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1.
Annu Rev Physiol ; 83: 451-475, 2021 02 10.
Artigo em Inglês | MEDLINE | ID: mdl-33176563

RESUMO

Aldosterone excess is a pathogenic factor in many hypertensive disorders. The discovery of numerous somatic and germline mutations in ion channels in primary hyperaldosteronism underscores the importance of plasma membrane conductances in determining the activation state of zona glomerulosa (zG) cells. Electrophysiological recordings describe an electrically quiescent behavior for dispersed zG cells. Yet, emerging data indicate that in native rosette structures in situ, zG cells are electrically excitable, generating slow periodic voltage spikes and coordinated bursts of Ca2+ oscillations. We revisit data to understand how a multitude of conductances may underlie voltage/Ca2+ oscillations, recognizing that zG layer self-renewal and cell heterogeneity may complicate this task. We review recent data to understand rosette architecture and apply maxims derived from computational network modeling to understand rosette function. The challenge going forward is to uncover how the rosette orchestrates the behavior of a functional network of conditional oscillators to control zG layer performance and aldosterone secretion.


Assuntos
Aldosterona/metabolismo , Canais Iônicos/metabolismo , Zona Glomerulosa/metabolismo , Zona Glomerulosa/fisiologia , Animais , Cálcio/metabolismo , Comunicação Celular/fisiologia , Humanos
2.
Genet Med ; 23(5): 927-933, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33500570

RESUMO

PURPOSE: Cystic fibrosis (CF), caused by pathogenic variants in the CF transmembrane conductance regulator (CFTR), affects multiple organs including the exocrine pancreas, which is a causal contributor to cystic fibrosis-related diabetes (CFRD). Untreated CFRD causes increased CF-related mortality whereas early detection can improve outcomes. METHODS: Using genetic and easily accessible clinical measures available at birth, we constructed a CFRD prediction model using the Canadian CF Gene Modifier Study (CGS; n = 1,958) and validated it in the French CF Gene Modifier Study (FGMS; n = 1,003). We investigated genetic variants shown to associate with CF disease severity across multiple organs in genome-wide association studies. RESULTS: The strongest predictors included sex, CFTR severity score, and several genetic variants including one annotated to PRSS1, which encodes cationic trypsinogen. The final model defined in the CGS shows excellent agreement when validated on the FGMS, and the risk classifier shows slightly better performance at predicting CFRD risk later in life in both studies. CONCLUSION: We demonstrated clinical utility by comparing CFRD prevalence rates between the top 10% of individuals with the highest risk and the bottom 10% with the lowest risk. A web-based application was developed to provide practitioners with patient-specific CFRD risk to guide CFRD monitoring and treatment.


Assuntos
Fibrose Cística , Diabetes Mellitus , Biomarcadores , Canadá , Fibrose Cística/complicações , Fibrose Cística/diagnóstico , Fibrose Cística/genética , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Diabetes Mellitus/epidemiologia , Diabetes Mellitus/genética , Estudo de Associação Genômica Ampla , Humanos , Recém-Nascido
3.
Kidney Int ; 98(3): 630-644, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32446934

RESUMO

Kidney function and blood pressure homeostasis are regulated by purinergic signaling mechanisms. These autocrine/paracrine signaling pathways are initiated by the release of cellular ATP, which influences kidney hemodynamics and steady-state renin secretion from juxtaglomerular cells. However, the mechanism responsible for ATP release that supports tonic inputs to juxtaglomerular cells and regulates renin secretion remains unclear. Pannexin 1 (Panx1) channels localize to both afferent arterioles and juxtaglomerular cells and provide a transmembrane conduit for ATP release and ion permeability in the kidney and the vasculature. We hypothesized that Panx1 channels in renin-expressing cells regulate renin secretion in vivo. Using a renin cell-specific Panx1 knockout model, we found that male Panx1 deficient mice exhibiting a heightened activation of the renin-angiotensin-aldosterone system have markedly increased plasma renin and aldosterone concentrations, and elevated mean arterial pressure with altered peripheral hemodynamics. Following ovariectomy, female mice mirrored the male phenotype. Furthermore, constitutive Panx1 channel activity was observed in As4.1 renin-secreting cells, whereby Panx1 knockdown reduced extracellular ATP accumulation, lowered basal intracellular calcium concentrations and recapitulated a hyper-secretory renin phenotype. Moreover, in response to stress stimuli that lower blood pressure, Panx1-deficient mice exhibited aberrant "renin recruitment" as evidenced by reactivation of renin expression in pre-glomerular arteriolar smooth muscle cells. Thus, renin-cell Panx1 channels suppress renin secretion and influence adaptive renin responses when blood pressure homeostasis is threatened.


