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BACKGROUND: Hip fractures are prevalent among older people, often leading to reduced mobility, muscle loss, and bone density decline. Malnutrition exacerbates the prognosis post surgery. This study aimed to evaluate the impact of a 12-week regimen of a high-calorie, high-protein oral supplement with ß-hydroxy-ß-methylbutyrate (HC-HP-HMB-ONS) on nutritional status, daily activities, and compliance in malnourished or at-risk older patients with hip fractures receiving standard care. SUBJECTS AND METHODS: A total of 270 subjects ≥75 years of age, residing at home or in nursing homes, malnourished or at risk of malnutrition, and post hip fracture surgery, received HC-HP-HMB-ONS for 12 weeks. Various scales and questionnaires assessed outcomes. RESULTS: During the 12 weeks of follow-up, 82.8% consumed ≥75% of HC-HP-HMB-ONS. By week 12, 62.4% gained or maintained weight (+0.3 kg), 29.2% achieved normal nutritional status (mean MNA score +2.8), and 46.8% improved nutritional status. Biochemical parameters improved significantly. Subjects reported good tolerability (mean score 8.5/10), with 87.1% of healthcare providers concurring. CONCLUSIONS: The administration of HC-HP-HMB-ONS markedly enhanced nutritional status and biochemical parameters in older hip-fracture patients, with high compliance and tolerability. Both patients and healthcare professionals expressed satisfaction with HC-HP-HMB-ONS.
Assuntos
Suplementos Nutricionais , Fraturas do Quadril , Desnutrição , Estado Nutricional , Valeratos , Humanos , Idoso , Masculino , Feminino , Estudos Prospectivos , Idoso de 80 Anos ou mais , Desnutrição/etiologia , Valeratos/administração & dosagem , Dieta Rica em Proteínas , Administração Oral , Ingestão de Energia , Proteínas Alimentares/administração & dosagem , Resultado do TratamentoRESUMO
Today, type 2 diabetes mellitus (T2DM) and skeletal muscle atrophy (SMA) have become increasingly common occurrences. Whether the onset of T2DM increases the risk of SMA or vice versa has long been under investigation. Both conditions are associated with negative changes in skeletal muscle health, which can, in turn, lead to impaired physical function, a lowered quality of life, and an increased risk of mortality. Poor nutrition can exacerbate both T2DM and SMA. T2DM and SMA are linked by a vicious cycle of events that reinforce and worsen each other. Muscle insulin resistance appears to be the pathophysiological link between T2DM and SMA. To explore this association, our review (i) compiles evidence on the clinical association between T2DM and SMA, (ii) reviews mechanisms underlying biochemical changes in the muscles of people with or at risk of T2DM and SMA, and (iii) examines how nutritional therapy and increased physical activity as muscle-targeted treatments benefit this population. Based on the evidence, we conclude that effective treatment of patients with T2DM-SMA depends on the restoration and maintenance of muscle mass. We thus propose that regular intake of key functional nutrients, along with guidance for physical activity, can help maintain euglycemia and improve muscle status in all patients with T2DM and SMA.
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Diabetes Mellitus Tipo 2 , Humanos , Qualidade de Vida , Atrofia Muscular/etiologia , Músculo Esquelético , Exercício FísicoRESUMO
BACKGROUND: Low-calorie diets, high in protein and low in carbohydrates, are commonly recommended for patients with pre-diabetes and type 2 diabetes. The objective of this study was to carry out a cost-benefit analysis (CBA) of a low-calorie versus a standard diet from the perspective of the Saudi Arabian health system. METHODS: The CBA compares costs and benefits of the two diet strategies over a 1-year time horizon. Costs included diet and diabetes treatment-related resources while benefits were measured in terms of the costs of diabetes complications avoided. Data on costs and benefits were collected from published literature and subject matter experts. Incremental costs were estimated as the cost difference between low-calorie and standard diet. Incremental benefits were estimated as cost difference from medical complications when following a low-calorie or standard diet. The incremental absolute cost-benefit ratio was calculated to show the difference between the costs and benefits of the low-calorie diet. Incremental relative cost-benefit ratio was calculated to show the cost per dollar of benefit obtained. Monte Carlo simulation modeled variability in outcomes due to variation in costs and uncertainty of diabetes complications. RESULTS: The 1 year cost of standard diet was US$2515 ± 156 compared to US$2469 ± 107 per patient for a low-calorie diet. Incremental benefit is estimated at US$21,438 ± 7367 per patient. The estimated incremental absolute cost-benefit ratio was US$ - 21,360 establishing that benefits are greater than costs, while the estimated incremental relative cost-benefit ratio is 0.0037, establishing that benefits are 270 times greater than costs. CONCLUSION: The low-calorie diet was the dominant strategy compared to the standard diet in modeled scenarios. These findings highlight the importance of a low-calorie diet as part of diabetes management programs for outpatients with type 2 diabetes.
