Luciana Morganti Ferreira Maselli

Color and genomic ancestry in Brazilians: a study with forensic microsatellites.

The population of Brazil, formed by extensive admixture between Amerindians, Europeans and Africans, is one of the most variable in the world. We have recently published a study that used ancestry-informative markers to conclude that in Brazil, at an individual level, color, as determined by physical evaluation, was a poor predictor of genomic ancestry, estimated by molecular markers. To corroborate these findings we undertook the present investigation based on data from 12 commercially available forensic microsatellites that were utilized to estimate the personal genomic origin for each of 752 individuals from the city of São Paulo, belonging to different Brazilian color categories (275 Whites, 192 Intermediates and 285 Blacks). The genotypes permitted the calculation of a personal likelihood-ratio estimator of African or European ancestry. Although the 12 marker set proved capable of discriminating between European and African individuals, we observed very significant overlaps among the three color categories of Brazilians. This was confirmed quantitatively using a Bayesian analysis of population structure that did not demonstrate significant genetic differentiation between the three color groups. These results corroborate and validate our previous conclusions using ancestry-informative markers that in Brazil at the individual level there is significant dissociation of color and genomic ancestry.

Características biológicas das células-tronco mesenquimais

Celulas-tronco sao celulas indiferenciadas. Como tal, apresentam uma serie de caracteristicas que as tornam candidatas a utilizacao terapeutica. As principais caracteristicas das celulas-tronco sao a capacidade de autorrenovacao e de se diferenciarem em diversos tipos celulares. Desta forma, acredita-se que celulas-tronco presentes nos diferentes tecidos tenham papel regenerativo quando estes sofrem uma lesao ou injuria. Entre os tecidos conhecidos por apresentarem celulas-tronco apos a vida pos-natal, a medula ossea foi a mais estudada, por muitos anos, como fonte tanto de celulas-tronco hematopoeticas quanto de celulas-tronco mesenquimais, tambem denominadas de celulas mesenquimais estromais da medula ossea ou celulas estromais mesenquimais multipotentes. Estas celulas sao um grupo de celulas clonogenicas, presentes no estroma da medula ossea, que, quando submetidas a diferentes estimulos apropriados, sao capazes de se diferenciarem em varias linhagens de celulas, como a osteogenica, a condrogenica e a adipogenica e, possivelmente, em outros tipos celulares nao mesodermicos, como celulas neurais ou hepatocitos. Nesta revisao, as principais caracteristicas das celulas-tronco mesenquimais serao abordadas, incluindo os marcadores moleculares e de membrana, as caracteristicas de divisao e de diferenciacao, a heterogeneidade e as aplicacoes clinicas potenciais.

Impact of antiretroviral therapy on lipid metabolism of human immunodeficiency virus-infected patients: Old and new drugs

For human immunodeficiency virus (HIV)-infected patients, the 1990s were marked by the introduction of highly active antiretroviral therapy (HAART) representing a new perspective of life for these patients. The use of HAART was shown to effectively suppress the replication of HIV-1 and dramatically reduce mortality and morbidity, which led to a better and longer quality of life for HIV-1-infected patients. Apart from the substantial benefits that result from the use of various HAART regimens, laboratory and clinical experience has shown that HAART can induce severe and considerable adverse effects related to metabolic complications of lipid metabolism, characterized by signs of lipodystrophy, insulin resistance, central adiposity, dyslipidemia, increased risk of cardiovascular disease and even an increased risk of atherosclerosis. New drugs are being studied, new therapeutic strategies are being implemented, and the use of statins, fibrates, and inhibitors of intestinal cholesterol absorption have been effective alternatives. Changes in diet and lifestyle have also shown satisfactory results.

