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Dive into the research topics where Kelen C. R. Malmegrim is active.

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Featured researches published by Kelen C. R. Malmegrim.


JAMA | 2009

C-Peptide Levels and Insulin Independence Following Autologous Nonmyeloablative Hematopoietic Stem Cell Transplantation in Newly Diagnosed Type 1 Diabetes Mellitus

Carlos Eduardo Barra Couri; Maria Carolina Oliveira; Ana Beatriz P. L. Stracieri; Daniela A. Moraes; Fabiano Pieroni; George M.N. Barros; Maria Isabel A. Madeira; Kelen C. R. Malmegrim; Maria Cristina Foss-Freitas; Belinda Pinto Simões; Edson Zangiacomi Martinez; Milton Cesar Foss; Richard K. Burt; Júlio C. Voltarelli

CONTEXT In 2007, the effects of the autologous nonmyeloablative hematopoietic stem cell transplantation (HSCT) in 15 patients with type 1 diabetes mellitus (DM) were reported. Most patients became insulin free with normal levels of glycated hemoglobin A(1c) (HbA(1c)) during a mean 18.8-month follow-up. To investigate if this effect was due to preservation of beta-cell mass, continued monitoring was performed of C-peptide levels after stem cell transplantation in the 15 original and 8 additional patients. OBJECTIVE To determine C-peptide levels after autologous nonmyeloablative HSCT in patients with newly diagnosed type 1 DM during a longer follow-up. DESIGN, SETTING, AND PARTICIPANTS A prospective phase 1/2 study of 23 patients with type 1 DM (aged 13-31 years) diagnosed in the previous 6 weeks by clinical findings with hyperglycemia and confirmed by measurement of serum levels of anti-glutamic acid decarboxylase antibodies. Enrollment was November 2003-April 2008, with follow-up until December 2008 at the Bone Marrow Transplantation Unit of the School of Medicine of Ribeirão Preto, Ribeirão Preto, Brazil. Hematopoietic stem cells were mobilized via the 2007 protocol. MAIN OUTCOME MEASURES C-peptide levels measured during the mixed-meal tolerance test, before, and at different times following HSCT. Secondary end points included morbidity and mortality from transplantation, temporal changes in exogenous insulin requirements, and serum levels of HbA(1c). RESULTS During a 7- to 58-month follow-up (mean, 29.8 months; median, 30 months), 20 patients without previous ketoacidosis and not receiving corticosteroids during the preparative regimen became insulin free. Twelve patients maintained this status for a mean 31 months (range, 14-52 months) and 8 patients relapsed and resumed insulin use at low dose (0.1-0.3 IU/kg). In the continuous insulin-independent group, HbA(1c) levels were less than 7.0% and mean (SE) area under the curve (AUC) of C-peptide levels increased significantly from 225.0 (75.2) ng/mL per 2 hours pretransplantation to 785.4 (90.3) ng/mL per 2 hours at 24 months posttransplantation (P < .001) and to 728.1 (144.4) ng/mL per 2 hours at 36 months (P = .001). In the transient insulin-independent group, mean (SE) AUC of C-peptide levels also increased from 148.9 (75.2) ng/mL per 2 hours pretransplantation to 546.8 (96.9) ng/mL per 2 hours at 36 months (P = .001), which was sustained at 48 months. In this group, 2 patients regained insulin independence after treatment with sitagliptin, which was associated with increase in C-peptide levels. Two patients developed bilateral nosocomial pneumonia, 3 patients developed late endocrine dysfunction, and 9 patients developed oligospermia. There was no mortality. CONCLUSION After a mean follow-up of 29.8 months following autologous nonmyeloablative HSCT in patients with newly diagnosed type 1 DM, C-peptide levels increased significantly and the majority of patients achieved insulin independence with good glycemic control. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00315133.


Annals of the New York Academy of Sciences | 2008

Autologous hematopoietic stem cell transplantation for type 1 diabetes.

Júlio C. Voltarelli; Carlos Eduardo Barra Couri; Ana Beatriz P. L. Stracieri; Maria Cristina Ferreira de Oliveira; Daniela A. Moraes; Fabiano Pieroni; George M.N. Barros; Maria Isabel A. Madeira; Kelen C. R. Malmegrim; Maria Cristina Foss-Freitas; Belinda Pinto Simões; Milton Cesar Foss; Elizabeth Squiers; Richard K. Burt

In this review, we present (1) the scientific basis for the use of high‐dose immunosuppression followed by autologous peripheral blood hematopoietic stem cell transplantation for newly diagnosed type 1 diabetes (T1D); (2) an update of the clinical and laboratory outcome of 20 patients transplanted at the University Hospital of the Ribeirão Preto Medical School, University of São Paulo, Brazil, and followed up to January/2008, including 4 relapses among 19 patients without previous ketoacidosis; (3) a commentary on criticisms to our article that appeared in four articles from the scientific literature; and (4) a discussion of the prospectives for cellular therapy for T1D.


