Subgingival biofilm microbiome in individuals with asthma and periodontitis: Metagenomic analysis.

OBJECTIVE: This observational study aimed to explore the metagenomics of subgingival biofilms in individuals with varying degrees of asthma, from severe to none, to elucidate the association between the subgingival microbiome and asthma. MATERIALS AND METHODS: Subgingival biofilm samples were collected from thirty participants at the Asthma Control Program Outpatient Clinic in Bahia (ProAR). These samples were categorized into six groups based on the severity of asthma and the presence or absence of periodontitis. We employed next-generation sequencing (Illumina MiSeq), targeting the 16S rRNA gene, to characterize the microbial communities present. Our analysis included descriptive statistics and sequencing data, evaluated using multivariate statistical methods such as the Shannon index, principal coordinate analysis, and the Bray-Curtis dissimilarity. RESULTS: Our findings indicate a higher prevalence of periodontally detrimental bacterial genera in individuals with severe asthma and periodontitis. Additionally, individuals with asthma, but without periodontitis, exhibited a tendency toward dysbiosis, particularly in cases of severe asthma. CONCLUSION: This research provides new insights into the composition of the subgingival microbiome in individuals with varying severities of asthma and periodontitis. The genera identified in this study underscore the need for further investigations to build upon these findings.

MTOR gene variants are associated with severe COVID-19 outcomes: A multicenter study.

BACKGROUND: The worst outcomes linked to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection have been attributed to the cytokine storm, which contributes significantly to the immunopathogenesis of the disease. The mammalian target of rapamycin (mTOR) pathway is essential for orchestrating innate immune cell defense including cytokine production and is dysregulated in severe Coronavirus Disease 2019 (COVID-19) individuals. The individual genetic background might play a role in the exacerbated immune response. OBJECTIVE: In this study, we aimed to investigate the association between MTOR genetic variants and COVID-19 outcomes. METHODS: This study enrolled groups of individuals with severe (n = 285) and mild (n = 207) COVID-19 from Brazilian states. The MTOR variants, rs1057079 and rs2536, were genotyped. A logistic regression analysis and Kaplan-Meier survival curves were performed. We applied a genotyping risk score to estimate the cumulative contribution of the risk alleles. Tumor necrosis factor (TNF) and interleukin-6 (IL-6) plasma levels were also measured. RESULTS: The T allele of the MTOR rs1057079 variant was associated with a higher likelihood of developing the most severe form of COVID-19. In addition, higher levels of IL-6 and COVID-19 death was linked to the T allele of the rs2536 variant. These variants exhibited a cumulative risk when inherited collectively. CONCLUSIONS: These results show a potential pathogenetic role of MTOR gene variants and may be useful for predicting severe outcomes following COVID-19 infection, resulting in a more effective allocation of health resources.

Exploring dysregulated immune response genes and endothelial dysfunction biomarkers as predictors of severe COVID-19.

Identifying individuals and factors associated with severe cases of COVID-19 is crucial as the pandemic continues to spread globally. Effective biomarkers for predicting severe cases are essential for optimizing clinical management, therapy, and preventing unfavorable outcomes. This exploratory observational study aimed to investigate the expression of dysregulated immune response genes (ARG1, NOS2, ITGA4, and SELPLG) in total leukocytes, plasmatic levels of P-selectin and PSGL-1, and their clinical associations in patients with mild and severe COVID-19. Data from 117 confirmed COVID-19 patients (severe = 58, mild = 59) were collected upon admission. Gene expression was measured using RT-qPCR, and plasma protein levels assessed with ELISA assay. The severe COVID-19 patient group had a higher median age of 62.0 (p = 0.0001), a higher proportion of black individuals (86.2%, p < 0.0001), and more males (65.5%, p = 0.007). The neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR) were significantly higher in the severe COVID-19 patient group (p < 0.0001), indicating ongoing systemic inflammation. Severe COVID-19 patients also exhibited increased expression of ARG1 (p < 0.05) and SELPLG (p < 0.0001) genes, as well as higher concentrations of soluble P-selectin (p < 0.005) and PSGL-1 (p < 0.05) proteins. Multivariate analysis revealed that NLR, PLR, the expression of SELPLG and sPSGL-1 were independent predictors of COVID-19 severity. In conclusion, this study suggests that biomarkers of endothelial dysfunction and dysregulated leukocyte responses are associated with COVID-19 severity, serving as promising predictive tools for optimizing clinical management and patient monitoring.

