RESUMEN
Regenerative medicine is a branch of translational research that aims to reestablish irreparably damaged tissues and organs by stimulating the body's own repair mechanisms via the implantation of stem cells differentiated into specialized cell types. A rich source of adult stem cells is located inside the tooth and is represented by human dental pulp stem cells, or hDPSCs. These cells are characterized by a high proliferative rate, have self-renewal and multi-lineage differentiation properties and are often used for tissue engineering and regenerative medicine. The present review will provide an overview of hDPSCs and related features with a special focus on their potential applications in regenerative medicine of the nervous system, such as, for example, after spinal cord injury. Recent advances in the identification and characterization of dental stem cells and in dental tissue engineering strategies suggest that bioengineering approaches may successfully be used to regenerate districts of the central nervous system, previously considered irreparable.
Asunto(s)
Tratamiento Basado en Trasplante de Células y Tejidos/métodos , Pulpa Dental/citología , Células Madre Mesenquimatosas/fisiología , Regeneración Nerviosa/fisiología , Traumatismos de la Médula Espinal/terapia , Animales , Pulpa Dental/metabolismo , Humanos , Células Madre Mesenquimatosas/citología , Células Madre Mesenquimatosas/metabolismoRESUMEN
Amyotrophic lateral sclerosis (ALS) is a fatal and disabling neurodegenerative disease characterized by upper and lower motor neurons depletion. In our previous work, comprehensive genomic profiling of 41 motor cortex samples enabled to discriminate controls from sporadic ALS patients, and segregated these latter into two distinct subgroups (SALS1 and SALS2), each associated with different deregulated genes. In the present study, we focused our attention on two of them, Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) and its type 1 receptor (PAC1R), and validated the results of the transcriptome experiments by quantitative reverse transcription-polymerase chain reaction (qRT-PCR), immunohistochemistry and Western blot analysis. To assess the functional role of PACAP and PAC1R in ALS, we developed an in vitro model of human induced pluripotent stem cells (iPSC)-derived motor neurons and examined the trophic effects of exogenous PACAP following neurodegenerative stimuli. Treatment with 100 nm PACAP was able to effectively rescue iPSC-derived motor neurons from apoptosis, as shown by cell viability assay and protein dosage of the apoptotic marker (BAX). All together, these data suggest that perturbations in the PACAP-PAC1R pathway may be involved in ALS pathology and represent a potential drug target to enhance motor neuron viability.
Asunto(s)
Esclerosis Amiotrófica Lateral/patología , Corteza Motora/metabolismo , Neuronas Motoras/metabolismo , Polipéptido Hipofisario Activador de la Adenilato-Ciclasa/metabolismo , Receptores del Polipéptido Activador de la Adenilato-Ciclasa Hipofisaria/metabolismo , Esclerosis Amiotrófica Lateral/metabolismo , Humanos , Células Madre Pluripotentes Inducidas/metabolismo , Transducción de Señal/fisiologíaRESUMEN
We compared, in 20 subjects, the effects of high blood lactate levels on amplitude and latency of P1, N1, P2 and N2 components of lower limb somatosensory evoked potential (SEP), an useful, noninvasive tool for assessing the transmission of the afferent volley from periphery up to the cortex. SEPs were recorded from CPz located over the somatosensory vertex and referenced to FPz with a clavicle ground. Measurements were carried out before, at the end as well as 10 and 20 min after the conclusion of a maximal exercise carried out on a mechanically braked cycloergometer. After the exercise, P2-N2 amplitudes as well as latency of P1 and N1 components showed small but significant reductions. On the contrary, latency of N2 component exhibited a significant increase after the exercise's conclusion. These results suggest that blood lactate appears to have a protective effect against fatigue, at least at level of primary somatosensory cortex, although at the expense of efficiency of adjacent areas.