Immunobiology | 2013

Dynamic changes of the Th17/Tc17 and regulatory T cell populations interfere in the experimental autoimmune diabetes pathogenesis.

Juliana Navarro Ueda Yaochite; Carolina Caliari-Oliveira; Mariana Rodrigues Davanso; Daniela Carlos; Kelen C. R. Malmegrim; Cristina R. Cardoso; Leandra Naira Zambelli Ramalho; Patrícia Vianna Bonini Palma; João Santana da Silva; Fernando Q. Cunha; Dimas Tadeu Covas; Júlio C. Voltarelli

A balance between proinflammatory (Th17 and Tc17) and anti-inflammatory (regulatory T cells) subsets of T cells is essential to maintain immunological tolerance and prevent the onset of several autoimmune diseases, including type 1 diabetes. However, the kinetics of these subsets and disease severity during the streptozotocin (STZ)-induced diabetes course has not been determined. Thus, susceptible C57BL/6 mice were administrated with multiple low doses of STZ and we evaluated the frequency/absolute number of these T cell subsets in the pancreatic lymph nodes (PLNs) and spleen and Th1, Th17, Treg cytokine production in the pancreatic tissue. At different time points of the disease progression (6, 11, 18 and 25 days after the last STZ administration), the histopathological alterations were also evaluated by H&E and immunohistochemistry staining. During the initial phase of diabetes development (day 6), we noted increased numbers of CD4(+) and CD8(+) T cells in spleen and PLNs. At the same time, the frequencies of Th17 and Tc17 cells in PLNs were also enhanced. In addition, the early augment of interferon gamma (IFN-γ), tumoral necrosis factor (TNF-α), IL-6 and IL-17 levels in pancreatic tissue correlated with pancreatic islet inflammation and mild β-cell damage. Notably, the absolute number of Treg cells increased in PLNs during over time when compared to control group. Interestingly, increased IL-10 levels were associated with control of the inflammatory process during the late phase of the type 1 diabetes (day 25). In agreement, mice lacking the expression of IL-17 receptor (Il17r) showed impairment in STZ-induced diabetes progression, reduced peri-insulitis and beta cells preservation when compared with wild-type mice. Our findings suggest that dynamic changes of pathogenic Th17/Tc17 and regulatory T cell subsets numbers is associated with early strong inflammation in the pancreatic islets followed by late regulatory profile during the experimental STZ-induced diabetes course.


Bone Marrow Transplantation | 2015

Autologous hematopoietic SCT normalizes miR-16, -155 and -142-3p expression in multiple sclerosis patients

Lucas C. M. Arruda; Julio C. C. Lorenzi; A P A Sousa; Dalila L. Zanette; P.V.B. Palma; Rodrigo A. Panepucci; D S Brum; Amilton Antunes Barreira; Dimas Tadeu Covas; Belinda Pinto Simões; Wilson A. Silva; M C Oliveira; Kelen C. R. Malmegrim

Autologous hematopoietic SCT (AHSCT) has been investigated in the past as a therapeutic alternative for multiple sclerosis (MS). Despite advances in clinical management, knowledge about mechanisms involved with clinical remission post transplantation is still limited. Abnormal microRNA and gene expression patterns were described in MS and have been suggested as disease biomarkers and potential therapeutic targets. Here we assessed T- and B-cell reconstitution, microRNAs and immunoregulatory gene expression after AHSCT. Early immune reconstitution was mainly driven by peripheral homeostatic proliferation. AHSCT increased CD4+CD25hiFoxP3+ regulatory T-cell counts and expression of CTLA-4 and GITR (glucocorticoid-induced TNFR) on CD4+CD25hi T cells. We found transient increase in exhausted PD-1+ T cells and of suppressive CD8+CD28−CD57+ T cells. At baseline, CD4+ and CD8+ T cells from MS patients presented upregulated miR-16, miR-155 and miR-142-3p and downregulated FOXP3, FOXO1, PDCD1 and IRF2BP2. After transplantation, the expression of FOXP3, FOXO1, PDCD1 and IRF2BP2 increased, reaching control levels at 2 years. Expression of miR-16, miR-155 and miR-142-3p decreased towards normal levels at 6 months post therapy, remaining downregulated until the end of follow-up. These data strongly suggest that AHSCT normalizes microRNA and gene expression, thereby improving the immunoregulatory network. These mechanisms may be important for disease control in the early periods after AHSCT.