Assuntos
Conexinas , Renina , Trifosfato de Adenosina , Animais , Pressão Sanguínea , Conexinas/genética , Feminino , Homeostase , Masculino , Camundongos , Camundongos Knockout , Proteínas do Tecido Nervoso/genética
4.
Prev Sci ; 21(5): 650-660, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32363411

RESUMO

In Lebanon, approximately one in four adolescents suffers from a psychiatric disorder. Alarmingly, 94% of adolescents with a mental disorder have not sought any treatment. This study assessed the effectiveness of an evidence-based school-based universal mental health intervention (the FRIENDS program) in reducing depression and anxiety symptoms in middle school students in Lebanon. A total of 280 6th graders aged 11-13 years were recruited from 10 schools in Beirut. Schools were matched on size and tuition and randomly assigned to intervention or control groups. The FRIENDS program was translated into Arabic, adapted, and then implemented by trained mental health professionals during 10 classroom sessions over 3 months. We assessed sociodemographic and relevant psychological symptoms by self-report, using the Scale for Childhood Anxiety and Related Disorders (SCARED), Mood and Feelings Questionnaire (MFQ), and Strengths and Difficulties Questionnaire (SDQ), at baseline. We re-administered these scales at 3 months post-intervention. There was a significant time × group interaction for the SDQ emotional score (p = 0.011) and total MFQ score (p = 0.039) indicating significant improvement in depressive and emotional symptoms in the intervention group. Subgroup analysis by gender showed a significant time × group interaction for the total SCARED score (p = 0.025) in females but not in males (p = 0.137), consistent with a reduction of anxiety symptoms in this stratum of the intervention group as compared with the control group. The FRIENDS program was effective in reducing general emotional and depressive symptoms among middle school students in this Lebanese study population. This intervention provides an opportunity for promoting mental health in Lebanese schools and reducing the treatment gap in mental health care.


Assuntos
Promoção da Saúde , Resiliência Psicológica , Adolescente , Transtornos de Ansiedade , Criança , Feminino , Humanos , Líbano , Masculino , Instituições Acadêmicas , Autorrelato
5.
Int J Psychol ; 55 Suppl 1: 78-87, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31313297

RESUMO

A randomised, waitlist controlled, trial was conducted to evaluate the effects of the Adult Resilience Program (ARP), a universal prevention social-emotional programme for adolescents and adults, on self-reported depression, anxiety, stress, resilience, and self-esteem. Seventy-six students from a private university in Singapore were randomised to the ARP group or wait-list control (WLC) group and assessments were conducted at pre-intervention (T1), post-intervention (T2), and 6-month follow-up (T3). A 2 × 3 mixed between-within groups multivariate analysis of variance with the between-group factor of Group (ARP, WLC) and the within-group factor of time (T1, T2, and T3) and the dependent variables of depression, anxiety, stress, resilience and self-esteem, with age and stage of degree as covariates showed a significant decrease over time in depression (ηp2  = .20), and anxiety (ηp2  = .06). There was a significant decrease in stress for the ARP only from T1 to T2 (ηp2  = .16). While there was a significant interaction of Time and Group for resilience (ηp2  = .07), there was no significant change in resilience for the ARP group alone. The results provide preliminary support that the ARP can impart essential skills that can have a positive impact on mental health in university students.


