Enfermedad de Parkinson: actualización de estudios preclínicos con el uso de células troncales pluripotentes inducidas / Parkinson's disease: An update on preclinical studies of induced pluripotent stem cells

La enfermedad de Parkinson (EP) es la segunda enfermedad neurodegenerativa más común a nivel mundial en adultos mayores. Se caracteriza por la pérdida de neuronas dopaminérgicas (nDAs) en la sustancia nigra pars compacta del mesencéfalo y en algunos casos acompañada de la aparición de cuerpos intracitoplasmáticos de Lewy de -sinucleína, signo patognomónico de la enfermedad. La EP se diagnostica clínicamente por la presencia de alteraciones motoras principalmente, y en la actualidad los tratamientos presentan nula actividad neuroprotectora. Aún no se han establecido las causas exactas de la EP, por lo que en los últimos años se ha buscado el desarrollo de modelos preclínicos más precisos, utilizando células troncales pluripotentes inducidas, permitiendo el estudio de la enfermedad de manera in vitro para generar conocimiento novedoso sobre su patogénesis y el descubrimiento de nuevos posibles blancos terapéuticos o el desarrollo de nuevos fármacos.(AU)

Parkinson's disease (PD) is the second most prevalent neurodegenerative disease among adults worldwide. It is characterised by the death of dopaminergic neurons in the substantia nigra pars compacta and, in some cases, presence of intracytoplasmic inclusions of α-synuclein, called Lewy bodies, a pathognomonic sign of the disease. Clinical diagnosis of PD is based on the presence of motor alterations. The treatments currently available have no neuroprotective effect. The exact causes of PD are poorly understood. Therefore, more precise preclinical models have been developed in recent years that use induced pluripotent stem cells. In vitro studies can provide new information on PD pathogenesis and may help to identify new therapeutic targets or to develop new drugs.(AU)

Parkinson's disease: an update on preclinical studies of induced pluripotent stem cells.

Parkinson's disease (PD) is the second most prevalent neurodegenerative disease among adults worldwide. It is characterised by the death of dopaminergic neurons in the substantia nigra pars compacta and, in some cases, presence of intracytoplasmic inclusions of α-synuclein, called Lewy bodies, a pathognomonic sign of the disease. Clinical diagnosis of PD is based on the presence of motor alterations. The treatments currently available have no neuroprotective effect. The exact causes of PD are poorly understood. Therefore, more precise preclinical models have been developed in recent years that use induced pluripotent stem cells (iPSC). In vitro studies can provide new information on PD pathogenesis and may help to identify new therapeutic targets or to develop new drugs.

Parkinson's disease: An update on preclinical studies of induced pluripotent stem cells. / Enfermedad de Parkinson: actualización de estudios preclínicos con el uso de células troncales pluripotentes inducidas.

Parkinson's disease (PD) is the second most prevalent neurodegenerative disease among adults worldwide. It is characterised by the death of dopaminergic neurons in the substantia nigra pars compacta and, in some cases, presence of intracytoplasmic inclusions of α-synuclein, called Lewy bodies, a pathognomonic sign of the disease. Clinical diagnosis of PD is based on the presence of motor alterations. The treatments currently available have no neuroprotective effect. The exact causes of PD are poorly understood. Therefore, more precise preclinical models have been developed in recent years that use induced pluripotent stem cells. In vitro studies can provide new information on PD pathogenesis and may help to identify new therapeutic targets or to develop new drugs.

The 2018 Bo Lindell Laureate Lecture: Finding common ground between science, ethics, and experience.

