Mairim Alexandra Solis’s research while affiliated with The Gorgas Memorial Institute for Health Studies (GMI) and other places

Background Intrauterine fetal demise is a recognized complication of coronavirus disease 2019 in pregnant women and is associated with histopathological placental lesions. The pathological mechanism and virus-induced immune response in the placenta are not fully understood. A detailed description of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-induced inflammation in the placenta during fetal demise is crucial for improved clinical management. Case presentation We report the case of a 27-week gestation SARS-CoV-2-asymptomatic unvaccinated pregnant woman without comorbidities or other risk factors for negative pregnancy outcomes with a diagnosis of intrauterine fetal demise. Histopathological findings corresponded to patterns of subacute inflammation throughout the anatomic compartments of the placenta, showing severe chorioamnionitis, chronic villitis and deciduitis, accompanied by maternal and fetal vascular malperfusion. Our immunohistochemistry results revealed infiltration of CD68⁺ macrophages, CD56⁺ Natural Killer cells and scarce CD8⁺ T cytotoxic lymphocytes at the site of placental inflammation, with the SARS-CoV-2 nucleocapsid located in stromal cells of the chorion and chorionic villi, and in decidual cells. Conclusion This case describes novel histopathological lesions of inflammation with infiltration of plasma cells, neutrophils, macrophages, and natural killer cells associated with malperfusion in the placenta of a SARS-CoV-2-infected asymptomatic woman with intrauterine fetal demise. A better understanding of the inflammatory effects exerted by SARS-CoV-2 in the placenta will enable strategies for better clinical management of pregnant women unvaccinated for SARS-CoV-2 to avoid fatal fetal outcomes during future transmission waves.

Mesenchymal stem cells (MSCs) experience functional decline with systemic aging, resulting in reduced proliferation, increased senescence, and lower differentiation potential. The placenta represents a valuable source of MSCs, but the possible effect of donor age on the properties of placenta-derived mesenchymal stem cells (PDMSCs) has not been thoroughly studied. Thus, the aim of this study was to underscore the effect of maternal age on the biological characteristics and stemness properties of PDMSCs. PDMSCs were isolated from 5 donor age groups (A: 18-21, B: 22-25, C: 26-30, D:31-35 and E: ≥36 years) for comparison of morphological, proliferative and differentiation properties. The pluripotency markers NANOG, OCT4, and SSEA4, as well as multipotency and differentiation markers, showed higher expression in PDMSCs from mothers aged 22-35 years, with up to a 7-fold increase in adipogenesis. Cumulative population doubling, cell growth curves, and colony-forming unit-fibroblast assays revealed higher self-renewal ability in donors 26-30 years old. An increase in the proliferative characteristics of PDMSCs correlated with increased telomere shortening, suggesting that shorter telomere lengths could be related to cellular division rather than aging. A clear understanding of the effect of maternal age on MSC regenerative potential will assist in increasing the effectiveness of future cell therapies.

There is limited evidence regarding severe acute respiratory syndrome coronavirus 2 infection in the placenta of pregnant women who tested positive, and if this could be a route for vertical transmission of the virus in utero. We present the cases of 2 pregnant women in their third trimester who were admitted for delivery by cesarean delivery and who, through universal screening, tested positive for coronavirus disease 2019. The maternal and fetal sides of the placenta were sectioned from both patients for viral analysis. Real-time polymerase chain reaction analysis of the placental-extracted RNA revealed a severe acute respiratory syndrome coronavirus 2 infection on the fetal side of the placenta in both patients. The virus was isolated from the patient with the lowest cycle threshold value on the fetal side of the placenta. Whole genome sequencing showed that the virus detected in this placenta was from the B1 lineage. Immunohistochemical analysis of the placental tissue detected severe acute respiratory syndrome coronavirus 2 in the endothelial cells of chorionic villi vessels proximal to both the maternal and fetal sides, with a granular cytoplasmic pattern and perinuclear reinforcement. Histologic examination of the placenta also detected a dense infiltrate of lymphoid cells around decidual vessels and endothelial cells with cytopathic changes, especially on the maternal side. Nasopharyngeal swabs from the infants that were subjected to reverse transcription quantitative polymerase chain reaction testing were negative for severe acute respiratory syndrome coronavirus 2 at 24 hours after birth. A follow-up analysis of the infants for immunoglobin G and immunoglobin M expression, clinical manifestations, and long-term developmental abnormalities is recommended.