Assuntos
Serviços de Saúde Mental/normas , Medicina Preventiva/métodos , Resiliência Psicológica , Adolescente , Adulto , Criança , Feminino , Humanos , Masculino , Adulto Jovem
6.
Aust J Rural Health ; 28(2): 209-214, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32390201

RESUMO

OBJECTIVE: To assess the efficacy of a train-the-trainer model for sporting coaches delivering a youth sports-based resilience program. DESIGN: A quasi-experimental design was applied, with a pre-post comparison, utilising purposive sampling to take advantage of an existing naturally formed group. SETTING AND PARTICIPANTS: A total of 11 coaches and 86 athletes involved in a community rowing program. MAIN OUTCOME MEASURE(S): Coaches responded to paper-based measures of resilience and knowledge/attitudes pre- and post-completion of a training workshop. Athletes responded to online measures of stress, efficacy and life satisfaction pre- and post-completion of a resilience program. RESULTS: Following the completion of the train-the-trainer workshop, coaches reported significant increases in general knowledge and confidence in teaching resilience skills. Following the delivery of the resilience program, athlete self-efficacy and satisfaction with life scores were significantly higher, with significant reductions in reported stress for athletes trained by the varsity-level coaches. CONCLUSION: There is support for investing in a train-the-trainer model for the delivery of a resilience skills program within a sports context. Caution is given to investing in the training and support of the coaches, particularly coaches with less coaching experience. These results are consistent with previous research and demonstrate support for coach-led resilience programs being effective in community settings, with implications for rural and remote locations.


Assuntos
Atletas/psicologia , Conhecimentos, Atitudes e Prática em Saúde , Resiliência Psicológica , Esportes/psicologia , Capacitação de Professores/métodos , Adolescente , Adulto , Feminino , Humanos , Masculino , Avaliação de Programas e Projetos de Saúde , Autoeficácia
7.
J Physiol ; 594(20): 5851-5860, 2016 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-26845064

RESUMO

Zona glomerulosa cells (ZG) of the adrenal gland constantly integrate fluctuating ionic, hormonal and paracrine signals to control the synthesis and secretion of aldosterone. These signals modulate Ca2+ levels, which provide the critical second messenger to drive steroid hormone production. Angiotensin II is a hormone known to modulate the activity of voltage-dependent L- and T-type Ca2+ channels that are expressed on the plasma membrane of ZG cells in many species. Because the ZG cell maintains a resting membrane voltage of approximately -85 mV and has been considered electrically silent, low voltage-activated T-type Ca2+ channels are assumed to provide the primary Ca2+ signal that drives aldosterone production. However, this view has recently been challenged by human genetic studies identifying somatic gain-of-function mutations in L-type CaV 1.3 channels in aldosterone-producing adenomas of patients with primary hyperaldosteronism. We provide a review of these assumptions and challenges, and update our understanding of the state of the ZG cell in a layer in which native cellular associations are preserved. This updated view of Ca2+ signalling in ZG cells provides a unifying mechanism that explains how transiently activating CaV 3.2 channels can generate a significant and recurring Ca2+ signal, and how CaV 1.3 channels may contribute to the Ca2+ signal that drives aldosterone production.


Assuntos
Córtex Suprarrenal/metabolismo , Aldosterona/metabolismo , Canais de Cálcio/metabolismo , Zona Glomerulosa/metabolismo , Animais , Cálcio/metabolismo , Humanos
9.
Depress Anxiety ; 30(9): 829-41, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23658135

RESUMO

BACKGROUND: Investigations of age effects on youth anxiety outcomes in randomized trials (RCTs) of cognitive behavior therapy (CBT) have failed to yield a clear result due to inadequate statistical power and methodologic weaknesses. We conducted an individual patient data metaanalysis to address this gap. QUESTION: Does age moderate CBT effect size, measured by a clinically and statistically significant interaction between age and CBT exposure? METHODS: All English language RCTs of CBT for anxiety in 6-19 year olds were identified using systematic review methods. Investigators of eligible trials were invited to submit their individual patient data. The anxiety disorder interview schedule (ADIS) primary diagnosis severity score was the primary outcome. Age effects were investigated using multilevel modeling to account for study level data clustering and random effects. RESULTS: Data from 17 of 23 eligible trials were obtained (74%); 16 studies and 1,171 (78%) cases were available for the analysis. No interaction between age and CBT exposure was found in a model containing age, sex, ADIS baseline severity score, and comorbid depression diagnosis (power ≥ 80%). Sensitivity analyses, including modeling age as both a categorical and continuous variable, revealed this result was robust. CONCLUSIONS: Adolescents who receive CBT in efficacy research studies show benefits comparable to younger children. However, CBT protocol modifications routinely carried out by expert trial therapists may explain these findings. Adolescent CBT protocols are needed to facilitate the transportability of efficacy research effects to usual care settings where therapists may have less opportunity for CBT training and expertise development.


