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1.
Cell Rep ; 43(4): 114047, 2024 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-38607916

RESUMO

Using 13C6 glucose labeling coupled to gas chromatography-mass spectrometry and 2D 1H-13C heteronuclear single quantum coherence NMR spectroscopy, we have obtained a comparative high-resolution map of glucose fate underpinning ß cell function. In both mouse and human islets, the contribution of glucose to the tricarboxylic acid (TCA) cycle is similar. Pyruvate fueling of the TCA cycle is primarily mediated by the activity of pyruvate dehydrogenase, with lower flux through pyruvate carboxylase. While the conversion of pyruvate to lactate by lactate dehydrogenase (LDH) can be detected in islets of both species, lactate accumulation is 6-fold higher in human islets. Human islets express LDH, with low-moderate LDHA expression and ß cell-specific LDHB expression. LDHB inhibition amplifies LDHA-dependent lactate generation in mouse and human ß cells and increases basal insulin release. Lastly, cis-instrument Mendelian randomization shows that low LDHB expression levels correlate with elevated fasting insulin in humans. Thus, LDHB limits lactate generation in ß cells to maintain appropriate insulin release.


Assuntos
Secreção de Insulina , Células Secretoras de Insulina , L-Lactato Desidrogenase , Ácido Láctico , Humanos , Células Secretoras de Insulina/metabolismo , Animais , L-Lactato Desidrogenase/metabolismo , Camundongos , Ácido Láctico/metabolismo , Glucose/metabolismo , Insulina/metabolismo , Isoenzimas/metabolismo , Ciclo do Ácido Cítrico , Camundongos Endogâmicos C57BL , Masculino
2.
Acta Physiol (Oxf) ; 240(3): e14101, 2024 03.
Artigo em Inglês | MEDLINE | ID: mdl-38243723

RESUMO

AIM: Despite its abundance in pancreatic islets of Langerhans and proven antihyperglycemic effects, the impact of the essential amino acid, taurine, on islet ß-cell biology has not yet received due consideration, which prompted the current studies exploring the molecular selectivity of taurine import into ß-cells and its acute and chronic intracellular interactions. METHODS: The molecular aspects of taurine transport were probed by exposing the clonal pancreatic BRIN BD11 ß-cells and primary mouse and human islets to a range of the homologs of the amino acid (assayed at 2-20 mM), using the hormone release and imaging of intracellular signals as surrogate read-outs. Known secretagogues were employed to profile the interaction of taurine with acute and chronic intracellular signals. RESULTS: Taurine transporter TauT was expressed in the islet ß-cells, with the transport of taurine and homologs having a weak sulfonate specificity but significant sensitivity to the molecular weight of the transporter. Taurine, hypotaurine, homotaurine, and ß-alanine enhanced insulin secretion in a glucose-dependent manner, an action potentiated by cytosolic Ca2+ and cAMP. Acute and chronic ß-cell insulinotropic effects of taurine were highly sensitive to co-agonism with GLP-1, forskolin, tolbutamide, and membrane depolarization, with an unanticipated indifference to the activation of PKC and CCK8 receptors. Pre-culturing with GLP-1 or KATP channel inhibitors sensitized or, respectively, desensitized ß-cells to the acute taurine stimulus. CONCLUSION: Together, these data demonstrate the pathways whereby taurine exhibits a range of beneficial effects on insulin secretion and ß-cell function, consistent with the antidiabetic potential of its dietary low-dose supplementation.


Assuntos
Células Secretoras de Insulina , Ilhotas Pancreáticas , Humanos , Animais , Camundongos , Taurina/farmacologia , Transdução de Sinais , Peptídeo 1 Semelhante ao Glucagon , Hipoglicemiantes
3.
Diabetologia ; 67(3): 528-546, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38127123