p> Resumen Introducción : Las células madre mesenquimales (MSCs) tienen la capacidad única de auto-renovación y pluripotencia con la cual apoyan en la regeneración de tejidos en organismos vivos. El mayor potencial terapéutico de las MSCs derivadas de la placenta (PDMSCs) humana, como fuente más joven de MSCs,estimula la búsqueda de las mejores condiciones de cultivo que preserven su capacidad de proliferar y diferenciarse. Sin embargo, estudios relacionados a la caracterización de la multipotencialidad de las PDMSCs durante periodos prolongados de cultivo, no han sido reportados en Panamá. Por lo tanto, el objetivo de este estudio fue el de implementar un proceso de aislamiento y cultivo que preserve las propiedades multipotentes en PDMSCs. Materiales y Métodos: Placentas humanas a término completo fueron obtenidas para el aislamiento de las MSCs. Las PDMSCs fueron caracterizadas según su morfología, expresión positiva de marcadores CD90, CD73, CD105, y capacidad de proliferación y diferenciación a linajes mesodérmicos. Resultados :Se ha demostradola obtención de poblaciones de PDMSCs con morfología fibroblástica, adherencia plástica, expresión positiva de los marcadores CD90, CD73 y CD105, y capacidad de diferenciación osteogénica, adipogénica y condrogénica. Posterior al aislamiento y crio-preservación, las PDMSCs mantuvieron una viabilidad mayor de 95%, una tasa de proliferación pormás de 40 días en cultivo, y la expresión positiva de los marcadores CD90, CD73, y CD105 al pasaje 16. Conclusión: Nuestros resultados demuestran una metodología eficiente para obtención y cultivo de PDMSCs que mantienen sus características multipotentes durante períodos prolongados de cultivo, abriendo el camino para futuras terapias celulares. Abstract Introduction: Human mesenchymal stem cells are (MSCs) unique in their pluripotency and their ability to self-renew in order to support tissue regeneration in living organisms. The increased therapeutic potential of PDMSCs as a pool of younger MSCs with a vast capacity for expansion, minor predisposition for tumor formationor immune reactions spurs the search for the best culture conditions to preserve their ability to differentiate and proliferate. However, studies regarding characterization of multipotentisolated PDMSCsduring prolonged periods of culture has not been reported thus far in Panama. Therefore, in this study we seek to implement isolation and culture procedures that preserve multipotent characteristics in PDMSCs. Materials and Methods: Full-term human placentas were obtained for the isolation of MSCs. PDMSCs where characterized based on their morphology, positive expression of CD90, CD73, and CD105, and their ability to proliferate and differentiate to mesodermal lineages. Results: It was demonstrated that our isolated PDMSCspresented the MSC characteristics of fibroblastic morphology, plastic adherence, positive expression of CD90, CD73, and CD105 markers, as well asosteogenesis, adipogenesis, and osteogenic differentiation ability. When PDMSCs were cultured after isolation or cryopreservation, viability was maintained above 95%, with their proliferation rate maintained after 40 days, and positive expression of CD90, CD73, and CD105markers kept after 16 passages. Conclusion: Taken together, our results demonstrated a methodology to obtain successful source of isolated human PDMSCs that kept their multipotent properties over time, opening the path for future cellular therapies. Introducción Las células madres mesenquimales (MSC, por sus siglas en inglés) son un tipo de células madres adultas que residen en una variedad de tejidos, incluyendo la placenta ( 1 ). Estas células multipotentes han generado un gran interés debido a su capacidad de diferenciación hacia una variedad de linajes, incluyendo osteoblastos, condrocitos, adipocitos y hepatocitos, así como su uso potencial en medicina regenerativa ( 2 ). Numerosos esfuerzos se han realizado para elucidar el mecanismo mediante el cual las células madres sediferenciana linajes específicos y su aplicación como terapia celular para un sinfín de enfermedades. Estas células, pueden ser aisladas fácilmente de diversos tejidos postnatales, pero con un número limitado de divisiones celulares antes de adquirir senescencia replicativa. El uso de células madre de un tejido fetal, como la placenta, ofrece una fuente más joven de células madre adultas. Las células madre mesenquimales derivadas de la placenta humana (PDMSC) contienen características pluripotentes y un mayor potencial de expansión en comparación con otras células madre adultas, ya que su entorno de nicho fetal contiene características celulares y bioquímicas muy específicas que las preservan hasta que señalizaciones activen su auto-renovacióny migración. El hecho de que las PDMSCs no induzcan reacción inmunológica( 3 , 4 )hace de estas células una excelente opción terapéutica.Estudios han demostrado la expresión positiva de los marcadores pluripotentes NANOG, SSEA-4 y OCT4 en PDMSCs( 5 ). Cuando las MSC son cultivadas durante períodos prolongados, se disminuye la capacidad de proliferación y diferenciación, lo que limita su uso futuro en terapias celulares( 6 ). El uso potencial de las células madre en medicina regenerativa dependerá de la capacidad de estas células para preservar sus propiedades de manera estable durante períodos prolongados de cultivo celular, además de una comprensión profunda de estas células. Investigaciones que promuevan tratamientosde medicina regenerativa a través de terapias con células madre son escasas en Panamá. A su vez, el sistema de salud público, el cual en la actualidad no satisface las necesidades de un segmento importante de la población, podría beneficiarse de intervenciones de terapia celular. Por lo tanto, el objetivo de este estudio fue el de implementar en Panamá procedimientos de aislamiento y cultivo que preserven las características multipotentes en las PDMSCs. Los resultados obtenidos permitirán un avance en los estudios preclínicos relacionados con células madre para el desarrollo de terapias celulares.</p

