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1.
Front Med (Lausanne) ; 10: 1246796, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38116038

RESUMO

Here, we report the first adult case of pancreatic yolk sac tumor with ectopic adrenocorticotropic hormone (ACTH) syndrome. The patient was a 27-year-old woman presenting with abdominal distension, Cushingoid features, and hyperpigmentation. Endogenous Cushing's syndrome was biochemically confirmed. The ACTH level was in the normal range, which raised the suspicion of ACTH precursor-dependent disease. Elevated ACTH precursors were detected, supporting the diagnosis of ectopic ACTH syndrome. Functional imaging followed by tissue sampling revealed a pancreatic yolk sac tumor. The final diagnosis was Cushing's syndrome due to a yolk sac tumor. The patient received a steroidogenesis inhibitor and subsequent bilateral adrenalectomy for control of hypercortisolism. Her yolk sac tumor was treated with chemotherapy and targeted therapy. Cushing's syndrome secondary to a yolk sac tumor is extremely rare. This case illustrated the utility of ACTH precursor measurement in confirming an ACTH-related pathology and distinguishing an ectopic from a pituitary source for Cushing's syndrome.

2.
Health Commun ; : 1-16, 2023 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-38111218

RESUMO

To investigate how clinicians correct patient misconceptions, we analyzed 23 video recordings of primary care visits. Analysis focused on operationalizing, identifying, and characterizing clinician corrections, integrating two inductive approaches: microanalysis of clinical interaction and conversation analysis. According to our definition, patient misconception-clinician correction episodes met three essential criteria: (1) the clinician refuted something the patient had said, (2) which the patient had presented without uncertainty, and (3) which contained a proposition that was factually incorrect. We identified 59 such episodes; the patient misconceptions most commonly related to medication issues; fewer than half had foreseeable implications for patients' future actions. We identified seven clinician correction practices: Three direct practices (displaying surprise, marking disagreement, contradicting the patient) and four indirect practices (presenting the correct proposition, providing explanations, invoking an outside authority, demonstrating with evidence). We found an almost equal distribution of these direct and indirect practices.

4.
J Contin Educ Nurs ; 54(7): 322-326, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37390304

RESUMO

BACKGROUND: The United States faces a national shortage of nurse educators who need more educational preparation to successfully transition into an academic setting. A professional learning community (PLC), using the National League for Nursing certified nurse educator (CNE) core competencies, offers an innovative way to meet the learning needs of nurse educators. METHOD: A qualitative descriptive design was used to summarize the experiences of the faculty members who participated in the CNE PLC. RESULTS: The following five themes were discovered: aspirations for involvement, significance of learning in a community, value of the CNE core competencies, challenges to participation, and value of engagement. CONCLUSION: A PLC is an effective way to meet the professional needs of faculty in the academic and clinical settings by embracing the notion that learning occurs through interaction with others. This project expands beyond the conventional new faculty onboarding workshops, which tend to be unidirectional and focused on information delivery. [J Contin Educ Nurs. 2023;54(7):322-326.].


Assuntos
Docentes de Enfermagem , Aprendizagem , Humanos , Escolaridade , Certificação
6.
Nurse Educ ; 48(1): 29-32, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36066580

RESUMO

BACKGROUND: A standardized survey to describe the quality of care received from prelicensure nursing students during simulation can measure simulation program effectiveness. PURPOSE: The purpose of this study was to compare national Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) survey data with data received from standardized patients (SPs) using a modified HCAHPS survey. METHODS: SPs completed a modified HCAHPS survey immediately following each in-person simulated encounter. One year of SP responses (N = 385) from one baccalaureate nursing program was compared with the national HCAHPS survey data from the same time. RESULTS: All SP responses were less than the national proportions. However, when the level of stringency was adjusted, the responses more similarly aligned to the national proportions. CONCLUSIONS: Findings suggest HCAHPS data can be used to model correlates of the quality of care SPs receive during simulation events.