RESUMO

AIMS/HYPOTHESIS: Diabetes mellitus is associated with impaired insulin secretion, often aggravated by oversecretion of glucagon. Therapeutic interventions should ideally correct both defects. Glucagon-like peptide 1 (GLP-1) has this capability but exactly how it exerts its glucagonostatic effect remains obscure. Following its release GLP-1 is rapidly degraded from GLP-1(7-36) to GLP-1(9-36). We hypothesised that the metabolite GLP-1(9-36) (previously believed to be biologically inactive) exerts a direct inhibitory effect on glucagon secretion and that this mechanism becomes impaired in diabetes. METHODS: We used a combination of glucagon secretion measurements in mouse and human islets (including islets from donors with type 2 diabetes), total internal reflection fluorescence microscopy imaging of secretory granule dynamics, recordings of cytoplasmic Ca2+ and measurements of protein kinase A activity, immunocytochemistry, in vivo physiology and GTP-binding protein dissociation studies to explore how GLP-1 exerts its inhibitory effect on glucagon secretion and the role of the metabolite GLP-1(9-36). RESULTS: GLP-1(7-36) inhibited glucagon secretion in isolated islets with an IC50 of 2.5 pmol/l. The effect was particularly strong at low glucose concentrations. The degradation product GLP-1(9-36) shared this capacity. GLP-1(9-36) retained its glucagonostatic effects after genetic/pharmacological inactivation of the GLP-1 receptor. GLP-1(9-36) also potently inhibited glucagon secretion evoked by ß-adrenergic stimulation, amino acids and membrane depolarisation. In islet alpha cells, GLP-1(9-36) led to inhibition of Ca2+ entry via voltage-gated Ca2+ channels sensitive to ω-agatoxin, with consequential pertussis-toxin-sensitive depletion of the docked pool of secretory granules, effects that were prevented by the glucagon receptor antagonists REMD2.59 and L-168049. The capacity of GLP-1(9-36) to inhibit glucagon secretion and reduce the number of docked granules was lost in alpha cells from human donors with type 2 diabetes. In vivo, high exogenous concentrations of GLP-1(9-36) (>100 pmol/l) resulted in a small (30%) lowering of circulating glucagon during insulin-induced hypoglycaemia. This effect was abolished by REMD2.59, which promptly increased circulating glucagon by >225% (adjusted for the change in plasma glucose) without affecting pancreatic glucagon content. CONCLUSIONS/INTERPRETATION: We conclude that the GLP-1 metabolite GLP-1(9-36) is a systemic inhibitor of glucagon secretion. We propose that the increase in circulating glucagon observed following genetic/pharmacological inactivation of glucagon signalling in mice and in people with type 2 diabetes reflects the removal of GLP-1(9-36)'s glucagonostatic action.


Assuntos
Diabetes Mellitus Tipo 2 , Hipoglicemia , Ilhotas Pancreáticas , Fragmentos de Peptídeos , Humanos , Glucagon/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Peptídeo 1 Semelhante ao Glucagon/metabolismo , Ilhotas Pancreáticas/metabolismo , Hipoglicemia/metabolismo , Insulina/metabolismo
4.
Diabetes Obes Metab ; 25(12): 3529-3537, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37646197

RESUMO

BACKGROUND: Donor hyperglycaemia following brain death has been attributed to reversible insulin resistance. However, our islet and pancreas transplant data suggest that other mechanisms may be predominant. We aimed to determine the relationships between donor insulin use and markers of beta-cell death and beta-cell function in pancreas donors after brain death. METHODS: In pancreas donors after brain death, we compared clinical and biochemical data in 'insulin-treated' and 'not insulin-treated donors' (IT vs. not-IT). We measured plasma glucose, C-peptide and levels of circulating unmethylated insulin gene promoter cell-free DNA (INS-cfDNA) and microRNA-375 (miR-375), as measures of beta-cell death. Relationships between markers of beta-cell death and islet isolation outcomes and post-transplant function were also evaluated. RESULTS: Of 92 pancreas donors, 40 (43%) required insulin. Glycaemic control and beta-cell function were significantly poorer in IT donors versus not-IT donors [median (IQR) peak glucose: 8 (7-11) vs. 6 (6-8) mmol/L, p = .016; C-peptide: 3280 (3159-3386) vs. 3195 (2868-3386) pmol/L, p = .046]. IT donors had significantly higher levels of INS-cfDNA [35 (18-52) vs. 30 (8-51) copies/ml, p = .035] and miR-375 [1.050 (0.19-1.95) vs. 0.73 (0.32-1.10) copies/nl, p = .05]. Circulating donor miR-375 was highly predictive of recipient islet graft failure at 3 months [adjusted receiver operator curve (SE) = 0.813 (0.149)]. CONCLUSIONS: In pancreas donors, hyperglycaemia requiring IT is strongly associated with beta-cell death. This provides an explanation for the relationship of donor IT with post-transplant beta-cell dysfunction in transplant recipients.