Asunto(s)
Potenciales Evocados Somatosensoriales , Ejercicio Físico , Ácido Láctico/sangre , Extremidad Inferior/fisiología , Fatiga Muscular , Corteza Somatosensorial/fisiología , Adulto , Ciclismo/fisiología , Análisis Químico de la Sangre , Femenino , Humanos , Masculino , Nervio Tibial/fisiología , Adulto JovenRESUMEN
We studied, in healthy adult subjects, the association of high blood lactate levels, induced with an exhaustive exercise (12 subjects) or an intravenous infusion (four subjects) of a lactate solution (3 mg/kg in 1 min), with amplitude and latency of visual-evoked potentials. Amplitude of N75, P100, and N145 components did not show significant changes, whereas latency of P100 was reduced at exercise's end and that of N145 increased 10 min after the conclusion. Therefore, an increase of blood lactate induced by an exhaustive exercise or an intravenous infusion appears to induce an improvement in the conduction time between eye and striate cortex, while it seems to evoke a worsening of intracortical communication between striate and extrastriate areas.
Asunto(s)
Potenciales Evocados Visuales/fisiología , Ácido Láctico/sangre , Tiempo de Reacción/fisiología , Adulto , Análisis de Varianza , Glucemia , Electroencefalografía , Potenciales Evocados Visuales/efectos de los fármacos , Ejercicio Físico/fisiología , Femenino , Humanos , Ácido Láctico/farmacología , Masculino , Estimulación Luminosa , Psicofísica , Factores de Tiempo , Adulto JovenRESUMEN
There are several evidences indicating that an impairment in attention-executive functions is present in prodromal Alzheimer's disease and predict future global cognitive decline. In particular, the issue of temporal orienting of attention in patients with mild cognitive impairment (MCI) due to Alzheimer's disease has been overlooked. The present research aimed to explore whether subtle deficits of cortical activation are present in these patients early in the course of the disease. We studied the upper-alpha event-related synchronization/desynchronization phenomenon during a paradigm of temporal orientation of attention. MCI patients (n = 27) and healthy elderly controls (n = 15) performed a task in which periodically omitted tones had to be predicted and their virtual onset time had to be marked by pressing a button. Single-trial responses were measured, respectively, before and after the motor response. Then, upper-alpha responses were compared to upper-alpha power during eyes-closed resting state. The time course of the task was characterized by two different behavioral conditions: (1) a pre-event epoch, in which the subject awaited the virtual onset of the omitted tone, (2) a post-event epoch (after button pressing), in which the subject was in a post-motor response condition. The principal findings are: (1) during the waiting epoch, only healthy elderly had an upper-alpha ERD at the level of both temporal and posterior brain regions; (2) during the post-motor epoch, the aMCI patients had a weaker upper-alpha ERS on prefrontal regions; (3) only healthy elderly showed a laterality effect: (a) during the waiting epoch, the upper-alpha ERD was greater at the level of the right posterior-temporal lead; during the post-motor epoch, the upper alpha ERS was greater on the left prefrontal lead. The relevance of these findings is that the weaker upper-alpha response observed in aMCI patients is evident even if the accuracy of the behavioral performance (i.e., button pressing) is still spared. This abnormal upper-alpha response might represent an early biomarker of the attention-executive network impairment in MCI due to Alzheimer's disease.
Asunto(s)
Ritmo alfa/fisiología , Atención/fisiología , Disfunción Cognitiva/fisiopatología , Sincronización Cortical/fisiología , Estimulación Acústica , Anciano , Anciano de 80 o más Años , Estudios de Casos y Controles , Electroencefalografía , Función Ejecutiva , Femenino , Humanos , Masculino , Persona de Mediana Edad , Análisis Numérico Asistido por Computador , Desempeño Psicomotor , Tiempo de Reacción , Factores de TiempoRESUMEN
Blood levels of lactate and glucose were measured in 15 healthy male athletes with the purpose of evaluating possible correlation between their blood values and intensity and selectivity of attention, after a 30-min steady-state test performed at 60 and 80% of maximal oxygen consumption (VO2max). On the basis of the results, we conclude that, during aerobic exercise, a worsening of attentional capabilities does not occur unless there is an increase of blood lactate above 4 mmol/l.
Asunto(s)
Atención/fisiología , Glucemia/análisis , Ejercicio Físico/fisiología , Ácido Láctico/sangre , Humanos , Masculino , Adulto JovenRESUMEN
The influence of blood lactate on brainstem excitability was tested by using the blink reflex (BR) recovery cycle on 18 sprinters. Blood lactate was measured before maximal cycling, at the end, as well as 5 and 10 min after the exhaustion. Blood lactate was associated with a decrement of R2 whereas only small changes were observed after an intravenous infusion of lactate. It seems, therefore, that lactate influences BR mainly by acting at the cortical level.