Blood plasma and bone marrow interstitial fluid metabolomics of sickle cell disease patients with osteonecrosis: An exploratory study to dissect biochemical alterations.

Individuals with sickle cell disease (SCD) often experience numerous vaso-occlusive crisis events throughout their lives, which can progress to severe damage of several organs, including avascular necrosis, also known as osteonecrosis (ON). Osteonecrosis is one of the most devastating musculoskeletal clinical manifestations of sickle cell disease, afflicting up to 50% of the SCD patients. Herein, a NMR-based untargeted metabolomics approach was used to assess the metabolome alterations of blood plasma and bone marrow interstitial fluid (BMIF) samples of SCD patients with osteonecrosis. Furthermore, biochemical signatures associated with different osteonecrosis stages were assessed by analysing the metabolome of blood plasma and bone marrow interstitial fluid samples of SCD patients with different stages of the disease based on the Fiat and Arlet classification (FAC). Multivariate statistical analysis allowed a clear discrimination between the studied groups and it provided important insights into the different osteonecrosis stages. Citrate was pointed out as a possible biomarker to differentiate SCD patients with and without osteonecrosis. Acetate, creatinine, histidine, tyrosine, glucose, and NI5 seems to be key metabolites associated to different stages of the disease. Although this is a pioneer exploratory study, we acknowledge that fact that it is limited by the group sizes and absence of a validation cohort. Nevertheless, multivariate statistical analyses indicated that the metabolome of blood plasma and BMIF samples encompasses a complex metabolic regulation system for osteonecrosis.

Secretome from human adipose-derived mesenchymal stem cells promotes blood vessel formation and pericyte coverage in experimental skin repair.

Human adipose tissue-derived stem cells (hASC) secretome display various therapeutically relevant effects in regenerative medicine, such as induction of angiogenesis and tissue repair. The benefits of hASC secretome are primarily orchestrated by trophic factors that mediate autocrine and paracrine effects in host cells. However, the composition and the innate characteristics of hASC secretome can be highly variable depending on the culture conditions. Here, we evaluated the combined effect of serum-free media and hypoxia preconditioning on the hASCs secretome composition and biological effects on angiogenesis and wound healing. The hASCs were cultured in serum-free media under normoxic (NCM) or hypoxic (HCM) preconditioning. The proteomic profile showed that pro- and anti-antiangiogenic factors were detected in NCM and HCM secretomes. In vitro studies demonstrated that hASCs secretomes enhanced endothelial proliferation, survival, migration, in vitro tube formation, and in vivo Matrigel plug angiogenesis. In a full-thickness skin-wound mouse model, injection of either NCM or HCM significantly accelerated the wound healing. Finally, hASC secretomes were potent in increasing endothelial density and vascular coverage of resident pericytes expressing NG2 and nestin to the lesion site, potentially contributing to blood vessel maturation. Overall, our data suggest that serum-free media or hypoxic preconditioning enhances the vascular regenerative effects of hASC secretome in a preclinical wound healing model.

Gene expression profile of chronic oral graft-versus-host disease.