Assuntos
Qualidade da Assistência à Saúde , Humanos , Pesquisa em Educação em Enfermagem
7.
Mol Metab ; 66: 101627, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36374777

RESUMO

OBJECTIVE: The hypothalamus regulates feeding and glucose homeostasis through the balanced action of different neuropeptides, which are cleaved and activated by the proprotein convertases PC1/3 and PC2. However, the recent association of polymorphisms in the proprotein convertase FURIN with type 2 diabetes, metabolic syndrome, and obesity, prompted us to investigate the role of FURIN in hypothalamic neurons controlling glucose and feeding. METHODS: POMC-Cre+/- mice were bred with Furinfl/fl mice to generate conditional knockout mice with Furin-deletion in neurons expressing proopiomelanocortin (POMCFurKO), and Furinfl/fl mice were used as controls. POMCFurKO and controls were periodically monitored on both normal chow diet and high fat diet (HFD) for body weight and glucose tolerance by established in-vivo procedures. Food intake was measured in HFD-fed FurKO and controls. Hypothalamic Pomc mRNA was measured by RT-qPCR. ELISAs quantified POMC protein and resulting peptides in the hypothalamic extracts of POMCFurKO mice and controls. The in-vitro processing of POMC was studied by biochemical techniques in HEK293T and CHO cell lines lacking FURIN. RESULTS: In control mice, Furin mRNA levels were significantly upregulated on HFD feeding, suggesting an increased demand for FURIN activity in obesogenic conditions. Under these conditions, the POMCFurKO mice were hyperphagic and had increased body weight compared to Furinfl/fl mice. Moreover, protein levels of POMC were elevated and ACTH concentrations markedly reduced. Also, the ratio of α-MSH/POMC was decreased in POMCFurKO mice compared to controls. This indicates that POMC processing was significantly reduced in the hypothalami of POMCFurKO mice, highlighting for the first time the involvement of FURIN in the cleavage of POMC. Importantly, we found that in vitro, the first stage in processing where POMC is cleaved into proACTH was achieved by FURIN but not by PC1/3 or the other proprotein convertases in cell lines lacking a regulated secretory pathway. CONCLUSIONS: These results suggest that FURIN processes POMC into proACTH before sorting into the regulated secretory pathway, challenging the dogma that PC1/3 and PC2 are the only convertases responsible for POMC cleavage. Furthermore, its deletion affects feeding behaviors under obesogenic conditions.


Assuntos
Diabetes Mellitus Tipo 2 , Comportamento Alimentar , Furina , Hipotálamo , Pró-Opiomelanocortina , Animais , Humanos , Camundongos , alfa-MSH/metabolismo , Peso Corporal , Dieta Hiperlipídica/efeitos adversos , Comportamento Alimentar/fisiologia , Furina/genética , Furina/metabolismo , Glucose , Células HEK293 , Hipotálamo/metabolismo , Pró-Opiomelanocortina/genética , Pró-Opiomelanocortina/metabolismo , Pró-Proteína Convertase 1/genética , Pró-Proteína Convertase 1/metabolismo , Pró-Proteína Convertase 2/genética , Pró-Proteína Convertase 2/metabolismo , Pró-Proteína Convertases/genética , Pró-Proteína Convertases/metabolismo , RNA Mensageiro/metabolismo , Subtilisinas/genética , Subtilisinas/metabolismo
8.
Curr Biol ; 32(21): 4699-4706.e4, 2022 11 07.
Artigo em Inglês | MEDLINE | ID: mdl-36182699

RESUMO

Loss of appetite and negative energy balance are common features of endotoxemia in all animals and are thought to have protective roles by reducing nutrient availability to host and pathogen metabolism. Accordingly, fasting and caloric restriction have well-established anti-inflammatory properties. However, in response to reduced nutrient availability at the cellular and organ levels, negative energy balance also recruits distinct energy-sensing brain circuits, but it is not known whether these neuronal systems have a role in its anti-inflammatory effects. Here, we report that hypothalamic AgRP neurons-a critical neuronal population for the central representation of negative energy balance-have parallel immunoregulatory functions. We found that when endotoxemia occurs in fasted mice, the activity of AgRP neurons remains sustained, but this activity does not influence feeding behavior and endotoxemic anorexia. Furthermore, we found that endotoxemia acutely desensitizes AgRP neurons, which also become refractory to inhibitory signals. Mimicking this sustained AgRP neuron activity in fed mice by chemogenetic activation-a manipulation known to recapitulate core behavioral features of fasting-results in reduced acute tumor necrosis factor alpha (TNF-α) release during endotoxemia. Mechanistically, we found that endogenous glucocorticoids play an important role: glucocorticoid receptor deletion from AgRP neurons prevents their endotoxemia-induced desensitization, and importantly, it counteracts the fasting-induced suppression of TNF-α release, resulting in prolonged sickness. Together, these findings provide evidence directly linking AgRP neuron activity to the acute response during endotoxemia, suggesting that these neurons are a functional component of the immunoregulatory effects associated with negative energy balance and catabolic metabolism.


