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1.
BMC Psychiatry ; 22(1): 7, 2022 01 04.
Artigo em Inglês | MEDLINE | ID: mdl-34983463

RESUMO

BACKGROUND: Suicide is an important contributor to the burden of mental health disorders, but community-based suicide data are scarce in many low- and middle-income countries (LMIC) including Kenya. Available data on suicide underestimates the true burden due to underreporting related to stigma and legal restrictions, and under-representation of those not utilizing health facilities. METHODS: We estimated the cumulative incidence of suicide via verbal autopsies from the Health and Demographic Surveillance System (HDSS) in Kisumu County, Kenya. We then used content analysis of open history forms among deaths coded as accidents to identify those who likely died by suicide but were not coded as suicide deaths. We finally conducted a case-control study of suicides (both verbal autopsy confirmed and likely suicides) compared to accident-caused deaths to assess factors associated with suicide in this HDSS. RESULTS: A total of 33 out of 4306 verbal autopsies confirmed suicide as the cause of death. Content analysis of a further 228 deaths originally attributed to accidents identified 39 additional likely suicides. The best estimate of suicide-specific mortality rate was 14.7 per 100,000 population per year (credibility window = 11.3 - 18.0). The most common reported method of death was self-poisoning (54%). From the case-control study interpersonal difficulties and stressful life events were associated with increased odds of suicide in both confirmed suicides and confirmed combined with suspected suicides. Other pertinent factors such as age and being male differed depending upon which outcome was used. CONCLUSION: Suicide is common in this area, and interventions are needed to address drivers. The twofold increase in the suicide-specific mortality rate following incorporation of misattributed suicide deaths exemplify underreporting and misclassification of suicide cases at community level. Further, verbal autopsies may underreport suicide specifically among older and female populations.


Assuntos
Suicídio , Autopsia , Estudos de Casos e Controles , Causas de Morte , Feminino , Humanos , Quênia/epidemiologia , Masculino
2.
Diabetologia ; 58(7): 1503-12, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25930156

RESUMO

AIMS/HYPOTHESIS: There are potential advantages to the low-temperature (-196 °C) banking of isolated islets, including the maintenance of viable islets for future research. We therefore assessed the in vitro and in vivo function of islets cryopreserved for nearly 20 years. METHODS: Human islets were cryopreserved from 1991 to 2001 and thawed between 2012 and 2014. These were characterised by immunostaining, patch-clamp electrophysiology, insulin secretion, transcriptome analysis and transplantation into a streptozotocin (STZ)-induced mouse model of diabetes. RESULTS: The cryopreservation time was 17.6 ± 0.4 years (n = 43). The thawed islets stained positive with dithizone, contained insulin-positive and glucagon-positive cells, and displayed levels of apoptosis and transcriptome profiles similar to those of freshly isolated islets, although their insulin content was lower. The cryopreserved beta cells possessed ion channels and exocytotic responses identical to those of freshly isolated beta cells. Cells from a subset of five donors demonstrated similar perifusion insulin secretion profiles pre- and post-cryopreservation. The transplantation of cryopreserved islets into the diabetic mice improved their glucose tolerance but did not completely normalise their blood glucose levels. Circulating human insulin and insulin-positive grafts were detectable at 10 weeks post-transplantation. CONCLUSIONS/INTERPRETATION: We have demonstrated the potential for long-term banking of human islets for research, which could enable the use of tissue from a large number of donors with future technologies to gain new insight into diabetes.