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This is a retrospective study of data from clinical practice to observe the effect of a high-calorie, high-protein oral nutritional supplement (ONS) with ß-hydroxy-ß-methylbutyrate (HMB) on nutritional status, body weight, and muscle-related parameters in 283 adult patients with or at risk of malnutrition under standard of care, 63% being cancer patients. They were recommended to increase physical activity and energy and protein intake from regular diet plus two servings per day of a specialized ONS enriched with HMB or standard ONS for up to 6 months. Dietary records, adherence and tolerance to ONS, nutritional status, body composition, handgrip strength, and blood analysis at the beginning and the end of the intervention were recorded. This program improved nutritional status from 100% malnourished or at risk of malnutrition at baseline to 80% well-nourished at final visit. It also increased body weight by 3.6-3.8 kg, fat-free mass by 0.9 to 1.3 kg, and handgrip strength by 4.7 to 6.2 kg. In a subgroup of patients (n = 43), phase angle (PhA), and body cell mass (BCM) increased only in the patients receiving the ONS enriched with HMB (0.95 (0.13) vs. -0.36 (0.4), and 2.98 (0.5) vs. -0.6 (1.5) kg, mean difference (SE) from baseline for PhA and BCM, respectively), suggesting the potential efficacy of this supplement on muscle health.
Assuntos
Composição Corporal/efeitos dos fármacos , Proteínas Alimentares/administração & dosagem , Suplementos Nutricionais , Ingestão de Alimentos/fisiologia , Ingestão de Energia/fisiologia , Desnutrição/metabolismo , Fenômenos Fisiológicos da Nutrição/fisiologia , Estado Nutricional/efeitos dos fármacos , Valeratos/administração & dosagem , Vitamina D/administração & dosagem , Administração Oral , Peso Corporal/efeitos dos fármacos , Feminino , Força da Mão , Humanos , Masculino , Desnutrição/dietoterapia , Desnutrição/etiologia , Pessoa de Meia-Idade , Neoplasias/complicações , Estudos Retrospectivos , Fatores de Tempo , Valeratos/farmacologia , Vitamina D/farmacologiaRESUMO
OBJECTIVE: The aim of this study was to compare the metabolic benefits of diabetes-specific formulas (DSF) high in monounsaturated fatty acids (MUFA) with standard formulas (STDF) in adult patients with type 1, type 2 diabetes or stress-induced hyperglycaemia. RESEARCH DESIGN AND METHODS: A systematic review and meta-analysis were conducted through a literature search using different electronic databases from the index date to December 2018. We included randomised controlled trials that assessed the health benefits of high MUFA DSF vs STDF. Included outcomes were glycaemic control, lipid metabolism and tolerance. Effect sizes were calculated as standardised mean differences (SMDs) (<0.4 were considered small, 0.4-0.7 moderate and >0.7 large). This systematic review was registered as CRD42018108931 on Prospero. RESULTS: Of 385 references reviewed, 18 studies involving 845 adults met our inclusion criteria and contributed to the meta-analysis. Use of a high MUFA DSF compared with a STDF was associated with a statistically significant decrease in peak of postprandial glucose [SMD -1.53, 95% confidence interval (CI) -2.44 to -0.61], incremental glucose response (SMD -1.19, 95% CI -1.71 to -0.68), area under the curve of plasma insulin (SMD -0.65, 95% CI -1.03 to -0.26), mean blood glucose level (SMD -0.41, 95% CI -0.63 to -0.19), glycosylated haemoglobin (HbA1c) change (SMD -0.63, 95% CI -1.21 to -0.05), glucose variability (SMD -0.93, -1.55 to -0.31), mean administered insulin dose (SMD -0.49, 95% CI -0.85 to -0.14), mean blood triglycerides (SMD -0.34, 95% CI -0.65 to -0.03) and increase of mean blood high-density lipoproteins (SMD +0.42, 95% CI 0.08 to 0.76). Non-significant differences were found for tolerance [odds ratio (OR) 0.95, 95% CI 0.87 to 1.05]. CONCLUSIONS: This meta-analysis shows that a DSF (oral supplements and tube feeds) high in MUFAs can improve glucose control and metabolic risk factors among patients with diabetes or stress-induced hyperglycaemia compared with a STDF.