Cell Transplantation | 2015

Bone marrow mesenchymal stromal cells isolated from multiple sclerosis patients have distinct gene expression profile and decreased suppressive function compared with healthy counterparts.

Gislane Lelis Vilela de Oliveira; Kalil A. de Lima; Amanda M. Colombini; Daniel G. Pinheiro; Rodrigo A. Panepucci; Patrícia Vianna Bonini Palma; Doralina G. Brum; Dimas Tadeu Covas; Belinda Pinto Simões; M C Oliveira; Eduardo A. Donadi; Kelen C. R. Malmegrim

Multiple sclerosis (MS) is a chronic inflammatory autoimmune disease of the central nervous system, due to an immune reaction against myelin proteins. Multipotent mesenchymal stromal cells (MSCs) present immunosuppressive effects and have been used for the treatment of autoimmune diseases. In our study, gene expression profile and in vitro immunomodulatory function tests were used to compare bone marrow-derived MSCs obtained from MS patients, at pre- and postautologous hematopoietic stem cell transplantation (AHSCT) with those from healthy donors. Patient MSCs comparatively exhibited i) senescence in culture; ii) similar osteogenic and adipogenic differentiation potential; iii) decreased expression of CD105, CD73, CD44, and HLA-A/B/C molecules; iv) distinct transcription at pre-AHSCT compared with control MSCs, yielding 618 differentially expressed genes, including the downregulation of TGFB1 and HGF genes and modulation of the FGF and HGF signaling pathways; v) reduced antiproliferative effects when pre-AHSCT MSCs were cocultured with allogeneic T-lymphocytes; vi) decreased secretion of IL-10 and TGF-β in supernatants of both cocultures (pre- and post-AHSCT MSCs); and vii) similar percentages of regulatory cells recovered after MSC cocultures. The transcriptional profile of patient MSCs isolated 6 months posttransplantation was closer to pre-AHSCT samples than from healthy MSCs. Considering that patient MSCs exhibited phenotypic changes, distinct transcriptional profile and functional defects implicated in MSC immunomodulatory and immunosuppressive activity, we suggest that further MS clinical studies should be conducted using allogeneic bone marrow MSCs derived from healthy donors. We also demonstrated that treatment of MS patients with AHSCT does not reverse the transcriptional and functional alterations observed in patient MSCs.


Frontiers in Immunology | 2017

Immunological Balance Is Associated with Clinical Outcome after Autologous Hematopoietic Stem Cell Transplantation in Type 1 Diabetes

Kelen C. R. Malmegrim; Júlia T. C. de Azevedo; Lucas C. M. Arruda; Joana R. F. Abreu; Carlos Eduardo Barra Couri; Gislane Lelis Vilela de Oliveira; Patrícia Vianna Bonini Palma; Gabriela Trentin Scortegagna; Ana Beatriz P. L. Stracieri; Daniela A. Moraes; Juliana B. E. Dias; Fabiano Pieroni; Renato Cunha; Luiza Guilherme; Nathália Moreira Santos; Milton Cesar Foss; Dimas Tadeu Covas; Richard K. Burt; Belinda Pinto Simões; Júlio C. Voltarelli; Bart O. Roep; Maria Cristina Ferreira de Oliveira

Autologous hematopoietic stem cell transplantation (AHSCT) increases C-peptide levels and induces insulin independence in patients with type 1 diabetes. This study aimed to investigate how clinical outcomes may associate with the immunological status, especially concerning the balance between immunoregulation and autoreactivity. Twenty-one type 1 diabetes patients were monitored after AHSCT and assessed every 6 months for duration of insulin independence, C-peptide levels, frequencies of islet-specific autoreactive CD8+ T cells (CTL), regulatory lymphocyte subsets, thymic function, and T-cell repertoire diversity. In median follow-up of 78 (range 15–106) months, all patients became insulin-independent, resuming insulin after median of 43 (range 6–100) months. Patients were retrospectively divided into short- or prolonged-remission groups, according to duration of insulin independence. For the entire follow-up, CD3+CD4+ T-cell numbers remained lower than baseline in both groups, whereas CD3+CD8+ T-cell levels did not change, resulting in a CD4/CD8 ratio inversion. Memory CTL comprehended most of T cells detected on long-term follow-up of patients after AHSCT. B cells reconstituted to baseline levels at 2–3 months post-AHSCT in both patient groups. In the prolonged-remission-group, baseline islet-specific T-cell autoreactivity persisted after transplantation, but regulatory T cell counts increased. Patients with lower frequencies of autoreactive islet-specific T cells remained insulin-free longer and presented greater C-peptide levels than those with lower frequencies of these cells. Therefore, immune monitoring identified a subgroup of patients with superior clinical outcome of AHSCT. Our study shows that improved immunoregulation may balance autoreactivity endorsing better metabolic outcomes in patients with lower frequencies of islet-specific T cells. Development of new strategies of AHSCT is necessary to increase frequency and function of T and B regulatory cells and decrease efficiently autoreactive islet-specific T and B memory cells in type 1 diabetes patients undergoing transplantation.