Assuntos
Ácidos Nucleicos Livres , Hiperglicemia , Transplante das Ilhotas Pancreáticas , MicroRNAs , Humanos , Peptídeo C , Morte Encefálica , Insulina/genética , Doadores de Tecidos , Morte Celular
5.
Transpl Int ; 36: 11374, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37547751

RESUMO

The advent of Machine Perfusion (MP) as a superior form of preservation and assessment for cold storage of both high-risk kidney's and the liver presents opportunities in the field of beta-cell replacement. It is yet unknown whether such techniques, when applied to the pancreas, can increase the pool of suitable donor organs as well as ameliorating the effects of ischemia incurred during the retrieval process. Recent experimental models of pancreatic MP appear promising. Applications of MP to the pancreas, needs refinement regarding perfusion protocols and organ viability assessment criteria. To address the "Role of pancreas machine perfusion to increase the donor pool for beta cell replacement," the European Society for Organ Transplantation (ESOT) assembled a dedicated working group comprising of experts to review literature pertaining to the role of MP as a method of improving donor pancreas quality as well as quantity available for transplant, and to develop guidelines founded on evidence-based reviews in experimental and clinical settings. These were subsequently refined during the Consensus Conference when this took place in Prague.


Assuntos
Preservação de Órgãos , Transplante de Órgãos , Humanos , Preservação de Órgãos/métodos , Pâncreas , Perfusão/métodos , Doadores de Tecidos
6.
Life Sci ; 316: 121402, 2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-36669678

RESUMO

AIMS: Despite its high concentration in pancreatic islets of Langerhans and broad range of antihyperglycemic effects, the route facilitating the import of dietary taurine into pancreatic ß-cell and mechanisms underlying its insulinotropic activity are unclear. We therefore studied the impact of taurine on beta-cell function, alongside that of other small neutral amino acids, L-alanine and L-proline. MAIN METHODS: Pharmacological profiling of insulin secretion was conducted using clonal BRIN BD11 ß-cells, the impact of taurine on the metabolic fate of glucose carbons was assessed using NMR and the findings were verified by real-time imaging of Ca2+ dynamics in the cytosol of primary mouse and human islet beta-cells. KEY FINDINGS: In our hands, taurine, alanine and proline induced secretory responses that were dependent on the plasma membrane depolarisation, import of Ca2+, homeostasis of K+ and Na+ as well as on cell glycolytic and oxidative metabolism. Taurine shifted the balance between the oxidation and anaplerosis towards the latter, in BRIN BD11 beta-cells. Furthermore, the amino acid signalling was significantly attenuated by inhibition of Na+-K+-Cl- symporter (NKCC). SIGNIFICANCE: These data suggest that taurine, like L-alanine and L-proline, acutely induces glucose-dependent insulin-secretory responses by modulating electrogenic Na+ transport, with potential role of intracellular K+ and Cl- in the signal transduction. The acute action delineated would be consistent with antidiabetic potential of dietary taurine supplementation.