Detection of Plasmodium falciparum and Plasmodium vivax subclinical infection in non-endemic region: implications for blood transfusion and malaria epidemiology

BackgroundIn Brazil, malaria is endemic in the Amazon River basin and non-endemic in the extra-Amazon region, which includes areas of São Paulo state. In this state, a number of autochthonous cases of malaria occur annually, and the prevalence of subclinical infection is unknown. Asymptomatic infections may remain undetected, maintaining transmission of the pathogen, including by blood transfusion. In these report it has been described subclinical Plasmodium infection in blood donors from a blood transfusion centre in São Paulo, Brazil.MethodsIn this cross-sectional study, representative samples of blood were obtained from 1,108 healthy blood donors at the Fundação Pró-Sangue Hemocentro de São Paulo, the main blood transfusion centre in São Paulo. Malaria exposure was defined by the home region (exposed: forest region; non-exposed: non-forest region). Real-time PCR was used to detect Plasmodium falciparum and Plasmodium vivax. Subclinical malaria cases were geo-referenced.ResultsEighty-four (7.41%) blood donors tested positive for Plasmodium; 57 of these were infected by P. falciparum, 25 by P. vivax, and 2 by both. The prevalence of P. falciparum and P. vivax was 5.14 and 2.26, respectively. The overall prevalence ratio (PR) was 3.23 (95% confidence interval (CI) 2.03, 5.13); P. falciparum PR was 16.11 (95% CI 5.87, 44.21) and P. vivax PR was 0.47 (95% CI 0.2, 1.12). Plasmodium falciparum subclinical malaria infection in the Atlantic Forest domain was present in the mountain regions while P. vivax infection was observed in cities from forest-surrounded areas.ConclusionsThe presence of Plasmodium in healthy blood donors from a region known as non-endemic, which is important in the context of transfusion biosafety, was described. Infected recipients may become asymptomatic carriers and a reservoir for parasites, maintaining their transmission. Furthermore, P. falciparum PR was positively associated with the forest environment, and P. vivax was associated with forest fragmentation.

Plasmodium falciparum in the southeastern Atlantic forest: a challenge to the bromeliad-malaria paradigm?

BackgroundRecently an unexpectedly high prevalence of Plasmodium falciparum was found in asymptomatic blood donors living in the southeastern Brazilian Atlantic forest. The bromeliad-malaria paradigm assumes that transmission of Plasmodium vivax and Plasmodium malariae involves species of the subgenus Kerteszia of Anopheles and only a few cases of P. vivax malaria are reported annually in this region. The expectations of this paradigm are a low prevalence of P. vivax and a null prevalence of P. falciparum. Therefore, the aim of this study was to verify if P. falciparum is actively circulating in the southeastern Brazilian Atlantic forest remains.MethodsIn this study, anophelines were collected with Shannon and CDC-light traps in seven distinct Atlantic forest landscapes over a 4-month period. Field-collected Anopheles mosquitoes were tested by real-time PCR assay in pools of ten, and then each mosquito from every positive pool, separately for P. falciparum and P. vivax. Genomic DNA of P. falciparum or P. vivax from positive anophelines was then amplified by traditional PCR for sequencing of the 18S ribosomal DNA to confirm Plasmodium species. Binomial probabilities were calculated to identify non-random results of the P. falciparum-infected anopheline findings.ResultsThe overall proportion of anophelines naturally infected with P. falciparum was 4.4% (21/480) and only 0.8% (4/480) with P. vivax. All of the infected mosquitoes were found in intermixed natural and human-modified environments and most were Anopheles cruzii (22/25 = 88%, 18 P. falciparum plus 4 P. vivax). Plasmodium falciparum was confirmed by sequencing in 76% (16/21) of positive mosquitoes, whereas P. vivax was confirmed in only 25% (1/4). Binomial probabilities suggest that P. falciparum actively circulates throughout the region and that there may be a threshold of the forested over human-modified environment ratio upon which the proportion of P. falciparum-infected anophelines increases significantly.ConclusionsThese results show that P. falciparum actively circulates, in higher proportion than P. vivax, among Anopheles mosquitoes of fragments of the southeastern Brazilian Atlantic forest. This finding challenges the classical bromeliad-malaria paradigm, which considers P. vivax circulation as the driver for the dynamics of residual malaria transmission in this region.