Assuntos
Criopreservação , Ilhotas Pancreáticas/fisiologia , Bancos de Tecidos , Adulto , Animais , Diabetes Mellitus Experimental/terapia , Exocitose/fisiologia , Feminino , Proteínas de Homeodomínio/genética , Humanos , Insulina/sangue , Insulina/metabolismo , Células Secretoras de Insulina/fisiologia , Canais Iônicos/metabolismo , Transplante das Ilhotas Pancreáticas , Masculino , Camundongos , Camundongos Knockout , Técnicas de Patch-Clamp , Transcriptoma/genética
3.
J Vasc Interv Radiol ; 25(1): 133-7, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24365507

RESUMO

Defining radiographic treatment success after percutaneous renal ablation is challenging due to variable ablation zone imaging findings over time. The present report describes two cases of progressively more evident enhancing soft-tissue nodules in the perinephric fat more than 2 years after cryoablation. Despite features concerning for tumor recurrence on computed tomography and magnetic resonance imaging, biopsies revealed fat necrosis in both cases. Renal ablation zone soft-tissue nodules can appear long after ablation, enhance with contrast medium, mimic applicator tract or ablation zone tumor seeding, and may require biopsy for confirmation of benignity.


Assuntos
Carcinoma de Células Renais/cirurgia , Meios de Contraste , Criocirurgia/efeitos adversos , Necrose Gordurosa/diagnóstico por imagem , Iohexol , Neoplasias Renais/cirurgia , Imageamento por Ressonância Magnética , Tomografia Computadorizada Multidetectores , Inoculação de Neoplasia , Compostos Organometálicos , Adulto , Idoso , Biópsia por Agulha , Carcinoma de Células Renais/diagnóstico por imagem , Carcinoma de Células Renais/patologia , Diagnóstico Diferencial , Necrose Gordurosa/etiologia , Humanos , Neoplasias Renais/diagnóstico por imagem , Neoplasias Renais/patologia , Masculino , Valor Preditivo dos Testes , Fatores de Tempo , Resultado do Tratamento
5.
Zoo Biol ; 33(4): 360-71, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24753001

RESUMO

Common loon chicks were reared in captivity in association with studies to evaluate the effects of radiotransmitter implants and to assess the ecological risk of dietary methylmercury. Here we report on hatching and rearing methods used to successfully raise chicks to 105 days of age. We experienced a 91.5% hatch rate, and 89.6% of loon chicks survived to the end of the study at 105 days. Baseline information on observed rates of fish consumption, behavioral development, and growth patterns are provided. Husbandry techniques are provided that should prove valuable to wildlife rehabilitators caring for abandoned or injured loons, and biologists contemplating methods for restoring loons to areas within their former breeding range.


Assuntos
Criação de Animais Domésticos/métodos , Animais de Zoológico , Aves/crescimento & desenvolvimento , Crescimento e Desenvolvimento/fisiologia , Animais , Comportamento Animal/fisiologia , Pesos e Medidas Corporais/veterinária
6.
Transplant Direct ; 10(7): e1667, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38911274

RESUMO

Background: Limited information is available regarding outcomes of islet cell isolation (ICI) and transplantation (ITx) using medical assistance in dying (MAiD) donors. We aimed to assess the feasibility and outcomes of ICI and ITx in MAiD donors. Methods: ICI and ITx from MAiD were compared with donation after circulatory death (DCD) type III between 2016 and 2023. Differences of isolated islet equivalents (IEQs), numeric viability and other quantitative in vitro metabolic measures were assessed. Results: Overall, 81 ICIs were available of whom 34 (42%) and 47 (58%) from MAiD and DCD-III, respectively. There were no differences of pancreas and digested tissue weight and islets viability among the 2 groups; however, cold ischemic time was longer in MAiD (11.5 versus 9.1 h; P = 0.021). The IEQ (P < 0.001) and percent trapped (P < 0.001) were higher in the DCD-III; however, MAiD islets demonstrated a higher purity (P = 0.020). Overall, 15 ITx were performed of whom 3 (8.8%) and 12 (25.5%) from MAiD and DCD-III, respectively (P = 0.056). Patients had a median fasting C-peptide of 0.51 ng/mL (interquartile range, 0.30-0.76 nmol/L), with no differences between groups (MAiD = 0.52 versus DCD-III = 0.51; P = 0.718). The median HbA1c was 6.2% (interquartile range, 5.7%-7%) (MAiD = 6.3% versus DCD-III = 6.1%; P = 0.815) and BETA2 scores (MAiD = 7.4 versus DCD-III = 12.8; P = 0.229) did not differ. Conclusions: ICI from MAiD donor pancreas may be successfully transplanted with comparable outcomes to DCD-III and may be used for research. These results justify additional efforts to consider MAiD as another valuable source of grafts for ITx. Further multicenter studies and larger clinical experience are needed to validate our findings.

