis of the patients. Molecular diagnosis was then performed for at risk members of these families. This article reveals the importance of molecular diagnosis for suspected patients and of presymptomatic diagnosis for at risk members, especially that a close follow-up of carriers allows an early detection of tumors and prevents the metastasis stage, the most common cause of death of these patients

Diagnóstico molecular da doença de Von Hippel-Lindau (VHL) em famílias brasileiras: estudo ampliado / Molecular diagnosis of the disease of Von Hippel-Lindau (VHL) in Brazilian families: study extended

A doença de von Hippel-Lindau (VHL) é uma doença hereditária multissistêmica, causada por mutação no gene VHL que predispõe o portador a manifestações benignas e malignas em diversos órgãos. O início dos sintomas pode ocorrer a partir dos primeiros anos de vida e inclui entre outros, angioma de retina, hemangioblastoma de sistema nervoso central (SNC), feocromocitoma, carcinoma renal do tipo células claras e cistos múltiplos renais, pancreáticos, hepáticos e de epidídimo. O diagnóstico clínico baseia-se em critérios que consideram a história familial e a apresentação clínica das lesões. Muitas vezes o diagnóstico é dificultado ou retardado até que estes critérios sejam preenchidos. O aconselhamento genético e avanços dos métodos de diagnóstico e de tratamento vêm mudando o curso desta enfermidade com a diminuição da morbidade e da mortalidade, contribuindo para a melhoria da qualidade de vida das famílias afetadas por esse mal e para o entendimento da doença. O diagnóstico molecular da doença baseia-se na aplicação de técnicas de biologia molecular que visam a detecção de mutações germinativas no gene VHL. O teste genético em pacientes com VHL permite avaliar a amplitude do fenótipo da doença baseado no estudo de outras famílias com a mesma mutação... Neste estudo, foram analisadas 100 indivíduos, sendo 83 indivíduos pertencentes a 20 famílias com diagnóstico de VHL; sete indivíduos pertencentes a duas famílias em que VHL era um diagnóstico diferencial; oito pacientes com tumores relacionados a VHL aparentemente esporádicos, além de dois familiares de uma paciente com hemangioblastoma aparentemente esporádico na qual foi identificada mutação germinativa no gene VHL. A taxa de 100% de detecção de mutação foi alcançada no estudo das 20 famílias com VHL através da combinação das técnicas de seqüenciamento direto e de Southern-blot quantitativo...(AU)

von Hippei-Lindau (VHL) disease [MIN 193300] is a heritable monogenetic disorder transmitted in a autosomal dominant pattern that predisposes affected individuais to the development to many typical lesions, including retina! angiomas, hemangioblastomas of the central nervous system, multiple cysts of the kidneys and pancreas, pheochromocytoma (PHE), renal cell carcinoma (RCC), and pancreatic tumors. The molecular basis of the disease is the presence of germline mutations in the VHL tumor suppressor gene. A total of 17 consecutive families with VHL (15 from Brazil, one from Portugal, and one from Equator) and three Brazilian VHL patients without family history were included in this study. Genetic counseling with signed informed consent was offered to ali participants. The mutation detection strategy consisted in direct sequencing of the coding regions of the VHL gene and quantitative Southern-blotting. We identify germline mutations in ali probands, giving rise to a 1 00°/o mutation detection rate. These consisted in 16-point mutations (9 missense, 3 frameshift, 1 in-frame deletion, 2 splice defect, 1 non-sense), 3 partia! deletions and 1 complete deletion of the VHL gene. As observed in other studies, mutations in the codon 167 confer a high risk for PHE and RCC, and mutations that predicted a truncated protein were related to VHL type 1. Twelve families (60°/o) could be characterized as having a high risk to renal carcinoma based on the family occurrence or characteristics of the mutations. Three out four families with large deletions had a high incidence of HB of the SNC. Also, we observed a tendency of the germline point mutations to concentrate among exons 1 and 2 of the VHL gene, including boundaries (87.5°/o). In addition, eight novel VHL gene mutations and two polymorphisms (one novel) are described. We concluded that the combination of direct sequencing and quantitative Southern-blotting represented a good strategy for germline mutation detection in the VHL gene and can be considered the gold standard when 1 00°/o mutation detection is needed. This preliminary study suggests that VHL families in Brazil, which are mostly of Portuguese origin, may have unique features in respect to VHL mutations and risk of malignancies, and this may be considered in the approach of genetic counseling and screening for patients of Portuguese descendents (AU)

Síndrome de Von Hippel-Lindau / Von Hippel-Lindau syndrome

O objetivo dessa apresentação é a discussão do caso de uma paciente com a Síndrome de von Hippel-Lindau, sob os seus diferentes aspectos clínicos, laboratoriais, radiológicos e terapêuticos. A seguir será apresentado o estudo genético realizado na paciente e serão discutidas a principais alterações gênicas envolvidas no aparecimento dessa síndrome clínica.

Familial cancers

Although cancer is common in the general population, only a small proportion is thought to be due to highly penetrant cancer genes. Families with a highly penetrant cancer predisposing gene may be recognised by the presence of a high number of individuals within the family with a particular cancer type, or individuals with features associated with rare inherited cancers, such as retinal changes or multiple colonic polyps. It is likely that there are many other less penetrant genes, which, in combination with environmental influences, will confer a greater lifetime predisposition to cancers. These genes are currently being identified through epidemiological studies

Von Hippel-Lindau's disease

Os autores relatam os achados de autópsia de pacientes de uma mesma família e o diagnóstico por biópsia de hemangioblastoma de um terceiro membro desta mesma família. O primeiro paciente tinha 34 anos por ocasiao do óbito e os achados de necrópsia mostraram hemangioblastoma de retina, cerebelo, bulbo e medula espinhal, além de carcinoma renal, feocromocitoma, lesoes císticas de rim e pâncreas, hidromielia e meningiomas atípicos. Seu irmao morreu com 30 anos de idade e a autópsia revelou hemangioblastomas de cerebelo, carcinoma renal e cistoadenoma de células de células claras de epidídimo. A terceira paciente era filha do primeiro paciente e apresentou cefaléia e ataxia. A tomografia computadorizada mostrou lesao cerebelar cística e a biópsia confirmou tratar-se de hemangioblastoma. Sao feitas consideraçoes epidemiológicas sobre lesoes viscerais e do sistema nervoso mais comumente encontradas, além de discutir critérios diagnósticos.