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INTRODUCTION: In remote Australian hospitals there are no onsite paediatric intensive care units (PICUs), increasing the reliance on aeromedical retrieval to access tertiary care. Nasal high flow (NHF) therapy is an oxygen therapy used in tertiary hospitals to treat paediatric patients with respiratory conditions. In rural and remote Queensland, Australia, the use of NHF therapy is inconsistent and there are no guidelines on how this therapy should be implemented in practice. Therefore, three remote hospitals within the Torres Strait and Cape York commenced a project to improve consistent and equitable access to NHF therapy. Implementing NHF therapy in remote hospitals may improve health and social outcomes for children with acute respiratory distress. A clinical guideline for the use of NHF therapy in the three participating remote hospitals was published on 28 October 2021. This study aimed to develop a clinical guideline for the use of NHF therapy in three remote hospitals. METHODS: A modified Delphi technique was used to develop the guideline. Remote medicine and nursing clinicians at the three study sites, retrieval experts, a receiving tertiary-based paediatrician, PICU specialists and NHF therapy experts made up the expert panel of participants. These experts participated in an iterative round table discussion to develop remote-specific guidelines for the use of NHF therapy. Prior to the meeting, panellists were provided with an executive summary of the current literature on NHF therapy implementation with key questions for consideration. Participants were able to add relevant issues ad hoc. A final guideline representing the panellists' recommendations was submitted to the Torres and Cape Health Service for ratification. RESULTS: Remote-specific decisions on the following topics were produced: environment of care, nasogastric tube usage, timings of chest X-ray, automatic approvals to arrange courier services for pathology, medication use, staff training; staff ratios, observations regimes, both tertiary and local medical consultation frequency and the experience level of the medical officer required to attend to these consultations, location of the on-call medical officer, documentation, escalation of care considerations and disposition of the patient in relation to retrievals. DISCUSSION: Decisions were made to mitigate two highly representative remote factors: delays in the workplace practices, such as time to arrange treatment locally and delays in retrievals; and burden of the lack of access to services, such as lack of access to trained staff, staffing levels on-shift, adequate oxygen and equipment/consumable supplies. CONCLUSION: The aim was to develop a clinical guideline that was contextualised to the remote hospital. This outcome was achieved by using a modified Delphi technique, with a panel of experts providing the decision-making for the guideline. Consistency and safety were addressed by reducing delays in workplace practices; examples were time to arrange treatment locally and mitigate delays in an unknown time to retrievals, access to trained staff, staffing levels, and communication between remote and tertiary teams.
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Hospitais , Oxigênio , Humanos , Criança , Austrália , Técnica Delphi , QueenslandRESUMO
PAPP-A knock-out (KO) mice are a valuable model for investigating the effects of down-regulating localized insulin-like growth factor (IGF) action, which has been shown to extend lifespan and healthspan when the PAPP-A gene is globally deleted. Based on previous mouse models of brain-specific reduction in IGF signaling associated with longevity, we sought to generate brain-specific PAPP-A KO mice and determine effects on metabolism and lifespan. Mice with the PAPP-A gene floxed (fPAPP-A) were crossed with Nestin promoter-driven Cre recombinase transgenic mice. This cross-breeding of mice for Nestin-Cre and mice with other floxed target alleles has been used extensively to investigate brain-specific effects. Our cross-breeding generated four genotypes for study: fPAPP-A/Nestin positive (brain-specific PAPP-A KO); fPAPP-A/Nestin negative (Control for floxed PAPP-A); WT/Nestin positive (Control for Nestin-Cre); WT/Nestin negative (Wild-type Control). The basic genotype screen of neonatal tail snip DNA clearly indicated PAPP-A gene status and the presence (pos) or absence (neg) of Nestin-Cre. We then determined tissue specificity of PAPP-A gene excision. We had expected fPAPP-A/pos mice to be relatively brain-specific for PAPP-A gene deletion and the controls (fPAPP-A/neg, WT/neg and WT/pos mice) to show no effect on PAPP-A expression in brain or other tissues. However, in fPAPP-A/neg mice we found evidence of PAPP-A excision in all tissues examined, i.e., in the presumed absence of Nestin-Cre, indicating germline recombination. We further found that fPAPP-A/pos mice showed near complete excision of the PAPP-A gene in brain, but some also showed germline recombination affecting all tissues tested. To determine if the level of excision indicated by tissue genotyping approximated PAPP-A mRNA expression, we performed RT-qPCR. fPAPP-A/pos mice that showed markedly decreased whole brain PAPP-A mRNA expression (~80%), with little or no effect on expression in the other tissues tested, were designated as "brain-specific" PAPP-A KO. fPAPP-A/pos mice that showed germline recombination had similar decreases in PAPP-A expression in brain but also showed 40-65% decreased PAPP-A mRNA expression in other tissues as well, which was especially striking in kidney, tibia, thymus and spleen. These were designated as "non-specific" PAPP-A KO mice. With unknown and unpredictable specificity until harvest, we chose to assess a surrogate marker of lifespan i.e., thymic involution, in 15- to 18-month-old fPAPP-A/pos and WT/pos mice, the latter an important control for a possible effect of Nestin-Cre per se. Diminished thymic involution as indicated by increased thymic weight (135%, P = 0.035) and decreased histological disruption was seen in "non-specific" PAPP-A KO mice, similar to what was previously reported in 18-month-old global PAPP-A KO mice. There was no significant difference between "brain-specific" PAPP-A KO and control mice. This study highlights the importance of thorough characterization of assumed tissue-specific mouse models and awareness of potential germline recombination for proper data interpretation.