Assuntos
Endotoxemia , Fator de Necrose Tumoral alfa , Camundongos , Animais , Proteína Relacionada com Agouti/genética , Proteína Relacionada com Agouti/metabolismo , Fator de Necrose Tumoral alfa/genética , Endotoxemia/metabolismo , Endotoxemia/patologia , Hipotálamo/metabolismo , Neurônios/fisiologia , Metabolismo Energético
9.
J Clin Endocrinol Metab ; 107(9): e3699-e3704, 2022 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-35737586

RESUMO

OBJECTIVE: Patients with pro-opiomelanocortin (POMC) defects generally present with early-onset obesity, hyperphagia, hypopigmentation and adrenocorticotropin (ACTH) deficiency. Rodent models suggest that adequate cleavage of ACTH to α-melanocortin-stimulating hormone (α-MSH) and desacetyl-α-melanocortin-stimulating hormone (d-α-MSH) by prohormone convertase 2 at the KKRR region is required for regulating food intake and energy balance. METHODS: We present 2 sisters with a novel POMC gene variant, leading to an ACTH defect at the prohormone convertase 2 cleavage site, and performed functional studies of this variant. RESULTS: The patients had obesity, hyperphagia and hypocortisolism, with markerly raised levels of ACTH but unaffected pigmentation. Their ACTH has reduced potency to stimulate the melanocortin (MC) 2 receptor, explaining their hypocortisolism. CONCLUSION: The hyperphagia and obesity support evidence that adequate cleavage of ACTH to α-MSH and d-α-MSH is also required in humans for feeding control.


Assuntos
Hormônio Adrenocorticotrópico , Pró-Opiomelanocortina , Insuficiência Adrenal , Humanos , Hiperfagia/genética , Obesidade/genética , Pró-Opiomelanocortina/genética , Pró-Proteína Convertase 2 , alfa-MSH
10.
Qual Health Res ; 32(8-9): 1246-1258, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35616449

RESUMO

The quality of healthcare communication can impact both experiences and outcomes. We highlight aspects of communication that can be systematically examined using Conversation Analysis (CA) and provide guidance about how researchers can incorporate CA into healthcare studies. CA is a qualitative method for studying naturally occurring communication by analyzing recurrent, systematic practices of verbal and nonverbal behavior. CA involves examining audio- or video-recorded conversations and their transcriptions to identify practices speakers use to communicate and interpret behavior. We explain what distinguishes CA from other methods that study communication and highlight three accessible CA approaches that researchers can use in their research design, analysis, or implementation of communication interventions. Specifically, these approaches focus on how talk is produced (specific words, framing, and syntax), by whom, and when it occurs in the conversation. These approaches can be leveraged to generate hypotheses and to identify patterns of behavior that inform empirically driven communication interventions.


Assuntos
Comunicação , Atenção à Saúde , Serviços de Saúde , Humanos
11.
Multivariate Behav Res ; 57(2-3): 356-384, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-33327792

RESUMO

We compare two methods for obtaining similarity data in the conceptual domain. In the Spatial Arrangement Method (SpAM), participants organize stimuli on a computer screen so that the distance between stimuli represents their perceived dissimilarity. In Total-Set Pairwise Rating Method (PRaM), participants rate the (dis)similarity of all pairs of stimuli on a Likert scale. In each of three studies, we had participants indicate the similarity of four sets of conceptual stimuli with either PRaM or SpAM. Studies 1 and 2 confirm two caveats that have been raised for SpAM. (i) While SpAM takes significantly less time to complete than PRaM, it yields less reliable data than PRaM does. (ii) Because of the spatial manner in which similarity is measured in SpAM, the method is biased against feature representations. Despite these differences, averaging SpAM and PRaM dissimilarity data across participants yields comparable aggregate data. Study 3 shows that by having participants only judge half of the pairs in PRaM, its duration can be significantly reduced, without affecting the dissimilarity distribution, but at the cost of a smaller reliability. Having participants arrange multiple subsets of the stimuli does not do away with the spatial bias of SpAM.


