RESUMEN
PURPOSE: The purpose of this study was to investigate the effects of ageing, sex and body mass index (BMI) on translocator protein (TSPO) availability in healthy subjects using positron emission tomography (PET) and the radioligand [11C]PBR28. METHODS: [11C]PBR28 data from 140 healthy volunteers (72 males and 68 females; N = 78 with HAB and N = 62 MAB genotype; age range 19-80 years; BMI range 17.6-36.9) were acquired with High Resolution Research Tomograph at three centres: Karolinska Institutet (N = 53), Turku PET centre (N = 62) and Yale University PET Center (N = 25). The total volume of distribution (VT) was estimated in global grey matter, frontal, temporal, occipital and parietal cortices, hippocampus and thalamus using multilinear analysis 1. The effects of age, BMI and sex on TSPO availability were investigated using linear mixed effects model, with TSPO genotype and PET centre specified as random intercepts. RESULTS: There were significant positive correlations between age and VT in the frontal and temporal cortex. BMI showed a significant negative correlation with VT in all regions. Additionally, significant differences between males and females were observed in all regions, with females showing higher VT. A subgroup analysis revealed a positive correlation between VT and age in all regions in male subjects, whereas age showed no effect on TSPO levels in female subjects. CONCLUSION: These findings provide evidence that individual biological properties may contribute significantly to the high variation shown in TSPO binding estimates, and suggest that age, BMI and sex can be confounding factors in clinical studies.
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Índice de Masa Corporal , Tomografía de Emisión de Positrones , Receptores de GABA/química , Adulto , Factores de Edad , Anciano , Anciano de 80 o más Años , Envejecimiento , Femenino , Genotipo , Humanos , Masculino , Persona de Mediana Edad , Pirimidinas , Factores Sexuales , Adulto JovenRESUMEN
Dopamine type 2 and type 3 receptors (D2R/D3R) appear critical to addictive disorders. Cocaine-use disorder (CUD) is associated with lower D2R availability and greater D3R availability in regions primarily expressing D2R or D3R concentrations, respectively. However, these CUD-related alterations in D2R and D3R have not been concurrently detected using available dopaminergic radioligands. Furthermore, receptor availability in regions of mixed D2R/D3R concentration in CUD remains unclear. The current study aimed to extend investigations of CUD-related alterations in D2R and D3R availability using regional and source-based analyses of [11C]-(+)-PHNO positron emission tomography (PET) of 26 individuals with CUD and 26 matched healthy comparison (HC) participants. Regional analysis detected greater binding potential (BPND) in CUD in the midbrain, consistent with prior [11C]-(+)-PHNO research, and lower BPND in CUD in the dorsal striatum, consistent with research using non-selective D2R/D3R radiotracers. Exploratory independent component analysis (ICA) identified three sources of BPND (striatopallidal, pallidonigral, and mesoaccumbens sources) that represent systems of brain regions displaying coherent variation in receptor availability. The striatopallidal source was associated with estimates of regional D2R-related proportions of BPND (calculated using independent reports of [11C]-(+)-PHNO receptor binding fractions), was lower in intensity in CUD and negatively associated with years of cocaine use. By comparison, the pallidonigral source was associated with estimates of regional D3R distribution, was greater in intensity in CUD and positively associated with years of cocaine use. The current study extends previous D2R/D3R research in CUD, demonstrating both lower BPND in the D2R-rich dorsal striatum and greater BPND in the D3R-rich midbrain using a single radiotracer. In addition, exploratory ICA identified sources of [11C]-(+)-PHNO BPND that were correlated with regional estimates of D2R-related and D3R-related proportions of BPND, were consistent with regional differences in CUD, and suggest receptor alterations in CUD may also be present in regions of mixed D2R/D3R concentration.
