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1.
Int J Mol Sci ; 24(24)2023 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-38139339

RESUMEN

Globally, a leg is amputated approximately every 30 seconds, with an estimated 85 percent of these amputations being attributed to complications arising from diabetic foot ulcers (DFU), as stated by the American Diabetes Association. Peripheral arterial disease (PAD) is a risk factor resulting in DFU and can, either independently or in conjunction with diabetes, lead to recurring, slow-healing ulcers and amputations. According to guidelines amputation is the recommended treatment for patients with no-option critical ischemia of the limb (CTLI). In this article we propose cell therapy as an alternative strategy for those patients. We also suggest the optimal time-frame for an effective therapy, such as implanting autologous mononuclear cells (MNCs), autologous and allogeneic mesenchymal stromal cells (MSC) as these treatments induce neuropathy relief, regeneration of the blood vessels and tissues, with accelerated ulcer healing, with no serious side effects, proving that advanced therapy medicinal product (ATMPs) application is safe and effective and, hence, can significantly prevent limb amputation.


Asunto(s)
Diabetes Mellitus , Pie Diabético , Enfermedad Arterial Periférica , Enfermedades del Sistema Nervioso Periférico , Humanos , Pie Diabético/etiología , Pie Diabético/terapia , Factores de Riesgo , Enfermedad Arterial Periférica/terapia , Enfermedad Arterial Periférica/complicaciones , Enfermedades del Sistema Nervioso Periférico/complicaciones , Amputación Quirúrgica , Tratamiento Basado en Trasplante de Células y Tejidos , Isquemia/terapia , Isquemia/complicaciones
2.
Front Immunol ; 14: 1232472, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37767093

RESUMEN

An unprecedented global social and economic impact as well as a significant number of fatalities have been brought on by the coronavirus disease 2019 (COVID-19), produced by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Acute SARS-CoV-2 infection can, in certain situations, cause immunological abnormalities, leading to an anomalous innate and adaptive immune response. While most patients only experience mild symptoms and recover without the need for mechanical ventilation, a substantial percentage of those who are affected develop severe respiratory illness, which can be fatal. The absence of effective therapies when disease progresses to a very severe condition coupled with the incomplete understanding of COVID-19's pathogenesis triggers the need to develop innovative therapeutic approaches for patients at high risk of mortality. As a result, we investigate the potential contribution of promising combinatorial cell therapy to prevent death in critical patients.

3.
Am J Trop Med Hyg ; 109(3): 523-526, 2023 09 06.
Artículo en Inglés | MEDLINE | ID: mdl-37524331

RESUMEN

Peru was severely affected by COVID-19 with a fatality rate that reached up to 6%. In this study, the relationship between SARS-CoV-2 variants and COVID-19 disease outcome in Amazonas, a region of northeastern Peru, was evaluated. The variants were determined by genomic sequencing, and clinical-epidemiological data were collected from 590 patients between April 2021 and February 2022. There was no association between mortality and hospitalization with any of the variants, but we did find that Omicron is more likely to infect vaccinated and nonvaccinated people. A significant association was also found between unvaccinated patients and hospitalization. Interestingly, in the indigenous population, there were fewer hospitalizations than in the general population. In conclusion, SARS-CoV-2 variants were not associated with the disease outcome in the Amazonas region, and indigenous population were found to be less vulnerable to severe COVID-19 illness.


Asunto(s)
COVID-19 , SARS-CoV-2 , Humanos , SARS-CoV-2/genética , COVID-19/epidemiología , Prevalencia , Perú/epidemiología
4.
Rev. Fac. Med. Hum ; 22(3): 533-539, julio-Septiembre 2022.
Artículo en Inglés, Español | LILACS-Express | LILACS | ID: biblio-1381859

