RESUMEN
BACKGROUND/IMPORTANCE: Dietary interventions, vitamins, and nutritional supplementation are playing an increasingly important role in the management of neuropathic pain. Current pharmacological treatments are poorly tolerated and ineffective in many cases. OBJECTIVE: This systematic review aims to study the efficacy of dietary interventions, vitamins, and nutritional supplementation in the management of chronic neuropathic pain in adults. EVIDENCE REVIEW: The review followed PRISMA guidelines and was registered with PROSPERO (#CRD42022300312). Ten databases and gray literature, including Embase.com, MEDLINE and Web of Science, were systematically searched using a combination of keywords and controlled vocabulary related to chronic neuropathic pain and oral non-pharmacological supplements. Studies on adult humans published between 2000 and 2021 were considered for inclusion. The Cochrane Handbook was used to assess risk of bias, and Grading of Recommendations Assessment, Development, and Evaluation was used to determine overall quality of evidence. FINDINGS: Forty studies were included in the final review, and results were categorized according to pain type including pain related to chemotherapy-induced peripheral neuropathy (CIPN, 22 studies, including 3 prospective cohorts), diabetic peripheral neuropathy (DPN, 13 studies, including 2 prospective), complex regional pain syndrome (CRPS-I, 3 studies, including 1 prospective), and other (2 studies, both RCT). The CIPN studies used various interventions including goshajinkigan (4 studies), vitamin E (5), vitamin B12 (3), glutamine (3), N-acetyl-cysteine (2), acetyl-l-carnitine (2), guilongtonluofang (1), ninjin'yoeito (1), alpha-lipoic acid (1), l-carnosine (1), magnesium and calcium (1), crocin (1), and antioxidants (1), with some studies involving multiple interventions. All CIPN studies involved varying cancers and/or chemotherapies, advising caution for generalizability of results. Interventions for DPN included alpha-lipoic acid (5 studies), vitamin B12 (3), acetyl-l-carnitine (3), vitamin E (1), vitamin D (2), and a low-fat plant-based diet (1). Vitamin C was studied to treat CRPS-I (3 studies, including 1 prospective). Magnesium (1) and St. John's wort (1) were studied for other or mixed neuropathologies. CONCLUSIONS: Based on the review, we cannot recommend any supplement use for the management of CIPN, although further research into N-acetyl-cysteine, l-carnosine, crocin, and magnesium is warranted. Acetyl-l-carnitine was found to be likely ineffective or harmful. Alpha-lipoic acid was not found effective. Studies with goshajinkigan, vitamin B12, vitamin E, and glutamine had conflicting results regarding efficacy, with one goshajinkigan study finding it harmful. Guilongtonluofang, ninjin'yoeito, and antioxidants showed various degrees of potential effectiveness. Regarding DPN, our review supports the use of alpha-lipoic acid, acetyl-l-carnitine, and vitamin D. The early use of vitamin C prophylaxis for the development of CRPS-I also seems promising. Further research is warranted to confirm these findings.