The present system of radiological protection has evolved with the advancement of science; evolution of ethical and societal values; and the lessons of our individual, collective, and historical experience. In communicating with each other and members of the public, words are often not enough to completely relay thoughts, ideas, or experiences. Art is a shared experience, beyond the spoken language, where many can find common ground. This paper provides several examples of utilising the visual arts, cinema, and popular culture for communication in different contexts, with discussion of how each relates to the ethical values of the system of radiological protection. In this way, we find inter-relationships between science, ethics, and experience. Experience improves understanding; empathy, or the awareness and feeling of another's experience, can lead to similar understanding. Drawing on art and the broader human experience will help us improve our communication, promote transparency, and encourage empathy. Through this, we will be more likely to develop trust with stakeholders, which is an essential, yet challenging, aspect of radiological protection.

Radiation protection challenges in applications of ionising radiation on animals in veterinary practice.

As we work towards a holistic approach to radiation protection, we begin to consider and integrate protection beyond humans to include, among other things, non-human biota. Non-human biota not only includes environmental flora and fauna, but also livestock, companion animals, working animals, etc. Although under consideration, there is currently little guidance in terms of protection strategies for types of non-human biota beyond wildlife. For example, in recent years, veterinary procedures that make use of ionising radiation have increased in number and have diversified considerably, which has made radiation protection in veterinary applications of ionising radiation more challenging, both for humans and the animal patients. In fact, the common belief that doses to professionals and members of the public from these applications will be very low to negligible, and doses to the animals will not be acutely harmful nor even affect their lifetime probability of developing cancer, needs to be revisited in the light of higher dose diagnostic and interventional techniques, and certainly in the case of therapeutic applications. This paper provides a brief overview of the initiatives of the International Commission on Radiological Protection concerning radiation protection aspects of veterinary practice, and poses a variety of perspectives for consideration and further discussion.

New transgenic models of Parkinson's disease using genome editing technology. / Nuevos modelos transgénicos para el estudio de la enfermedad de Parkinson basados en sistemas de edición con nucleasas.

INTRODUCTION: Parkinson's disease (PD) is the second most common neurodegenerative disorder. It is characterised by selective loss of dopaminergic neurons in the substantia nigra pars compacta, which results in dopamine depletion, leading to a number of motor and non-motor symptoms. DEVELOPMENT: In recent years, the development of new animal models using nuclease-based genome-editing technology (ZFN, TALEN, and CRISPR/Cas9 nucleases) has enabled the introduction of custom-made modifications into the genome to replicate key features of PD, leading to significant advances in our understanding of the pathophysiology of the disease. CONCLUSIONS: We review the most recent studies on this new generation of in vitro and in vivo PD models, which replicate the most relevant symptoms of the disease and enable better understanding of the aetiology and mechanisms of PD. This may be helpful in the future development of effective treatments to halt or slow disease progression.

Neuroprotective effects of phytochemicals on dopaminergic neuron cultures. / Efecto neuroprotector de fitoquímicos en cultivo de neuronas dopaminérgicas.

INTRODUCTION: Parkinson's disease is a progressive neurodegenerative disorder characterised by a loss of dopaminergic neurons in the substantia nigra pars compacta, which results in a significant decrease in dopamine levels and consequent functional motor impairment. DEVELOPMENT: Although its aetiology is not fully understood, several pathogenic mechanisms, including oxidative stress, have been proposed. Current therapeutic approaches are based on dopamine replacement drugs; these agents, however, are not able to stop or even slow disease progression. Novel therapeutic approaches aimed at acting on the pathways leading to neuronal dysfunction and death are under investigation. CONCLUSIONS: In recent years, such natural molecules as polyphenols, alkaloids, and saponins have been shown to have a neuroprotective effect due to their antioxidant and anti-inflammatory properties. The aim of our review is to analyse the most relevant studies worldwide addressing the benefits of some phytochemicals used in in vitro models of Parkinson's disease.

Effects of Sildenafil and Tadalafil on Edema and Reactive Oxygen Species Production in an Experimental Model of Lung Ischemia-Reperfusion Injury.