Assuntos
Fatores Etários , Transtornos de Ansiedade/terapia , Terapia Cognitivo-Comportamental , Adolescente , Criança , Feminino , Humanos , Masculino , Resultado do Tratamento , Adulto Jovem
10.
Clin Child Psychol Psychiatry ; 28(2): 795-809, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35996946

RESUMO

BACKGROUND: Anxiety disorders are among the most common psychiatric disorders in childhood and can develop as early as the preschool years. Therefore, providing young children who display early signs of anxiety with skills to prevent the development of later psychopathology is invaluable. The current study evaluates the effectiveness of Fun FRIENDS, an anxiety prevention and resilience program for young children. METHOD: Fifty-seven kindergartners across three classrooms participated in a 15-week anxiety prevention program and teachers completed a behavioral screening measure and anxiety questionnaire at pre, post, 3 month, and 10-month follow-up assessment points. RESULTS: Anxiety positively correlated with emotional symptoms, peer difficulties, and total difficulties at pre-intervention. Anxiety symptoms decreased from pre-intervention to follow-up. Additionally, prosocial behaviors improved and moderated the relationship between pre-and post-intervention anxiety symptoms. CONCLUSIONS: These findings yield promising implications regarding the effectiveness of prevention and intervention programs on increasing social emotional skills and reducing anxiety symptoms in young children.


Assuntos
Transtornos de Ansiedade , Ansiedade , Humanos , Criança , Pré-Escolar , Ansiedade/prevenção & controle , Transtornos de Ansiedade/prevenção & controle , Transtornos de Ansiedade/psicologia , Emoções , Instituições Acadêmicas
11.
Hypertension ; 79(11): 2552-2564, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-36129175

RESUMO

BACKGROUND: Ion channel mutations in calcium regulating genes strongly associate with AngII (angiotensin II)-independent aldosterone production. Here, we used an established mouse model of in vivo aldosterone autonomy, Cyp11b2-driven deletion of TWIK-related acid-sensitive potassium channels (TASK-1 and TASK-3, termed zona glomerulosa [zG]-TASK-loss-of-function), and selective pharmacological TASK channel inhibition to determine whether channel dysfunction in native, electrically excitable zG cell rosette-assemblies: (1) produces spontaneous calcium oscillatory activity and (2) is sufficient to drive substantial aldosterone autonomy. METHODS: We imaged calcium activity in adrenal slices expressing a zG-specific calcium reporter (GCaMP3), an in vitro experimental approach that preserves the native rosette assembly and removes potentially confounding extra-adrenal contributions. In parallel experiments, we measured acute aldosterone production from adrenal slice cultures. RESULTS: Absent from untreated WT slices, we find that either adrenal-specific genetic deletion or acute pharmacological TASK channel inhibition produces spontaneous oscillatory bursting behavior and steroidogenic activity (2.4-fold) that are robust, sustained, and equivalent to activities evoked by 3 nM AngII in WT slices. Moreover, spontaneous activity in zG-TASK-loss-of-function slices and inhibitor-evoked activity in WT slices are unresponsive to AngII regulation over a wide range of concentrations (50 pM to 3 µM). CONCLUSIONS: We provide proof of principle that spontaneous activity of zG cells within classic rosette assemblies evoked solely by a change in an intrinsic, dominant resting-state conductance can be a significant source of AngII-independent aldosterone production from native tissue.