7.
medRxiv ; 2024 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-38496562

RESUMO

Population level variation and molecular mechanisms behind insulin secretion in response to carbohydrate, protein, and fat remain uncharacterized despite ramifications for personalized nutrition. Here, we define prototypical insulin secretion dynamics in response to the three macronutrients in islets from 140 cadaveric donors, including those diagnosed with type 2 diabetes. While islets from the majority of donors exhibited the expected relative response magnitudes, with glucose being highest, amino acid moderate, and fatty acid small, 9% of islets stimulated with amino acid and 8% of islets stimulated with fatty acids had larger responses compared with high glucose. We leveraged this insulin response heterogeneity and used transcriptomics and proteomics to identify molecular correlates of specific nutrient responsiveness, as well as those proteins and mRNAs altered in type 2 diabetes. We also examine nutrient-responsiveness in stem cell-derived islet clusters and observe that they have dysregulated fuel sensitivity, which is a hallmark of functionally immature cells. Our study now represents the first comparison of dynamic responses to nutrients and multi-omics analysis in human insulin secreting cells. Responses of different people's islets to carbohydrate, protein, and fat lay the groundwork for personalized nutrition. ONE-SENTENCE SUMMARY: Deep phenotyping and multi-omics reveal individualized nutrient-specific insulin secretion propensity.

8.
bioRxiv ; 2024 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-38948734

RESUMO

Comprehensive molecular and cellular phenotyping of human islets can enable deep mechanistic insights for diabetes research. We established the Human Islet Data Analysis and Sharing (HI-DAS) consortium to advance goals in accessibility, usability, and integration of data from human islets isolated from donors with and without diabetes at the Alberta Diabetes Institute (ADI) IsletCore. Here we introduce HumanIslets.com , an open resource for the research community. This platform, which presently includes data on 547 human islet donors, allows users to access linked datasets describing molecular profiles, islet function and donor phenotypes, and to perform various statistical and functional analyses at the donor, islet and single-cell levels. As an example of the analytic capacity of this resource we show a dissociation between cell culture effects on transcript and protein expression, and an approach to correct for exocrine contamination found in hand-picked islets. Finally, we provide an example workflow and visualization that highlights links between type 2 diabetes status, SERCA3b Ca 2+ -ATPase levels at the transcript and protein level, insulin secretion and islet cell phenotypes. HumanIslets.com provides a growing and adaptable set of resources and tools to support the metabolism and diabetes research community.

9.
J Vasc Interv Radiol ; 24(10): 1559-65, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24070512

RESUMO

This report describes the authors' first experiences with the use of the Biodesign Enterocutaneous Fistula Plug (EFP). Six patients presented with intraperitoneal abscess and associated chronic bowel fistulas. The fistulas were treated by delivering an EFP by using radiologic guidance. The EFP placement procedure was successfully performed in all patients. All fistulas were closed within 2 weeks. Fistula recurrence occurred in two patients (33%) at 9 and 12 months after the procedure. One recurrence was associated with an adverse reaction to chemotherapy. The other was associated with the silicone flange migrating out of the bowel lumen. The Biodesign EFP offers a promising new approach for the treatment of enterocutaneous fistulas.