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Diabetes Mellitus Tipo 1/dietoterapia , Diabetes Mellitus Tipo 2/dietoterapia , Dieta para Diabéticos/métodos , Ácidos Graxos Monoinsaturados/administração & dosagem , Alimentos Formulados , Hiperglicemia/dietoterapia , Glicemia/metabolismo , Diabetes Mellitus Tipo 1/sangue , Diabetes Mellitus Tipo 2/sangue , Suplementos Nutricionais , Nutrição Enteral , Hemoglobinas Glicadas/metabolismo , Controle Glicêmico/métodos , Humanos , Hiperglicemia/sangue , Insulina/sangue , Metabolismo dos Lipídeos , Período Pós-Prandial , Ensaios Clínicos Controlados Aleatórios como AssuntoRESUMO
Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid involved in numerous physiological and pathophysiological processes. We have previously reported a S1P-induced nocifensive response in mice by excitation of sensory neurons via activation of an excitatory chloride current. The underlying molecular mechanism for the S1P-induced chloride conductance remains elusive. In the present study, we identified two CLCN voltage-gated chloride channels, CLCN3 and CLCN5, which mediated a S1P-induced excitatory Cl- current in sensory neurons by combining RNA-seq, adenovirus-based gene silencing and whole-cell electrophysiological voltage-clamp recordings. Downregulation of CLCN3 and CLCN5 channels by adenovirus-mediated delivery of shRNA dramatically reduced S1P-induced Cl- current and membrane depolarization in sensory neurons. The mechanism of S1P-induced activation of the chloride current involved Rho GTPase but not Rho-associated protein kinase. Although S1P-induced potentiation of TRPV1-mediated ionic currents also involved Rho-dependent process, the lack of correlation of the S1P-activated Cl- current and the potentiation of TRPV1 by S1P suggests that CLCN3 and CLCN5 are necessary components for S1P-induced excitatory Cl- currents but not for the amplification of TRPV1-mediated currents in sensory neurons. This study provides a novel mechanistic insight into the importance of bioactive sphingolipids in nociception.
RESUMO
The bioactive lipid sphingosine-1-phosphate (S1P) is an important regulator in the nervous system. Here, we explored the role of S1P and its receptors in vitro and in preclinical models of peripheral nerve regeneration. Adult sensory neurons and motor neuron-like cells were exposed to S1P in an in vitro assay, and virtually all neurons responded with a rapid retraction of neurites and growth cone collapse which were associated with RhoA and ROCK activation. The S1P1 receptor agonist SEW2871 neither activated RhoA or neurite retraction, nor was S1P-induced neurite retraction mitigated in S1P1-deficient neurons. Depletion of S1P3 receptors however resulted in a dramatic inhibition of S1P-induced neurite retraction and was on the contrary associated with a significant elongation of neuronal processes in response to S1P. Opposing responses to S1P could be observed in the same neuron population, where S1P could activate S1P1 receptors to stimulate elongation or S1P3 receptors and retraction. S1P was, for the first time in sensory neurons, linked to the phosphorylation of collapsin response-mediated protein-2 (CRMP2), which was inhibited by ROCK inhibition. The improved sensory recovery after crush injury further supported the relevance of a critical role for S1P and receptors in fine-tuning axonal outgrowth in peripheral neurons.
