DSpace Repository :: Browsing by Author "De Gregorio, Cristian"

Browsing by Author "De Gregorio, Cristian"

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A Novel Morphine Drinking Model of Opioid Dependence in Rats
(2022) Berríos, Pablo; Quezada, Mauricio; Santapau, Daniela; Morales, Paola; Olivares, Belén; Ponce, Carolina; Ávila, Alba; De Gregorio, Cristian; Ezquer, Marcelo; Quintanilla, María; Herrera, Mario; Israel, Yedy; Ezquer, Fernando
Abstract: An animal model of voluntary oral morphine consumption would allow for a pre-clinical evaluation of new treatments aimed at reducing opioid intake in humans. However, the main limitation of oral morphine consumption in rodents is its bitter taste, which is strongly aversive. Taste aversion is often overcome by the use of adulterants, such as sweeteners, to conceal morphine taste or bitterants in the alternative bottle to equalize aversion. However, the adulterants’ presence is the cause for consumption choice and, upon removal, the preference for morphine is not preserved. Thus, current animal models are not suitable to study treatments aimed at reducing consumption elicited by morphine itself. Since taste preference is a learned behavior, just-weaned rats were trained to accept a bitter taste, adding the bitterant quinine to their drinking water for one week. The latter was followed by allowing the choice of quinine or morphine (0.15 mg/mL) solutions for two weeks. Then, quinine was removed, and the preference for morphine against water was evaluated. Using this paradigm, we show that rats highly preferred the consumption of morphine over water, reaching a voluntary morphine intake of 15 mg/kg/day. Morphine consumption led to significant analgesia and hyperlocomotion, and to a marked deprivation syndrome following the administration of the opioid antagonist naloxone. Voluntary morphine consumption was also shown to generate brain oxidative stress and neuroinflammation, signs associated with opioid dependence development. We present a robust two-bottle choice animal model of oral morphine self-administration for the evaluation of therapeutic interventions for the treatment of morphine dependence.
Administration of Secretome Derived from Human Mesenchymal Stem Cells Induces Hepatoprotective Effects in Models of Idiosyncratic Drug-Induced Liver Injury Caused by Amiodarone or Tamoxifen
(2023) Huang, Ya-Lin; De Gregorio, Cristian; Silva, Verónica; Elorza, Álvaro; Léniz, Patricio; Aliaga, Víctor; Maracaja, Vinicius; Budini, Mauricio; Ezquer, Fernando; Ezquer, Marcelo
Drug-induced liver injury (DILI) is one of the leading causes of acute liver injury. While many factors may contribute to the susceptibility to DILI, obese patients with hepatic steatosis are particularly prone to suffer DILI. The secretome derived from mesenchymal stem cell has been shown to have hepatoprotective effects in diverse in vitro and in vivo models. In this study, we evaluate whether MSC secretome could improve DILI mediated by amiodarone (AMI) or tamoxifen (TMX). Hepatic HepG2 and HepaRG cells were incubated with AMI or TMX, alone or with the secretome of MSCs obtained from human adipose tissue. These studies demonstrate that coincubation of AMI or TMX with MSC secretome increases cell viability, prevents the activation of apoptosis pathways, and stimulates the expression of priming phase genes, leading to higher proliferation rates. As proof of concept, in a C57BL/6 mouse model of hepatic steatosis and chronic exposure to AMI, the MSC secretome was administered endovenously. In this study, liver injury was significantly attenuated, with a decrease in cell infiltration and stimulation of the regenerative response. The present results indicate that MSC secretome administration has the potential to be an adjunctive cell-free therapy to prevent liver failure derived from DILI caused by TMX or AMI.