Assuntos
Implantes Absorvíveis , Colágeno , Fístula Intestinal/diagnóstico por imagem , Fístula Intestinal/cirurgia , Radiografia Intervencionista/métodos , Idoso , Análise de Falha de Equipamento , Humanos , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Desenho de Prótese , Resultado do Tratamento
10.
Nat Med ; 12(3): 304-6, 2006 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-16501570

RESUMO

We evaluated the ability of neonatal porcine islets to engraft and restore glucose control in pancreatectomized rhesus macaques. Although porcine islets transplanted into nonimmunosuppressed macaques were rapidly rejected by a process consistent with cellular rejection, recipients treated with a CD28-CD154 costimulation blockade regimen achieved sustained insulin independence (median survival, >140 days) without evidence of porcine endogenous retrovirus dissemination. Thus, neonatal porcine islets represent a promising solution to the crucial supply problem in clinical islet transplantation.


Assuntos
Sobrevivência de Enxerto/imunologia , Transplante das Ilhotas Pancreáticas/imunologia , Macaca/imunologia , Suínos , Animais , Animais Recém-Nascidos , Terapia Baseada em Transplante de Células e Tecidos , Rejeição de Enxerto/imunologia , Ilhotas Pancreáticas/citologia , Ilhotas Pancreáticas/imunologia , Pancreatectomia , Suínos/imunologia , Fatores de Tempo , Transplante Heterólogo/imunologia
11.
Am Soc Clin Oncol Educ Book ; 43: e397478, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37141553

RESUMO

Significant advancements have been made in the treatment of advanced melanoma with the use of immune checkpoint inhibitors, novel immunotherapies, and BRAF/MEK-targeted therapies with numerous frontline treatment options. However, there remains suboptimal evidence to guide treatment decisions in many patients. These include patients with newly diagnosed disease, immune checkpoint inhibitor (ICI)-resistant/ICI-refractory disease, CNS metastases, history of autoimmune disease, and/or immune-related adverse events (irAEs). Uveal melanoma (UM) is a rare melanoma associated with a poor prognosis in the metastatic setting. Systemic treatments, including checkpoint inhibitors, failed to demonstrate any survival benefit. Tebentafusp, a bispecific molecule, is the first treatment to improve overall survival (OS) in patients with HLA A*02:01-positive metastatic UM.


Assuntos
Melanoma , Neoplasias Uveais , Humanos , Melanoma/tratamento farmacológico , Imunoterapia
12.
Ecol Evol ; 13(1): e9704, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36687801

RESUMO

Fecundity, the number of young produced by a breeding pair during a breeding season, is a primary component in evolutionary and ecological theory and applications. Fecundity can be influenced by many environmental factors and requires long-term study due to the range of variation in ecosystem dynamics. Fecundity data often include a large proportion of zeros when many pairs fail to produce any young during a breeding season due to nest failure or when all young die independently after fledging. We conducted color banding and monthly censuses of Florida scrub-jays (Aphelocoma coerulescens) across 31 years, 15 populations, and 761 territories along central Florida's Atlantic coast. We quantified how fecundity (juveniles/pair-year) was influenced by habitat quality, presence/absence of nonbreeders, population density, breeder experience, and rainfall, with a zero-inflated Bayesian hierarchical model including both a Bernoulli (e.g., brood success) and a Poisson (counts of young) submodel, and random effects for year, population, and territory. The results identified the importance of increasing "strong" quality habitat, which was a mid-successional state related to fire frequency and extent, because strong territories, and the proportion of strong territories in the overall population, influenced fecundity of breeding pairs. Populations subject to supplementary feeding also had greater fecundity. Territory size, population density, breeder experience, and rainfall surprisingly had no or small effects. Different mechanisms appeared to cause annual variation in fecundity, as estimates of random effects were not correlated between the success and count submodels. The increased fecundity for pairs with nonbreeders, compared to pairs without, identified empirical research needed to understand how the proportion of low-quality habitats influences population recovery and sustainability, because dispersal into low-quality habitats can drain nonbreeders from strong territories and decrease overall fecundity. We also describe how long-term study resulted in reversals in our understanding because of complications involving habitat quality, sociobiology, and population density.