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As people age they become increasingly susceptible to chronic and extremely debilitating brain diseases. The precise cause of the neuronal degeneration underlying these disorders, and indeed normal brain ageing remains however elusive. Considering the limits of existing preventive methods, there is a desire to develop effective and safe strategies. Growing preclinical and clinical research in healthy individuals or at the early stage of cognitive decline has demonstrated the beneficial impact of nutrition on cognitive functions. The present review is the most recent in a series produced by the Nutrition and Mental Performance Task Force under the auspice of the International Life Sciences Institute Europe (ILSI Europe). The latest scientific advances specific to how dietary nutrients and non-nutrient may affect cognitive ageing are presented. Furthermore, several key points related to mechanisms contributing to brain ageing, pathological conditions affecting brain function, and brain biomarkers are also discussed. Overall, findings are inconsistent and fragmented and more research is warranted to determine the underlying mechanisms and to establish dose-response relationships for optimal brain maintenance in different population subgroups. Such approaches are likely to provide the necessary evidence to develop research portfolios that will inform about new dietary recommendations on how to prevent cognitive decline.
Assuntos
Envelhecimento , Transtornos Cognitivos , Dieta Saudável , Envelhecimento/fisiologia , Envelhecimento/psicologia , Encéfalo/fisiologia , Cognição/fisiologia , Transtornos Cognitivos/dietoterapia , Transtornos Cognitivos/fisiopatologia , Transtornos Cognitivos/prevenção & controle , Humanos , Degeneração Neural/prevenção & controle , Necessidades Nutricionais , Valor Nutritivo/fisiologiaRESUMO
The expression and function of TRPV1 are influenced by its interaction with cellular proteins. Here, we identify Whirlin, a cytoskeletal PDZ-scaffold protein implicated in hearing, vision and mechanosensory transduction, as an interacting partner of TRPV1. Whirlin associates with TRPV1 in cell lines and in primary cultures of rat nociceptors. Whirlin is expressed in 55% of mouse sensory C-fibers, including peptidergic and non-peptidergic nociceptors, and co-localizes with TRPV1 in 70% of them. Heterologous expression of Whirlin increased TRPV1 protein expression and trafficking to the plasma membrane, and promoted receptor clustering. Silencing Whirlin expression with siRNA or blocking protein translation resulted in a concomitant degradation of TRPV1 that could be prevented by inhibiting the proteasome. The degradation kinetics of TRPV1 upon arresting protein translation mirrored that of Whirlin in cells co-expressing both proteins, suggesting a parallel degradation mechanism. Noteworthy, Whirlin expression significantly reduced TRPV1 degradation induced by prolonged exposure to capsaicin. Thus, our findings indicate that Whirlin and TRPV1 are associated in a subset of nociceptors and that TRPV1 protein stability is increased through the interaction with the cytoskeletal scaffold protein. Our results suggest that the WhirlinTRPV1 complex may represent a novel molecular target and its pharmacological disruption might be a therapeutic strategy for the treatment of peripheral TRPV1-mediated disorders.