Assuntos
Aldosterona , Hiperaldosteronismo , Camundongos , Animais , Angiotensina II/farmacologia , Sinalização do Cálcio , Cálcio/metabolismo , Hiperaldosteronismo/genética , Zona Glomerulosa/metabolismo
12.
Proc Natl Acad Sci U S A ; 105(6): 2203-8, 2008 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-18250325

RESUMO

When inappropriate for salt status, the mineralocorticoid aldosterone induces cardiac and renal injury. Autonomous overproduction of aldosterone from the adrenal zona glomerulosa (ZG) is also the most frequent cause of secondary hypertension. Yet, the etiology of nontumorigenic primary hyperaldosteronism caused by bilateral idiopathic hyperaldosteronism remains unknown. Here, we show that genetic deletion of TWIK-related acid-sensitive K (TASK)-1 and TASK-3 channels removes an important background K current that results in a marked depolarization of ZG cell membrane potential. Although TASK channel deletion mice (TASK-/-) adjust urinary Na excretion and aldosterone production to match Na intake, they produce more aldosterone than control mice across the range of Na intake. Overproduction of aldosterone is not the result of enhanced activity of the renin-angiotensin system because circulating renin concentrations remain either unchanged or lower than those of control mice at each level of Na intake. In addition, TASK-/- mice fail to suppress aldosterone production in response to dietary Na loading. Autonomous aldosterone production is also demonstrated by the failure of an angiotensin type 1 receptor blocker, candesartan, to normalize aldosterone production to control levels in TASK-/- mice. Thus, TASK-/- channel knockout mice exhibit the hallmarks of primary hyperaldosteronism. Our studies establish an animal model of nontumorigenic primary hyperaldosteronism and identify TASK channels as a possible therapeutic target for primary hyperaldosteronism.


Assuntos
Hiperaldosteronismo/genética , Proteínas do Tecido Nervoso/fisiologia , Canais de Potássio de Domínios Poros em Tandem/fisiologia , Aldosterona/urina , Animais , Sequência de Bases , Primers do DNA , Hibridização In Situ , Camundongos , Camundongos Knockout , Proteínas do Tecido Nervoso/genética , Canais de Potássio de Domínios Poros em Tandem/genética , Radioimunoensaio
13.
Mol Cell Endocrinol ; 530: 111287, 2021 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-33891993

RESUMO

How morphology informs function is a fundamental biological question. Here, we review the morphological features of the adrenal zona glomerulosa (zG), highlighting recent cellular and molecular discoveries that govern its formation. The zG consists of glomeruli enwrapped in a Laminin-ß1-enriched basement membrane (BM). Within each glomerulus, zG cells are organized as rosettes, a multicellular structure widely used throughout development to mediate epithelial remodeling, but not often found in healthy adult tissues. Rosettes arise by constriction at a common cellular contact point mediated/facilitated by adherens junctions (AJs). In mice, small, dispersed AJs first appear postnatally and enrich along the entire cell-cell contact around 10 days after birth. Subsequently, these AJ-rich contacts contract, allowing rosettes to form. Concurrently, flat sheet-like domains in the nascent zG, undergo invagination and folding, gradually giving rise to the compact round glomeruli that comprise the adult zG. How these structures impact adrenal function is discussed.


Assuntos
Zona Glomerulosa/anatomia & histologia , Zona Glomerulosa/fisiologia , Junções Aderentes/metabolismo , Animais , Membrana Basal/metabolismo , Humanos , Laminina/metabolismo
14.
Elife ; 102021 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-33410749

RESUMO

Pannexin 1 (Panx1) is a membrane channel implicated in numerous physiological and pathophysiological processes via its ability to support release of ATP and other cellular metabolites for local intercellular signaling. However, to date, there has been no direct demonstration of large molecule permeation via the Panx1 channel itself, and thus the permselectivity of Panx1 for different molecules remains unknown. To address this, we expressed, purified, and reconstituted Panx1 into proteoliposomes and demonstrated that channel activation by caspase cleavage yields a dye-permeable pore that favors flux of anionic, large-molecule permeants (up to ~1 kDa). Large cationic molecules can also permeate the channel, albeit at a much lower rate. We further show that Panx1 channels provide a molecular pathway for flux of ATP and other anionic (glutamate) and cationic signaling metabolites (spermidine). These results verify large molecule permeation directly through caspase-activated Panx1 channels that can support their many physiological roles.