BACKGROUND: Lung ischemia-reperfusion injury is characterized by formation of reactive oxygen species and cellular swelling leading to pulmonary edema and primary graft dysfunction. Phosphodiesterase 5 inhibitors could ameliorate lung ischemia-reperfusion injury by interfering in many molecular pathways. The aim of this work was to evaluate and compare the effects of sildenafil and tadalafil on edema and reactive oxygen species formation in an ex vivo nonhuman animal model of lung ischemia-reperfusion injury. METHODS: Thirty-two Wistar rats were distributed, treated, perfused and the cardiopulmonary blocks were managed as follows: control group: immediate excision and reperfusion without pretreatment; ischemia reperfusion group: treatment with dimethylsulfoxide 0.9% and excision 1 hour later; sildenafil group: treatment with sildenafil (0.7 mg/kg) and excision 1 hour later; and tadalafil group: treatment with tadalafil (0.15 mg/kg) and excision 2 hours later. All cardiopulmonary blocks except control group were preserved for 8 hours and then reperfused. Pulmonary arterial pressure, pulmonary venous pressure, and capillary filtration coefficient were measured. Reactive oxygen species were measured. RESULTS: Edema was similar between control and sildenafil groups, but significantly greater in the ischemia-reperfusion (P ≤ .04) and tadalafil (P ≤ .003) groups compared with the sildenafil group. The malondialdehyde levels were significantly lower in the sildenafil (P ≤ .001) and tadalafil (P ≤ .001) groups than the ischemia-reperfusion group. CONCLUSIONS: Administration of sildenafil, but not tadalafil, decreased edema in lung ischemia-reperfusion injury. Both drugs decreased reactive oxygen species formation in a lung ischemia-reperfusion injury model.

Fructans from Agave tequilana with a Lower Degree of Polymerization Prevent Weight Gain, Hyperglycemia and Liver Steatosis in High-Fat Diet-Induced Obese Mice.

Fructans from agave have received specific attention because of their highly branched fructan content. We have previously reported that the degree of polymerization (dp) influences their biological activity. Therefore, the aim of this study was to investigate the effect of unfractionated and fractionated fructans (higher and lower dps) from Agave tequilana in high-fat diet-induced (HFD) obese mice. Fructans with a lower dp (HFD+ScF) decreased weight gain by 30 %, body fat mass by 51 %, hyperglycemia by 25 % and liver steatosis by 40 %. Interestingly, unfractionated fructans (HFD+F) decreased glucose and triglycerides (TG), whereas fractionated fructans with a higher dp (HFD+LcF) decreased TG but not glucose; in contrast, HFD+ScF decreased glucose but not TG. Our findings suggest that both higher and lower dp agave fructans have complementary effects in metabolic disorders related to obesity. These findings may contribute to the development of improved food supplements with a specific ratio combination of fructans with different dps.

Application of computational models to estimate organ radiation dose in rainbow trout from uptake of molybdenum-99 with comparison to iodine-131.

This study compares three anatomical phantoms for rainbow trout (Oncorhynchus mykiss) for the purpose of estimating organ radiation dose and dose rates from molybdenum-99 ((99)Mo) uptake in the liver and GI tract. Model comparison and refinement is important to the process of determining accurate doses and dose rates to the whole body and the various organs. Accurate and consistent dosimetry is crucial to the determination of appropriate dose-effect relationships for use in environmental risk assessment. The computational phantoms considered are (1) a geometrically defined model employing anatomically relevant organ size and location, (2) voxel reconstruction of internal anatomy obtained from CT imaging, and (3) a new model utilizing NURBS surfaces to refine the model in (2). Dose Conversion Factors (DCFs) for whole body as well as selected organs of O. mykiss were computed using Monte Carlo modeling and combined with empirical models for predicting activity concentration to estimate dose rates and ultimately determine cumulative radiation dose (µGy) to selected organs after several half-lives of (99)Mo. The computational models provided similar results, especially for organs that were both the source and target of radiation (less than 30% difference between all models). Values in the empirical model as well as the 14 day cumulative organ doses determined from (99)Mo uptake are compared to similar models developed previously for (131)I. Finally, consideration is given to treating the GI tract as a solid organ compared to partitioning it into gut contents and GI wall, which resulted in an order of magnitude difference in estimated dose for most organs.