Assuntos
Regulação da Expressão Gênica/fisiologia , Proteínas de Membrana/metabolismo , Complexos Multiproteicos/metabolismo , Nociceptores/metabolismo , Canais de Cátion TRPV/biossíntese , Animais , Células Cultivadas , Proteínas de Membrana/genética , Camundongos , Complexos Multiproteicos/genética , Nociceptores/citologia , Complexo de Endopeptidases do Proteassoma/genética , Complexo de Endopeptidases do Proteassoma/metabolismo , Estabilidade Proteica , Proteólise , RNA Interferente Pequeno , Ratos , Ratos Wistar , Canais de Cátion TRPV/genéticaRESUMO
OBJECTIVE: Diabetes during gestation is one of the most common pregnancy complications associated with adverse health effects for the mother and the child. Maternal diabetes has been proposed to negatively affect the cognitive abilities of the child, but experimental research assessing its impact is conflicting. The main aim of our study was to compare the cognitive function in children of diabetic and healthy pregnant women. METHODS: A systematic review and meta-analysis was conducted through a literature search using different electronic databases from the index date to January 31, 2015. We included studies that assessed the cognitive abilities in children (up to 14 years) of diabetic and non-diabetic mothers using standardized and validated neuropsychological tests. RESULTS: Of 7,698 references reviewed, 12 studies involving 6,140 infants met our inclusion criteria and contributed to meta-analysis. A random effect model was used to compute the standardized mean differences and 95% confidence interval (CI) were calculated. Infants (1-2 years) of diabetic mothers had significantly lower scores of mental and psychomotor development compared to control infants. The effect size for mental development was -0.41 (95% CI -0.59, -0.24; p<0.0001) and for psychomotor development was -0.31 (95% CI -0.55, -0.07; p = 0.0125) with non-significant heterogeneity. Diabetes during pregnancy could be associated with decreased intelligence quotient scores in school-age children, although studies showed significant heterogeneity. CONCLUSION: The association between maternal diabetes and deleterious effects on mental/psychomotor development and overall intellectual function in the offspring must be taken with caution. Results are based on observational cohorts and a direct causal influence of intrauterine hyperglycemia remains uncertain. Therefore, more trials that include larger populations are warranted to elucidate whether gestational diabetes mellitus (GDM) has a negative impact on offspring central nervous system (CNS).
Assuntos
Desenvolvimento Infantil , Cognição , Diabetes Gestacional/epidemiologia , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Inteligência , Competência Mental , Gravidez , Desempenho PsicomotorRESUMO
Clinical pain, as a consequence of inflammation or injury of peripheral organs (inflammatory pain) or nerve injury (neuropathic pain), represents a serious public health issue. Treatment of pain-related suffering requires knowledge of how pain signals are initially interpreted and subsequently transmitted and perpetuated. To limit duration and intensity of pain, inhibitory signals participate in pain perception. Cortistatin is a cyclic-neuropeptide that exerts potent inhibitory actions on cortical neurons and immune cells. Here, we found that cortistatin is a natural analgesic component of the peripheral nociceptive system produced by peptidergic nociceptive neurons of the dorsal root ganglia in response to inflammatory and noxious stimuli. Moreover, cortistatin is produced by GABAergic interneurons of deep layers of dorsal horn of spinal cord. By using cortistatin-deficient mice, we demonstrated that endogenous cortistatin critically tunes pain perception in physiological and pathological states. Furthermore, peripheral and spinal injection of cortistatin potently reduced nocifensive behavior, heat hyperalgesia and tactile allodynia in experimental models of clinical pain evoked by chronic inflammation, surgery and arthritis. The analgesic effects of cortistatin were independent of its anti-inflammatory activity and directly exerted on peripheral and central nociceptive terminals via Gαi-coupled somatostatin-receptors (mainly sstr2) and blocking intracellular signaling that drives neuronal plasticity including protein kinase A-, calcium- and Akt/ERK-mediated release of nociceptive peptides. Moreover, cortistatin could modulate, through its binding to ghrelin-receptor (GHSR1), pain-induced sensitization of secondary neurons in spinal cord. Therefore, cortistatin emerges as an anti-inflammatory factor with potent analgesic effects that offers a new approach to clinical pain therapy, especially in inflammatory states.