Background and objectives: Hyaluronan preserves the proliferation and differentiation potential of mesenchymal stem cells. Supplementation of low-concentration hyaluronan (SHA) in stem cells culture medium increases its proliferative rate, whereas coated-surface hyaluronan (CHA) maintains cells in a slow-proliferating mode. We have previously demonstrated that in CHA, the metabolic proliferative state of stem cells was influenced by upregulating mitochondrial biogenesis and function. However, the effect of SHA on stem cells' energetic status remains unknown. In this study, we demonstrate the effect that low-concentration SHA at 0.001 mg/ml (SHA0.001) and high-concentration SHA at 5 mg/ml (SHA5) exert on stem cells' mitochondrial function compared with CHA and noncoated tissue culture surface (control). Methods and results: Fast-proliferating human placenta-derived mesenchymal stem cells (PDMSCs) cultured on SHA0.001 exhibited reduced mitochondrial mass, lower mitochondrial DNA copy number, and lower oxygen consumption rate compared with slow-proliferating PDMSCs cultured on CHA at 5.0 (CHA5) or 30 µg/cm2 (CHA30). The reduced mitochondrial biogenesis observed in SHA0.001 was accompanied by a 2-fold increased ATP content and lactate production, suggesting that hyaluronan-induced fast-proliferating PDMSCs may rely less on mitochondrial function as an energy source and induce a mitochondrial functional switch to glycolysis. Conclusions: PDMSCs cultured on both CHA and SHA exhibited a reduction in reactive oxygen species levels. The results from this study clarify our understandings on the effect of hyaluronan on stem cells and provide important insights into the effect of distinct supplementation methods used during cell therapies.

Abstract Latin America is a fast-growing region that currently faces unique challenges in the treatment of all forms of diabetes mellitus. The burden of this disease will be even greater in the coming years due, in part, to the large proportion of young adults living in urban areas and engaging in unhealthy lifestyles. Unfortunately, the national health systems in Latin-American countries are unprepared and urgently need to reorganize their health care services to achieve diabetic therapeutic goals. Stem cell research is attracting increasing attention as a promising and fast-growing field in Latin America. As future healthcare systems will include the development of regenerative medicine through stem cell research, Latin America is urged to issue a call-to-action on stem cell research. Increased efforts are required in studies focused on stem cells for the treatment of diabetes. In this review, we aim to inform physicians, researchers, patients and funding sources about the advances in stem cell research for possible future applications in diabetes mellitus. Emerging studies are demonstrating the potential of stem cells for β cell differentiation and pancreatic regeneration. The major economic burden implicated in patients with diabetes complications suggests that stem cell research may relieve diabetic complications. Closer attention should be paid to stem cell research in the future as an alternative treatment for diabetes mellitus.