Assuntos
Aminoácidos Neutros , Ilhotas Pancreáticas , Camundongos , Animais , Humanos , Insulina/metabolismo , Taurina/farmacologia , Taurina/metabolismo , Aminoácidos Neutros/metabolismo , Aminoácidos Neutros/farmacologia , Linhagem Celular , Ilhotas Pancreáticas/metabolismo , Alanina/farmacologia , Alanina/metabolismo , Glucose/metabolismo , Hipoglicemiantes/farmacologia , Prolina/metabolismo
7.
Sci Rep ; 12(1): 19321, 2022 11 11.
Artigo em Inglês | MEDLINE | ID: mdl-36369239

RESUMO

The impact of ischaemia can severely damage procured donor organs for transplantation. The pancreas, and pancreatic islets in particular, is one of the most sensitive tissues towards hypoxia. The present study was aimed to assess the effect of hypoxic preconditioning (HP) performed ex-vivo in islets isolated from heart-beating donor (HBD) and non heart-beating donor (NHBD) rats. After HP purified islets were cultured for 24 h in hypoxia followed by islet characterisation. Post-culture islet yields were significantly lower in sham-treated NHBD than in HBD. This difference was reduced when NHBD islets were preconditioned. Similar results were observed regarding viability, apoptosis and in vitro function. Reactive oxygen species generation after hypoxic culture was significantly enhanced in sham-treated NHBD than in HBD islets. Again, this difference could be diminished through HP. qRT-PCR revealed that HP decreases pro-apoptotic genes but increases HIF-1 and VEGF. However, the extent of reduction and augmentation was always substantially higher in preconditioned NHBD than in HBD islets. Our findings indicate a lower benefit of HBD islets from HP than NHBD islets. The ischaemic preconditioning paradox suggests that HP should be primarily applied to islets from marginal donors. This observation needs evaluation in human islets.


Assuntos
Precondicionamento Isquêmico , Ilhotas Pancreáticas , Animais , Humanos , Ratos , Hipóxia , Doadores de Tecidos
8.
BMJ Paediatr Open ; 6(1)2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-36053577

RESUMO

OBJECTIVE: To establish short-term and medium-term complications 1-year postdiagnosis, of acute pancreatitis (AP) in children aged 0-14 years. DESIGN: One-year follow-up of a prospective monthly surveillance of new cases of AP in children under 15 years through the British Paediatric Surveillance Unit (BPSU) from April 2013 to April 2014. SETTING: A monthly surveillance of >3700 consultant paediatricians and paediatric surgeons in the UK and Ireland using the BPSU. PATIENTS: Children aged 0-14 years with a new diagnosis of AP. MAIN OUTCOME MEASURES: The outcomes following AP, including the incidence of complications and comorbidity at diagnosis and at 1 year. RESULTS: Of the 94 new confirmed cases of AP identified in the UK during the study period, 90 cases (96%) were included in the 1-year follow-up. 30 patients (32%) developed further episode(s) of AP. Over one-fifth of patients developed one or more major complication. At initial admission, the most common of these was pancreatic necrosis (n=8, 9%), followed by respiratory failure (n=7, 7%). Reported complications by 1 year were pseudocyst formation (n=9, 10%), diabetes requiring insulin therapy (n=4, 4%) and maldigestion (n=1, 1%). At 1-year postdiagnosis, only 59% of children made a full recovery with no acute or chronic complications or recurrent episodes of AP. Two patients died, indicating a case fatality of ~2.0%. CONCLUSIONS: AP in childhood is associated with significant short-term and medium-term complications and comorbidities including risk of recurrence in approximately a third of cases.


Assuntos
Pancreatite Necrosante Aguda , Doença Aguda , Criança , Humanos , Morbidade , Pancreatite Necrosante Aguda/epidemiologia , Estudos Prospectivos
9.
Transpl Int ; 35: 10507, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36033644

RESUMO

A global online survey was administered to 69 islet transplantation programs, covering 84 centers and 5 networks. The survey addressed questions on program organization and activity in the 2000-2020 period, including impact on activity of national health care coverage policies. We obtained full data from 55 institutions or networks worldwide and basic activity data from 6 centers. Additional data were obtained from alternative sources. A total of 94 institutions and 5 networks was identified as having performed islet allotransplantation. 4,365 islet allotransplants (2,608 in Europe, 1,475 in North America, 135 in Asia, 119 in Oceania, 28 in South America) were reported in 2,170 patients in the survey period. From 15 centers active at the start of the study period, the number of simultaneously active islet centers peaked at 54, to progressively decrease to 26 having performed islet allotransplants in 2020. Notably, only 16 centers/networks have done >100 islet allotransplants in the survey period. Types of transplants performed differed notably between North America and the rest of the world, in particular with respect to the near-absence of simultaneous islet-kidney transplantation. Absence of heath care coverage has significantly hampered transplant activity in the past years and the COVID-19 pandemic in 2020.