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Analgésicos/uso terapêutico , Neuropeptídeos/metabolismo , Dor/tratamento farmacológico , Animais , Anti-Inflamatórios não Esteroides/uso terapêutico , Células Cultivadas , Modelos Animais de Doenças , Vias de Administração de Medicamentos , Feminino , Gânglios Espinais/citologia , Inflamação/complicações , Inflamação/tratamento farmacológico , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Atividade Motora/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Neuropeptídeos/deficiência , Nitrobenzenos/uso terapêutico , Dor/etiologia , Dor/genética , Medição da Dor , Limiar da Dor/efeitos dos fármacos , Medula Espinal/citologia , Sulfonamidas/uso terapêutico , Fatores de TempoRESUMO
The biolipid sphingosine-1-phosphate (S1P) is an essential modulator of innate immunity, cell migration, and wound healing. It is released locally upon acute tissue injury from endothelial cells and activated thrombocytes and, therefore, may give rise to acute post-traumatic pain sensation via a yet elusive molecular mechanism. We have used an interdisciplinary approach to address this question, and we find that intradermal injection of S1P induced significant licking and flinching behavior in wild-type mice and a dose-dependent flare reaction in human skin as a sign of acute activation of nociceptive nerve terminals. Notably, S1P evoked a small excitatory ionic current that resulted in nociceptor depolarization and action potential firing. This ionic current was preserved in "cation-free" solution and blocked by the nonspecific Cl(-) channel inhibitor niflumic acid and by preincubation with the G-protein inhibitor GDP-ß-S. Notably, S1P(3) receptor was detected in virtually all neurons in human and mouse DRG. In line with this finding, S1P-induced neuronal responses and spontaneous pain behavior in vivo were substantially reduced in S1P(3)(-/-) mice, whereas in control S1P(1) floxed (S1P(1)(fl/fl)) mice and mice with a nociceptor-specific deletion of S1P(1)(-/-) receptor (SNS-S1P(1)(-/-)), neither the S1P-induced responses in vitro nor the S1P-evoked pain-like behavior was altered. Therefore, these findings indicate that S1P evokes significant nociception via G-protein-dependent activation of an excitatory Cl(-) conductance that is largely mediated by S1P(3) receptors present in nociceptors, and point to these receptors as valuable therapeutic targets for post-traumatic pain.
Assuntos
Lisofosfolipídeos/toxicidade , Medição da Dor/métodos , Dor/metabolismo , Receptores de Lisoesfingolipídeo/fisiologia , Esfingosina/análogos & derivados , Adulto , Animais , Células Cultivadas , Método Duplo-Cego , Feminino , Gânglios Espinais/efeitos dos fármacos , Gânglios Espinais/fisiologia , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Dor/induzido quimicamente , Medição da Dor/efeitos dos fármacos , Esfingosina/toxicidadeRESUMO
Carbon dots were synthesized by a simple and green strategy for selective and sensitive Cu(2+) ion detection using both down and upconversion fluorescence. These fluorescent nanosensors show low cytotoxicity and are applied for intracellular sensing and imaging of Cu(2+) in biological systems.
Assuntos
Carbono/química , Cobre/análise , Nanopartículas/química , Animais , Carbono/farmacologia , Fluorescência , Química Verde , Camundongos , Células NIH 3T3RESUMO
Sphingosine-1-phosphate (S1P) is a key regulator of immune response. Immune cells, epithelia and blood cells generate high levels of S1P in inflamed tissue. However, it is not known if S1P acts on the endings of nociceptive neurons, thereby contributing to the generation of inflammatory pain. We found that the S1P1 receptor for S1P is expressed in subpopulations of sensory neurons including nociceptors. Both S1P and agonists at the S1P1 receptor induced hypersensitivity to noxious thermal stimulation in vitro and in vivo. S1P-induced hypersensitivity was strongly attenuated in mice lacking TRPV1 channels. S1P and inflammation-induced hypersensitivity was significantly reduced in mice with a conditional nociceptor-specific deletion of the S1P1 receptor. Our data show that neuronally expressed S1P1 receptors play a significant role in regulating nociceptor function and that S1P/S1P1 signaling may be a key player in the onset of thermal hypersensitivity and hyperalgesia associated with inflammation.