Asunto(s)
Carnosina , Síndromes de Dolor Regional Complejo , Neuralgia , Ácido Tióctico , Humanos , Adulto , Acetilcarnitina/uso terapéutico , Magnesio/uso terapéutico , Ácido Tióctico/uso terapéutico , Carnosina/uso terapéutico , Glutamina/uso terapéutico , Cisteína/uso terapéutico , Estudios Prospectivos , Suplementos Dietéticos , Vitaminas/uso terapéutico , Neuralgia/tratamiento farmacológico , Vitamina E/uso terapéutico , Ácido Ascórbico/uso terapéutico , Dieta , Antioxidantes/uso terapéutico , Vitamina B 12 , Vitamina D/uso terapéuticoRESUMEN
BACKGROUND: 100% soybean oil emulsions (SO100) are associated with poor docosahexaenoic acid (DHA) and arachidonic acid (ARA) status in extremely low birth weight (ELBW) infants. A multi-oil emulsion with 15% fish oil (FO15) contains more DHA and ARA than SO100. This study compares clinical outcomes, namely growth and fatty acids, in ELBW infants who received S0100 or FO15. METHODS: This observational study included ELBW infants born between 2014 and 2019 who received SO100 or FO15 for >7 days. Gas chromatography/mass spectrometry was used to measure erythrocyte fatty acids. RESULTS: The mean ± SD gestational age was 27 ± 3 and 26 ± 2 weeks for SO100 (n = 43) and FO15 (n = 43), respectively (P = 0.2). DHA (-0.3 ± 0.10% per week, P = 0.026, for FO15 vs -0.2 ± 0.05% per week, P < 0.001, for SO100) and ARA (-0.8 ± 0.21% per week for FO15 vs -0.9 ± 0.17% per week for SO100; P < 0.001 for both) declined in both groups with no difference between groups (P interaction > 0.7 for both). After controlling for days to reach full feeds, the mean difference in weight z score trajectories was similar (Est = -0.08; 95% CI, -0.82 to 0.04; P = 0.2), and SO100 was associated with a nonsignificant increased odds for cholestasis (odds ratio, 3.1; 95% CI, 0.96-10.2; P = 0.059). There was no difference in other clinical comorbidities. CONCLUSIONS: In comparison with ELBW infants who received SO100, infants who received FO15 still demonstrated a decline in DHA and ARA. Growth and other clinical outcomes were unchanged.
Asunto(s)
Aceites de Pescado , Nutrición Parenteral , Recién Nacido , Humanos , Emulsiones/química , Nutrición Parenteral/métodos , Recien Nacido Prematuro , Aceite de Soja , Ácidos Docosahexaenoicos , Ácido AraquidónicoRESUMEN
BACKGROUND: This study aimed to evaluate the association between complementary and alternative medicine (CAM) use and fear of cancer recurrence (FCR) among breast cancer survivors, using a validated multidimensional FCR-assessing instrument. Despite the debate over its medical effects, the use of CAM in breast cancer survivors is increasing. METHODS: We recruited 326 breast cancer survivors who had completed the primary cancer treatment. Information on CAM use was obtained using a self-administered questionnaire, and FCR was assessed using the Korean version of the FCR Inventory (FCRI). Multivariate linear regression analysis was performed to evaluate the association between CAM use and FCR. RESULTS: CAM users had higher total FCR scores than CAM non-users after covariate adjustment (CAM users: 74.6 vs. CAM non-users: 68.7; P=0.047). Among the FCRI subscales, CAM users showed higher coping strategy scores (CAM users: 22.3 vs. CAM non-users: 20.6; P=0.034) in the multivariable adjusted analysis. The use of multiple types of CAM was associated with increased FCR in a dose-dependent manner (P=0.002). CONCLUSION: Breast cancer survivors who used CAM had a higher FCR than CAM non-users. The dose-response relationship between the use of multiple types of CAM and FCR suggests that breast cancer survivors who use multiple types of CAM should be provided with appropriate psychological interventions to decrease FCR.