RESUMEN

Introducción En los últimos años, el número de casos de malaria en las comunidades nativas de Condorcanqui, Amazonas ha aumentado considerablemente. La malaria por Plasmodium vivax es endémica en la región y en 2019 fue reportada la reintroducción de P. falciparum. Métodos En este estudio, recopilamos y analizamos los datos de malaria y COVID-19 reportados por la Dirección Regional de Salud (DIRESA) durante el 2020. Además, realizamos un análisis de razón de posibilidades "odds ratio" para evaluar las asociaciones significativas entre los síntomas de la COVID-19 y las infecciones previas de malaria. Resultados En el 2020, se reportaron 1547 casos de malaria (97% por P. vivax) y 5968 de COVID-19. Por otro lado, 96 pacientes contrajeron COVID-19 después de contraer una infección de malaria. De éstos, 87 eran sintomáticos (90,6%) y en su mayoría adultos de 30 a 59 años (62,3%). Además, encontramos que las infecciones previas de malaria están asociadas a la presencia de síntomas como fiebre, tos, dolor de garganta y dificultad respiratoria. Sin embargo, no hubo asociación significativa entre estos casos y la hospitalización o la muerte. Conclusión Nuestro análisis sugiere que las infecciones previas por malaria podrían afectar la sintomatología de la COVID-19, lo que destaca la importancia de un programa continuo de control y vigilancia de la malaria para evitar posibles sindemias con la COVID-19.


Introduction In recent years, the number of malaria cases in native communities from Condorcanqui, Amazonas has considerably increased. Plasmodium vivax malaria is endemic in the region and the re-introduction of P. falciparum was reported in 2019. Methods Here, we compiled and analyzed malaria and COVID-19 data reported by the Regional Direction of Health (DIRESA) during the 2020. Additionally, we performed an odds ratio analysis to evaluate significant associations between COVID-19 symptoms and previous malaria infections. Results In 2020, 1547 malaria (97% were P. vivax) and 5968 COVID-19 cases were reported. Furthermore, 96 patients got COVID-19 after getting a malaria infection. From these, 87 were symptomatic (90.6%), and mostly adults, ages 30 to 59 (62.3%). Also, we found that malaria previous infections represent a risk for the presence of symptoms such as fever, cough, throat pain, and respiratory difficulty. Nevertheless, there was no significant association between these cases and hospitalization or death. Conclusion Our analysis suggests that previous malaria infections might affect COVID-19 symptomatology, which highlights the importance of a continuing control and surveillance malaria program to avoid potential syndemics with COVID-19.

5.
Int J Mol Sci ; 23(7)2022 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-35409280

RESUMEN

The transcription factor, early growth response-1 (EGR-1), is involved in the regulation of cell differentiation, proliferation, and apoptosis in response to different stimuli. EGR-1 is described to be involved in pancreatic endoderm differentiation, but the regulatory mechanisms controlling its action are not fully elucidated. Our previous investigation reported that exposure of mouse embryonic stem cells (mESCs) to the chemical nitric oxide (NO) donor diethylenetriamine nitric oxide adduct (DETA-NO) induces the expression of early differentiation genes such as pancreatic and duodenal homeobox 1 (Pdx1). We have also evidenced that Pdx1 expression is associated with the release of polycomb repressive complex 2 (PRC2) and P300 from the Pdx1 promoter; these events were accompanied by epigenetic changes to histones and site-specific changes in the DNA methylation. Here, we investigate the role of EGR-1 on Pdx1 regulation in mESCs. This study reveals that EGR-1 plays a negative role in Pdx1 expression and shows that the binding capacity of EGR-1 to the Pdx1 promoter depends on the methylation level of its DNA binding site and its acetylation state. These results suggest that targeting EGR-1 at early differentiation stages might be relevant for directing pluripotent cells into Pdx1-dependent cell lineages.