Assuntos
Trifosfato de Adenosina/metabolismo , Conexinas/genética , Canais Iônicos/genética , Proteínas do Tecido Nervoso/genética , Transdução de Sinais , Proteínas de Xenopus/genética , Animais , Caspases/metabolismo , Conexinas/metabolismo , Humanos , Canais Iônicos/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Spodoptera/genética , Spodoptera/metabolismo , Xenopus/genética , Xenopus/metabolismo , Proteínas de Xenopus/metabolismo
15.
Nature ; 424(6945): 209-13, 2003 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-12853961

RESUMO

Low-voltage-activated (LVA) T-type calcium channels have a wide tissue distribution and have well-documented roles in the control of action potential burst generation and hormone secretion. In neurons of the central nervous system and secretory cells of the adrenal and pituitary, LVA channels are inhibited by activation of G-protein-coupled receptors that generate membrane-delimited signals, yet these signals have not been identified. Here we show that the inhibition of alpha1H (Ca(v)3.2), but not alpha(1G) (Ca(v)3.1) LVA Ca2+ channels is mediated selectively by beta2gamma2 subunits that bind to the intracellular loop connecting channel transmembrane domains II and III. This region of the alpha1H channel is crucial for inhibition, because its replacement abrogates inhibition and its transfer to non-modulated alpha1G channels confers beta2gamma2-dependent inhibition. betagamma reduces channel activity independent of voltage, a mechanism distinct from the established betagamma-dependent inhibition of non-L-type high-voltage-activated channels of the Ca(v)2 family. These studies identify the alpha1H channel as a new effector for G-protein betagamma subunits, and highlight the selective signalling roles available for particular betagamma combinations.


Assuntos
Canais de Cálcio Tipo T/metabolismo , Proteínas Heterotriméricas de Ligação ao GTP/metabolismo , Motivos de Aminoácidos , Bloqueadores dos Canais de Cálcio/metabolismo , Canais de Cálcio Tipo T/química , Linhagem Celular , AMP Cíclico/metabolismo , Humanos , Potenciais da Membrana , Subunidades Proteicas/metabolismo , Receptores de Dopamina D1/antagonistas & inibidores , Receptores de Dopamina D1/metabolismo , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/metabolismo , Transfecção , Células Tumorais Cultivadas
16.
BMC Public Health ; 10: 464, 2010 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-20696032

RESUMO

BACKGROUND: Despite the recognition of obesity in young people as a key health issue, there is limited evidence to inform health professionals regarding the most appropriate treatment options. The Eat Smart study aims to contribute to the knowledge base of effective dietary strategies for the clinical management of the obese adolescent and examine the cardiometablic effects of a reduced carbohydrate diet versus a low fat diet. METHODS AND DESIGN: Eat Smart is a randomised controlled trial and aims to recruit 100 adolescents over a 2 1/2 year period. Families will be invited to participate following referral by their health professional who has recommended weight management. Participants will be overweight as defined by a body mass index (BMI) greater than the 90th percentile, using CDC 2000 growth charts. An accredited 6-week psychological life skills program 'FRIENDS for Life', which is designed to provide behaviour change and coping skills will be undertaken prior to volunteers being randomised to group. The intervention arms include a structured reduced carbohydrate or a structured low fat dietary program based on an individualised energy prescription. The intervention will involve a series of dietetic appointments over 24 weeks. The control group will commence the dietary program of their choice after a 12 week period. Outcome measures will be assessed at baseline, week 12 and week 24. The primary outcome measure will be change in BMI z-score. A range of secondary outcome measures including body composition, lipid fractions, inflammatory markers, social and psychological measures will be measured. DISCUSSION: The chronic and difficult nature of treating the obese adolescent is increasingly recognised by clinicians and has highlighted the need for research aimed at providing effective intervention strategies, particularly for use in the tertiary setting. A structured reduced carbohydrate approach may provide a dietary pattern that some families will find more sustainable and effective than the conventional low fat dietary approach currently advocated. This study aims to investigate the acceptability and effectiveness of a structured reduced dietary carbohydrate intervention and will compare the outcomes of this approach with a structured low fat eating plan. TRIAL REGISTRATION: The protocol for this study is registered with the International Clinical Trials Registry (ISRCTN49438757).