Among the complications observed after allogeneic hematopoietic stem cell transplantation, graft-versus-host disease (GVHD) is the primary cause of post-transplant mortality. The oral cavity is the second most affected organ target in chronic GVHD. Tissue damage results from the upregulation of inflammatory mediators, which play a critical role in the immunopathogenesis of the disease. This case series observational study aims to evaluate the participation of cytokines, chemokines, transcription factors, and heat shock proteins in the pathogenesis of oral GVHD (oGVHD), describing the mRNA expression of 28 genes selected. Peripheral blood mononuclear cells were isolated from six participants with oGVHD and two without GVHD, and relative expression of transcripts with established roles as inflammatory mediators was determined in triplicate using the human RT2 Profiler™ PCR Array. The gene expression levels in the group with oGVHD were mainly up-regulated compared to those without GVHD. PBMC from oGVDH expressed consistently higher IFN-γ, TNF, IL-1ß, CCL2, HSP60 (HSPD1) and HSP90 (HSP90B1). These results can provide a basis for developing new molecular diagnostics and targets therapies for the clinical management of oGVHD.

Quantification and Comprehensive Analysis of Mesenchymal Stromal Cells in Bone Marrow Samples from Sickle Cell Disease Patients with Osteonecrosis.

The potential use of bone marrow mesenchymal stromal cells (BM-MSCs) for the treatment of osteonecrosis in sickle cell disease (SCD) patients is increasing. However, convenient BM-MSC quantification and functional property assays are critical factors for cell-based therapies yet to be optimized. This study was designed to quantify the MSC population in bone marrow (BM) samples from SCD patients with osteonecrosis (SCD group) and patients with osteoarticular complications not related to SCD (NS group), using flow cytometry for CD271+CD45-/low cell phenotype and CFU-F assay. We also compared expanded BM-MSC osteogenic differentiation, migration, and cytokine secretion potential between these groups. The mean total cell number, CFU-F count, and CD271+CD45-/low cells in BM mononuclear concentrate were significantly higher in SCD than in NS patients. A significant correlation between CD271+CD45-/low cell number and CFU-F counts was found in SCD (r = 0.7483; p = 0.0070) and NS (r = 0.7167; p = 0.0370) BM concentrates. An age-related quantitative reduction of CFU-F counts and CD271+CD45-/low cell number was noted. Furthermore, no significant differences in the morphology, replicative capacity, expression of surface markers, multidifferentiation potential, and secretion of cytokines were found in expanded BM-MSCs from SCD and NS groups after in vitro culturing. Collectively, this work provides important data for the suitable measurement and expansion of BM-MSC in support to advanced cell-based therapies for SCD patients with osteonecrosis.

CD4+ T Cell Profile and Activation Response in Sickle Cell Disease Patients with Osteonecrosis.

Recent evidence suggests that abnormalities involving CD4+T lymphocytes are associated with the pathophysiology of osteonecrosis (ON); however, few studies have addressed the CD4+T cells in ON related to sickle cell disease (SCD/ON). In addition, T cells producing multiple cytokines simultaneously are often present in the inflammatory milieu and may be implicated in the immune response observed in SCD/ON. In the present study, we aimed to characterize the functional status of CD4+T cells in SCD by simultaneously determining the frequency of IFN-γ +, IL-4+, and IL-17+ CD4+T in cell cultures under exogenous stimuli. Peripheral blood mononuclear cells (PB-MNCs) from 9 steady-state SCD patients, 15 SCD/ON patients, and 19 healthy controls had functional status of CD4+T cells analyzed. Bone marrow mononuclear cells (BM-MNCs) from 24 SCD/ON patients (SCD BM) and 18 patients with ON not related to SCD (non-SCD BM) were also analyzed. We found that PB-MNC of SCD patients with or without ON presented significantly reduced TCD4+, TCD8+, and TCD4+ naïve cell frequencies and increased frequency of circulating CD4+T cells able to simultaneously produce IFN-γ +/IL4+ and IL-17+/IL4+ compared to healthy controls. Conversely, the polyclonal stimulation of BM-MNC induced an increased frequency of CD4+IFN-γ + and CD4+IL-17+ in SCD BM compared to non-SCD BM. The increased proportion of CD4+ T cells able to produce a broad spectrum of proinflammatory cytokines after a strong stimulus indicates that the immune system in SCD/ON patients presents an expressive pool of partially differentiated cells ready to take on effector function. It is possible that this increased subpopulation may extend to inflammatory sites of target organs and may contribute to the maintenance of inflammation and the pathophysiology of osteonecrosis in sickle cell disease.