RESUMEN
BACKGROUND: Access to primary care was hindered by the coronavirus disease 2019 (COVID-19) pandemic. OBJECTIVE: Evaluate changes in health screening rates before and during the pandemic. DESIGN: Retrospective analysis of health maintenance and disease management screening rates among primary care patients before and during the pandemic. PARTICIPANTS: Over 150,000 patients of a large, academic health system. MAIN MEASURES: Six quality measures were analyzed: colon cancer, breast cancer, cervical cancer, diabetes Hgb A1C, diabetes eye, and diabetes nephropathy monitoring. Based on US Preventative Services Task Force screening guidelines, we determined which patients were due for at least one of the quality measures. We tracked completion rates during three time periods: pre-pandemic (January 1-March 3, 2020), stay-at-home (March 4-May 8, 2020), and phased reopening (May 9-July 8, 2020). Differences in quality measure completion rates were evaluated using mixed-effects logistic regression models. KEY RESULTS: Compared to pre-pandemic rates, completion of all health screenings declined during the stay-at-home period: mammograms (OR: 0.34; 95% CI: 0.31-0.37), cervical cancer (OR: 0.83; 95% CI: 0.76-0.91), colorectal cancer (OR: 0.25; 95% CI: 0.23-0.28), diabetes eye (OR: 0.34; 95% CI: 0.29-0.41), diabetes Hgb A1c (OR: 0.41; 95% CI: 0.37-0.46), and diabetes nephropathy (OR: 0.46, 95% CI: 0.41-0.53). During phased reopening, completion of all quality measures increased compared to the stay-at-home period, except for cervical cancer screening (OR: 0.83; 95% CI: 0.76-0.92). There was a persistent reduction in completion of all quality measures, except for diabetic nephropathy monitoring (OR: 0.99; 95% CI: 0.89-1.09), during phased reopening compared to pre-pandemic. CONCLUSIONS: Healthcare screening rates were reduced during the early part of the COVID-19 pandemic and did not fully recover to pre-pandemic rates by July 2020. Future research should aim to clarify the long-term impacts of delayed health screenings. New interventions should be considered for expanding remote preventative health services.
Asunto(s)
COVID-19 , Prestación Integrada de Atención de Salud , Neoplasias del Cuello Uterino , COVID-19/epidemiología , Detección Precoz del Cáncer , Femenino , Humanos , Pandemias/prevención & control , Atención Primaria de Salud , Indicadores de Calidad de la Atención de Salud , Estudios RetrospectivosRESUMEN
OBJECTIVE: To describe the incidence of systemic overlap and typical coronavirus disease 2019 (COVID-19) symptoms in healthcare personnel (HCP) following COVID-19 vaccination and association of reported symptoms with diagnosis of severe acute respiratory coronavirus virus 2 (SARS-CoV-2) infection in the context of public health recommendations regarding work exclusion. DESIGN: This prospective cohort study was conducted between December 16, 2020, and March 14, 2021, with HCP who had received at least 1 dose of either the Pfizer-BioNTech or Moderna COVID-19 vaccine. SETTING: Large healthcare system in New England. INTERVENTIONS: HCP were prompted to complete a symptom survey for 3 days after each vaccination. Reported symptoms generated automated guidance regarding symptom management, SARS-CoV-2 testing requirements, and work restrictions. Overlap symptoms (ie, fever, fatigue, myalgias, arthralgias, or headache) were categorized as either lower or higher severity. Typical COVID-19 symptoms included sore throat, cough, nasal congestion or rhinorrhea, shortness of breath, ageusia and anosmia. RESULTS: Among 64,187 HCP, a postvaccination electronic survey had response rates of 83% after dose 1 and 77% after dose 2. Report of ≥3 lower-severity overlap symptoms, ≥1 higher-severity overlap symptoms, or at least 1 typical COVID-19 symptom after dose 1 was associated with increased likelihood of testing positive. HCP with prior COVID-19 infection were significantly more likely to report severe overlap symptoms after dose 1. CONCLUSIONS: Reported overlap symptoms were common; however, only report of ≥3 low-severity overlap symptoms, at least 1 higher-severity overlap symptom, or any typical COVID-19 symptom were associated with infection. Work-related restrictions for overlap symptoms should be reconsidered.