Asunto(s)
Endodermo , Células Madre Embrionarias de Ratones , Animales , Diferenciación Celular/genética , Células Madre Embrionarias , Endodermo/metabolismo , Ratones , Óxido Nítrico/metabolismo
6.
Antioxidants (Basel) ; 11(3)2022 Mar 03.
Artículo en Inglés | MEDLINE | ID: mdl-35326146

RESUMEN

Nitric oxide (NO) is a gaseous biomolecule endogenously synthesized with an essential role in embryonic development and several physiological functions, such as regulating mitochondrial respiration and modulation of the immune response. The dual role of NO in embryonic stem cells (ESCs) has been previously reported, preserving pluripotency and cell survival or inducing differentiation with a dose-dependent pattern. In this line, high doses of NO have been used in vitro cultures to induce focused differentiation toward different cell lineages being a key molecule in the regenerative medicine field. Moreover, optimal conditions to promote pluripotency in vitro are essential for their use in advanced therapies. In this sense, the molecular mechanisms underlying stemness regulation by NO have been studied intensively over the current years. Recently, we have reported the role of low NO as a hypoxia-like inducer in pluripotent stem cells (PSCs), which supports using this molecule to maintain pluripotency under normoxic conditions. In this review, we stress the role of NO levels on stem cells (SCs) fate as a new approach for potential cell therapy strategies. Furthermore, we highlight the recent uses of NO in regenerative medicine due to their properties regulating SCs biology.

7.
Lancet Reg Health Am ; 15: 100347, 2022 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-36778067

RESUMEN

Background: Malaria is one of the biggest impediments to global progress. In Peru, it is still a major public health problem. Measures of health and economic burden due to malaria are relevant considerations for the assessment of current policies. Methods: We used estimates from the Global Burden of Diseases Study 2019 for malaria in Peru, grouped by gender and age, from 1990 to 2019. Results are presented as absolute numbers and age-standardized rates with 95% uncertainty intervals (UI). We collected economic data from the World Bank and The National Institute of Statistics and Informatics of Peru and Loreto to calculate the economic burden of productivity loss (EBPL) using the human capital approach. Economic values were presented in constant dollars, soles, and percentages. Findings: Rates of deaths, years of life lost (YLLs), years lived with disability (YLDs), and disability-adjusted life years (DALYs), as well as the EBPL, were drastically reduced from 1990 to 2019. DALYs had a greater percentage of YLDs in 2019 than in 1990. DALYs rates showed no preference between sexes, but the "< 1 year" age group had the highest DALYs values over the study period. We found that the EBPL due to malaria for Loreto was considerably higher than Peru's in terms of GDP percentage. Interpretation: Our study shows that the fight against malaria in Peru reduced remarkably the impact of the disease since 1990; however, during the last decade the estimates were stable or even increased. Our results help to measure the malaria impact on the health status of the Peruvian population as well as the economic pressure that it exerts, constituting remarkable tools for policymaking aimed at reducing the burden of this disease. Strengthening the malaria elimination program is important to achieve the elimination of the disease in the coming years. Funding: This study was supported by the Universidad Nacional Toribio Rodríguez de Mendoza and FONDECYT: Contrato Nº 09-2019-FONDECYT-BMINC.INV and FONDECYT-BM, Perú (Program INCORPORACIÓN DE INVESTIGADORES E038-2019-01, Registry Number: 64007).

8.
Antioxidants (Basel) ; 10(9)2021 Sep 02.
Artículo en Inglés | MEDLINE | ID: mdl-34573040

RESUMEN

The optimization of conditions to promote the stemness of pluripotent cells in vitro is instrumental for their use in advanced therapies. We show here that exposure of human iPSCs and human ESCs to low concentrations of the chemical NO donor DETA/NO leads to stabilization of hypoxia-inducible factors (HIF-1α and HIF-2α) under normoxia, with this effect being dependent on diminished Pro 402 hydroxylation and decreased degradation by the proteasome. Moreover, the master genes of pluripotency, NANOG and OCT-4, were upregulated. NO also induces a shift in the metabolic profile of PSCs, with an increased expression of hypoxia response genes in glycolysis. Furthermore, a reduction in the mitochondrial membrane potential with lower oxygen consumption and increased expression of mitochondrial fusion regulators, such as DRP1, was observed. The results reported here indicate that NO mimics hypoxia response in human PSCs and enhances their stemness properties when cultured under normoxic conditions.