Assuntos
Carboidratos da Dieta/metabolismo , Gorduras na Dieta/metabolismo , Obesidade/dietoterapia , Redução de Peso , Adolescente , Criança , Carboidratos da Dieta/administração & dosagem , Gorduras na Dieta/administração & dosagem , Feminino , Humanos , Masculino
17.
J Endocrinol ; 244(1): 237-247, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31652415

RESUMO

Aldosterone, which plays a key role in the regulation of blood pressure, is produced by zona glomerulosa (ZG) cells of the adrenal cortex. Exaggerated overproduction of aldosterone from ZG cells causes primary hyperaldosteronism. In ZG cells, calcium entry through voltage-gated calcium channels plays a central role in the regulation of aldosterone secretion. Previous studies in animal adrenals and human adrenal adrenocortical cell lines suggest that the T-type but not the L-type calcium channel activity drives aldosterone production. However, recent clinical studies show that somatic mutations in L-type calcium channels are the second most prevalent cause of aldosterone-producing adenoma. Our objective was to define the roles of T and L-type calcium channels in regulating aldosterone secretion from human adrenals. We find that human adrenal ZG cells mainly express T-type CaV3.2/3.3 and L-type CaV1.2/1.3 calcium channels. TTA-P2, a specific inhibitor of T-type calcium channel subtypes, reduced basal aldosterone secretion from acutely prepared slices of human adrenals. Surprisingly, nifedipine, the prototypic inhibitor of L-type calcium channels, also decreased basal aldosterone secretion, suggesting that L-type calcium channels are active under basal conditions. In addition, TTA-P2 or nifedipine also inhibited aldosterone secretion stimulated by angiotensin II- or elevations in extracellular K+. Remarkably, blockade of either L- or T-type calcium channels inhibits basal and stimulated aldosterone production to a similar extent. Low concentrations of TTA-P2 and nifedipine showed additive inhibitory effect on aldosterone secretion. We conclude that T- and L-type calcium channels play equally important roles in controlling aldosterone production from human adrenals.


Assuntos
Glândulas Suprarrenais/metabolismo , Aldosterona/biossíntese , Canais de Cálcio Tipo L/metabolismo , Canais de Cálcio Tipo T/metabolismo , Benzamidas/metabolismo , Linhagem Celular , Humanos , Nifedipino/metabolismo , Piperidinas/metabolismo
18.
Front Cell Neurosci ; 14: 605312, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33384586

RESUMO

Our previous studies implicated glycosylation of the CaV3.2 isoform of T-type Ca2+ channels (T-channels) in the development of Type 2 painful peripheral diabetic neuropathy (PDN). Here we investigated biophysical mechanisms underlying the modulation of recombinant CaV3.2 channel by de-glycosylation enzymes such as neuraminidase (NEU) and PNGase-F (PNG), as well as their behavioral and biochemical effects in painful PDN Type 1. In our in vitro study we used whole-cell recordings of current-voltage relationships to confirm that CaV3.2 current densities were decreased ~2-fold after de-glycosylation. Furthermore, de-glycosylation induced a significant depolarizing shift in the steady-state relationships for activation and inactivation while producing little effects on the kinetics of current deactivation and recovery from inactivation. PDN was induced in vivo by injections of streptozotocin (STZ) in adult female C57Bl/6j wild type (WT) mice, adult female Sprague Dawley rats and CaV3.2 knock-out (KO mice). Either NEU or vehicle (saline) were locally injected into the right hind paws or intrathecally. We found that injections of NEU, but not vehicle, completely reversed thermal and mechanical hyperalgesia in diabetic WT rats and mice. In contrast, NEU did not alter baseline thermal and mechanical sensitivity in the CaV3.2 KO mice which also failed to develop painful PDN. Finally, we used biochemical methods with gel-shift analysis to directly demonstrate that N-terminal fragments of native CaV3.2 channels in the dorsal root ganglia (DRG) are glycosylated in both healthy and diabetic animals. Our results demonstrate that in sensory neurons glycosylation-induced alterations in CaV3.2 channels in vivo directly enhance diabetic hyperalgesia, and that glycosylation inhibitors can be used to ameliorate painful symptoms in Type 1 diabetes. We expect that our studies may lead to a better understanding of the molecular mechanisms underlying painful PDN in an effort to facilitate the discovery of novel treatments for this intractable disease.

