RESUMO
Sickle cell disease is characterized by vaso-occlusive phenomena and haemolytic anaemia. There is a significant concern that the overlap of COVID-19 lung disease with acute chest syndrome that occurs in sickle cell patients may result in serious complications. Case reports of sickle cell patients with COVID-19 have been published. Here, we present a case series of COVID-19 infection in sickle cell patients in a developing country (Brazil). Only 10 patients tested positive so far for SARS-CoV-2 of 600 patients followed at our institution, of which 8 needed hospitalization (one in the intensive care unit), with no deaths. Even in a middle-income country, COVID-19 was reported to be relatively mild in sickle cell patients. In relation to risk factors, blood type O seems to confer some protection against developing severe COVID-19, a finding that could guide clinicians to adopt more clinical surveillance for patients with non-O blood type in sickle cell patients.
Assuntos
Sistema ABO de Grupos Sanguíneos/sangue , Anemia Falciforme/sangue , Anemia Falciforme/terapia , COVID-19/sangue , COVID-19/terapia , SARS-CoV-2/metabolismo , Adulto , Anemia Falciforme/epidemiologia , Brasil , COVID-19/epidemiologia , Criança , Países em Desenvolvimento , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
Mesenchymal stem cells (MSCs) were initially identified as progenitors of skeletal tissues within mammalian bone marrow and cells with similar properties were also obtained from other tissues such as adipose and dental pulp. Although MSCs have been extensively investigated, their native behavior and in vivo identity remain poorly defined. Uncovering the in vivo identity of MSCs has been challenging due to the lack of exclusive cell markers, cellular alterations caused by culture methods, and extensive focus on in vitro properties for characterization. Although MSC site of origin influences their functional properties, these mesenchymal progenitors can be found in the perivascular space in virtually all organs from where they were obtained. However, the precise identity of MSCs within the vascular wall is highly controversial. The recurrent concept that MSCs correspond to pericytes in vivo has been supported mainly by their perivascular localization and expression of some molecular markers. However, this view has been a subject of controversy, in part, due to the application of loose criteria to define pericytes and due to the lack of a marker able to unequivocally identify these cells. Furthermore, recent evidences indicate that subpopulations of MSCs can be found at extravascular sites such as the endosteum. In this opinion review, we bring together the advances and pitfalls on the search for the in vivo identity of MSCs and highlight the recent evidences that suggest that perivascular MSCs are adventitial cells, acting as precursors of pericytes and other stromal cells during tissue homeostasis.
Assuntos
Células-Tronco Mesenquimais/citologia , Pericitos/citologia , Animais , Osso e Ossos/citologia , Transição Epitelial-Mesenquimal , HumanosRESUMO
Mesenchymal stromal cells (MSCs) are cultured cells that can give rise to mature mesenchymal cells under appropriate conditions and secrete a number of biologically relevant molecules that may play an important role in regenerative medicine. Evidence indicates that pericytes (PCs) correspond to mesenchymal stem cells in vivo and can give rise to MSCs when cultured, but a comparison between the gene expression profiles of cultured PCs (cPCs) and MSCs is lacking. We have devised a novel methodology to isolate PCs from human adipose tissue and compared cPCs to MSCs obtained through traditional methods. Freshly isolated PCs expressed CD34, CD140b, and CD271 on their surface, but not CD146. Both MSCs and cPCs were able to differentiate along mesenchymal pathways in vitro, displayed an essentially identical surface immunophenotype, and exhibited the ability to suppress CD3(+) lymphocyte proliferation in vitro. Microarray expression data of cPCs and MSCs formed a single cluster among other cell types. Further analyses showed that the gene expression profiles of cPCs and MSCs are extremely similar, although MSCs differentially expressed endothelial cell (EC)-specific transcripts. These results confirm, using the power of transcriptomic analysis, that PCs give rise to MSCs and suggest that low levels of ECs may persist in MSC cultures established using traditional protocols.
Assuntos
Tecido Adiposo/citologia , Células-Tronco Mesenquimais/metabolismo , Pericitos/metabolismo , Transcriptoma , Adolescente , Adulto , Antígenos CD/genética , Antígenos CD/metabolismo , Diferenciação Celular , Células Cultivadas , Feminino , Humanos , Masculino , Células-Tronco Mesenquimais/citologia , Pessoa de Meia-Idade , Pericitos/citologia , Cultura Primária de Células/métodosRESUMO
The human T-cell lymphotropic virus type 1 (HTLV-1) was the first human retrovirus known as a direct causal agent of a malignant disease. The vertical route of HTLV transmission is the most frequent pathway of the virus contamination. This study was performed to determine the prevalence ratio of HTLV-1 infection among nursing women. From January 2004 to January 2005, blood samples from 1033 nursing mothers from Paraíba, Brazil were evaluated for HTLV antibodies by ELISA and HTLV-1 viral particles confirmed by polymerase chain reaction (PCR). HTLV antibodies were detected in 7 women. The overall seroprevalence ratio was 0.68% and HTLV-1 viral sequences were confirmed by PCR in 2 women. These preliminary data suggest that HTLV screening should be introduced as a mandatory test before breastfeeding and breast milk donation in Paraíba, Brazil. Additionally, counseling programs would help reduce the prevalence ratio of HTLV-1 infected individuals in this Brazilian region.