Leukemia Inhibitory Factor (LIF) Overexpression Increases the Angiogenic Potential of Bone Marrow Mesenchymal Stem/Stromal Cells.

Mesenchymal stem/stromal cells (MSCs) have the ability to secrete bioactive molecules, exerting multiple biological effects, such as tissue regeneration, reduction of inflammation, and neovascularization. The therapeutic potential of MSCs can be increased by genetic modification to overexpress cytokines and growth factors. Here we produced mouse MSCs overexpressing human leukemia inhibitory factor (LIF) to assess their proangiogenic potential in vitro and in vivo. Mouse bone marrow-derived MSCs were transduced by using a second-generation lentiviral system to express human LIF. Leukemia inhibitory factor expression was confirmed by RT-qPCR and by ELISA, allowing the quantification of the transcript and secreted protein, respectively. Flow cytometry analysis and trilineage differentiation assay showed that the MSC_LIF cell line maintained the immunophenotype and a multipotency characteristic of MSCs. The immunosuppressive activity of MSC_LIF was confirmed using a lymphoproliferation assay. Moreover, gene expression analysis demonstrated upregulation of genes coding for strategic factors in the neovascularization process, such as angiogenin, IL-8, MCP-1, and VEGF, and for the perivascular cell markers αSMA, Col4a1, SM22, and NG2. To evaluate the pro-angiogenic potential of MSC_LIF, we first tested its effects on endothelial cells obtained from umbilical vein in a scratch wound healing assay. Conditioned medium (CM) from MSC_LIF promoted a significant increase in cell migration compared to CM from control MSC. Additionally, in vitro tube formation of endothelial cells was increased by the presence of MSC_LIF, as shown in microvessel sprouting in aortic ring cultures. Finally, an in vivo Matrigel plug assay was performed, showing that MSC_LIF were more potent in promoting in vivo angiogenesis and tissue vascularization than control MSCs. In conclusion, LIF overexpression is a promising strategy to increase the proangiogenic potential of MSCs and sets precedents for future investigations of their potential applications for the treatment of ischemic diseases and tissue repair.

Investigating the potential of the secretome of mesenchymal stem cells derived from sickle cell disease patients.

Sickle cell disease (SCD) is a monogenic red cell disorder associated with multiple vascular complications, microvessel injury and wound-healing deficiency. Although stem cell transplantation with bone marrow-derived mesenchymal stem cells (BMSC) can promote wound healing and tissue repair in SCD patients, therapeutic efficacy is largely dependent on the paracrine activity of the implanted BM stromal cells. Since in vitro expansion and culture conditions are known to modulate the innate characteristics of BMSCs, the present study investigated the effects of normoxic and hypoxic cell-culture preconditioning on the BMSC secretome, in addition to the expression of paracrine molecules that induce angiogenesis and skin regeneration. BMSCs derived from SCD patients were submitted to culturing under normoxic (norCM) and hypoxic (hypoCM) conditions. We found that hypoxically conditioned cells presented increased expression and secretion of several well-characterized trophic growth factors (VEGF, IL8, MCP-1, ANG) directly linked to angiogenesis and tissue repair. The hypoCM secretome presented stronger angiogenic potential than norCM, both in vitro and in vivo, as evidenced by HUVEC proliferation, survival, migration, sprouting formation and in vivo angiogenesis. After local application in a murine wound-healing model, HypoCM showed significantly improved wound closure, as well as enhanced neovascularization in comparison to untreated controls. In sum, the secretome of hypoxia-preconditioned BMSC has increased expression of trophic factors involved in angiogenesis and skin regeneration. Considering that these preconditioned media are easily obtainable, this strategy represents an alternative to stem cell transplantation and could form the basis of novel therapies for vascular regeneration and wound healing in individuals with sickle cell disease.

Role of Schwann cells in cutaneous wound healing.