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Trastornos Relacionados con Cocaína/diagnóstico por imagen , Dopaminérgicos/metabolismo , Oxazinas/metabolismo , Receptores de Dopamina D2/metabolismo , Receptores de Dopamina D3/metabolismo , Adulto , Encéfalo/efectos de los fármacos , Encéfalo/metabolismo , Mapeo Encefálico , Trastornos Relacionados con Cocaína/metabolismo , Progresión de la Enfermedad , Dopaminérgicos/farmacología , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Masculino , Persona de Mediana Edad , Oxazinas/farmacología , Tomografía de Emisión de Positrones , Radiofármacos , Receptores de Dopamina D2/efectos de los fármacos , Receptores de Dopamina D3/efectos de los fármacosRESUMEN
Recruiting participants with chronic medical conditions is time-consuming and expensive. Electronic medical record databases and patient portals may enable outreach to larger numbers of patients in comparison to face-to-face methods. We aimed to describe the yields, benefits, and limitations of recruitment strategies used for a randomized clinical trial of cognitive behavioral therapy for insomnia among patients with chronic stable heart failure (NCT02660385). We used multiple recruitment strategies including clinic-based recruitment, letters to patients identified from electronic databases, the patient portal, brochures and posters placed in clinics, presentations to heart failure support groups, and online advertising. We screened 10,291 medical records, enrolled 231 participants, and 195 participants completed baseline data collection. We enrolled 92 (23%) participants using clinic-based recruitment, 24 and 29 (6% and 10%) using letters to patients from two electronic databases, and 42 (55%) via the patient portal. Multiple recruitment strategies and flexibility are needed to achieve recruitment goals.
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Terapia Cognitivo-Conductual , Insuficiencia Cardíaca , Publicidad/métodos , Registros Electrónicos de Salud , Insuficiencia Cardíaca/terapia , Humanos , Selección de PacienteRESUMEN
BACKGROUND: Positron emission tomography (PET) work with the dopamine D3 receptor (D3R) preferring ligand [11C]PHNO in obese individuals has demonstrated higher binding and positive correlations with body mass index (BMI) in otherwise healthy individuals. These findings implicated brain reward areas including the substantia nigra/ventral tegmental area (SN/VTA) and pallidum. In cocaine use disorder (CUD), similar SN/VTA binding profiles have been found compared to healthy control subjects. This study investigates whether BMI-[11C]PHNO relationships are similar in individuals with CUD. METHODS: Non-obese CUD subjects (N = 12) were compared to age-matched obese CUD subjects (N = 14). All subjects underwent [11C]PHNO acquisition using a High Resolution Research Tomograph PET scanner. Parametric images were computed using the simplified reference tissue model with cerebellum as the reference region. [11C]PHNO measures of receptor availability were calculated and expressed as non-displaceable binding potential (BPND). RESULTS: In between-group analyses, D2/3R availability in non-obese and obese CUD groups was not significantly different overall. BMI was inversely correlated withBPND in the SN/VTA (r = -0.45, p = 0.02 uncorrected) in all subjects. CONCLUSION: These data suggest that obesity in CUD was not associated with significant differences in D2/3R availability. This in contrast to previous findings in non-CUD individuals that found increased availability of D3Rs in the SN/VTA associated with obesity. These findings could potentially reflect dysregulation of D3R in CUD, impacting how affected individuals respond to natural stimuli such as food.
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Trastornos Relacionados con Cocaína/patología , Obesidad/patología , Tomografía de Emisión de Positrones , Receptores de Dopamina D2/metabolismo , Receptores de Dopamina D3/metabolismo , Adulto , Índice de Masa Corporal , Globo Pálido/diagnóstico por imagen , Humanos , Ligandos , Persona de Mediana Edad , Sustancia Negra/diagnóstico por imagen , Área Tegmental Ventral/diagnóstico por imagenAsunto(s)
Agonistas alfa-Adrenérgicos/efectos adversos , Anfetamina/efectos adversos , Enfermedades del Sistema Nervioso Autónomo/inducido químicamente , Estimulantes del Sistema Nervioso Central/efectos adversos , Guanfacina/efectos adversos , Trastorno por Déficit de Atención con Hiperactividad/complicaciones , Trastorno por Déficit de Atención con Hiperactividad/tratamiento farmacológico , Enfermedades del Sistema Nervioso Autónomo/fisiopatología , Presión Sanguínea/efectos de los fármacos , Dopamina/metabolismo , Interacciones Farmacológicas , HumanosRESUMEN
Most prior work with positron emission tomography (PET) dopamine subtype 2/3 receptor (D2/3R) non-selective antagonist tracers suggests that obese (OB) individuals exhibit lower D2/3Rs when compared with normal weight (NW) individuals. A D3-preferring D2/3R agonist tracer, [11C](+)PHNO, has demonstrated that body mass index (BMI) was positively associated with D2/3R availability within striatal reward regions. To date, OB individuals have not been studied with [11C](+)PHNO. We assessed D2/3R availability in striatal and extrastriatal reward regions in 14 OB and 14 age- and gender-matched NW individuals with [11C](+)PHNO PET utilizing a high-resolution research tomograph. Additionally, in regions where group D2/3R differences were observed, secondary analyses of 42 individuals that constituted an overweight cohort was done to study the linear association between BMI and D2/3R availability in those respective regions. A group-by-brain region interaction effect (F7, 182=2.08, p=0.047) was observed. Post hoc analyses revealed that OB individuals exhibited higher tracer binding in D3-rich regions: the substantia nigra/ventral tegmental area (SN/VTA) (+20%; p=0.02), ventral striatum (VST) (+14%; p<0.01), and pallidum (+11%; p=0.02). BMI was also positively associated with D2/3R availability in the SN/VTA (r=0.34, p=0.03), VST (r=0.36, p=0.02), and pallidum (r=0.30, p=0.05) across all subjects. These data suggest that individuals who are obese have higher D2/3R availability in brain reward regions densely populated with D3Rs, potentially identifying a novel pharmacologic target for the treatment of obesity.