13.
Med Sci Sports Exerc ; 55(9): 1540-1547, 2023 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-37101347

RESUMO

PURPOSE: Reduced bone mineral density of the distal femur (BMD DF ) can persist long term after anterior cruciate ligament reconstruction (ACLR), even in athletes who return to high levels of competition. These deficits may have implications for the onset and progression of knee osteoarthritis. It is unknown if clinically modifiable factors are associated with losses in BMD DF . This study evaluated the potential influence of knee extensor peak torque (PT), rate of torque development (RTD), as well as peak knee flexion (PKF) angle and peak knee extensor moment (PKEM) during running, on longitudinal changes in BMD DF post-ACLR. METHODS: After ACLR, 57 Division I collegiate athletes underwent serial whole-body dual-energy x-ray absorptiometry (DXA) scans between 3 and 24 months post-ACLR. Of these, 43 athletes also had isometric knee extensor testing (21 female, 105 observations), and 54 had running analyses (26 female, 141 observations). Linear mixed-effects models, controlling for sex, assessed the influence of surgical limb quadriceps performance (PT and RTD), running mechanics (PKF and PKEM), and time post-ACLR on BMD DF (5% and 15% of femur length). Simple slope analyses were used to explore interactions. RESULTS: Athletes with RTD less than 7.20 (N·m)·kg -1 ·s -1 (mean) at 9.3 months post-ACLR demonstrated significant decreases in 15% BMD DF over time ( P = 0.03). Athletes with PKEM during running less than 0.92 (N·m)·kg -1 (-1 SD below mean) at 9.8 months post-ACLR demonstrated significant decreases in 15% BMD DF over time ( P = 0.02). Significant slopes were not detected at -1 SD below the mean for PT (1.75 (N·m)·kg -1 , P = 0.07) and PKF (31.3°, P = 0.08). CONCLUSIONS: Worse quadriceps RTD and running PKEM were associated with a greater loss of BMD DF between 3 and 24 months post-ACLR.


Assuntos
Lesões do Ligamento Cruzado Anterior , Corrida , Humanos , Feminino , Lesões do Ligamento Cruzado Anterior/cirurgia , Fenômenos Biomecânicos , Articulação do Joelho , Músculo Quadríceps , Fêmur , Atletas , Força Muscular
14.
Nat Genet ; 55(1): 54-65, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36543916

RESUMO

Identification of the genes and processes mediating genetic association signals for complex diseases represents a major challenge. As many of the genetic signals for type 2 diabetes (T2D) exert their effects through pancreatic islet-cell dysfunction, we performed a genome-wide pooled CRISPR loss-of-function screen in a human pancreatic beta cell line. We assessed the regulation of insulin content as a disease-relevant readout of beta cell function and identified 580 genes influencing this phenotype. Integration with genetic and genomic data provided experimental support for 20 candidate T2D effector transcripts including the autophagy receptor CALCOCO2. Loss of CALCOCO2 was associated with distorted mitochondria, less proinsulin-containing immature granules and accumulation of autophagosomes upon inhibition of late-stage autophagy. Carriers of T2D-associated variants at the CALCOCO2 locus further displayed altered insulin secretion. Our study highlights how cellular screens can augment existing multi-omic efforts to support mechanistic understanding and provide evidence for causal effects at genome-wide association studies loci.


Assuntos
Diabetes Mellitus Tipo 2 , Células Secretoras de Insulina , Humanos , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/metabolismo , Estudo de Associação Genômica Ampla , Insulina/genética , Células Secretoras de Insulina/metabolismo
15.
BMJ Open ; 13(2): e064169, 2023 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-36725099