9.
Parasitol Int ; 85: 102428, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34329752

RESUMEN

Fascioliasis is a zoonotic disease caused by parasites of the genus Fasciola spp. which cause an important loss to the livestock industry. The objectives of this study were: to estimate the prevalence of fascioliasis in three provinces of Amazonas, to evaluate possible risk factors of infection in cattle and to genetically characterize the Fasciola haplotypes circulating in this area. According to the results the prevalence of fascioliasis in cattle was 90.13% (712/790). Odds ratio results showed a significant association between fascioliasis and the Brown Swiss breed (OR = 2.62; 95% CI: 1.57-4.35; p < 0.001), and with female cattle older than 30 months (OR = 1.71; 95% CI: 1.05-2.79; p < 0.031). According to the molecular genetic studies using the gene marker NAD1, six haplotypes of Fasciola hepatica were found in the 35 infected livers collected. The results obtained in this study are concerning due to the high prevalence presented and it reveals the necessity of a continuing monitoring because of the high risk of transmission to humans.


Asunto(s)
Enfermedades de los Bovinos/epidemiología , Fascioliasis/veterinaria , Animales , Bovinos , Enfermedades de los Bovinos/parasitología , Fascioliasis/epidemiología , Fascioliasis/parasitología , Femenino , Masculino , Perú/epidemiología , Prevalencia , Factores de Riesgo
10.
Am J Trop Med Hyg ; 104(5): 1811-1813, 2021 03 29.
Artículo en Inglés | MEDLINE | ID: mdl-33782210

RESUMEN

In November 2018, we diagnosed a cluster of falciparum malaria cases in three Chilean travelers returning from Nigeria. Two patients were treated with sequential intravenous artesunate plus oral atovaquone/proguanil (AP) and one with oral AP. The third patient, a 23-year-old man, presented with fever on day 29 after oral AP treatment and was diagnosed with recrudescent falciparum malaria. The patient was then treated with oral mefloquine, followed by clinical recovery and resolution of parasitemia. Analysis of day 0 and follow-up blood samples, collected on days 9, 29, 34, 64, and 83, revealed that parasitemia had initially decreased but then increased on day 29. Sequencing confirmed Tyr268Cys mutation in the cytochrome b gene, associated with atovaquone resistance, in isolates collected on days 29 and 34 and P. falciparum dihydrofolate reductase mutation Asn51Ile, associated with proguanil resistance in all successfully sequenced samples. Molecular characterization of imported malaria contributes to clinical management in non-endemic countries, helps ascertain the appropriateness of antimalarial treatment policies, and contributes to the reporting of drug resistance patterns from endemic regions.


Asunto(s)
Antimaláricos/uso terapéutico , Resistencia a Medicamentos/genética , Malaria Falciparum/tratamiento farmacológico , Parasitemia/tratamiento farmacológico , Plasmodium falciparum/genética , Proteínas Protozoarias/genética , Adulto , Artesunato/uso terapéutico , Atovacuona/uso terapéutico , Chile , Citocromos b/genética , Combinación de Medicamentos , Femenino , Expresión Génica , Humanos , Malaria Falciparum/diagnóstico , Malaria Falciparum/parasitología , Malaria Falciparum/patología , Masculino , Mefloquina/uso terapéutico , Mutación , Nigeria , Parasitemia/diagnóstico , Parasitemia/parasitología , Parasitemia/patología , Plasmodium falciparum/efectos de los fármacos , Plasmodium falciparum/crecimiento & desarrollo , Plasmodium falciparum/patogenicidad , Proguanil/uso terapéutico , Recurrencia , Tetrahidrofolato Deshidrogenasa/genética , Viaje
11.
Malar J ; 20(1): 88, 2021 Feb 12.
Artículo en Inglés | MEDLINE | ID: mdl-33579285