Lyophilized allografts without pre-treatment with glutaraldehyde are more suitable than cryopreserved allografts for pulmonary artery reconstruction.

Various methods are available for preservation of vascular grafts for pulmonary artery (PA) replacement. Lyophilization and cryopreservation reduce antigenicity and prevent thrombosis and calcification in vascular grafts, so both methods can be used to obtain vascular bioprostheses. We evaluated the hemodynamic, gasometric, imaging, and macroscopic and microscopic findings produced by PA reconstruction with lyophilized (LyoPA) grafts and cryopreserved (CryoPA) grafts in dogs. Eighteen healthy crossbred adult dogs of both sexes weighing between 18 and 20 kg were used and divided into three groups of six: group I, PA section and reanastomosis; group II, PA resection and reconstruction with LyoPA allograft; group III, PA resection and reconstruction with CryoPA allograft. Dogs were evaluated 4 weeks after surgery, and the status of the graft and vascular anastomosis were examined macroscopically and microscopically. No clinical, radiologic, or blood-gas abnormalities were observed during the study. The mean pulmonary artery pressure (MPAP) in group III increased significantly at the end of the study compared with baseline (P=0.02) and final [P=0.007, two-way repeat-measures analysis of variance (RM ANOVA)] values. Pulmonary vascular resistance of groups II and III increased immediately after reperfusion and also at the end of the study compared to baseline. The increase shown by group III vs group I was significant only if compared with after surgery and study end (P=0.016 and P=0.005, respectively, two-way RM ANOVA). Microscopically, permeability was reduced by ≤75% in group III. In conclusion, substitution of PAs with LyoPA grafts is technically feasible and clinically promising.

Lyophilized allografts without pre-treatment with glutaraldehyde are more suitable than cryopreserved allografts for pulmonary artery reconstruction

Various methods are available for preservation of vascular grafts for pulmonary artery (PA) replacement. Lyophilization and cryopreservation reduce antigenicity and prevent thrombosis and calcification in vascular grafts, so both methods can be used to obtain vascular bioprostheses. We evaluated the hemodynamic, gasometric, imaging, and macroscopic and microscopic findings produced by PA reconstruction with lyophilized (LyoPA) grafts and cryopreserved (CryoPA) grafts in dogs. Eighteen healthy crossbred adult dogs of both sexes weighing between 18 and 20 kg were used and divided into three groups of six: group I, PA section and reanastomosis; group II, PA resection and reconstruction with LyoPA allograft; group III, PA resection and reconstruction with CryoPA allograft. Dogs were evaluated 4 weeks after surgery, and the status of the graft and vascular anastomosis were examined macroscopically and microscopically. No clinical, radiologic, or blood-gas abnormalities were observed during the study. The mean pulmonary artery pressure (MPAP) in group III increased significantly at the end of the study compared with baseline (P=0.02) and final [P=0.007, two-way repeat-measures analysis of variance (RM ANOVA)] values. Pulmonary vascular resistance of groups II and III increased immediately after reperfusion and also at the end of the study compared to baseline. The increase shown by group III vs group I was significant only if compared with after surgery and study end (P=0.016 and P=0.005, respectively, two-way RM ANOVA). Microscopically, permeability was reduced by ≤75% in group III. In conclusion, substitution of PAs with LyoPA grafts is technically feasible and clinically promising.

Development of the endocrine pancreas and novel strategies for ß-cell mass restoration and diabetes therapy.