Stem Cell Research & Therapy | 2016

Multipotent mesenchymal stromal cells from patients with newly diagnosed type 1 diabetes mellitus exhibit preserved in vitro and in vivo immunomodulatory properties

Juliana Navarro Ueda Yaochite; Kalil A. de Lima; Carolina Caliari-Oliveira; Patrícia Vianna Bonini Palma; Carlos Eduardo Barra Couri; Belinda Pinto Simões; Dimas Tadeu Covas; Júlio C. Voltarelli; Maria Carolina Oliveira; Eduardo A. Donadi; Kelen C. R. Malmegrim

BackgroundType 1 diabetes mellitus (T1D) is characterized by autoimmune responses resulting in destruction of insulin-producing pancreatic beta cells. Multipotent mesenchymal stromal cells (MSCs) exhibit immunomodulatory potential, migratory capacity to injured areas and may contribute to tissue regeneration by the secretion of bioactive factors. Therefore, MSCs are considered as a promising approach to treat patients with different autoimmune diseases (AID), including T1D patients. Phenotypical and functional alterations have been reported in MSCs derived from patients with different AID. However, little is known about the properties of MSCs derived from patients with T1D. Since autoimmunity and the diabetic microenvironment may affect the biology of MSCs, it becomes important to investigate whether these cells are suitable for autologous transplantation. Thus, the aim of the present study was to evaluate the in vitro properties and the in vivo therapeutic efficacy of MSCs isolated from bone marrow of newly diagnosed T1D patients (T1D-MSCs) and to compare them with MSCs from healthy individuals (C-MSCs).MethodsT1D-MSCs and C-MSCs were isolated and cultured until third passage. Then, morphology, cell diameter, expression of surface markers, differentiation potential, global microarray analyses and immunosuppressive capacity were in vitro analyzed. T1D-MSCs and C-MSCs therapeutic potential were evaluated using a murine experimental model of streptozotocin (STZ)-induced diabetes.ResultsT1D-MSCs and C-MSCs presented similar morphology, immunophenotype, differentiation potential, gene expression of immunomodulatory molecules and in vitro immunosuppressive capacity. When administered into diabetic mice, both T1D-MSCs and C-MSCs were able to reverse hyperglycemia, improve beta cell function and modulate pancreatic cytokine levels.ConclusionsThus, bone marrow MSCs isolated from T1D patients recently after diagnosis are not phenotypically or functionally impaired by harmful inflammatory and metabolic diabetic conditions. Our results provide support for the use of autologous MSCs for treatment of newly diagnosed T1D patients.


Stem Cell Research & Therapy | 2015

Therapeutic efficacy and biodistribution of allogeneic mesenchymal stem cells delivered by intrasplenic and intrapancreatic routes in streptozotocin-induced diabetic mice

Juliana Navarro Ueda Yaochite; Carolina Caliari-Oliveira; Lucas Eduardo Botelho de Souza; Lourenço Sbragia Neto; Patrícia Vianna Bonini Palma; Dimas Tadeu Covas; Kelen C. R. Malmegrim; Júlio C. Voltarelli; Eduardo A. Donadi