Assuntos
Inflamação/genética , Dor/genética , Receptores de Lisoesfingolipídeo/genética , Receptores de Lisoesfingolipídeo/fisiologia , Células Receptoras Sensoriais/metabolismo , Animais , Temperatura Alta/efeitos adversos , Hiperalgesia/genética , Hiperalgesia/metabolismo , Inflamação/complicações , Inflamação/fisiopatologia , Lisofosfolipídeos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Nociceptores/metabolismo , Nociceptores/fisiologia , Dor/etiologia , Dor/fisiopatologia , Receptores de Lisoesfingolipídeo/metabolismo , Transdução de Sinais/genética , Transdução de Sinais/fisiologia , Pele/inervação , Pele/metabolismo , Esfingosina/análogos & derivados , Esfingosina/metabolismoRESUMO
The synthesis and characterization of a novel water-compatible microsized material, based on fluorescent conjugated polymers (CPs), and its applicability for optical sensing of inorganic ions of environment interest (copper and cyanide) in water media is here described. Polyfluorene-based fluorescent CPs were synthesized and functionalized with imidazole moieties (selective recognition element) and a terminal double bond (covalently linked to an organic matrix) through a postfunctionalization strategy. Further, microspheres of the novel imidazole-functionalized fluorescent CPs, able to work in water media, were synthesized via a microemulsion and polymerization procedure. The synthesized imidazole-functionalized CP microspheres were then evaluated as fluorescence "turn-Off" sensing materials for Cu(2+) detection in aqueous media. Analyte detection was based on the quenching effect of the Cu(2+), selectively recognized by the imidazole group, on the polymer fluorescence emission. The developed optosensor exhibits a detection limit of 1 µg/L for the determination of Cu(2+) in water with a reproducibility of 4%. The synthesized microsized material was also evaluated for the "turn-on" optosensing of cyanide in water, measuring the recovery of the emission signal from the CP that has been previously deactivated by the presence of quencher species. The "turn-On" optosensor allows the selective determination of free cyanide in aqueous solution with high sensitivity (detection limit of 18 µg/L), obtaining a reproducibility of 2.9%. A high sample throughput (between 7 and 12 samples per hour) was achieved in both cases. Analytical applicability of the fluorescent CP microsphere materials has been successfully demonstrated by tap and mineral water analysis.
Assuntos
Cobre/análise , Cianetos/análise , Microesferas , Fenômenos Ópticos , Polímeros/química , Água/química , Cobre/química , Cianetos/química , Concentração de Íons de Hidrogênio , Imidazóis/química , Concentração Osmolar , Polímeros/síntese química , Espectrometria de FluorescênciaRESUMO
The transient receptor potential vanilloid 1 (TRPV1) channel is a thermosensory receptor implicated in diverse physiological and pathological processes. The TRP domain, a highly conserved region in the C terminus adjacent to the internal channel gate, is critical for subunit tetramerization and channel gating. Here, we show that cell-penetrating, membrane-anchored peptides patterned after this protein domain are moderate and selective TRPV1 antagonists both in vitro and in vivo, blocking receptor activity in intact rat primary sensory neurons and their peripheral axons with mean decline time of 30 min. The most potent lipopeptide, TRP-p5, blocked all modes of TRPV1 gating with micromolar efficacy (IC(50)<10 µM), without significantly affecting other thermoTRP channels. In contrast, its retrosequence or the corresponding sequences of other TRPV channels did not alter TRPV1 channel activity (IC(50)>100 µM). TRP-p5 did not affect the capsaicin sensitivity of the vanilloid receptor. Our data suggest that TRP-p5 interferes with protein-protein interactions at the level of the TRP domain that are essential for the "conformational" change that leads to gate opening. Therefore, these palmitoylated peptides, which we termed TRPducins, are noncompetitive, voltage-independent, sequence-specific TRPV1 blockers. Our findings indicate that TRPducin-like peptides may embody a novel molecular strategy that can be exploited to generate a selective pharmacological arsenal for the TRP superfamily of ion channels.