RESUMEN

BACKGROUND: Malaria remains a serious health threat in the Amazonas Region of Peru and approximately 95% of the cases, mainly Plasmodium vivax, are found in native communities of The Rio Santiago District, Condorcanqui Province. In 2019, more than one thousand malaria cases were reported, with an unusual number of Plasmodium falciparum autochthonous cases. The present study aims to report this P. falciparum outbreak while describing the epidemiology of malaria and the risk factors associated in the native communities of Amazonas, Peru. METHODS: The DIRESA-Amazonas in collaboration with the Condorcanqui Health Network and the Institute of Tropical Diseases of the UNTRM carried out a malaria Active Case Detection (ACD III) between January 31st and February 10th of 2020. A total of 2718 (47.4%) individuals from 21 native communities grouped in eight sanitary districts, were screened for malaria infections. Each participant was screened for malaria using microscopy. Follow-up surveys were conducted for all malaria positive individuals to collect socio-demographic data. Spatial clustering of infection risk was calculated using a generalized linear model (GLM). Analysis of risk considered factors such as gender, age, type of infection, symptomatology, and parasitaemia. RESULTS: The study suggests that the P. falciparum index case was imported from Loreto and later spread to other communities of Rio Santiago during 2019. The ACD III reported 220 (8.1%) malaria cases, 46 P. falciparum, 168 P. vivax and 6 mixed infections. SaTScan analysis detected a cluster of high infection risk in Middle Rio Santiago and a particular high P. falciparum infection risk cluster in Upper Rio Santiago. Interestingly, the evaluation of different risk factors showed significant associations between low parasitaemia and P. falciparum asymptomatic cases. CONCLUSION: This is the first report of a P. falciparum outbreak in native communities of Condorcanqui, Amazonas. Timely identification and treatment of symptomatic and asymptomatic cases are critical to achieve malaria control and possible elimination in this area. However, the current malaria situation in Condorcanqui is uncertain, given that malaria ACD activities have been postponed due to COVID-19.


Asunto(s)
Brotes de Enfermedades , Malaria Falciparum/epidemiología , Adolescente , Adulto , Niño , Preescolar , Femenino , Humanos , Masculino , Persona de Mediana Edad , Perú/epidemiología , Población Rural , Adulto Joven
12.
Epidemiologia (Basel) ; 2(4): 490-501, 2021 Oct 09.
Artículo en Inglés | MEDLINE | ID: mdl-36417212

RESUMEN

Despite early control measures, SARS-CoV-2 reached all regions of Peru during the first wave of the pandemic, including native communities of the Peruvian Amazon. Here, we aimed to describe the epidemiological situation of COVID-19 in the Amazonas region of Peru using an open database of 11,124 COVID-19 cases reported from 19 March to 29 July 2020, including 3278 cases from native communities. A high-incidence area in northern Amazonas (Condorcanqui) reported a cumulative incidence of 63.84/1000 inhabitants with a much lower death rate (0.95%) than the national average. Our results showed at least eight significant factors for mortality, and the Native Amazonian ethnicity as a protective factor. Molecular confirmatory tests are necessary to better explain the high incidence of antibody response reported in these communities.