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Longevidade , Proteína Plasmática A Associada à Gravidez , Animais , Encéfalo/metabolismo , Genótipo , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Proteína Plasmática A Associada à Gravidez/genéticaRESUMO
Pathogenicity of visceral adipose tissue (VAT) has been linked to the metabolic stress of enlarging mature adipocytes and a limited ability to recruit new adipocytes. One of the major distinguishing features of VAT preadipocytes is the high expression of the zinc metalloprotease, pregnancy-associated plasma protein-A (PAPP-A), when compared to subcutaneous adipose tissue (SAT). In this study we used 2 different approaches to investigate the effect of PAPP-A inhibition on different fat depots in mice on a high-fat diet (HFD) for 15 weeks. Conditional knockdown of PAPP-A gene expression in female adult mice resulted in significant decreases of 30% to 40% in adipocyte size in VAT (mesenteric and pericardial depots) compared to control mice. There was no effect on SAT (inguinal) or intra-abdominal perigonadal fat. Liver lipid was also significantly decreased without any effect on heart and skeletal muscle lipid. We found similar effects when using a pharmacological approach. Weekly injections of a specific immunoneutralizing monoclonal antibody (mAb-PA 1/41) or isotype control were given to male and female wild-type mice on HFD for 15 weeks. Adipocyte size was significantly decreased (30%-50%) only in VAT with mAb-PA 1/41 treatment. In this model, cell number was significantly increased in mesenteric fat in mice treated with mAb-PA 1/41, suggesting hyperplasia along with reduced hypertrophy in this VAT depot. Gene expression data indicated a significant decrease in F4/80 (macrophage marker) and interleukin-6 (proinflammatory cytokine) and a significant increase in adiponectin (anti-inflammatory adipokine with beneficial metabolic effects) in mesenteric fat compared to inguinal fat in mice treated with mAb-PA 1/41. Furthermore, there was significantly decreased liver lipid content with mAb-PA 1/41 treatment. Thus, using 2 different models systems we provide proof of principle that PAPP-A inhibition is a potential therapeutic target to prevent visceral obesity and its metabolic sequelae, such as fatty liver.
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Fármacos Antiobesidade/farmacologia , Anticorpos Monoclonais/farmacologia , Obesidade Abdominal , Proteína Plasmática A Associada à Gravidez/antagonistas & inibidores , Proteína Plasmática A Associada à Gravidez/genética , Tecido Adiposo/efeitos dos fármacos , Tecido Adiposo/metabolismo , Tecido Adiposo/patologia , Animais , Dieta Hiperlipídica/efeitos adversos , Feminino , Técnicas de Inativação de Genes , Gordura Intra-Abdominal/efeitos dos fármacos , Gordura Intra-Abdominal/metabolismo , Metabolismo dos Lipídeos/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/metabolismo , Camundongos , Camundongos da Linhagem 129 , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Obesos , Obesidade Abdominal/genética , Obesidade Abdominal/prevenção & controle , Proteína Plasmática A Associada à Gravidez/imunologia , Gordura Subcutânea/metabolismoRESUMO
Although implicated in cardiovascular disease, little is known about the fat surrounding the heart. In humans, epicardial fat is the visceral fat depot of the heart, which directly contacts the myocardium. This strategically placed fat depot is thought to produce bioactive molecules that could affect cardiac function. A major limitation in understanding the biology of epicardial fat is its restricted access in humans and its seeming absence in commonly-used experimental animal models. Although laboratory mice do not have epicardial fat per se, they do have a fat depot around the heart. In this study, we found that mouse pericardial fat has the molecular signature, small adipocyte size, and resistance to differentiation consistent with visceral fat. In addition, we show that mouse pericardial fat is regulated by pregnancy-associated plasma protein-A (PAPP-A), a key modulator of local insulin-like growth factor bioavailability. PAPP-A is highly expressed in mouse pericardial fat at levels equivalent to those in mesenteric visceral fat and 10-fold higher than in subcutaneous inguinal fat (Pâ¯=â¯.0003). Cultured pre-adipocytes isolated from pericardial fat show 2-fold increased PAPP-A secretion compared to pre-adipocytes isolated from inguinal fat. Furthermore, PAPP-A knock-out mice fed a high fat diet for 20â¯weeks have significantly reduced pericardial fat (by 60%; Pâ¯<â¯.0001) compared to wild-type littermates. There was no significant difference in inguinal fat between wild-type and PAPP-A knock-out mice. These data characterize a new mouse model of visceral-like pericardial fat and lay a foundation for understanding its role in human heart disease.