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Encéfalo/diagnóstico por imagen , Obesidad/diagnóstico por imagen , Tomografía de Emisión de Positrones , Receptores de Dopamina D2/metabolismo , Receptores de Dopamina D3/metabolismo , Adulto , Índice de Masa Corporal , Encéfalo/efectos de los fármacos , Estudios de Casos y Controles , Estudios de Cohortes , Agonistas de Dopamina/farmacocinética , Femenino , Humanos , Masculino , Persona de Mediana Edad , Oxazinas/farmacocinética , Adulto JovenRESUMEN
BACKGROUND: Previous work in healthy non-human primates and humans has shown that social status correlates positively with dopamine 2/3 receptor (D2/3R) availability imaged with antagonist radioligands and positron emission tomography (PET). Further work in non-human primates suggests that this relationship is disrupted by chronic cocaine administration. This exploratory study examined the relationship between social status and D2/3R availability in healthy (HH) and cocaine dependent (CD) humans using the D3-preferring, agonist radioligand, [(11)C](+)PHNO. METHODS: Sixteen HH and sixteen CD individuals completed the Barratt Simplified Measure of Social Status (BSMSS) and underwent [(11)C](+)PHNO scanning to measure regional brain D2/3R binding potentials (BPND). Correlations between BPND and BSMSS scores were then assessed within each group. RESULTS: Within HH and CD groups, inverse associations between BSMSS score and BPND were observed in the substantia nigra/ventral tegmental area (SN/VTA) and the ventral striatum, and for the CD group alone, the amygdala. After adjusting for body mass index and age, negative correlations remained significant in the SN/VTA for HH and in the amygdala for CD subjects. CONCLUSION: These preliminary data utilizing a dopamine agonist tracer demonstrate, for the first time, an inverse association between social status and D2/3R availability in the D3R rich extrastriatal regions of HH and CD humans.
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Trastornos Relacionados con Cocaína/metabolismo , Agonistas de Dopamina/metabolismo , Jerarquia Social , Oxazinas/metabolismo , Receptores de Dopamina D2/metabolismo , Receptores de Dopamina D3/metabolismo , Adulto , Amígdala del Cerebelo/metabolismo , Estudios de Casos y Controles , Femenino , Neuroimagen Funcional , Humanos , Masculino , Tomografía de Emisión de Positrones , Sustancia Negra/metabolismo , Área Tegmental Ventral/metabolismo , Adulto JovenRESUMEN
BACKGROUND & AIMS: Restrained food consumption may alter metabolic function and contribute to eventual weight gain; however, sex differences in these relationships have not been assessed. The objective of this study was to examine the relationship between restrained eating and insulin resistance and the influence of body mass index and sex on this relationship in a large community sample of both men and women. We hypothesized that restrained eating would be related to insulin resistance and this relationship would be influenced by sex and body mass index. METHODS: In this cross-sectional, observational study, we studied 487 individuals from the community (men N = 222, women N = 265), who ranged from lean (body mass index 18.5-24.9 kg/m(2), N = 173), overweight (body mass index 25-29.9 kg/m(2), N = 159) to obese (body mass index >30 kg/m(2), N = 155) weight categories. We assessed restrained eating using the Dutch Eating Behavior Questionnaire and obtained fasting morning plasma insulin and glucose on all subjects. RESULTS: In men, but not in women, restrained eating was related to homeostatic model assessment of insulin resistance (HOMA-IR) (p < 0.0001). Furthermore, HOMA-IR was significantly higher in men who were high- versus low-restrained eaters (p = 0.0006). CONCLUSIONS: This study is the first to report sex differences with regard to the relationship between restrained eating and insulin resistance. Our results suggest that high restrained eating is associated with insulin resistance in men but not in women.