14.
ACS Omega ; 5(32): 20270-20282, 2020 Aug 18.
Artículo en Inglés | MEDLINE | ID: mdl-32832780

RESUMEN

Pluripotent stem cells maintain the property of self-renewal and differentiate into all cell types under clear environments. Though the gene regulatory mechanism for pluripotency has been investigated in recent years, it is still not completely understood. Here, we show several signaling pathways involved in the maintenance of pluripotency. To investigate whether AMPK is involved in maintaining the pluripotency in mouse embryonic stem cells (mESCs) and elucidating the possible molecular mechanisms, implicated D3 and R1/E mESC lines were used in this study. Cells were cultured in the absence or presence of LIF and treated with 1 mM and 0.5 mM 5-aminoimidazole-4-carboxamide-1-ß-d-ribofuranoside (AICAR), 2 mM metformin, compound C, and the PI3K inhibitor LY294002 for 24, 72, and 120 h. The levels of Nanog, Oct3/4, and REX1 and Brachyury, Notch2, and Gata4 mRNAs and Nanog or OCT3/4 protein levels were analyzed. Alkaline phosphatase and the cellular cycle were determined. The pGSK3ß, GSK3ß, p-ß-catenin, and ß-catenin protein levels were also investigated. We found that AMPK activators such as AICAR and metformin increase mRNA expression of pluripotency markers and decrease mRNA expression of differentiation markers in R1/E and D3 ES cells. AICAR increases phosphatase activity and arrests the cellular cycle in the G1 phase in these cells. We describe that AICAR effects were mediated by AMPK activation using a chemical inhibitor or by silencing this gene. AICAR effects were also mediated by PI3K, GSK3ß, and ß-catenin in R1/E ES cells. According to our findings, we provide a mechanism by which AICAR increases and maintains a pluripotency state through enhanced Nanog expression, involving AMPK/PI3K and p-GSK3ß Ser21/9 pathways backing up the AICAR function as a potential target for this drug controlling pluripotency. The highlights of this study are that AICAR (5-aminoimidazole-4-carboxamied-1-b-riboside), an AMP protein kinase (AMPK) activator, blocks the ESC differentiation and AMPK is a key enzyme for pluripotency and shows valuable data to clarify the molecular pluripotency mechanism.

15.
Front Immunol ; 11: 609961, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33633730

RESUMEN

Snakebite envenoming is a global neglected disease with an incidence of up to 2.7 million new cases every year. Although antivenoms are so-far the most effective treatment to reverse the acute systemic effects induced by snakebite envenoming, they have a limited therapeutic potential, being unable to completely neutralize the local venom effects. Local damage, such as dermonecrosis and myonecrosis, can lead to permanent sequelae with physical, social, and psychological implications. The strong inflammatory process induced by snake venoms is associated with poor tissue regeneration, in particular the lack of or reduced skeletal muscle regeneration. Mesenchymal stromal cells (MSCs)-based therapies have shown both anti-inflammatory and pro-regenerative properties. We postulate that using allogeneic MSCs or their cell-free products can induce skeletal muscle regeneration in snakebite victims, improving all the three steps of the skeletal muscle regeneration process, mainly by anti-inflammatory activity, paracrine effects, neovascularization induction, and inhibition of tissue damage, instrumental for microenvironment remodeling and regeneration. Since snakebite envenoming occurs mainly in areas with poor healthcare, we enlist the principles and potential of MSCs-based therapies and discuss regulatory issues, good manufacturing practices, transportation, storage, and related-procedures that could allow the administration of these therapies, looking forward to a safe and cost-effective treatment for a so far unsolved and neglected health problem.


Asunto(s)
Trasplante de Células Madre Mesenquimatosas , Células Madre Mesenquimatosas/metabolismo , Desarrollo de Músculos , Músculo Esquelético/fisiopatología , Regeneración , Mordeduras de Serpientes/cirugía , Animales , Humanos , Mediadores de Inflamación/metabolismo , Trasplante de Células Madre Mesenquimatosas/efectos adversos , Músculo Esquelético/metabolismo , Músculo Esquelético/patología , Necrosis , Fenotipo , Transducción de Señal , Mordeduras de Serpientes/diagnóstico , Mordeduras de Serpientes/metabolismo , Mordeduras de Serpientes/fisiopatología , Resultado del Tratamiento
16.
Front Immunol ; 10: 1151, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31231366