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Adipócitos/fisiologia , Tecido Adiposo/fisiologia , Pericárdio/fisiologia , Proteína Plasmática A Associada à Gravidez/fisiologia , Adipócitos/citologia , Tecido Adiposo/citologia , Animais , Células Cultivadas , Modelos Animais de Doenças , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Pericárdio/citologiaRESUMO
Pregnancy-associated plasma protein-A (PAPP-A) knockout (KO) mice, generated through homologous recombination in embryonic stem cells, have a significantly increased lifespan compared to wild-type littermates. However, it is unknown whether this longevity advantage would pertain to PAPP-A gene deletion in adult animals. In the present study, we used tamoxifen (Tam)-inducible Cre recombinase-mediated excision of the floxed PAPP-A (fPAPP-A) gene in mice at 5 months of age. fPAPP-A mice, which were either positive (pos) or negative (neg) for Tam-Cre, received Tam treatment with quarterly boosters. Only female mice could be used with this experimental design. fPAPP-A/neg and fPAPP-A/pos mice had similar weights at the start of the experiment and showed equivalent weight gain. We found that fPAPP-A/pos mice had a significant extension of life span (P = 0.005). The median life span was increased by 21% for fPAPP-A/pos compared to fPAPP-A/neg mice. Analysis of mortality in life span quartiles indicated that the proportion of deaths of fPAPP-A/pos mice were lower than fPAPP-A/neg mice at young adult ages (P = 0.002 for 601-800 days) and higher than fPAPP-A/neg mice at older ages (P = 0.004 for >1000 days). Thus, survival curves and age-specific mortality indicate that female mice with knockdown of PAPP-A gene expression as adults have an extended healthy life span.
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Técnicas de Silenciamento de Genes/métodos , Longevidade/genética , Proteína Plasmática A Associada à Gravidez/deficiência , Animais , Peso Corporal , Feminino , Expressão Gênica , Integrases/genética , Integrases/metabolismo , Camundongos , Camundongos Knockout , Gravidez , Proteína Plasmática A Associada à Gravidez/genética , Análise de Sobrevida , Tamoxifeno/químicaRESUMO
UNLABELLED: Mice deficient in pregnancy-associated plasma protein-A (PAPP-A), an IGF binding protein protease, have been shown to be resistant to experimentally induced atherosclerosis and diabetic nephropathy, and, in the laboratory environment, live 30-40% longer than wild-type littermates in association with delayed incidence and occurrence of age-related neoplasms and degenerative diseases. OBJECTIVE: PAPP-A is highly expressed in the cerebellum and hippocampus of the mouse brain. Therefore, the studies presented here were aimed at determining motor behavior, learning and retention in PAPP-A knock-out (KO) mice compared to wild-type (WT) littermates with age. DESIGN: Balance and coordination were assessed using an accelerating rotarod; learning and memory were assessed in a Stone T-maze. RESULTS: Time on the rotarod decreased with age but there was no significant difference between PAPP-A KO and WT mice at any of the testing ages. Latency to reach the goal box and number of errors committed in the Stone T-maze did not change with age and there were no significant differences between PAPP-A KO and WT mice. CONCLUSION: Lack of PAPP-A in mice did not impact central regulation of coordination, learning or memory.
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Longevidade/fisiologia , Aprendizagem em Labirinto , Memória/fisiologia , Neurônios Motores/fisiologia , Proteína Plasmática A Associada à Gravidez/fisiologia , Teste de Desempenho do Rota-Rod , Animais , Feminino , Masculino , Camundongos , Camundongos Knockout , GravidezRESUMO
Niemann-Pick, type C (NP-C) disease is an autosomal recessive neurovisceral storage disorder in which cholesterol and sphingolipids accumulate. There is no specific treatment for this disease, which is characterized by progressive neurological deterioration, sometimes accompanied by hepatosplenomegaly. We and others have shown that overexpression of certain Rab GTPases corrects defective membrane trafficking and reduces lipid storage in cultured NP-C fibroblasts. Here, we tested the possibility that Rab protein overexpression might also have beneficial effects in vivo using a murine model of NP-C. We first generated several lines of transgenic mice that ubiquitously overexpress Rab9 up to approximately 30-fold more than endogenous levels and found that the transgene expression had no obvious effects on fertility, behavior, or lifespan in normal mice. These transgenic strains were then crossed with NP-C mutant mice to produce NP-C homozygous recessive mice with and without the Rab9 transgene. Life expectancy of the NPC1 homozygous recessive animals was extended up to 22% depending on gender and the transgenic strain that was used. Histological studies and lipid analysis of brain sections indicated that the NP-C mice carrying the Rab9 transgene had dramatically reduced storage of GM(2) and GM(3) gangliosides relative to NP-C animals lacking the transgene. These results demonstrate that Rab9 overexpression has the potential to reduce stored lipids and prolong lifespan in vivo.