Asunto(s)
COVID-19 , Prestación Integrada de Atención de Salud , Humanos , COVID-19/diagnóstico , COVID-19/epidemiología , COVID-19/prevención & control , SARS-CoV-2 , Prueba de COVID-19 , Estudios Prospectivos , Vacunas contra la COVID-19 , Vacuna nCoV-2019 mRNA-1273 , VacunaciónRESUMEN
BACKGROUND: Every day, we see more patients present to hospitals and clinics seeking gender-affirmation care to ameliorate the symptoms of gender dysphoria. However, to provide a multidisciplinary approach, it is important to offer an integrated clinical program that provides mental health assessment, endocrine therapy, physical therapy, research, and the full spectrum of surgical services devoted to transgender patients. This article describes our experience on building a specialized, multidisciplinary, academic state-of-the-art gender-affirmation program. METHODS: Herein, we describe the main and critical components on how to build a multidisciplinary academic gender-affirmation program. We share our lessons learned from this experience and describe how to overcome some of the obstacles during the process. RESULTS: Building a multidisciplinary academic gender-affirmation program requires an invested team, as each and every member is essential for feedback, referrals, and to improve patient's experience. Institutional support is essential and by far the most important component to overcome some of the obstacles during the process. Having all team members working under the same institution provides all the critical components needed to improve outcomes and patient satisfaction. In addition, the collection of prospective data with a well-structured research team will provide information needed to improve clinical services and standardize clinical protocols, while leaving space for innovation. CONCLUSIONS: This article describes the steps and experience needed to build a multidisciplinary holistic academic gender-affirmation program. We provide our lessons learned during the process that will help guide those who intend to start an academic gender-affirmation program.
RESUMEN
BACKGROUND: Pediatric integrative medicine (IM) includes the use of therapies not considered mainstream to help alleviate symptoms such as pain and anxiety. These therapies can be provided in the inpatient setting. METHODS: This 10-week study involved the integration of acupuncture, biofeedback, clinical hypnotherapy, guided imagery, meditation, and music therapy to address pain in children admitted to a large US children's hospital. RESULTS: Of 51 patients enrolled, 60% of the patients, 66% of their mothers, and 56% of their fathers used CAM (complementary and alternative medicine) in the preceding 1 year. Although 51 families requested integrative therapies, only 18 patients received them because of inadequate provider availability. All recorded pain scores improved with integrative therapies. One parent reported a possible side effect of irritability in the child after clinical hypnotherapy while 5 children reported opiate side effects. All participating families interviewed responded that IM services helped their child's pain and helped their child's mood, and that our hospital should have a permanent IM consult service. CONCLUSION: Integrative therapies can be helpful to address pain without significant side effects. Further studies are needed to investigate the integration, cost, and cost-effectiveness of integrative therapies in pediatric hospitals.
Asunto(s)
Niño Hospitalizado , Terapias Complementarias , Medicina Integrativa/métodos , Manejo del Dolor/métodos , Pediatría/métodos , Adolescente , Niño , Preescolar , Femenino , Hospitales Pediátricos , Humanos , Masculino , Dimensión del DolorRESUMEN
RATIONALE: Adolescent intermittent ethanol exposure (AIE) produces lasting, sex-specific social anxiety-like alterations in male, but not female rats. Oxytocin (OXT) and vasopressin (AVP) brain systems play opposite roles in regulating social preference/avoidance, with OXT increasing approach to, and AVP increasing avoidance of social stimuli. OBJECTIVES: To test the hypothesis that social anxiety-like alterations seen in adult males after AIE are associated with a shift in the balance between OXT and AVP toward AVP, effectiveness of pharmacological activation of the OXT system and blockade of endogenous activity at AVP receptors for reversing AIE-induced social anxiety-like alterations was assessed, along with examination of the effects of AIE on OXT, vasopressin V1a, and V1b receptor (OXT-R, V1a-R, and V1b-R) surface expression in the hypothalamus. METHODS: Sprague-Dawley male and female rats were given 4 g/kg ethanol (AIE) or water intragastrically every 48 h for a total of 11 exposures during postnatal days (P) 25-45. On P70-72, animals were given a social interaction test following administration of a selective OXT-R agonist WAY-267464, selective V1a-R antagonist SR-49059, or V1b-R antagonist SSR-149415, and hypothalamic tissue was collected. RESULTS: Social anxiety-like behavior was induced by AIE in males but not females, and was selectively reversed by the selective OXT-R agonist and V1b-R antagonist, but not V1a-R antagonist. AIE was also found to decrease OXT-R, but increase V1b-R neuronal surface expression relative to water-exposed controls in the hypothalamus of males, but not females. CONCLUSIONS: These findings demonstrate that AIE induces changes in OXT-R and AVP-R surface expression in the hypothalamus along with social anxiety-like alterations in male rats. These social anxiety-like alterations can be reversed either by activation of the OXT system or by suppression of the AVP system, data that support the hypothesis that social anxiety-like alterations induced by adolescent alcohol exposure in male rats are associated at least in part with an OXT/AVP imbalance.