Dermal wound healing is the process of repairing and remodeling skin following injury. Delayed or aberrant cutaneous healing poses a challenge for the health care system. The lack of detailed understanding of cellular and molecular mechanisms involved in this process hampers the development of effective targeted treatments. In a recent study, Parfejevs et al.-using state-of-the-art technologies, including in vivo sophisticated Cre/loxP techniques in combination with a mouse model of excisional cutaneous wounding-reveal that Schwann cells induce adult dermal wound healing. Strikingly, genetic ablation of Schwann cells delays wound contraction and closure, decreases myofibroblast formation, and impairs skin re-epithelization after injury. From a drug development perspective, Schwann cells are a new cellular candidate to be activated to accelerate skin healing. Here, we summarize and evaluate recent advances in the understanding of Schwann cells roles in the skin microenvironment.

Use of autologous bone marrow stem cell implantation for osteonecrosis of the knee in sickle cell disease: a preliminary report.

BACKGROUND: The purpose of our study was to evaluate safety, feasibility and clinical results of bone marrow mononuclear cell (BMC) implantation for early-stage osteonecrosis of the knee (OK) secondary to sickle cell disease. METHODS: Thirty-three SCD patients (45 knees) with OK treated with BMC implantation in the osteonecrotic lesion were clinically and functionally evaluated through the American Knee Society Clinical Score (KSS), Knee Functional Score (KFS) and Numeric Rating Scale (NRS) pain score. MRI and radiographic examinations of the knee were assessed during a period of five years after intervention. RESULTS: No complications or serious adverse event were associated with BMC implantation. From preoperative assessment to the latest follow-up, there was a significant (p < 0.001) improvement of clinical KSS (64.3 ± 9.7, range: 45-80 and 2.2 ± 4.1, range: 84-100, respectively), KFS (44.5 ± 8.0, range: 30-55 and 91.6 ± 5.8, range: 80-100, respectively) and reduction of NRS pain score (6.7 ± 1.2, range: 4-9 and 3.4 ± 1.0, range: 2-5, respectively). In total, 87% of patients (29/33) consistently experienced improvements in joint function and activity level as compared to preoperative score. No patient had additional surgery following BMC implantation. Radiographic assessment showed joint preservation and no progression to subchondral collapse at most recent follow-up. CONCLUSIONS: The technique of BMC implantation is a promising, relatively simple and safe procedure for OK in SCD patients. Larger and long-term controlled trials are needed to support its clinical effectiveness. TRIAL REGISTRATION: ClinicalTrials.gov NCT02448121 . Retrospectively registered 19 May 2015.

Osteonecrosis in sickle cell disease patients from Bahia, Brazil: a cross-sectional study.

PURPOSE: The aim of this study was to describe the clinical features of osteonecrosis (ON) in sickle cell disease (SCD) patients in Bahia, a Northeast state with the highest prevalence of the disease in Brazil. METHODS: Between 2006 and 2017, 283 cases of osteonecrosis in SCD patients were enrolled to analyse the age at diagnosis, genotype, gender, pain, distribution of the lesions and disease staging. MRI and radiograph were obtained at the participation. RESULTS: Of the 283 SCD cases, 120 (42.4%) were haemoglobin SS genotype while 163 (57.6%) were SC genotype. Two hundred and forty-six cases were bilateral and 37 were unilateral, with an average age at diagnosis of 33.7 (range 10-67) years. The most frequent identified ON site not only was the hip (74.6%), but also affected shoulder, knee and ankle. Most cases presented at early stage I (172, 60.8%) disease. No significant differences on the features of osteonecrosis were identified between haemoglobin SS and haemoglobin SC cases. CONCLUSIONS: Given the relatively high prevalence of bilateral osteonecrosis at early stages, painful symptoms and rather late age at diagnosis, SCD patients should have radiological examination of their joints more often in order to prevent severe functional disability and increase patient's life quality.

Autologous stem cell-based therapy for sickle cell leg ulcer: a pilot study.