Asunto(s)
Tronco Encefálico/fisiología , Ejercicio Físico/fisiología , Ácido Láctico/sangre , Adulto , Parpadeo/fisiología , Prueba de Esfuerzo , Humanos , MasculinoRESUMEN
We examined the hypothesis that the attention/executive deficits in mild cognitive impairment (MCI) due to Alzheimer's disease is associated to an abnormal cortical activation, revealed by the method of event-related synchronization/desynchronization (ERS/ERD) in the theta band during a paradigm of temporal orienting of attention. MCI patients (n = 25) and healthy elderly (HE) matched controls (n = 15) performed a task in which periodically omitted tones had to be predicted and their virtual onset time had to be marked by pressing a button. Single-trial theta responses were measured, respectively, before and after the motor response. Then, theta responses were compared to theta power during eyes closed resting state (ERD/ERS method).The temporal course of the task was characterized by two different behavioural conditions: (1) a pre-event epoch, in which the subject awaited the virtual onset of the omitted tone, (2) a post-event (after button pressing) epoch, in which the subject was in a post-motor response condition. The most important findings are summarized as follows: (1) in both groups, the pre-event epoch was characterized by theta ERS on temporal electrodes, but HE had a greater theta ERS compared to that of MCI group; (2) in both groups, during the post-motor condition, there was a theta ERS on prefrontal regions, and, also in this case, HE showed a greater theta enhancement compared to that of MCI patients; (3) HE showed evidence of lateralization: during the waiting epoch, theta ERS was dominant on the right posterior temporal lead (T6), whilst, during the post-motor epoch, theta ERS was greater on the left, as well as the midline prefrontal leads. Compared to the traditional neuropsychological measures for the episodic memory, these theta ERS indicators were less accurate in differentiating MCI patients from healthy elderly. The clinical relevance of these findings is that the weaker theta reactivity in MCI would indicate an early impairment in the temporal orienting of attention in the early stage of the clinical course of this neurodegenerative disease.
Asunto(s)
Disfunción Cognitiva/fisiopatología , Sincronización Cortical/fisiología , Ritmo Teta/fisiología , Anciano , Anciano de 80 o más Años , Mapeo Encefálico , Diagnóstico por Computador , Electroencefalografía , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas , Curva ROC , Tiempo de Reacción , DescansoRESUMEN
There is evidence that theta responses reflect cognitive performance: good performances are associated with a decrease in tonic theta power as well as an increase in phasic theta power. In the present study, both tonic and phasic theta activity were analysed in 22 patients with mild Alzheimer's disease (AD), and 16 healthy elderly controls. Single-trial theta power responses were evaluated by an active auditory oddball paradigm along an early poststimulus window (0-250 ms) and a late time window (250-500 ms), and then compared to prestimulus theta power during both target tone and standard tone processing. The main findings were: (1) in AD patients, there was an increased prestimulus theta power, as well as no significant poststimulus theta power increase upon both target and non-target stimulus processing; (2) in healthy aged controls, only during target tone processing, an enhancement of both early and late theta responses relative to the prestimulus baseline was found. Moreover, healthy controls had a frontal dominance of theta power. The results might indicate that, during target processing, theta response is not functionally sensitive in AD and cannot be involved in processing demands as efficiently as in healthy controls. From a psychophysiological point of view, this might suggest an impairment of attentional allocation resources. The psychological implications might be related to selective attention/working-memory impairment from the early stage of the disease. Our data confirm that both tonic and phasic theta are relevant indicators of cognitive performance: the lack of a phasic theta and an increase in tonic theta are congruous findings in cognitive decline. Another factor worth noting is that in AD patients theta response is not dominant at the frontal site (as observed in healthy controls), indicating a weaker frontal lobe network reactivity during stimulus processing.