Asunto(s)
Ansiedad/tratamiento farmacológico , Etanol/farmacología , Oxitocina/farmacología , Conducta Social , Vasopresinas/farmacología , Animales , Ansiedad/inducido químicamente , Modelos Animales de Enfermedad , Etanol/efectos adversos , Femenino , Hipotálamo/metabolismo , Masculino , Ratas , Ratas Sprague-Dawley , Receptores de Vasopresinas/metabolismo , Factores SexualesRESUMEN
Generalized morphea is associated with epoxy resin vapors and is characterized by the development of lesions shortly after exposure. Morphea presenting along with eosinophilic fasciitis (EF), or morphea/EF overlap, is rare and an indicator of poor prognosis and resistance to treatment. Here we present a case of generalized morphea/EF overlap linked to epoxy exposure. Our patient received multiple therapies-ultraviolet A1 phototherapy, prednisone, methotrexate, azathioprine, mycophenolate mofetil, cyclophosphamide, cyclosporine, and rituximab-none of which led to a significant response. The refractory nature of this disease warrants vigilance in its association with epoxy exposure.
RESUMEN
Icosapent ethyl (Vascepa®) is a high-purity ethyl ester of eicosapentaenoic acid (EPA) that is de-esterified to EPA following oral administration. Both EPA and docosahexaenoic acid (DHA) are long-chain omega-3 fatty acids that have been associated with triglyceride (TG)-lowering. However, DHA has been associated with increased low-density lipoprotein cholesterol (LDL-C) levels. Icosapent ethyl contains ≥96 % of the EPA ethyl ester, does not contain DHA, and is approved in the USA for use as an adjunct to diet to lower TG levels in adult patients with severe (≥500 mg/dL [≥5.65 mmol/L]) hypertriglyceridemia. In a pivotal phase III trial, oral icosapent ethyl 4 g/day significantly decreased the placebo-corrected median TG levels by 33.1 %. It did not increase LDL-C, had favorable effects on other lipid parameters, and had a tolerability profile similar to that of placebo. Therefore, icosapent ethyl is an effective and well-tolerated agent for the treatment of severe hypertriglyceridemia in adults.
Asunto(s)
Ácido Eicosapentaenoico/análogos & derivados , Hipertrigliceridemia/tratamiento farmacológico , Hipolipemiantes/uso terapéutico , Administración Oral , Adulto , Animales , LDL-Colesterol/sangre , Ensayos Clínicos Fase III como Asunto , Ácido Eicosapentaenoico/administración & dosificación , Ácido Eicosapentaenoico/efectos adversos , Ácido Eicosapentaenoico/uso terapéutico , Humanos , Hipertrigliceridemia/fisiopatología , Hipolipemiantes/administración & dosificación , Hipolipemiantes/efectos adversos , Índice de Severidad de la Enfermedad , Triglicéridos/sangreRESUMEN
Head direction (HD) cells, found in the rodent Papez circuit, are thought to form the neural circuitry responsible for directional orientation. Because NMDA transmission has been implicated in spatial tasks requiring directional orientation, we sought to determine if the NMDA antagonist dizocilpine (MK-801) would disrupt the directional signal carried by the HD network. Anterior thalamic HD cells were isolated in female Long-Evans rats and initially monitored for baseline directional activity while the animals foraged in a familiar enclosure. The animals were then administered MK-801 at a dose of .05 mg/kg or 0.1 mg/kg, or isotonic saline, and cells were re-examined for changes in directional specificity and landmark control. While the cells showed no changes in directional specificity and landmark control following administration of saline or the lower dose of MK-801, the higher dose of MK-801 caused a dramatic attenuation of the directional signal, characterized by decreases in peak firing rates, signal to noise, and directional information content. While the greatly attenuated directional specificity of cells in the high dose condition usually remained stable relative to the landmarks within the recording enclosure, a few cells in this condition exhibited unstable preferred directions within and between recording sessions. Our results are discussed relative to the possibility that the findings explain the effects of MK-801 on the acquisition and performance of spatial tasks.