Serum levels of IgG antibodies against oxidized LDL and atherogenic indices in HIV-1-infected patients treated with protease inhibitors.

Abstract Background: Antibodies against low-density lipoproteins (LDLs) that have been oxidized are associated with development of atherosclerotic lesions. In individuals infected with human immunodeficiency virus type 1 (HIV-1) with or without therapy, dyslipidemia and increased cardiovascular risk are observed. Methods: Serum levels of IgG antibodies against oxidized LDLs (IgG anti-oxLDL Abs) were determined by assay in 151 HIV-1-infected patients. Of these, 42 patients did not receive anti-retroviral therapy (ART-naïve), whereas 109 received highly active anti-retroviral therapy (HAART) consisting of lopinavir/ritonavir (LOP/r; n=50), efavirenz (EFV; n=30) and nevirapine (NVP; n=29) associated with nucleoside reverse transcriptase inhibitors. HIV-1 seronegative individuals (n=43) participated in the study. The following parameters were quantified: total cholesterol and its fractions, atherogenic indices (AIs), apolipoproteins A1 and B100, high sensitivity C-reactive protein, CD4+ and CD8+ T cells, and HIV-1-RNA. Results: Levels of IgG anti-oxLDL Abs were significantly higher (p<0.05) in the LOP/r group compared with the EFV and/or NVP and the seronegative group: median 0.32 (0.15, 0.58; 95% confidence interval) vs. 0.25 (0.13, 0.53) vs. 0.18 (0.04, 0.38), respectively. HIV-1-infected ART-naïve patients (n=42) presented antibodies levels similar to those observed for the LOP/r group, 0.33 (0.13, 0.63; p>0.05). The levels of IgG anti-oxLDL Abs correlated with an increase in AIs (r=0.216; p=0.036) and triglycerides (r=0.220; p=0.044) in the LOP/r group, and AIs in the ART-naïve group (r=0.300; p=0.046). Conclusions: Patients treated with LOP/r showed higher levels of IgG anti-oxLDL Abs compared with patients treated with EFV or NVP regimens, and these levels were associated with an increase in AIs.

Outside-in, inside-out: Proteomic analysis of endothelial stress mediated by 7-ketocholesterol

Oxysterols are cholesterol oxidation products formed through enzymatic or autoxidation mechanisms. 7-ketocholeterol (7KC) is one of most abundant oxysterols found in atherosclerotic lesions. Its role in atherosclerosis pathogenesis has been broadly studied in a variety of models. The arterial microenvironment is a multicellular dynamic compartment that, among other systemic factors, is continuously stimulated by 7KC. Endothelial cells have a key role on that environment, being in intimate contact with both the blood stream and the vessel wall, the site of disease origin. 7KC has been shown to promote endothelial cell death and/or dysfunction, depending on its concentration. However, its contribution to the cell microenvironment through cell stimulation has not received much attention. Here we applied mass spectrometry-based proteomics followed by bioinformatics workflow to analyze the effect of a non-toxic 7KC concentration on endothelial cell protein expression and secretion in vitro. Trypsin digests were prepared from the secretome of the endothelial cells and from the total cell pellet after 24h exposure to 7KC. All samples were analyzed by high resolution and accurate mass nano-LC MS/MS. After database search and statistical analysis, differentially expressed proteins were selected for further studies. Our workflow identified 1805 secreted proteins and 2203 intracellular proteins, and of these, 48 and 53, respectively, were regulated. Regulated proteins upon 7KC exposure are involved in unfolded protein response, vascular homeostasis, and reduced control of angiogenesis. Moreover, blood coagulation was another main pathway regulated through Tissue Factor Pathway Inhibitor (TFPI), an antithrombotic agent associated with coronary disease that we found to be more than 2 times downregulated. Taken together, these data show differential endothelial protein regulation and secretion upon 7KC exposure for short time periods under non-toxic conditions. Herewith, these data support the role of 7KC in atherosclerosis pathophysiology and thus reinforce the deleterious effect of endothelial cells stress in the arterial microenvironment.