Diabetes mellitus represents a serious public health problem owing to its global prevalence in the last decade. The causes of this metabolic disease include dysfunction and/or insufficient number of ß cells. Existing diabetes mellitus treatments do not reverse or control the disease. Therefore, ß-cell mass restoration might be a promising treatment. Several restoration approaches have been developed: inducing the proliferation of remaining insulin-producing cells, de novo islet formation from pancreatic progenitor cells (neogenesis), and converting non-ß cells within the pancreas to ß cells (transdifferentiation) are the most direct, simple, and least invasive ways to increase ß-cell mass. However, their clinical significance is yet to be determined. Hypothetically, ß cells or islet transplantation methods might be curative strategies for diabetes mellitus; however, the scarcity of donors limits the clinical application of these approaches. Thus, alternative cell sources for ß-cell replacement could include embryonic stem cells, induced pluripotent stem cells, and mesenchymal stem cells. However, most differentiated cells obtained using these techniques are functionally immature and show poor glucose-stimulated insulin secretion compared with native ß cells. Currently, their clinical use is still hampered by ethical issues and the risk of tumor development post transplantation. In this review, we briefly summarize the current knowledge of mouse pancreas organogenesis, morphogenesis, and maturation, including the molecular mechanisms involved. We then discuss two possible approaches of ß-cell mass restoration for diabetes mellitus therapy: ß-cell regeneration and ß-cell replacement. We critically analyze each strategy with respect to the accessibility of the cells, potential risk to patients, and possible clinical outcomes.

mRNA Transcript abundance during plant growth and the influence of Li(+) exposure.

Lithium (Li) toxicity in plants is, at a minimum, a function of Li(+) concentration, exposure time, species and growth conditions. Most plant studies with Li(+) focus on short-term acute exposures. This study examines short- and long-term effects of Li(+) exposure in Arabidopsis with Li(+) uptake studies and measured shoot mRNA transcript abundance levels in treated and control plants. Stress, pathogen-response and arabinogalactan protein genes were typically more up-regulated in older (chronic, low level) Li(+)-treatment plants and in the much younger plants from acute high-level exposures. The gene regulation behavior of high-level Li(+) resembled prior studies due to its influence on: inositol synthesis, 1-aminocyclopropane-1-carboxylate synthases and membrane ion transport. In contrast, chronically-exposed plants had gene regulation responses that were indicative of pathogen, cold, and heavy-metal stress, cell wall degradation, ethylene production, signal transduction, and calcium-release modulation. Acute Li(+) exposure phenocopies magnesium-deficiency symptoms and is associated with elevated expression of stress response genes that could lead to consumption of metabolic and transcriptional energy reserves and the dedication of more resources to cell development. In contrast, chronic Li(+) exposure increases expression signal transduction genes. The identification of new Li(+)-sensitive genes and a gene-based "response plan" for acute and chronic Li(+) exposure are delineated.

Development and comparison of computational models for estimation of absorbed organ radiation dose in rainbow trout (Oncorhynchus mykiss) from uptake of iodine-131.

This study develops and compares different, increasingly detailed anatomical phantoms for rainbow trout (Oncorhynchus mykiss) for the purpose of estimating organ absorbed radiation dose and dose rates from (131)I uptake in multiple organs. The models considered are: a simplistic geometry considering a single organ, a more specific geometry employing additional organs with anatomically relevant size and location, and voxel reconstruction of internal anatomy obtained from CT imaging (referred to as CSUTROUT). Dose Conversion Factors (DCFs) for whole body as well as selected organs of O. mykiss were computed using Monte Carlo modeling, and combined with estimated activity concentrations, to approximate dose rates and ultimately determine cumulative radiation dose (µGy) to selected organs after several half-lives of (131)I. The different computational models provided similar results, especially for source organs (less than 30% difference between estimated doses), and whole body DCFs for each model (∼3 × 10(-3) µGy d(-1) per Bq kg(-1)) were comparable to DCFs listed in ICRP 108 for (131)I. The main benefit provided by the computational models developed here is the ability to accurately determine organ dose. A conservative mass-ratio approach may provide reasonable results for sufficiently large organs, but is only applicable to individual source organs. Although CSUTROUT is the more anatomically realistic phantom, it required much more resource dedication to develop and is less flexible than the stylized phantom for similar results. There may be instances where a detailed phantom such as CSUTROUT is appropriate, but generally the stylized phantom appears to be the best choice for an ideal balance between accuracy and resource requirements.