Assuntos
Coleta de Dados , Reconhecimento Visual de Modelos , Coleta de Dados/métodos , Humanos , Reprodutibilidade dos Testes
12.
J Gen Intern Med ; 37(1): 78-86, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34159543

RESUMO

BACKGROUND: Physicians and patients report frustration after primary care visits for chronic pain. The need to shift between multiple clinical topics to address competing demands during visits may contribute to this frustration. OBJECTIVE: This study creates a novel measure, "visit linearity," to assess visit organization and examines whether visits that require less shifting back and forth between topics are associated with better patient and physician visit experiences. It also explores whether visit linearity differs depending on the following: (1) whether or not pain is a major topic of the visit and (2) whether or not pain is the first topic raised. DESIGN: This study analyzed 41 video-recorded visits using inductive, qualitative analysis informed by conversation analysis. We used linear regression to evaluate associations between visit organization and post-visit measures of participant experience. PARTICIPANTS: Patients were established adult patients planning to discuss pain management during routine primary care. Physicians were internal or family medicine residents. MAIN MEASURES: Visit linearity, total topics, return topics, topic shifts, time per topic, visit duration, pain main topic, pain first topic, patient experience, and physician difficulty. KEY RESULTS: Visits had a mean of 8.1 total topics (standard deviation (SD)=3.46), 14.5 topic shifts (SD=6.28), and 1.9 topic shifts per topic (SD=0.62). Less linear visits (higher topic shifts to topic ratio) were associated with greater physician visit difficulty (ß=7.28, p<0.001) and worse patient experience (ß= -0.62, p=0.03). Visit linearity was not significantly impacted by pain as a major or first topic raised. CONCLUSIONS: In primary care visits for patients with chronic pain taking opioids, more linear visits were associated with better physician and patient experience. Frequent topic shifts may be disruptive. If confirmed in future research, this finding implies that reducing shifts between topics could help decrease mutual frustration related to discussions about pain.


Assuntos
Analgésicos Opioides , Dor Crônica , Adulto , Dor Crônica/tratamento farmacológico , Humanos , Visita a Consultório Médico , Manejo da Dor , Relações Médico-Paciente , Atenção Primária à Saúde
13.
Health Commun ; 37(5): 535-547, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-33406915

RESUMO

This study examines patient-initiated additional concern presentations in general surgery visits to assess which factors contribute to them getting "helped." Concern presentations were analyzed for a variety of design features (e.g., social action (inquiry vs. informing), when patients initiate during a visit, how patients fit topic to previous talk or activity) and contextual factors (e.g., concern falls inside or outside surgeon's domain of expertise, chronic vs. acute concern-types, the history of the patient-physician relationship). This study uses a mixed-methods approach, combining case-level conversation analysis and aggregate-level statistical analysis. Data are video recordings of office visits from 2013-2015, with a longitudinal focus of following the same patients across time. In total, 62 patients spanning 175 visits were analyzed. 377 patient-initiated additional concerns were found, and 188 received help. Several factors were found to increase the likelihood of patients' concerns getting helped such as designing the concern as an inquiry, raising the concern early in the visit, and mentioning the concern more than once. These findings can help guide patients on how to better design additional concerns presentations to receive help and can benefit physicians by identifying more subtle practices patients are already using to broach concerns to help reduce unnoticed or unhelped concerns.


Assuntos
Relações Médico-Paciente , Médicos , Comunicação , Humanos , Visita a Consultório Médico , Gravação em Vídeo
14.
Exp Eye Res ; 215: 108908, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34954204

RESUMO

Opticin is an extracellular glycoprotein present in the vitreous. Its antiangiogenic properties offer the potential for therapeutic intervention in conditions such as proliferative diabetic retinopathy and retinopathy of prematurity. Here, we investigated the hypothesis that intravitreal administration of recombinant human opticin can safely protect against the development of pathological angiogenesis and promote its regression. We generated and purified recombinant human opticin and investigated its impact on the development and regression of pathological retinal neovascularization following intravitreal administration in murine oxygen-induced retinopathy. We also investigated its effect on normal retinal vascular development and function, following intravitreal injection in neonatal mice, by histological examination and electroretinography. In oxygen-induced retinopathy, intravitreal administration of human recombinant opticin protected against the development of retinal neovascularization to similar extent as aflibercept, which targets VEGF. Opticin also accelerated regression of established retinal neovascularization, though the effect at 18 h was less than that of aflibercept. Intravitreal administration of human recombinant opticin in neonatal mice caused no detectable perturbation of subsequent retinal vascular development or function. In summary we found that intraocular administration of recombinant human opticin protects against the development of pathological angiogenesis in mice and promotes its regression.