Recurrent chronic leg ulcers are among the most severe vasculopathic complications of sickle cell disease (SCD). Their treatment remains a challenge. Stem cell therapy with bone marrow mononuclear cells (BMMC) is a promising new therapeutic option for other forms of chronic ulcers. This prospective pilot study was performed to evaluate safety and feasibility of BMMC implantation in patients with SCD and chronic leg ulcers (SCLU). Ulcer closure, recurrence and local pain were evaluated. BMMC were successfully administered to 23 SCLU patients and no serious adverse events occurred. During the 6-month follow-up period, 91·3% of patients had improved ulcer pain compared with baseline and 29·2% of the treated ulcers achieved total healing. The frequency of progenitor stem cells (CD34CD45low and fibroblast colony-forming units) in BMMC was found to be significantly reduced in SCLU patients and compared to SCD patients without ulcers (P < 0·004 and P < 0·01, respectively). No relationship was observed between treatment outcome and the number of implanted BM progenitor stem cells. In conclusion, BMMC implantation is a feasible and safe procedure, showing favourable outcomes for the treatment of SCLU, and encouraging further controlled clinical trials.

Vascular Mural Cells Promote Noradrenergic Differentiation of Embryonic Sympathetic Neurons.

The sympathetic nervous system controls smooth muscle tone and heart rate in the cardiovascular system. Postganglionic sympathetic neurons (SNs) develop in close proximity to the dorsal aorta (DA) and innervate visceral smooth muscle targets. Here, we use the zebrafish embryo to ask whether the DA is required for SN development. We show that noradrenergic (NA) differentiation of SN precursors temporally coincides with vascular mural cell (VMC) recruitment to the DA and vascular maturation. Blocking vascular maturation inhibits VMC recruitment and blocks NA differentiation of SN precursors. Inhibition of platelet-derived growth factor receptor (PDGFR) signaling prevents VMC differentiation and also blocks NA differentiation of SN precursors. NA differentiation is normal in cloche mutants that are devoid of endothelial cells but have VMCs. Thus, PDGFR-mediated mural cell recruitment mediates neurovascular interactions between the aorta and sympathetic precursors and promotes their noradrenergic differentiation.

Efficacy of autologous stem cell-based therapy for osteonecrosis of the femoral head in sickle cell disease: a five-year follow-up study.

INTRODUCTION: Stem cell therapy with bone marrow-derived mononuclear cells (BMMCs) is an option for improving joint function in osteonecrosis of the femoral head (ONFH). Bone marrow-derived mesenchymal stromal cell (MSC) numbers and their osteogenic differentiation are decreased in patients with ONFH. However, whether this decrease also extends to the early stages of ONFH in sickle cell disease (SCD) is still unclear. METHODS: We conducted a phase I/II, non-controlled study to determine efficacy and safety of BMMC implantation using a minimally invasive technique in SCD patients with ONFH. Eighty-nine patients were recruited and followed up for 60 months after surgery. Clinical and radiographic findings were assessed, and data were completed by in vitro analysis. RESULTS: At the final follow-up (60 months) there was a significant improvement in clinical joint symptoms and pain relief as measured by the Harris Hip Score (P = 0.0005). In addition, after the BMMC implantation procedure, radiographic assessment showed disease stabilization and only 3.7 % of the treated patients did not achieve a satisfactory clinical result. The amount of fibroblast colony-forming units was 28.2 ± 13.9 per 1 million BMMCs after concentration. Flow cytometry analysis showed a significantly higher number of hematopoietic stem/endothelial progenitor cell markers in concentrated BMMCs when compared with bone marrow aspirate, indicating an enrichment of these cell types. Isolated MSCs from SCD patients with pre-collapse ONFH maintained the replicative capacity without significant loss of their specific biomolecular characteristics, multi-differentiation potential, and osteogenic differentiation activities. Cytokines and growth factors (interleukin-8, transforming growth factor-beta, stromal cell-derived factor-1alpha and vascular endothelial growth factor) that mediate endogenous bone regeneration were also produced by expanded MSCs from SCD patients. CONCLUSION: The autologous BMMC implantation with a minimally invasive technique resulted in significant pain relief and halted the progression of early stages of ONFH in SCD patients. MSCs from SCD patients display biological properties that may add to the efficiency of surgical treatment in ONFH. In summary, our results indicate that infusion of BMMCs enriched with stem/progenitor cells is a safe and effective treatment for the early stages of ONFH in SCD patients. TRIAL REGISTRATION: ClinicalTrials.gov NCT02448121; registered 15 May 2015.