RESUMO

OBJECTIVES: Motor neuron disease (MND) is an incurable progressive neurodegenerative disease with limited treatment options. There is a pressing need for innovation in identifying therapies to take to clinical trial. Here, we detail a systematic and structured evidence-based approach to inform consensus decision making to select the first two drugs for evaluation in Motor Neuron Disease-Systematic Multi-arm Adaptive Randomised Trial (MND-SMART: NCT04302870), an adaptive platform trial. We aim to identify and prioritise candidate drugs which have the best available evidence for efficacy, acceptable safety profiles and are feasible for evaluation within the trial protocol. METHODS: We conducted a two-stage systematic review to identify potential neuroprotective interventions. First, we reviewed clinical studies in MND, Alzheimer's disease, Huntington's disease, Parkinson's disease and multiple sclerosis, identifying drugs described in at least one MND publication or publications in two or more other diseases. We scored and ranked drugs using a metric evaluating safety, efficacy, study size and study quality. In stage two, we reviewed efficacy of drugs in MND animal models, multicellular eukaryotic models and human induced pluripotent stem cell (iPSC) studies. An expert panel reviewed candidate drugs over two shortlisting rounds and a final selection round, considering the systematic review findings, late breaking evidence, mechanistic plausibility, safety, tolerability and feasibility of evaluation in MND-SMART. RESULTS: From the clinical review, we identified 595 interventions. 66 drugs met our drug/disease logic. Of these, 22 drugs with supportive clinical and preclinical evidence were shortlisted at round 1. Seven drugs proceeded to round 2. The panel reached a consensus to evaluate memantine and trazodone as the first two arms of MND-SMART. DISCUSSION: For future drug selection, we will incorporate automation tools, text-mining and machine learning techniques to the systematic reviews and consider data generated from other domains, including high-throughput phenotypic screening of human iPSCs.


Assuntos
Doença dos Neurônios Motores , Humanos , Consenso , Células-Tronco Pluripotentes Induzidas , Doença dos Neurônios Motores/tratamento farmacológico , Ensaios Clínicos Controlados Aleatórios como Assunto
16.
Cureus ; 14(4): e23926, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35530859

RESUMO

This case report describes a 72-year-old female patient diagnosed with small cell lung carcinoma who was found to have elevated partial thromboplastin time (PTT) after reporting diarrhea and melanotic stool. Further investigations revealed the presence of a factor VIII inhibitor, possibly resulting from a side effect of immunotherapy or of possible paraneoplastic origin. The patient's PTT remained elevated following a course of steroid treatment, raising the likelihood of paraneoplastic etiology. This case represents a rare paraneoplastic syndrome, with a previously unreported presentation of melanotic stool as opposed to an acute bleeding episode.

17.
Islets ; 14(1): 101-113, 2022 12 31.
Artigo em Inglês | MEDLINE | ID: mdl-35285768

RESUMO

Designated a pandemic in March 2020, the spread of severe acute respiratory syndrome virus 2 (SARS-CoV2), the virus responsible for coronavirus disease 2019 (COVID-19), led to new guidelines and restrictions being implemented for individuals, businesses, and societies in efforts to limit the impacts of COVID-19 on personal health and healthcare systems. Here we report the impacts of the COVID-19 pandemic on pancreas processing and islet isolation/distribution outcomes at the Alberta Diabetes Institute IsletCore, a facility specializing in the processing and distribution of human pancreatic islets for research. While the number of organs processed was significantly reduced, organ quality and the function of cellular outputs were minimally impacted during the pandemic when compared to an equivalent period immediately prior. Despite the maintained quality of isolated islets, feedback from recipient groups was more negative. Our findings suggest this is likely due to disrupted distribution which led to increased transit times to recipient labs, particularly those overseas. Thus, to improve overall outcomes in a climate of limited research islet supply, prioritization of tissue recipients based on likely tissue transit times may be needed.