Assuntos
COVID-19 , Diabetes Mellitus Tipo 1 , Transplante das Ilhotas Pancreáticas , Transplante de Pâncreas , Humanos , Pandemias
10.
Acta Biomater ; 137: 92-102, 2022 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-34653695

RESUMO

Enzymatic digestion of the pancreas during islet isolation is associated with disintegration of the islet basement membrane (IBM) that can cause reduction of functional and morphological islet integrity. Attempts to re-establish IBM by coating the surface of culture vessels with various IBM proteins (IBMP) have resulted in loss of islet phenotype and function. This study investigated the capability of Collagen-IV, Laminin-521 and Nidogen-1, utilised as single or combined media supplements, to protect human islets cultured in hypoxia. When individually supplemented to media, all IBMP significantly improved islet survival and in-vitro function, finally resulting in as much as a two-fold increase of islet overall survival. In contrast, combining IBMP enhanced the production of chemokines and reactive oxygen species diminishing all positive effects of individually added IBMP. This impact was concentration-dependent and concerned nearly all parameters of islet integrity. Predictive extrapolation of these findings to data from 116 processed human pancreases suggests that more than 90% of suboptimal pancreases could be rescued for clinical islet transplantation increasing the number of transplantable preparations from actual 25 to 40 when adding Nidogen-1 to pretransplant culture. This study suggests that media supplementation with essential IBMP protects human islets from hypoxia. Amongst those, certain IBMP may be incompatible when combined or applied at higher concentrations. STATEMENT OF SIGNIFICANCE: Pancreatic islet transplantation is a minimally-invasive treatment that can reverse type 1 diabetes in certain patients. It involves infusing of insulin-producing cell-clusters (islets) from donor pancreases. Unfortunately, islet extraction is associated with damage of the islet basement membrane (IBM) causing reduced islet function and cell death. Attempts to re-establish the IBM by coating the surface of culture vessels with IBM proteins (IBMP) have been unsuccessful. Instead, we dissolved the most relevant IBM components Collagen-IV, Laminin-521 and Nidogen-1 in media routinely used for clinical islet culture and transplantation. We found human islet survival and function was substantially improved by IBMP, particularly Nidogen-1, when exposed to a hypoxic environment as found in vivo. We also investigated IBMP combinations. Our present findings have important clinical implications.


Assuntos
Transplante das Ilhotas Pancreáticas , Ilhotas Pancreáticas , Membrana Basal , Humanos , Hipóxia , Inflamação , Insulina , Proteínas de Membrana
11.
Crit Rev Clin Lab Sci ; 58(7): 493-512, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34130605

RESUMO

For more than one half-century, variability observed in clinical test result measurements has been ascribed to three major independent factors: (i) pre-analytical variation, occurring at sample collection and processing steps; (ii) analytical variation of the test method for which measurements are taken, and; (iii) biological variation (BV). Appreciation of this last source of variability is the major goal of this review article. Several recent advances have been made to generate, collate, and utilize BV data of biomarker tests within the clinical laboratory setting. Consideration of both prospective and retrospective study designs will be addressed. The prospective/direct study design will be described in accordance with recent recommendations discussed in the framework of a newly-developed system of checklist items. Potential value of retrospective/indirect study design, modeled on data mining from cohort studies or pathology laboratory information systems (LIS), offers an alternative approach to obtain BV estimates for clinical biomarkers. Moreover, updates to BV databases have made these data more current and widely accessible. Principal aims of this review are to provide the clinical laboratory scientist with a historical framework of BV concepts, to highlight useful applications of BV data within the clinical laboratory environment, and to discuss key terms and concepts related to statistical treatment of BV data.