IntroductionMesenchymal stromal/stem cells (MSCs) are multipotent cells that have the ability to express and secrete a wide range of immunomodulatory molecules, cytokines, growth factors and antiapoptotic proteins. MSCs modulate both innate and adaptive immune responses making them potential candidates for the treatment of patients with type 1 diabetes mellitus (T1D). However, one problem frequently associated with the systemic MSCs administration is the entrapment of the cells mainly in the lungs. In this sense, trying to avoid the lung barrier, the purpose of this study was to evaluate the long-term therapeutic efficacy and biodistribution of allogeneic adipose tissue-derived MSCs (ADMSCs) injected via two different delivery routes (intrasplenic/I.Sp and intrapancreatic/I.Pc) in a murine model of diabetes induced by streptozotocin (STZ).MethodsExperimental diabetes was induced in C57BL/6 male mice by multiple low-doses of STZ. MSCs were isolated from adipose tissue (ADMSCs) of Balb/c mice. A single dose of 1x106 ADMSCs was microinjected into the spleen or into the pancreas of diabetic mice. Control group received injection of PBS by I.Sp or I.Pc delivery routes. Glycemia, peripheral glucose response, insulin-producing β cell mass, regulatory T cell population, cytokine profile and cell biodistribution were evaluated after ADMSCs/PBS administration.ResultsADMSCs injected by both delivery routes were able to decrease blood glucose levels and improve glucose tolerance in diabetic mice. ADMSCs injected by I.Sp route reverted hyperglycemia in 70% of diabetic treated mice, stimulating insulin production by pancreatic β cells. Using the I.Pc delivery route, 42% of ADMSCs-treated mice responded to the therapy. Regulatory T cell population remained unchanged after ADMSCs administration but pancreatic TGF-β levels were increased in ADMSCs/I.Sp-treated mice. ADMSCs administrated by I.Sp route were retained in the spleen and in the liver and ADMSCs injected by I.Pc route remained in the pancreas. However, ADMSCs injected by these delivery routes remained only few days in the recipients.ConclusionConsidering the potential role of MSCs in the treatment of several disorders, this study reports alternative delivery routes that circumvent cell entrapment into the lungs promoting beneficial therapeutic responses in ADMSCs-treated diabetic mice.


Clinical Immunology | 2016

Immunological correlates of favorable long-term clinical outcome in multiple sclerosis patients after autologous hematopoietic stem cell transplantation

Lucas C. M. Arruda; Júlia T. C. de Azevedo; Gislane Lelis Vilela de Oliveira; Gabriela Trentin Scortegagna; Evandra Strazza Rodrigues; Patrícia Vianna Bonini Palma; Doralina G. Brum; Carlos Tostes Guerreiro; Vanessa D. Marques; Amilton Antunes Barreira; Dimas Tadeu Covas; Belinda Pinto Simões; Júlio C. Voltarelli; Maria Carolina Oliveira; Kelen C. R. Malmegrim

High dose immunosuppression followed by autologous hematopoietic stem cell transplantation (AHSCT) induces prolonged clinical remission in multiple sclerosis (MS) patients. However, how patient immune profiles are associated with clinical outcomes has not yet been completely elucidated. In this study, 37 MS patients were assessed for neurological outcomes, thymic function and long-term immune reconstitution after AHSCT. Patients were followed for a mean (SD) of 68.5 (13.9) months post-transplantation and were retrospectively clustered into progression- and non-progression groups, based on Expanded Disease Status Scale (EDSS) outcomes at last visit. After AHSCT, both patient groups presented increased regulatory T-cell subset counts, early expansion of central- and effector-memory CD8(+)T-cells and late thymic reactivation. However, the non-progression group presented early expansion of PD-1(+)CD8(+)T-cells and of PD-1-expressing CD19(+) B-cells. Here, we suggest that along with increased numbers of regulatory T-cell subsets, PD-1 inhibitory signaling is one possible immunoregulatory mechanism by which AHSCT restores immune tolerance in MS patients.


PLOS ONE | 2015

A methodology for the development of RESTful semantic web services for gene expression analysis

Gabriela Da Guardia; Luís Ferreira Pires; Ricardo Z. N. Vêncio; Kelen C. R. Malmegrim; Cléver Guareis de farias

Gene expression studies are generally performed through multi-step analysis processes, which require the integrated use of a number of analysis tools. In order to facilitate tool/data integration, an increasing number of analysis tools have been developed as or adapted to semantic web services. In recent years, some approaches have been defined for the development and semantic annotation of web services created from legacy software tools, but these approaches still present many limitations. In addition, to the best of our knowledge, no suitable approach has been defined for the functional genomics domain. Therefore, this paper aims at defining an integrated methodology for the implementation of RESTful semantic web services created from gene expression analysis tools and the semantic annotation of such services. We have applied our methodology to the development of a number of services to support the analysis of different types of gene expression data, including microarray and RNASeq. All developed services are publicly available in the Gene Expression Analysis Services (GEAS) Repository at http://dcm.ffclrp.usp.br/lssb/geas. Additionally, we have used a number of the developed services to create different integrated analysis scenarios to reproduce parts of two gene expression studies documented in the literature. The first study involves the analysis of one-color microarray data obtained from multiple sclerosis patients and healthy donors. The second study comprises the analysis of RNA-Seq data obtained from melanoma cells to investigate the role of the remodeller BRG1 in the proliferation and morphology of these cells. Our methodology provides concrete guidelines and technical details in order to facilitate the systematic development of semantic web services. Moreover, it encourages the development and reuse of these services for the creation of semantically integrated solutions for gene expression analysis.

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