RESUMEN

Cell therapy is a progressively growing field that is rapidly moving from preclinical model development to clinical application. Outcomes obtained from clinical trials reveal the therapeutic potential of stem cell-based therapy to deal with unmet medical treatment needs for several disorders with no therapeutic options. Among adult stem cells, mesenchymal stem cells (MSCs) are the leading cell type used in advanced therapies for the treatment of autoimmune, inflammatory and vascular diseases. To date, the safety and feasibility of autologous MSC-based therapy has been established; however, their indiscriminate use has resulted in mixed outcomes in preclinical and clinical studies. While MSCs derived from diverse tissues share common properties depending on the type of clinical application, they markedly differ within clinical trials in terms of efficacy, resulting in many unanswered questions regarding the application of MSCs. Additionally, our experience in clinical trials related to critical limb ischemia pathology (CLI) shows that the therapeutic efficacy of these cells in different animal models has only been partially reproduced in humans through clinical trials. Therefore, it is crucial to develop new research to identify pitfalls, to optimize procedures and to clarify the repair mechanisms used by these cells, as well as to be able to offer a next generation of stem cell that can be routinely used in a cost-effective and safe manner in stem cell-based therapies targeting CLI.

17.
PLoS One ; 12(11): e0187547, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-29099856

RESUMEN

ß-cells release hexameric Zn2+-insulin into the extracellular space, but monomeric Zn2+-free insulin appears to be the only biologically active form. The mechanisms implicated in dissociation of the hexamer remain unclear, but they seem to be Zn2+ concentration-dependent. In this study, we investigate the influence of albumin binding to Zn2+ on Zn2+-insulin dissociation into Zn2+-free insulin and its physiological, methodological and therapeutic relevance. Glucose and K+-induced insulin release were analyzed in isolated mouse islets by static incubation and perifusion experiments in the presence and absence of albumin and Zn2+ chelators. Insulin tolerance tests were performed in rats using different insulin solutions with and without Zn2+ and/or albumin. Albumin-free buffer does not alter quantification by RIA of Zn2+-free insulin but strongly affects RIA measurements of Zn2+-insulin. In contrast, accurate determination of Zn2+-insulin was obtained only when bovine serum albumin or Zn2+ chelators were present in the assay buffer solution. Albumin and Zn2+ chelators do not modify insulin release but do affect insulin determination. Preincubation with albumin or Zn2+ chelators promotes the conversion of "slow" Zn2+-insulin into "fast" insulin. Consequently, insulin diffusion from large islets is ameliorated in the presence of Zn2+ chelators. These observations support the notion that the Zn2+-binding properties of albumin improve the dissociation of Zn2+-insulin into subunits after exocytosis, which may be useful in insulin determination, insulin pharmacokinetic assays and islet transplantation.


Asunto(s)
Quelantes/química , Exocitosis , Insulina/metabolismo , Albúmina Sérica/metabolismo , Zinc/química , Animales , Glucemia/metabolismo , Islotes Pancreáticos/metabolismo , Masculino , Ratones , Radioinmunoensayo , Ratas , Ratas Wistar , Albúmina Sérica/química , Zinc/metabolismo
18.
World J Stem Cells ; 9(2): 26-36, 2017 Feb 26.
Artículo en Inglés | MEDLINE | ID: mdl-28289506

RESUMEN

Mitochondrial dysfunction and endoplasmic reticulum stress (ERS) are global processes that are interrelated and regulated by several stress factors. Nitric oxide (NO) is a multifunctional biomolecule with many varieties of physiological and pathological functions, such as the regulation of cytochrome c inhibition and activation of the immune response, ERS and DNA damage; these actions are dose-dependent. It has been reported that in embryonic stem cells, NO has a dual role, controlling differentiation, survival and pluripotency, but the molecular mechanisms by which it modulates these functions are not yet known. Low levels of NO maintain pluripotency and induce mitochondrial biogenesis. It is well established that NO disrupts the mitochondrial respiratory chain and causes changes in mitochondrial Ca2+ flux that induce ERS. Thus, at high concentrations, NO becomes a potential differentiation agent due to the relationship between ERS and the unfolded protein response in many differentiated cell lines. Nevertheless, many studies have demonstrated the need for physiological levels of NO for a proper ERS response. In this review, we stress the importance of the relationships between NO levels, ERS and mitochondrial dysfunction that control stem cell fate as a new approach to possible cell therapy strategies.