Assuntos
Hiperóxia , Neovascularização Retiniana , Retinopatia da Prematuridade , Animais , Modelos Animais de Doenças , Humanos , Hiperóxia/complicações , Recém-Nascido , Injeções Intravítreas , Camundongos , Camundongos Endogâmicos C57BL , Neovascularização Patológica , Oxigênio/toxicidade , Neovascularização Retiniana/tratamento farmacológico , Retinopatia da Prematuridade/tratamento farmacológico , Retinopatia da Prematuridade/prevenção & controle
15.
J Contin Educ Nurs ; 52(12): 554-557, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34870527

RESUMO

The use of backward design is an effective strategy to create innovative and transformative programs. This article describes the use of backward design to create an effective graduate program to prepare nurse educators. Two cohorts of graduates provided feedback regarding program outcomes. Respondents were all working in an educator role after graduation, in both clinical and academic settings. Overall, respondents reported agreement in their ability to perform as effective educators in each of the eight National League for Nursing core competencies for nurse educators. This innovative use of backward design has proven effective in educating the next generation of nurse educators to be leaders in a digital world. [J Contin Educ Nurs. 2021;52(12):554-557.].


Assuntos
Docentes de Enfermagem , Humanos
16.
Cancer Med ; 10(22): 8040-8057, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34608770

RESUMO

BACKGROUND: Multiple myeloma (MM) is an incurable cancer with complex treatment options. Trusting patient-clinician relationships are essential to promote effective shared decision-making that aligns best clinical practices with patient values and preferences. This study sought to shed light on the development of trust between MM patients and clinicians. METHODS: Nineteen individual semi-structured interviews were conducted with MM patients within 2 years of initial diagnosis or relapse for this qualitative study. Interviews were recorded and transcripts were coded thematically. RESULTS: We identified three main themes: (1) externally validated trust describes patients' predisposition to trust or distrust clinicians based on factors outside of patient-clinician interactions; (2) internally validated trust describes how patients develop trust based on interactions with specific clinicians. Internally validated trust is driven primarily by clinician communication practices that demonstrate competence, responsiveness, listening, honesty, and empathy; and (3) trust in relation to shared decision-making describes how patients relate the feeling of trust, or lack thereof, to the process of shared decision-making. CONCLUSION: Many factors contribute to the development of trust between MM patients and clinicians. While some are outside of clinicians' control, others derive from clinician behaviors and interpersonal communication skills. These findings suggest the possibility that trust can be enhanced through communication training or shared decision-making tools that emphasize relational communication. Given the important role trust plays in shared decision-making, clinicians working with MM patients should prioritize establishing positive, trusting relationships.


Assuntos
Tomada de Decisões/ética , Mieloma Múltiplo/epidemiologia , Confiança/psicologia , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pesquisa Qualitativa
18.
Artigo em Inglês | MEDLINE | ID: mdl-34281001

RESUMO

Preventable neonatal deaths due to prematurity, perinatal events, and infections are the leading causes of under-five mortality. The vast majority of these deaths are in resource-limited areas. Deaths due to infection have been associated with lack of access to clean water, overcrowded nurseries, and improper disinfection (reprocessing) of equipment, including vital resuscitation equipment. Reprocessing has recently come to heightened attention, with the COVID-19 pandemic bringing this issue to the forefront across all economic levels; however, it is particularly challenging in low-resource settings. In 2015, Eslami et al. published a letter to the editor in Resuscitation, highlighting concerns about the disinfection of equipment being used to resuscitate newborns in Kenya. To address the issue of improper disinfection, the global health nongovernment organization PATH gathered a group of experts and, due to lack of best-practice evidence, published guidelines with recommendations for reprocessing of neonatal resuscitation equipment in low-resource areas. The guidelines follow the gold-standard principle of high-level disinfection; however, there is ongoing concern that the complexity of the guideline would make feasibility and sustainability difficult in the settings for which it was designed. Observations from hospitals in Kenya and Malawi reinforce this concern. The purpose of this review is to discuss why proper disinfection of equipment is important, why this is challenging in low-resource settings, and suggestions for solutions to move forward.