Asunto(s)
Enfermedad de Alzheimer/fisiopatología , Corteza Cerebral/fisiopatología , Trastornos del Conocimiento/fisiopatología , Ritmo Teta/fisiología , Estimulación Acústica/métodos , Anciano , Anciano de 80 o más Años , Enfermedad de Alzheimer/diagnóstico , Trastornos del Conocimiento/diagnóstico , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
No information has yet been provided about the influence of blood lactate levels on the excitability of the cerebral cortex, in particular, of the motor cortex. The aim of the present study was to examine the effects of high blood lactate levels, induced with a maximal cycling or with an intravenous infusion, on motor cortex excitability. The study was carried out on 17 male athletes; all the subjects performed a maximal cycling test on a mechanically braked cycloergometer, whereas 6 of them were submitted to the intravenous infusion of a lactate solution (3 mg/kg in 1 min). Before the exercise or the injection, at the end, as well as 5 and 10 min after the conclusion, venous blood lactate was measured and excitability of the motor cortex was evaluated by using the transcranial magnetic stimulation. In both of these experimental conditions, it was observed that an increase of blood lactate is associated with a decrease of motor threshold, that is, an enhancement of motor cortex excitability. We conclude by hypothesizing that in the motor cortex the lactate could have a protective role against fatigue.
Asunto(s)
Potenciales Evocados Motores/fisiología , Ácido Láctico/sangre , Corteza Motora/fisiología , Análisis de Varianza , Glucemia/metabolismo , Electroencefalografía/métodos , Potenciales Evocados Motores/efectos de los fármacos , Ejercicio Físico/fisiología , Humanos , Ácido Láctico/farmacología , Masculino , Corteza Motora/efectos de los fármacos , Factores de Tiempo , Estimulación Magnética Transcraneal/métodos , Adulto JovenRESUMEN
The objective was to study whether repetitive transcranial magnetic stimulation (rTMS) of the motor cortex could induce modification of peripheral blood lactate values. Nineteen young healthy volunteers were included; during the study, all subjects were at rest, sitting on a comfortable armchair. The muscular activation was evaluated by continuous electromyographic record. TMS was performed by using a circular coil at the vertex. Resting motor threshold (rMT) was defined as the lowest TMS intensity able to induce motor responses of an amplitude >50 microV in the relaxed contralateral target muscle in approximately 50% of 20 consecutive stimuli. Venous blood lactate values were measured before, immediately after and 10 min after a single session of low frequencies (1Hz for 15 min) rTMS (LF rTMS) or high frequency (20 Hz for 15 min) rTMS (HF rTMS). As expected, LF rTMS induced a decrease of motor cortex excitability, whereas HF rTMS evoked an increase of motor cortex excitability. However, in the present investigation we observed that both conditions are associated to a significant increase of blood lactate. Since in our experimental conditions we can exclude a muscular production of lactate, the significant increment of peripheral blood lactate values, observed 10 min after the end of the rTMS session, is probably due to the crossing by brain-produced lactate of the blood-brain barrier.
Asunto(s)
Ácido Láctico/sangre , Corteza Motora/fisiología , Corteza Motora/efectos de la radiación , Estimulación Magnética Transcraneal , Adulto , Biofisica , Estimulación Eléctrica/métodos , Electromiografía/métodos , Potenciales Evocados Motores/fisiología , Humanos , Masculino , Músculo Esquelético/inervación , Músculo Esquelético/fisiología , Adulto JovenRESUMEN
The present study assessed auditory event-related potentials in patients with Alzheimer's disease (AD). Delta responses of 21 mild probable AD subjects according to NINCDS-ADRDA criteria, and 16 healthy elderly controls were evaluated by an active oddball paradigm. Averaged and single sweep potentials were analyzed during target tone processing. As far as time domain averaged event-related potentials (ERPs) are concerned, no significant group differences were observed for N100 and P200 components (both latency and amplitude); also, N200 and P300 amplitude did not differ between groups, whilst N200 and P300 latency were significantly prolonged in AD patients. Concerning delta frequency component of the averaged ERPs, no significant differences between groups were obtained for delta response amplitude as well as delta response topography (Fz, Cz, Pz). Analysis of delta responses was performed for single sweep maximal peak-to-peak amplitude. Significant between groups differences were revealed at the level of single sweep amplitude at the 3 midline sites (Fz, Cz, Pz), during target tone processing. In particular, the difference between healthy controls and AD subjects was at the level of stimulus-related delta amplitude changes: in all locations a significant enhancement of the delta response is recorded in healthy subjects (especially at the frontal location), whilst this delta reactivity was not detectable in AD patients. From a clinical point of view, the lack of delta reactivity might relate to a decision-making function impairment since mild Alzheimer's disease.