Semaphorin3A, Neuropilin-1, and PlexinA1 are required for lymphatic valve formation.

RATIONALE: The lymphatic vasculature plays a major role in fluid homeostasis, absorption of dietary lipids, and immune surveillance. Fluid transport depends on the presence of intraluminal valves within lymphatic collectors. Defective formation of lymphatic valves leads to lymphedema, a progressive and debilitating condition for which curative treatments are currently unavailable. How lymphatic valve formation is regulated remains largely unknown. OBJECTIVE: We investigated if the repulsive axon guidance molecule Semaphorin3A (Sema3A) plays a role in lymphatic valve formation. METHODS AND RESULTS: We show that Sema3A mRNA is expressed in lymphatic vessels and that Sema3A protein binds to lymphatic valves expressing the Neuropilin-1 (Nrp1) and PlexinA1 receptors. Using mouse knockout models, we show that Sema3A is selectively required for lymphatic valve formation, via interaction with Nrp1 and PlexinA1. Sema3a(-/-) mice exhibit defects in lymphatic valve formation, which are not due to abnormal lymphatic patterning or sprouting, and mice carrying a mutation in the Sema3A binding site of Nrp1, or deficient for Plxna1, develop lymphatic valve defects similar to those seen in Sema3a(-/-) mice. CONCLUSIONS: Our data demonstrate an essential direct function of Sema3A-Nrp1-PlexinA1 signaling in lymphatic valve formation.

Tratamento da Osteonecrose da Cabeça Femoral com celulas progenitoras autólogas em anemia falciforme / Femoral Head Necrosis treatment with autologous stem cells in sickle cell disease

OBJETIVO: Avaliação da segurança e eficácia do uso de células progenitoras autólogas da medula óssea (CMMO) no tratamento da Osteonecrose da Cabeça Femoral (OCF) de pacientes portadores de anemia falciforme. MÉTODOS: Foram estudados 8 pacientes portadores de anemia falciforme, com OCF nos estágios I e II (classificação de Ficat e Arlet). As CMMO retiradas da crista ilíaca posterior foram concentradas e reinfundidas na área central da osteonecrose. Os principais parâmetros avaliados foram segurança, sintomas clínicos e progressão da doença, através da avaliação clínica (Harris Hip Score) e radiológica. RESULTADOS: A maior parte dos pacientes (7 em 8) referiu melhora dos sintomas após o tratamento. Não houve complicações durante o procedimento anestésico e cirúrgico. A medida do escore (Harris Hip Score) no pré-operatório foi 78,5 +/- 6,2 pontos, com aumento significativo destes valores no pós-operatório (98,3 +/- 2,5 pontos) (p< 0,001). As avaliações radiográficas e os parâmetros celulares foram favoráveis. CONCLUSÃO: O implante autólogo de CMMO parece ser seguro e eficaz no tratamento dos estágios iniciais da OCF em pacientes falciformes. Embora os resultados iniciais sejam promissores, sua interpretação é limitada pelo número de pacientes avaliados e o período curto de duração do seguimento pós-operatório. Necessita-se estender o grupo em estudo e os parâmetros celulares avaliados.