Progesterone increases dopamine neurone number in differentiating mouse embryonic stem cells.

Progesterone participates in the regulation of several functions in mammals, including brain differentiation and dopaminergic transmission, but the role of progesterone in dopaminergic cell differentiation is unknown. We investigated the effects of progesterone on dopaminergic differentiation of embryonic stem cells using a five-stage protocol. Cells were incubated with different progesterone concentrations during the proliferation (stage 4) or differentiation (stage 5) phases. Progesterone added at 1, 10 and 100 nm during stage 4 increased the number of dopamine neurones at stage 5 by 72%, 80% and 62%, respectively, compared to the control group. The administration of progesterone at stage 5 did not induce significant changes in the number of dopamine neurones. These actions were not mediated by the activation of intracellular progesterone receptors because RU 486 did not block the positive effects of progesterone on differentiation to dopaminergic neurones. The results obtained suggest that progesterone should prove useful with respect to producing higher proportions of dopamine neurones from embryonic stem cells in the treatment of Parkinson's disease.

First Report of 'Candidatus Phytoplasma asteris'-Related Strains Infecting Lily in Mexico.

In recent years, lily (Lilium spp.) has become an important ornamental crop in diverse regions of Mexico. Since 2005, unusual symptoms have been observed on lily plants grown from imported bulbs in both greenhouse and production plots at San Pablo Ixayo, Boyeros, and Tequexquinauac, Mexico State. Symptoms included a zigzag line pattern on leaves, dwarfism, enlargement of stems, shortened internodes, leaves without petioles growing directly from bulbs, air bulbils, death of young roots, atrophy of flower buttons, and flower abortion. Symptoms were experimentally reproduced on healthy lily plants by graft inoculation. Total DNA was extracted from 50 diseased, 10 symptomless, and 10 graft-inoculated plants by the method of Dellaporta et al. (2). DNA samples were analyzed for phytoplasma presence by two different nested PCR assays. One assay employed ribosomal RNA gene primer pair P1/P7 followed by R16F2n/R16R2 (1), whereas ribosomal protein (rp) gene primer pairs rpF1/rpR1 and rp(I)F1A/rp(I)R1A (4) were used in a second assay. A DNA fragment approximately 1.2 kb long was consistently amplified from all symptomatic plant samples only by both assays. A comparative analysis of 16S rDNA sequences (Genbank Accession Nos. EF421158-EF421160 and EU124518-EU124520) and rp gene sequences (EU277012-EU277014), derived from PCR products, revealed that phytoplasma infecting lily were most similar (99.9% to 16S rDNA and 99.7% to rp) to carrot phytoplasma sp. ca2006/5 and also were similar (99.8% to 16SrDNA and 99.2% to rp) to broccoli phytoplasma sp. br273. Both carrot and broccoli phytoplasmas were classified as members of aster yellow 16S rDNA restriction fragment length polymorphism subgroup 16SrI-B (3). Although infection of lilies by aster yellows ('Ca. phytoplasma asteris') subgroup 16SrI-B and 16SrI-C was reported from the Czech Republic and Poland, to our knowledge, this is the first report of 'Ca. phytoplasma asteris'-related strains associated with lily plants in Mexico. References: (1) R. F. Davis et al. Microbiol. Res. 158:229, 2003. (2) S. L. Dellaporta et al. Plant Mol. Biol. Rep. 1:19, 1983. (3) B. Duduk et al. Bull. Insectol. 60 2:341, 2007. (4) I.-M. Lee et al. Int. J. Syst. Evol. Microbiol. 54:337, 2004.