Assuntos
Laboratórios , Biomarcadores , Humanos , Estudos Prospectivos , Estudos Retrospectivos
12.
Am J Kidney Dis ; 78(3): 418-428, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-33992729

RESUMO

Optimal glycemic control in kidney transplant recipients with diabetes is associated with improved morbidity and better patient and allograft survival. Transplant options for patients with diabetes requiring insulin therapy and chronic kidney disease who are suitable candidates for kidney transplantation should include consideration of ß-cell replacement therapy: pancreas or islet transplantation. International variation related to national regulatory policies exists in offering one or both options to suitable candidates and is further affected by pancreas/islet allocation policies and transplant waiting list dynamics. The selection of appropriate candidates depends on patient age, coexistent morbidities, the timing of referral to the transplant center (predialysis versus on dialysis) and availability of living kidney donors. Therefore, early referral (estimated glomerular filtration rate < 30 mL/min/1.73 m2) is of the utmost importance to ensure adequate time for informed decision making and thorough pretransplant evaluation. Obesity, cardiovascular disease, peripheral vascular disease, smoking, and frailty are some of the conditions that need to be addressed before acceptance on the transplant list, and ideally before dialysis becoming imminent. This review offers insights into selection of pancreas/islet transplant candidates by transplant centers and an update on posttransplant outcomes, which may have practice implications for referring nephrologists.


Assuntos
Diabetes Mellitus Tipo 1/complicações , Nefropatias/cirurgia , Transplante de Rim/métodos , Doadores Vivos , Complicações Pós-Operatórias/epidemiologia , Saúde Global , Sobrevivência de Enxerto , Humanos , Morbidade/tendências , Transplante Homólogo
13.
J Inflamm Res ; 14: 599-610, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33679137

RESUMO

BACKGROUND: Most islet transplant groups worldwide routinely use the TNFα inhibitor Etanercept in their peri-transplant protocols. Surprisingly, there have been no published dose-response studies on the effects of Etanercept on human islets. Our study aimed to address this by treating cultured human islets with increasing concentrations of Etanercept. MATERIALS AND METHODS: Isolated human islets were cultured for 3-4 days in normoxic (21% oxygen) or in hypoxic (2% oxygen) atmosphere using Etanercept dissolved in a range of 2.5-40 µg/mL prior to islet characterisation. RESULTS: In normoxic atmosphere, it was found that 5 µg/mL is the most efficient dose to preserve islet morphological and functional integrity during culture. Increasing the dose to 10 µg/mL or more resulted in detrimental effects with respect to viability and glucose-stimulated insulin release. When human islets were cultured for 3 to 4 days in clinically relevant hypoxia and treated with 5 µg/mL Etanercept, post-culture islet survival (P < 0.001) and in vitro function (P < 0.01) were significantly improved. This correlated with a substantially reduced cytokine production (P < 0.05), improved mitochondrial function (P < 0.01), and reduced production of reactive oxygen species (P < 0.001) in hypoxia-exposed islets. CONCLUSION: These findings suggest that the therapeutic window of Etanercept is very narrow and that this should be considered when optimising the dosage and route of Etanercept administration in islet-transplant recipients or when designing novel drug-delivering islet scaffolds.

14.
Semin Pediatr Surg ; 30(1): 151019, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33648712

RESUMO

Academic pediatric surgery faces challenges and opportunity. The author provides a brief overview of the landscape of academic surgery from a UK perspective and based on his considerable experience, makes suggestions for present and future directions.


Assuntos
Especialidades Cirúrgicas , Criança , Humanos , Reino Unido
15.
J Wrist Surg ; 10(1): 9-16, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33552688

RESUMO

Objective This study reports on the clinical outcomes of double screw fixation with autologous cancellous bone grafting and early active range of motion for delayed and nonunited scaphoid waist fractures with cavitary segmental bone loss. Patients and Methods Twenty-one consecutive patients underwent fixation using two 2.2 mm antegrade headless compression screws with autologous distal radius cancellous bone graft. Postoperatively, patients were allowed early active motion with a resting splint until union was achieved. Patients were reviewed radiologically and clinically to assess for fracture union, complications, residual pain, wrist function, and return to work and recreational activities. Results All but one patient was male, and the mean age was 23 years (range, 15-38 years). The average time from initial injury was 16 months (range, 3-144 months). Nineteen of 21 (90.5%) patients achieved union at a mean of 2.8 months (range, 1.4-9.2 months). Of the patients who failed, one underwent revision surgery with vascularized bone grafting at 10.6 months. The other patient refused further intervention as he was asymptomatic. Conclusion Double-screw fixation with bone grafting and early active range of motion is a safe and effective technique for management of delayed and nonunited unstable scaphoid fractures with cavitary bone loss. This potentially allows for earlier return to function, without compromise to union rates. Level of Evidence This is a Level IV, retrospective case series study.