Hyaluronan-coated surfaces preserve the proliferation and differentiation potential of mesenchymal stem cells by prolonging their G1-phase transit, which maintains cells in a slow-proliferative mode. Mitochondria are known to play a crucial role in stem cell self-renewal and differentiation. In this study, for the first time, the metabolic mechanism underlying the hyaluronan-regulated slow-proliferative maintenance of stem cells was investigated by evaluating mitochondrial functions. Human placenta-derived mesenchymal stem cells (PDMSCs) cultured on hyaluronan-coated surfaces at 0.5, 3.0, 5.0, and 30 µg/cm(2) were found to have an average 58% higher mitochondrial mass and an increase in mitochondrial DNA copy number compared to non-coated tissue culture surfaces (control), as well as a 3-fold increase in the gene expression of the mitochondrial biogenesis-related gene PGC-1α. Increase in mitochondrial biogenesis led to a hyaluronan dose-dependent increase in mitochondrial membrane potential, ATP content, and oxygen consumption rate, with reactive oxygen species (ROS) levels shown to be at least 3 times lower compared to the control. Although hyaluronan seemed to favor mitochondrial function, cell entry into a hyaluronan-regulated slow-proliferative mode led to a 5-fold reduction in ATP production and coupling efficiency levels. Together, these results suggest that hyaluronan-coated surfaces influence the metabolic proliferative state of stem cells by upregulating mitochondrial biogenesis and function with controlled ATP production. This more efficiently meets the energy requirements of slow-proliferating PDMSCs. A clear understanding of the metabolic mechanism induced by hyaluronan in stem cells will allow future applications that may overcome the current limitations faced in stem cell culture. This article is protected by copyright. All rights reserved.

Three Tables showing the full identified proteins are available as supplementary materials: (1) Table S1. Total proteins identified for OTCSH:YTCSL. (2) Table S2. Total proteins identified for OCHAL:OTCSH. (3) Table S3. Total proteins identified for OCHAL:YCHAH.

Our previous results showed that hyaluronan (HA) preserved human placenta-derived mesenchymal stem cells (PDMSC) in a slow cell cycling mode similar to quiescence, the pristine state of stem cells in vivo , and HA was found to prevent murine adipose-derived mesenchymal stem cells from senescence. Here, stable isotope labeling by amino acid in cell culture (SILAC) proteomic profiling was used to evaluate the effects of HA on aging phenomenon in stem cells, comparing (1) old and young passage PDMSC cultured on normal tissue culture surface (TCS); (2) old passage on HA-coated surface (CHA) compared to TCS; (3) old and young passage on CHA. The results indicated that senescence-associated protein transgelin (TAGLN) was upregulated in old TCS. Protein CYR61, reportedly senescence-related, was downregulated in old CHA compared to old TCS. The SIRT1-interacting Nicotinamide phosphoribosyltransferase (NAMPT) increased by 2.23-fold in old CHA compared to old TCS, and is 0.48-fold lower in old TCS compared to young TCS. Results also indicated that components of endoplasmic reticulum associated degradation (ERAD) pathway were upregulated in old CHA compared to old TCS cells, potentially for overcoming stress to maintain cell function and suppress senescence. Our data points to pathways that may be targeted by HA to maintain stem cells youth.

Scientific evidence suggests that stem cells possess the anti-aging ability to self-renew and maintain differentiation potentials, and quiescent state. The objective of this review is to discuss the micro-environment where stem cells reside in vivo, the secreted factors to which stem cells are exposed, the hypoxic environment, and intracellular factors including genome stability, mitochondria integrity, epigenetic regulators, calorie restrictions, nutrients, and vitamin D. Secreted tumor growth factor-β and fibroblast growth factor-2 are reported to play a role in stem cell quiescence. Extracellular matrices may interact with caveolin-1, the lipid raft on cell membrane to regulate quiescence. N-cadherin, the adhesive protein on niche cells provides support for stem cells. The hypoxic micro-environment turns on hypoxia-inducible factor-1 to prevent mesenchymal stem cells aging through p16 and p21 down-regulation. Mitochondria express glucosephosphate isomerase to undergo glycolysis and prevent cellular aging. Epigenetic regulators such as p300, protein inhibitors of activated Stats and H19 help maintain stem cell quiescence. In addition, calorie restriction may lead to secretion of paracrines cyclic ADP-ribose by intestinal niche cells, which help maintain intestinal stem cells. In conclusion, it is crucial to understand the anti-aging phenomena of stem cells at the molecular level so that the key to solving the aging mystery may be unlocked.