19.
J Cell Biochem ; 117(9): 2078-88, 2016 09.
Artículo en Inglés | MEDLINE | ID: mdl-26853909

RESUMEN

Nitric oxide (NO) delays mouse embryonic stem cell (mESC) differentiation by regulating genes linked to pluripotency and differentiation. Nevertheless, no profound study has been conducted on cell differentiation regulation by this molecule through signaling on essential biological functions. We sought to demonstrate that NO positively regulates the pluripotency transcriptional core, enforcing changes in the chromatin structure, in addition to regulating cell proliferation, and signaling pathways with key roles in stemness. Culturing mESCs with 2 µM of the NO donor diethylenetriamine/NO (DETA/NO) in the absence of leukemia inhibitory factor (LIF) induced significant changes in the expression of 16 genes of the pluripotency transcriptional core. Furthermore, treatment with DETA/NO resulted in a high occupancy of activating H3K4me3 at the Oct4 and Nanog promoters and repressive H3K9me3 and H3k27me3 at the Brachyury promoter. Additionally, the activation of signaling pathways involved in pluripotency, such as Gsk3-ß/ß-catenin, was observed, in addition to activation of PI3 K/Akt, which is consistent with the protection of mESCs from cell death. Finally, a decrease in cell proliferation coincides with cell cycle arrest in G2/M. Our results provide novel insights into NO-mediated gene regulation and cell proliferation and suggest that NO is necessary but not sufficient for the maintenance of pluripotency and the prevention of cell differentiation. J. Cell. Biochem. 117: 2078-2088, 2016. © 2016 Wiley Periodicals, Inc.


Asunto(s)
Diferenciación Celular/fisiología , Puntos de Control de la Fase G2 del Ciclo Celular/fisiología , Expresión Génica/fisiología , Puntos de Control de la Fase M del Ciclo Celular/fisiología , Células Madre Embrionarias de Ratones/metabolismo , Óxido Nítrico/metabolismo , Transducción de Señal/fisiología , Animales , Diferenciación Celular/efectos de los fármacos , Línea Celular , Puntos de Control de la Fase G2 del Ciclo Celular/efectos de los fármacos , Expresión Génica/efectos de los fármacos , Puntos de Control de la Fase M del Ciclo Celular/efectos de los fármacos , Ratones , Células Madre Embrionarias de Ratones/citología , Fosfatidilinositol 3-Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Transducción de Señal/efectos de los fármacos , Triazenos/farmacología
20.
Expert Opin Biol Ther ; 15(10): 1469-89, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26156425

RESUMEN

INTRODUCTION: Tremendous progress has been made in generating insulin-producing cells from pluripotent stem cells. The best outcome of the refined protocols became apparent in the first clinical trial announced by ViaCyte, based on the implantation of pancreatic progenitors that would further mature into functional insulin-producing cells inside the patient's body. AREAS COVERED: Several groups, including ours, have contributed to improve strategies to generate insulin-producing cells. Of note, the latest results have gained a substantial amount of interest as a method to create a potentially functional and limitless supply of ß-cell to revert diabetes mellitus. This review analyzes the accomplishments that have taken place over the last few decades, summarizes the state-of-art methods for ß-cell replacement therapies based on the differentiation of embryonic stem cells into glucose-responsive and insulin-producing cells in a dish and discusses alternative approaches to obtain new sources of insulin-producing cells. EXPERT OPINION: Undoubtedly, recent events preface the beginning of a new era in diabetes therapy. However, in our opinion, a number of significant hurdles still stand in the way of clinical application. We believe that the combination of the private and public sectors will accelerate the process of obtaining the desired safe and functional ß-cell surrogates.


Asunto(s)
Insulina/metabolismo , Células Madre Adultas/citología , Biomarcadores/metabolismo , Diferenciación Celular , Diabetes Mellitus/terapia , Células Madre Embrionarias/citología , Epigénesis Genética , Humanos , Secreción de Insulina , Células Secretoras de Insulina/citología , Células Secretoras de Insulina/trasplante , MicroARNs/metabolismo
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