16.
Cell ; 184(3): 810-826.e23, 2021 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-33406409

RESUMO

Development of the human intestine is not well understood. Here, we link single-cell RNA sequencing and spatial transcriptomics to characterize intestinal morphogenesis through time. We identify 101 cell states including epithelial and mesenchymal progenitor populations and programs linked to key morphogenetic milestones. We describe principles of crypt-villus axis formation; neural, vascular, mesenchymal morphogenesis, and immune population of the developing gut. We identify the differentiation hierarchies of developing fibroblast and myofibroblast subtypes and describe diverse functions for these including as vascular niche cells. We pinpoint the origins of Peyer's patches and gut-associated lymphoid tissue (GALT) and describe location-specific immune programs. We use our resource to present an unbiased analysis of morphogen gradients that direct sequential waves of cellular differentiation and define cells and locations linked to rare developmental intestinal disorders. We compile a publicly available online resource, spatio-temporal analysis resource of fetal intestinal development (STAR-FINDer), to facilitate further work.


Assuntos
Intestinos/citologia , Intestinos/crescimento & desenvolvimento , Análise de Célula Única , Células Endoteliais/citologia , Sistema Nervoso Entérico/citologia , Feto/embriologia , Fibroblastos/citologia , Humanos , Imunidade , Enteropatias/congênito , Enteropatias/patologia , Mucosa Intestinal/crescimento & desenvolvimento , Intestinos/irrigação sanguínea , Ligantes , Mesoderma/citologia , Neovascularização Fisiológica , Pericitos/citologia , Células-Tronco/citologia , Fatores de Tempo , Fatores de Transcrição/metabolismo
18.
Cell Transplant ; 29: 963689720952332, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33150790

RESUMO

Previous studies in rodents have indicated that function and survival of transplanted islets can be substantially improved by mesenchymal stem cells (MSC). The few human islet studies to date have confirmed these findings but have not determined whether physical contact between MSC and islets is required or whether the benefit to islets results from MSC-secreted proteins. This study aimed to investigate the protective capacity of MSC-preconditioned media for human islets. MSC were cultured for 2 or 5 days in normoxia or hypoxia before harvesting the cell-depleted media for human islet culture in normoxia or hypoxia for 6-8 or 3-4 days, respectively. To characterize MSC-preconditioned media, proteomic secretome profiling was performed to identify angiogenesis- and inflammation-related proteins. A protective effect of MSC-preconditioned media on survival and in vitro function of hypoxic human islets was observed irrespective of the atmosphere used for MSC preconditioning. Islet morphology changed markedly when media from hypoxic MSC were used for culture. However, PDX-1 and insulin gene expression did not confirm a change in the genetic phenotype of these islets. Proteomic profiling of preconditioned media revealed the heterogenicity of the secretome comprising angiogenic and antiapoptotic as well as angiostatic or proinflammatory mediators released at an identical pattern regardless whether MSC had been cultured in normoxic or hypoxic atmosphere. These findings do not allow a clear discrimination between normoxia and hypoxia as stimulus for protective MSC capabilities but indicate an ambivalent character of the MSC angiogenesis- and inflammation-related secretome. Nevertheless, culture of human islets in acellular MSC-preconditioned media resulted in improved morphological and functional islet integrity suggesting a disbalance in favor of protective factors. Further approaches should aim to eliminate potentially detrimental factors to enable the production of advanced clinical grade islet culture media with higher protective qualities.