Amelioration of morphine withdrawal syndrome by systemic and intranasal administration of mesenchymal stem cell-derived secretome in preclinical models of morphine dependence
(2023) Ezquer, Marcelo; Gallardo, Javiera; Quezada, Mauricio; Ponce, Carolina; Berríos, Pablo; Santapau, Daniela; De Gregorio, Cristian; Quintanilla, María; Morales, Paola; Herreraz, Mario; Israel, Yedy; Andrés, Paula; Hipólito, Lucia; Ezquer, Fernando
Background: Morphine is an opiate commonly used in the treatment of moderate to severe pain. However, prolonged administration can lead to physical dependence and strong withdrawal symptoms upon cessation of morphine use. These symptoms can include anxiety, irritability, increased heart rate, and muscle cramps, which strongly promote morphine use relapse. The morphine-induced increases in neuroinflammation, brain oxidative stress, and alteration of glutamate levels in the hippocampus and nucleus accumbens have been associated with morphine dependence and a higher severity of withdrawal symptoms. Due to its rich content in potent anti-inflammatory and antioxidant factors, secretome derived from human mesenchymal stem cells (hMSCs) is proposed as a preclinical therapeutic tool for the treatment of this complex neurological condition associated with neuroinflammation and brain oxidative stress. Methods: Two animal models of morphine dependence were used to evaluate the therapeutic efficacy of hMSC-derived secretome in reducing morphine withdrawal signs. In the first model, rats were implanted subcutaneously with mini-pumps which released morphine at a concentration of 10 mg/kg/day for seven days. Three days after pump implantation, animals were treated with a simultaneous intravenous and intranasal administration of hMSC-derived secretome or vehicle, and withdrawal signs were precipitated on day seven by i.p. naloxone administration. In this model, brain alterations associated with withdrawal were also analyzed before withdrawal precipitation. In the second animal model, rats voluntarily consuming morphine for three weeks were intravenously and intranasally treated with hMSC-derived secretome or vehicle, and withdrawal signs were induced by morphine deprivation. Results: In both animal models secretome administration induced a significant reduction of withdrawal signs, as shown by a reduction in a combined withdrawal score. Secretome administration also promoted a reduction in morphine-induced neuroinflammation in the hippocampus and nucleus accumbens, while no changes were observed in extracellular glutamate levels in the nucleus accumbens. Conclusion: Data presented from two animal models of morphine dependence suggest that administration of secretome derived from hMSCs reduces the development of opioid withdrawal signs, which correlates with a reduction in neuroinflammation in the hippocampus and nucleus accumbens.
El secretoma de células madre mesenquimáticas estimula la regeneración neurítica en neuronas del DRG de ratones diabéticos in vitro
(Facultad de Medicina, Clínica Alemana Universidad del Desarrollo, 2020) Masse, Constanza; Aravena, Manuel; Farías, José Ignacio; Hernández, Valentín; Troc, Constanza; De Gregorio, Cristian
Introducción: La diabetes es una enfermedad metabólica crónica que afecta cerca de 425 millones de personas a nivel mundial. Su complicaciónmáscomún es la neuropatía diabética, una patología neurodegenerativa que afecta principalmente a nervios sensitivos y autonómicos. En distintos estudios preliminares, se ha observado que el secretoma de las células madre mesenquimáticas produce efectos anti-apoptóticos, tróficos y regenerativos en distintas células y tejidos. Objetivo: Evaluar si el secretoma de células mesenquimáticas humanas derivadas de tejido adiposo (hAD-MSC) promueve la regeneración neurítica de neuronas de los ganglios de laraíz dorsal (DRG)de ratones diabéticos adultos in vitro. Metodología: Se extrajeron neuronas de DRG de 3 ratones db/db con diabetes mellitus tipo II (T2DM), con las cuales se realizaron 3 cultivos independientes. Las neuronas de cada cultivo recibieron NGF (comparador), vehículo (control negativo) o secretoma (tratamiento). Luego, se realizó inmunocitofluorescencia y posteriormente un análisis de Sholl. Resultado: El número de intersecciones de ramificaciones por neurona y radio máximo alcanzado por las neuritas fueron significativamente mayores (p<0,05) en los grupos NGF y secretoma, respecto al vehículo. Discusión: Se considera que el secretoma tiene potencial terapéuticopara un tratamiento de neuropatía diabética aunque, al ser un estudio in vitro, todavía no es extrapolable a estudios clínicos. Conclusión: La administración de secretoma de hAD-MSCs a neuronas de DRG de ratones db/db durante 48 horas promueve la regeneración de estas.