PURPOSE: To assess the efficacy and safety of autologous bone-marrow mononuclear cells (BMMC) implantation in necrotic lesions of the femoral head in patients with sickle cell disease. METHODS: We studied eight patients with stage-I or -II femoral head osteonecrosis according to the system by Ficat and Arlet. BMMCs were harvested and re-infused into the necrotic zone. The primary endpoints studied were safety, clinical symptoms and disease progression, these being assessed according to the Harris hip score (HHS) and to X-ray studies. RESULTS: After eight months, seven of the eight patients reported improvement from symptoms. There were no complications during anesthetic and surgery procedures. There was a significant postoperative increase in the HHS (98.3 +/- 2.5 points) compared to preoperative HHS (78.5 +/- 6.2 points) (p< 0.001). X-ray evaluation and cell parameters were found to be favorable. CONCLUSION: The autologous bone-marrow mononuclear cells implantation seems to be a safe and effective treatment for early stages of femoral head osteonecrosis in patients with sickle cell disease. Although promising, the interpretation of these early results is limited due to the small sample and to the short duration of follow-up. Further studies and advanced cellular assays are required to confirm the results.

Beta-carotene storage, conversion to retinoic acid, and induction of the lipocyte phenotype in hepatic stellate cells.

Hepatic stellate cells (HSCs) are the major site of retinol (ROH) metabolism and storage. GRX is a permanent murine myofibroblastic cell line, derived from HSCs, which can be induced to display the fat-storing phenotype by treatment with retinoids. Little is known about hepatic or serum homeostasis of beta-carotene and retinoic acid (RA), although the direct biogenesis of RA from beta-carotene has been described in enterocytes. The aim of this study was to identify the uptake, metabolism, storage, and release of beta-carotene in HSCs. GRX cells were plated in 25 cm(2) tissue culture flasks, treated during 10 days with 3 micromol/L beta-carotene and subsequently transferred into the standard culture medium. beta-Carotene induced a full cell conversion into the fat-storing phenotype after 10 days. The total cell extracts, cell fractions, and culture medium were analyzed by reverse phase high-performance liquid chromatography for beta-carotene and retinoids. Cells accumulated 27.48 +/- 6.5 pmol/L beta-carotene/10(6) cells, but could not convert it to ROH nor produced retinyl esters (RE). beta-Carotene was directly converted to RA, which was found in total cell extracts and in the nuclear fraction (10.15 +/- 1.23 pmol/L/10(6) cells), promoting the phenotype conversion. After 24-h chase, cells contained 20.15 +/- 1.12 pmol/L beta-carotene/10(6) cells and steadily released beta-carotene into the medium (6.69 +/- 1.75 pmol/ml). We conclude that HSC are the site of the liver beta-carotene storage and release, which can be used for RA production as well as for maintenance of the homeostasis of circulating carotenoids in periods of low dietary uptake.

Hepatic stellate cells uptake of retinol associated with retinol-binding protein or with bovine serum albumin.

Retinol is stored in liver, and the dynamic balance between its accumulation and mobilization is regulated by hepatic stellate cells (HSC). Representing less than 1% total liver protein, HSC can reach a very high intracellular retinoid (vitamin-A and its metabolites) concentration, which elicits their conversion from the myofibroblast to the fat-storing lipocyte phenotype. Circulating retinol is associated with plasma retinol-binding protein (RBP) or bovine serum albumin (BSA). Here we have used the in vitro model of GRX cells to compare incorporation and metabolism of BSA versus RBP associated [(3)H]retinol in HSC. We have found that lipocytes, but not myofibroblasts, expressed a high-affinity membrane receptor for RBP-retinol complex (KD = 4.93 nM), and both cell types expressed a low-affinity one (KD = 234 nM). The RBP-retinol complex, but not the BSA-delivered retinol, could be dislodged from membranes by treatments that specifically disturb protein-protein interactions (high RBP concentrations). Under both conditions, treatments that disturb the membrane lipid layer (detergent, cyclodextrin) released the membrane-bound retinol. RBP-delivered retinol was found in cytosol, microsomal fraction and, as retinyl esters, in lipid droplets, while albumin-delivered retinol was mainly associated with membranes. Disturbing the clathrin-mediated endocytosis did not interfere with retinol uptake. Retinol derived from the holo-RBP complex was differentially incorporated in lipocytes and preferentially reached esterification sites close to lipid droplets through a specific intracellular traffic route. This direct influx pathway facilitates the retinol uptake into HSC against the concentration gradients, and possibly protects cell membranes from undesirable and potentially noxious high retinol concentrations.