Assuntos
Meios de Cultivo Condicionados/farmacologia , Ilhotas Pancreáticas/metabolismo , Células-Tronco Mesenquimais/metabolismo , Proteoma/metabolismo , Proteômica , Diferenciação Celular , Linhagem da Célula , Células Cultivadas , Humanos , Hipóxia/patologia , Imunofenotipagem , Ilhotas Pancreáticas/efeitos dos fármacos , Ilhotas Pancreáticas/patologia
19.
J Am Pharm Assoc (2003) ; 60(6): e168-e172, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32591200

RESUMO

OBJECTIVE: With consideration of the narrow therapeutic index of levothyroxine (LT4), the objective of this study was to investigate the stability and consistency of compounded oral liquid formulations of LT4. METHODS: Six pharmacies and 6 student pharmacists provided compounded oral liquid formulations of LT4. Pharmacies used their standard compounding best practice including addition of excipients, labeling, and storage instructions. The student pharmacists were required to have completed all academic compounding training and were provided instructions and materials. All analyses were performed at the Pharmaceutical Education and Research Center, a Food and Drug Administration-registered pharmaceutical sciences laboratory. The compounded products were assayed for percent of labeled strength (%LS) of LT4 on days 3, 6, 13, 20, 27, and 34. Each compounding pharmacy and student pharmacist subsequently prepared a second compounded product sample approximately 30 days later to simulate a refill prescription. RESULTS: Individual product assays on days 3, 6, 13, 20, 27, and 34 demonstrated a range in variation of %LS from 12% to 47% (mean 26.5%). Wide variations of %LS of LT4 were observed between compounding sources. The assays for all products on day 3 demonstrated a range for %LS of LT4 from 77% to 113%, and those on day 34 ranged from 30% to 97%. Assay comparison of the original compounded product (month 1) to the refill compounded product (month 2) varied from 1% to 58%. Variations in excipients and flavorings were also present. One sample contained liothyronine and was not used for evaluation. These variations may be secondary to aliquot sampling of a suspension or product degradation. CONCLUSION: Compounded oral liquid LT4 products are unlikely to deliver the precise prescribed dosage and reliable product performance when administered to patients.


Assuntos
Farmácias , Farmácia , Composição de Medicamentos , Estabilidade de Medicamentos , Humanos , Farmacêuticos , Tiroxina
20.
Wellcome Open Res ; 5: 49, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32399500

RESUMO

Type 1 diabetes is a common autoimmune disease due to destruction of pancreatic ß cells, resulting in lifelong need for insulin. Evidence suggest that maintaining residual ß-cell function can improve glucose control and reduce risk of hypoglycaemia and vascular complications. Non-clinical, preclinical and some preliminary clinical data suggest that low-dose interleukin-2 (IL-2) therapy could block pancreatic ß cells destruction by increasing the number of functional regulatory T cells (Tregs) that inhibit islet-specific autoreactive effector T cells (Teffs). However, there is lack of data on the effect of low-dose IL-2 in newly diagnosed children and adolescents with T1D as well as lack of specific data on its potential effect on ß-cell function. The ' Interleukin-2 Therapy of Autoimmunity in Diabetes (ITAD)' is a phase 2, multicentre, double-blind, randomised, placebo-controlled trial in children and adolescents (6-18 years; having detectable C-peptide) initiated within 6 weeks of T1D diagnosis. A total of 45 participants will be randomised in a 2:1 ratio to receive either ultra-low dose IL-2 (aldesleukin), at a dose of 0.2 x 10 6 IU/m 2 twice-weekly, given subcutaneously, or placebo, for 6 months. The primary objective is to assess the effects of ultra-low dose aldesleukin administration on endogenous ß-cell function as measured by frequent home dried blood spot (DBS) fasting and post-prandial C-peptide in children and adolescents with newly diagnosed T1D. The secondary objectives are: 1) to assess the efficacy of regular dosing of aldesleukin in increasing Treg levels; 2) to confirm the clinical safety and tolerability of ultra-low dose aldesleukin; 3) to assess changes in the immune system indicating benefit or potential risk for future gains/loss in ß-cell function and immune function; 4) to assess treatment effect on glycaemic control. Trial registration: EudraCT 2017-002126-20 (06/02/2019).

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