19.
Nat Commun ; 11(1): 1679, 2020 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-32245948

RESUMO

Aldosterone-producing zona glomerulosa (zG) cells of the adrenal gland arrange in distinct multi-cellular rosettes that provide a structural framework for adrenal cortex morphogenesis and plasticity. Whether this cyto-architecture also plays functional roles in signaling remains unexplored. To determine if structure informs function, we generated mice with zG-specific expression of GCaMP3 and imaged zG cells within their native rosette structure. Here we demonstrate that within the rosette, angiotensin II evokes periodic Cav3-dependent calcium events that form bursts that are stereotypic in form. Our data reveal a critical role for angiotensin II in regulating burst occurrence, and a multifunctional role for the rosette structure in activity-prolongation and coordination. Combined our data define the calcium burst as the fundamental unit of zG layer activity evoked by angiotensin II and highlight a novel role for the rosette as a facilitator of cell communication.


Assuntos
Aldosterona/metabolismo , Angiotensina II/metabolismo , Cálcio/metabolismo , Zona Glomerulosa/metabolismo , Animais , Proteínas de Ligação ao Cálcio/genética , Citocromo P-450 CYP11B2/genética , Citocromo P-450 CYP11B2/metabolismo , Feminino , Genes Reporter/genética , Proteínas de Fluorescência Verde/genética , Microscopia Intravital , Masculino , Camundongos , Camundongos Transgênicos , Microscopia de Fluorescência , Técnicas de Cultura de Tecidos
20.
Nat Commun ; 11(1): 1680, 2020 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-32245949

RESUMO

Rosettes are widely used in epithelial morphogenesis during embryonic development and organogenesis. However, their role in postnatal development and adult tissue maintenance remains largely unknown. Here, we show zona glomerulosa cells in the adult adrenal cortex organize into rosettes through adherens junction-mediated constriction, and that rosette formation underlies the maturation of adrenal glomerular structure postnatally. Using genetic mouse models, we show loss of ß-catenin results in disrupted adherens junctions, reduced rosette number, and dysmorphic glomeruli, whereas ß-catenin stabilization leads to increased adherens junction abundance, more rosettes, and glomerular expansion. Furthermore, we uncover numerous known regulators of epithelial morphogenesis enriched in ß-catenin-stabilized adrenals. Among these genes, we show Fgfr2 is required for adrenal rosette formation by regulating adherens junction abundance and aggregation. Together, our data provide an example of rosette-mediated postnatal tissue morphogenesis and a framework for studying the role of rosettes in adult zona glomerulosa tissue maintenance and function.


Assuntos
Junções Aderentes/metabolismo , Morfogênese , Receptor Tipo 2 de Fator de Crescimento de Fibroblastos/metabolismo , Zona Glomerulosa/crescimento & desenvolvimento , beta Catenina/metabolismo , Junções Aderentes/genética , Junções Aderentes/ultraestrutura , Neoplasias das Glândulas Suprarrenais/cirurgia , Animais , Animais Recém-Nascidos , Feminino , Humanos , Masculino , Camundongos , Camundongos Knockout , Microscopia Eletrônica de Transmissão , Receptor Tipo 2 de Fator de Crescimento de Fibroblastos/genética , Zona Glomerulosa/citologia , Zona Glomerulosa/metabolismo , Zona Glomerulosa/ultraestrutura , beta Catenina/genética
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