Assuntos
COVID-19 , Desinfecção , Contaminação de Equipamentos , Feminino , Humanos , Recém-Nascido , Quênia , Malaui , Pandemias , Gravidez , Ressuscitação , SARS-CoV-2
19.
Sci Rep ; 11(1): 13776, 2021 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-34215821

RESUMO

Glucocorticoids (GCs) are widely prescribed anti-inflammatory medicines, but their use can lead to metabolic side-effects. These may occur through direct actions of GCs on peripheral organs, but could also be mediated by the hypothalamic AgRP neurons, which can increase food intake and modify peripheral metabolism. Therefore, the aim of this study was to examine the metabolic effects of chronic treatment with the GC corticosterone (Cort, 75 µg/ml in drinking water) in mice lacking the glucocorticoid receptor (GR) on AgRP neurons. Female AgRP-GR KO mice had delayed onset of Cort-induced hyperphagia. However, AgRP-GR KO had little impact on the increased body weight or adiposity seen with 3 weeks Cort treatment. Cort caused hepatic steatosis in control mice, but in Cort treated female AgRP-GR KO mice there was a 25% reduction in liver lipid content and lower plasma triglycerides. Additionally, Cort treatment led to hyperinsulinaemia, but compared to controls, Cort-treated AgRP-GR KO mice had both lower fasting insulin levels and lower insulin levels during a glucose tolerance test. In conclusion, these data indicate that GCs do act through AgRP neurons to contribute, at least in part, to the adverse metabolic consequences of chronic GC treatment.


Assuntos
Proteína Relacionada com Agouti/genética , Glucocorticoides/efeitos adversos , Inflamação/tratamento farmacológico , Receptores de Glucocorticoides/genética , Animais , Corticosterona/efeitos adversos , Corticosterona/farmacologia , Modelos Animais de Doenças , Glucocorticoides/farmacologia , Humanos , Hiperinsulinismo/induzido quimicamente , Hipotálamo/efeitos dos fármacos , Hipotálamo/patologia , Inflamação/complicações , Inflamação/patologia , Lipídeos/genética , Fígado/efeitos dos fármacos , Fígado/patologia , Camundongos , Neurônios/efeitos dos fármacos , Neurônios/patologia
20.
Endocrinology ; 2021 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-33693631

RESUMO

Pro-opiomelanocortin (POMC) neurons form an integral part of the central melanocortin system regulating food intake and energy expenditure. Genetic and pharmacological studies have revealed that defects in POMC synthesis, processing, and receptor signaling lead to obesity. It is well established that POMC is extensively processed by a series of enzymes, including prohormone convertases PC1/3 and PC2, and that genetic insufficiency of both PC1/3 and POMC is strongly associated with obesity risk. However, whether PC1/3-mediated POMC processing is absolutely tied to body weight regulation is not known. To investigate this question, we generated a Pomc-CreER  T2; Pcsk1  lox/lox mouse model in which Pcsk1 is specifically and temporally knocked out in POMC-expressing cells of adult mice by injecting tamoxifen at eight weeks of age. We then measured the impact of Pcsk1 deletion on POMC cleavage to ACTH and α-MSH, and on body weight. In whole pituitary, POMC cleavage was significantly impacted by the loss of Pcsk1, while hypothalamic POMC-derived peptide levels remained similar in all genotypes. However, intact POMC levels were greatly elevated in Pomc-CreER  T2; Pcsk1  lox/lox mice. Males expressed two-fold greater levels of pituitary PC1/3 protein than females, consistent with their increased POMC cleavage. Past studies show that mice with germline removal of PC1/3 do not develop obesity, while mice expressing mutant PC1/3 forms do develop obesity. We conclude that obesity pathways are not disrupted by PC1/3 loss solely in POMC-expressing cells, further disfavoring the idea that alterations in POMC processing underlie obesity in PCSK1 deficiency.

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