Assuntos
COVID-19 , Ilhotas Pancreáticas , COVID-19/epidemiologia , Humanos , Pandemias , RNA Viral , SARS-CoV-2
18.
Sci Adv ; 8(40): eabo3932, 2022 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-36197983

RESUMO

Pancreatic islet beta cells are essential for maintaining glucose homeostasis. To understand the impact of aging on beta cells, we performed meta-analysis of single-cell RNA sequencing datasets, transcription factor (TF) regulon analysis, high-resolution confocal microscopy, and measured insulin secretion from nondiabetic donors spanning most of the human life span. This revealed the range of molecular and functional changes that occur during beta cell aging, including the transcriptional deregulation that associates with cellular immaturity and reorganization of beta cell TF networks, increased gene transcription rates, and reduced glucose-stimulated insulin release. These alterations associate with activation of endoplasmic reticulum (ER) stress and autophagy pathways. We propose that a chronic state of ER stress undermines old beta cell structure function to increase the risk of beta cell failure and type 2 diabetes onset as humans age.

19.
PLoS One ; 17(1): e0263005, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35081145

RESUMO

The objective of this study is to optimize the cryopreservation of dissociated islet cells and obtain functional cells that can be used in single-cell transcriptome studies on the pathology and treatment of diabetes. Using an iterative graded freezing approach we obtained viable cells after cooling in 10% dimethyl sulfoxide and 6% hydroxyethyl starch at 1°C/min to -40°C, storage in liquid nitrogen, rapid thaw, and removal of cryoprotectants by serial dilution. The expression of epithelial cell adhesion molecule declined immediately after thaw, but recovered after overnight incubation, while that of an endocrine cell marker (HPi2) remained high after cryopreservation. Patch-clamp electrophysiology revealed differences in channel activities and exocytosis of various islet cell types; however, exocytotic responses, and the biophysical properties of voltage-gated Na+ and Ca2+ channels, are sustained after cryopreservation. Single-cell RNA sequencing indicates that overall transcriptome and crucial exocytosis genes are comparable between fresh and cryopreserved dispersed human islet cells. Thus, we report an optimized procedure for cryopreserving dispersed islet cells that maintained their membrane integrity, along with their molecular and functional phenotypes. Our findings will not only provide a ready source of cells for investigating cellular mechanisms in diabetes but also for bio-engineering pseudo-islets and islet sheets for modeling studies and potential transplant applications.


Assuntos
Criopreservação , Ilhotas Pancreáticas/metabolismo , Adolescente , Adulto , Idoso , Antígenos de Diferenciação/metabolismo , Canais de Cálcio/metabolismo , Crioprotetores/farmacologia , Feminino , Humanos , Ilhotas Pancreáticas/citologia , Transplante das Ilhotas Pancreáticas , Masculino , Pessoa de Meia-Idade , RNA-Seq , Análise de Célula Única , Canais de Sódio/metabolismo
20.
Cell Metab ; 34(2): 256-268.e5, 2022 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-35108513

RESUMO

In diabetes, glucagon secretion from pancreatic α cells is dysregulated. The underlying mechanisms, and whether dysfunction occurs uniformly among cells, remain unclear. We examined α cells from human donors and mice using electrophysiological, transcriptomic, and computational approaches. Rising glucose suppresses α cell exocytosis by reducing P/Q-type Ca2+ channel activity, and this is disrupted in type 2 diabetes (T2D). Upon high-fat feeding of mice, α cells shift toward a "ß cell-like" electrophysiological profile in concert with indications of impaired identity. In human α cells we identified links between cell membrane properties and cell surface signaling receptors, mitochondrial respiratory chain complex assembly, and cell maturation. Cell-type classification using machine learning of electrophysiology data demonstrated a heterogenous loss of "electrophysiologic identity" in α cells from donors with type 2 diabetes. Indeed, a subset of α cells with impaired exocytosis is defined by an enrichment in progenitor and lineage markers and upregulation of an immature transcriptomic phenotype, suggesting important links between α cell maturation state and dysfunction.


Assuntos
Diabetes Mellitus Tipo 2 , Células Secretoras de Glucagon , Ilhotas Pancreáticas , Animais , Diabetes Mellitus Tipo 2/metabolismo , Exocitose/fisiologia , Glucagon/metabolismo , Células Secretoras de Glucagon/metabolismo , Insulina/metabolismo , Ilhotas Pancreáticas/metabolismo , Camundongos
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