Células-tronco do líquido amniótico

Desde o primeiro isolamento e cultivo de celulas-tronco embrionarias humanas, ha mais de 10 anos, seu uso na pesquisa e terapia foi inibida por consideracoes eticas complexas e pelo risco de transformacao maligna destas celulas indiferenciadas apos transplante no paciente. As celulas-tronco adultas sao eticamente aceitas e o risco de transformacao maligna e muito baixo. Entretanto, seu potencial de diferenciacao e sua capacidade proliferativa sao limitados. Cerca de 6 anos atras, a descoberta de celulastronco no liquido amniotico que expressavam Oct-4, um marcador especifico de pluripotencialidade, com alta capacidade de proliferacao e diferenciacao, iniciou um novo campo promissor na area das celulas-tronco. Estas celulas tem potencial de se diferenciar em celulas dos tres folhetos germinativos. Nao formam tumores in vivo e nao levantam os questionamentos eticos associados com as celulas-tronco embrionarias humanas. Futuras investigacoes revelarao se as celulas-tronco do liquido amniotico realmente irao representar um tipo intermediario com vantagens em relacao tanto as celulas-tronco embrionarias quanto as adultas. Este artigo faz uma revisao acerca destes topicos e das caracteristicas biologicas das celulas-tronco do liquido amniotico.

Hepcidin: Homeostasis and Diseases Related to Iron Metabolism

Iron is an essential metal for cell survival that is regulated by the peptide hormone hepcidin. However, its influence on certain diseases is directly related to iron metabolism or secondary to underlying diseases. Genetic alterations influence the serum hepcidin concentration, which can lead to an iron overload in tissues, as observed in haemochromatosis, in which serum hepcidin or defective hepcidin synthesis is observed. Another genetic imbalance of iron is iron-refractory anaemia, in which serum concentrations of hepcidin are increased, precluding the flow and efflux of extra- and intracellular iron. During the pathogenesis of certain diseases, the resulting oxidative stress, as well as the increase in inflammatory cytokines, influences the transcription of the HAMP gene to generate a secondary anaemia due to the increase in the serum concentration of hepcidin. To date, there is no available drug to inhibit or enhance hepcidin transcription, mostly due to the cytotoxicity described in the in vitro models. The proposed therapeutic targets are still in the early stages of clinical trials. Some candidates are promising, such as heparin derivatives and minihepcidins. This review describes the main pathways of systemic and genetic regulation of hepcidin, as well as its influence on the disorders related to iron metabolism.

Human Paraoxonase-1 Activity Is Related to the Number of CD4+ T-Cells and Is Restored by Antiretroviral Therapy in HIV-1-Infected Individuals

Background. Paraoxonase-1 (PON1) activity is suggested to be altered in individuals infected with human immunodeficiency virus type-1 (HIV-1). We investigated PON1 activity in individuals receiving different regimens of highly active antiretroviral therapy (HAART). Methods. PON1 activity was evaluated in 91 HIV-1 seronegative and 624 HIV-1 infected individuals (115 were not undergoing therapy (ART-naïve), and 509 were receiving HAART). HIV-1 infected individuals were treated with the following: efavirenz (EFV; n = 195) or nevirapine (NVP; n = 95) or lopinavir/ritonavir (LOP/r; n = 219). Serum levels of total cholesterol (TC), HDL, and low-density lipoprotein (LDL) fractions and the atherogenic indices (AI, TC : HDL, and LDL : HDL ratios) were determined. Results. PON1 activity (U/L) was lower in the ART-naïve group compared with the other groups. PON1 activity correlated with CD4+ T-cell number of ART-naïve group (r = 0,121; P = 0,014). The LOP/r group showed a reduction in HDL and an increase in AI (TC : HDL ratio) in comparison with other groups. Conclusion. PON1 activity was reduced in untreated individuals, but not in individuals receiving HAART. PON1 activity correlated with the number of CD4+ T-cells. The findings suggest that the activity of PON1 is associated with the immune status of HIV-1 infected individuals.