Asunto(s)
Maleato de Dizocilpina/toxicidad , Antagonistas de Aminoácidos Excitadores/toxicidad , Neuronas/efectos de los fármacos , Orientación/efectos de los fármacos , Trastornos de la Percepción/inducido químicamente , Tálamo/citología , Potenciales de Acción/efectos de los fármacos , Animales , Relación Dosis-Respuesta a Droga , Femenino , Movimiento/efectos de los fármacos , Vías Nerviosas/efectos de los fármacos , Vías Nerviosas/fisiología , Ratas , Ratas Long-Evans , Conducta Espacial/efectos de los fármacosRESUMEN
Dietary restriction (DR) can extend lifespan and reduce disease burden across a wide range of animals and yeast but the mechanisms mediating these remarkably protective effects remain to be elucidated despite extensive efforts. Although it has generally been assumed that protective effects of DR are cell-autonomous, there is considerable evidence that many whole-body responses to nutritional state, including DR, are regulated by nutrient-sensing neurons. In this review, we explore the hypothesis that nutrient sensing neurons in the ventromedial hypothalamus hierarchically regulate the protective responses of dietary restriction. We describe multiple peripheral responses that are hierarchically regulated by the hypothalamus and we present evidence for non-cell autonomous signaling of dietary restriction gathered from a diverse range of models including invertebrates, mammalian cell culture, and rodent studies.
Asunto(s)
Envejecimiento/fisiología , Restricción Calórica , Hipotálamo/fisiología , Longevidad/fisiología , Animales , Neuronas/fisiologíaRESUMEN
Previous studies have proposed roles for hypothalamic reactive oxygen species (ROS) in the modulation of circuit activity of the melanocortin system. Here we show that suppression of ROS diminishes pro-opiomelanocortin (POMC) cell activation and promotes the activity of neuropeptide Y (NPY)- and agouti-related peptide (AgRP)-co-producing (NPY/AgRP) neurons and feeding, whereas ROS-activates POMC neurons and reduces feeding. The levels of ROS in POMC neurons were positively correlated with those of leptin in lean and ob/ob mice, a relationship that was diminished in diet-induced obese (DIO) mice. High-fat feeding resulted in proliferation of peroxisomes and elevated peroxisome proliferator-activated receptor γ (PPAR-γ) mRNA levels within the hypothalamus. The proliferation of peroxisomes in POMC neurons induced by the PPAR-γ agonist rosiglitazone decreased ROS levels and increased food intake in lean mice on high-fat diet. Conversely, the suppression of peroxisome proliferation by the PPAR antagonist GW9662 increased ROS concentrations and c-fos expression in POMC neurons. Also, it reversed high-fat feeding-triggered elevated NPY/AgRP and low POMC neuronal firing, and resulted in decreased feeding of DIO mice. Finally, central administration of ROS alone increased c-fos and phosphorylated signal transducer and activator of transcription 3 (pStat3) expression in POMC neurons and reduced feeding of DIO mice. These observations unmask a previously unknown hypothalamic cellular process associated with peroxisomes and ROS in the central regulation of energy metabolism in states of leptin resistance.