Maintenance of chronicity signatures in fibroblasts isolated from recessive dystrophic epidermolysis bullosa chronic wound dressings under culture conditions
(2023) De Gregorio, Cristian; Catalán, Evelyng; Garrido, Gabriel; Morandé, Pilar; Castillo, Jimena; Muñoz, Catalina; Cofré, Glenda; Huang, Ya-Lin; Cuadra, Bárbara; Murgas, Paola; Calvo, Margarita; Altermatt, Fernando; Joao, María; Palisson, Francis; South, Andrew; Ezquer, Marcelo; Ezquer, Marcelo; Fuentes, Ignacia
Background: Recessive Dystrophic Epidermolysis Bullosa (RDEB) is a rare inherited skin disease caused by variants in the COL7A1 gene, coding for type VII collagen (C7), an important component of anchoring fibrils in the basement membrane of the epidermis. RDEB patients suffer from skin fragility starting with blister formation and evolving into chronic wounds, inflammation and skin fibrosis, with a high risk of developing aggressive skin carcinomas. Restricted therapeutic options are limited by the lack of in vitro models of defective wound healing in RDEB patients. Results: In order to explore a more efficient, non-invasive in vitro model for RDEB studies, we obtained patient fibroblasts derived from discarded dressings) and examined their phenotypic features compared with fibroblasts derived from non-injured skin of RDEB and healthy-donor skin biopsies. Our results demonstrate that fibroblasts derived from RDEB chronic wounds (RDEB-CW) displayed characteristics of senescent cells, increased myofibroblast differentiation, and augmented levels of TGF-β1 signaling components compared to fibroblasts derived from RDEB acute wounds and unaffected RDEB skin as well as skin from healthy-donors. Furthermore, RDEB-CW fibroblasts exhibited an increased pattern of inflammatory cytokine secretion (IL-1β and IL-6) when compared with RDEB and control fibroblasts. Interestingly, these aberrant patterns were found specifically in RDEB-CW fibroblasts independent of the culturing method, since fibroblasts obtained from dressing of acute wounds displayed a phenotype more similar to fibroblasts obtained from RDEB normal skin biopsies. Conclusions: Our results show that in vitro cultured RDEB-CW fibroblasts maintain distinctive cellular and molecular characteristics resembling the inflammatory and fibrotic microenvironment observed in RDEB patients’ chronic wounds. This work describes a novel, non-invasive and painless strategy to obtain human fibroblasts chronically subjected to an inflammatory and fibrotic environment, supporting their use as an accessible model for in vitro studies of RDEB wound healing pathogenesis. As such, this approach is well suited to testing new therapeutic strategies under controlled laboratory conditions.
Sensory neuron cultures derived from adult db/db mice as a simplified model to study type-2 diabetes-associated axonal regeneration defects
(2021) De Gregorio, Cristian; Ezquer, Fernando
Diabetic neuropathy (DN) is an early common complication of diabetes mellitus (DM), leading to chronic pain, sensory loss and muscle atrophy. Owing to its multifactorial etiology, neuron in vitro cultures have been proposed as simplified systems for DN studies. However, the most used models currently available do not recreate the chronic and systemic damage suffered by peripheral neurons of type-2 DM (T2DM) individuals. Here, we cultured neurons derived from dorsal root ganglia from 6-month-old diabetic db/db-mice, and evaluated their morphology by the Sholl method as an easy-to-analyze readout of neuronal function. We showed that neurons obtained from diabetic mice exhibited neuritic regeneration defects in basal culture conditions, compared to neurons from non-diabetic mice. Next, we evaluated the morphological response to common neuritogenic factors, including nerve growth factor NGF and Laminin-1 (also called Laminin-111). Neurons derived from diabetic mice exhibited reduced regenerative responses to these factors compared to neurons from non-diabetic mice. Finally, we analyzed the neuronal response to a putative DN therapy based on the secretome of mesenchymal stem cells (MSC). Neurons from diabetic mice treated with the MSC secretome displayed a significant improvement in neuritic regeneration, but still reduced when compared to neurons derived from non-diabetic mice. This in vitro model recapitulates many alterations observed in sensory neurons of T2DM individuals, suggesting the possibility of studying neuronal functions without the need of adding additional toxic factors to culture plates. This model may be useful for evaluating intrinsic neuronal responses in a cell-autonomous manner, and as a throughput screening for the pre-evaluation of new therapies for DN.

Browsing by Author "De Gregorio, Cristian"

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