Asunto(s)
Metabolismo Energético/fisiología , Hipotálamo/metabolismo , Leptina/metabolismo , Neuronas/metabolismo , PPAR gamma/metabolismo , Peroxisomas/fisiología , Especies Reactivas de Oxígeno/metabolismo , Proteína Relacionada con Agouti/metabolismo , Anilidas/farmacología , Animales , Línea Celular , Ingestión de Alimentos/fisiología , Electrofisiología , Proteínas Fluorescentes Verdes , Hipotálamo/citología , Ratones , Ratones Obesos , Neuropéptido Y/metabolismo , PPAR gamma/antagonistas & inhibidores , Reacción en Cadena de la Polimerasa , Proopiomelanocortina/metabolismoRESUMEN
Leukemia inhibitory factor (LIF), a neuropoietic cytokine, has been implicated in the control of neuronal development. We previously reported that LIF plays a critical role in regulating the terminal differentiation of olfactory sensory neurons (OSNs). Here, we demonstrate that LIF plays a complementary role in supporting the survival of immature OSNs. Mature OSNs express LIF, which may be elaborated in a paracrine manner to influence adjacent neurons. LIF null mice display more apoptotic immature neurons than do their wild-type littermates. LIF treatment of dissociated OSNs in vitro significantly reduces the apoptosis of immature OSNs. Double immunocytochemical analysis indicates that the survival of immature OSNs is dependent on the presence of LIF. LIF activates the phosphoinositide 3-kinase (PI3K) pathways and induces the expression of the antiapoptotic molecule Bcl-2 in OSNs, whereas inhibition of the PI3K pathway blocks LIF-dependent OSN survival and Bcl-2 induction. Thus, LIF plays a central role in maintaining the size and integrity of the population of immature neurons within the olfactory epithelium; this population is critical to the rapid recovery of olfactory function after injury. LIF may play a similar role elsewhere in the CNS and thus be important for manipulation of stem cell populations for therapeutic interventions.
Asunto(s)
Supervivencia Celular/fisiología , Factor Inhibidor de Leucemia/metabolismo , Neuronas Receptoras Olfatorias/fisiología , Fosfatidilinositol 3-Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Animales , Apoptosis/fisiología , Western Blotting , Células Cultivadas , Cromonas/farmacología , Activación Enzimática , Inhibidores Enzimáticos/farmacocinética , Inmunohistoquímica , Etiquetado Corte-Fin in Situ , Factor Inhibidor de Leucemia/genética , Masculino , Ratones , Ratones Noqueados , Morfolinas/farmacología , Mucosa Olfatoria/citología , ARN Mensajero/metabolismo , Transducción de SeñalRESUMEN
Hydrolysis of acetylcholine catalyzed by acetylcholinesterase (AChE), one of the most efficient enzymes in nature, occurs at the base of a deep and narrow active center gorge. At the entrance of the gorge, the peripheral anionic site provides a binding locus for allosteric ligands, including substrates. To date, no structural information on substrate entry to the active center from the peripheral site of AChE or its subsequent egress has been reported. Complementary crystal structures of mouse AChE and an inactive mouse AChE mutant with a substituted catalytic serine (S203A), in various complexes with four substrates (acetylcholine, acetylthiocholine, succinyldicholine, and butyrylthiocholine), two non-hydrolyzable substrate analogues (m-(N,N,N-trimethylammonio)-trifluoroacetophenone and 4-ketoamyltrimethylammonium), and one reaction product (choline) were solved in the 2.05-2.65-A resolution range. These structures, supported by binding and inhibition data obtained on the same complexes, reveal the successive positions and orientations of the substrates bound to the peripheral site and proceeding within the gorge toward the active site, the conformations of the presumed transition state for acylation and the acyl-enzyme intermediate, and the positions and orientations of the dissociating and egressing products. Moreover, the structures of the AChE mutant in complexes with acetylthiocholine and succinyldicholine reveal additional substrate binding sites on the enzyme surface, distal to the gorge entry. Hence, we provide a comprehensive set of structural snapshots of the steps leading to the intermediates of catalysis and the potential regulation by substrate binding to various allosteric sites at the enzyme surface.