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Pancreatic endocrine cells employ a sophisticated system of paracrine and autocrine signals to synchronize their activities, including glutamate, which controls hormone release and ß-cell viability by acting on glutamate receptors expressed by endocrine cells. We here investigate whether alteration of the excitatory amino acid transporter 2 (EAAT2), the major glutamate clearance system in the islet, may occur in type 2 diabetes mellitus and contribute to ß-cell dysfunction. Increased EAAT2 intracellular localization was evident in islets of Langerhans from T2DM subjects as compared with healthy control subjects, despite similar expression levels. Chronic treatment of islets from healthy donors with high-glucose concentrations led to the transporter internalization in vesicular compartments and reduced [H3]-d-glutamate uptake (65 ± 5% inhibition), phenocopying the findings in T2DM pancreatic sections. The transporter relocalization was associated with decreased Akt phosphorylation protein levels, suggesting an involvement of the phosphoinositide 3-kinase (PI3K)/Akt pathway in the process. In line with this, PI3K inhibition by a 100-µM LY294002 treatment in human and clonal ß-cells caused the transporter relocalization in intracellular compartments and significantly reduced the glutamate uptake compared to control conditions, suggesting that hyperglycemia changes the trafficking of the transporter to the plasma membrane. Upregulation of the glutamate transporter upon treatment with the antibiotic ceftriaxone rescued hyperglycemia-induced ß-cells dysfunction and death. Our data underscore the significance of EAAT2 in regulating islet physiology and provide a rationale for potential therapeutic targeting of this transporter to preserve ß-cell survival and function in diabetes.NEW & NOTEWORTHY The glutamate transporter SLC1A2/excitatory amino acid transporter 2 (EAAT2) is expressed on the plasma membrane of pancreatic ß-cells and controls islet glutamate clearance and ß-cells survival. We found that the EAAT2 membrane expression is lost in the islets of Langerhans from type 2 diabetes mellitus (T2DM) patients due to hyperglycemia-induced downregulation of the phosphoinositide 3-kinase/Akt pathway and modification of its intracellular trafficking. Pharmacological rescue of EAAT2 expression prevents ß-cell dysfunction and death, suggesting EAAT2 as a new potential target of intervention in T2DM.
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Diabetes Mellitus Tipo 2 , Transportador 2 de Aminoácidos Excitadores , Ácido Glutámico , Hiperglucemia , Islotes Pancreáticos , Transportador 2 de Aminoácidos Excitadores/metabolismo , Humanos , Diabetes Mellitus Tipo 2/metabolismo , Ácido Glutámico/metabolismo , Hiperglucemia/metabolismo , Islotes Pancreáticos/metabolismo , Islotes Pancreáticos/efectos de los fármacos , Masculino , Persona de Mediana Edad , Femenino , Transporte de Proteínas , Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/efectos de los fármacos , Proteínas Proto-Oncogénicas c-akt/metabolismo , Anciano , Adulto , Animales , Fosfatidilinositol 3-Quinasas/metabolismoRESUMEN
AIMS: Several studies showed that Assisted Reproductive Technology (ART) could affect gestational diabetes mellitus (GDM) onset. The aim of this study was to estimate the prevalence of GDM risk factors in a cohort of women with singleton pregnancy obtained by ART and complicated by GDM. Maternal and neonatal outcomes were explored. METHODS: We retrospectively collected data of pregnancies of women with singleton pregnancy obtained by ART and complicated by GDM consecutively cared for at a specialized center for diabetes and pregnancy care. Prevalence and combination of GDM risk factors, their combinations and maternal-fetal outcomes were estimated. RESULTS: Overall, our cohort included 50 women (mean age of 40.4 ± 4.7 years, mean pre-pregnancy BMI 26.3 ± 6.2 kg/m2). The most frequent GDM traditional risk factors were age ≥ 35 years (94 %), family history of diabetes (44 %), overweight (29 %) and obesity (19 %). Combining risk factors, 5 groups were identified with 1, 2, 3, 4, or 5 risk factors with a prevalence respectively of 28 %, 46 %, 20 %, 4 %, and 2 %. Examining features of the above groups, pre-pregnancy weight (p < 0.0001) and pre-pregnancy BMI (p < 0.0001) statistically significant differed in the 5 groups, increasing with higher numbers of risk factors. Regarding neonatal outcomes only neonatal hypoglycemia (p = 0.03) differed significantly among the groups, with higher percentages in women with higher numbers of combined risk factors. CONCLUSION: Prevalence of GDM traditional risk factors in singleton ART pregnancies complicated by GDM is considerable. Such pregnancies need appropriate clinical attention because of the risk of adverse outcomes.
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Diabetes Gestacional , Embarazo , Recién Nacido , Femenino , Humanos , Adulto , Persona de Mediana Edad , Diabetes Gestacional/epidemiología , Diabetes Gestacional/etiología , Estudios Retrospectivos , Prevalencia , Factores de Riesgo , Sistema de Registros , Resultado del Embarazo/epidemiologíaRESUMEN
Intermittently Scanned Continuous Glucose Monitoring (isCGM) devices are increasingly being used in patients with type 2 diabetes mellitus (T2DM) on insulin therapy for their benefits regarding disease management. Evidence of isCGM use in patients with T2DM on basal or non-insulin therapy is lacking. This study aimed at assessing the efficacy and safety of isCGM in this population. This was an observational, retrospective, real-world study enrolling patients with T2DM who were starting the use of isCGM. Data from medical records (i.e., demographics, clinical characteristics, laboratory assessments, and isCGM metrics) were collected over three time periods (baseline, 3 and 6 months). The endpoints were glycated haemoglobin (HbA1c) changes and changes in isCGM metrics as defined by the International Consensus from baseline to 3 months and 6 months. Overall, 132 patients were included (69.5% male; mean age 68.2 ± 11.0 years; mean disease duration 19.0 ± 9.4 years; 79.7% on basal insulin ±non-insulin therapy; mean baseline HbA1c 8.1% ± 1.3%). The estimated mean change in HbA1c was statistically significant at three (-0.4 ± 1.0%; p = 0.003) and six months (-0.6 ± 1.3%; p < 0.0001). In conclusion, isCGM proved to be effective and safe in improving glycaemic control in patients with T2DM on basal insulin or non-insulin therapy.
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Type 2 diabetes mellitus (T2DM) is characterized by high blood glucose levels and lipid alterations. Besides pharmacological treatment, lifestyle modifications and nutraceuticals can be used to manage glucose and lipid profiles, which is crucial for preventing, or avoiding, serious consequences associated with the condition. This randomized controlled clinical trial on 75 patients with T2DM evaluated the effects of a combination of myo-inositol and d-chiro-inositol (40:1), α-lactalbumin, Gymnema sylvestre, and zinc on glucose and lipid profile. The intention-to-treat analysis displayed no significant differences in glucose parameters between the groups; however, the study group displayed reduced levels of total cholesterol (p = 0.01) and LDL (p = 0.03) after 3 months of supplementation. A subgroup analysis involving patients who did not modify their antidiabetic therapy, after 6 months displayed improved levels of total cholesterol (p = 0.03) and LDL (p = 0.04) in the study group versus placebo, along with a greater body weight reduction (p = 0.03) after 3 months. Furthermore, within the study group, levels of HDL (p = 0.03) and triglycerides (p = 0.04) improved after 3 months. These findings support supplementation with myo-inositol and d-chiro-inositol (40:1), α-lactalbumin, Gymnema sylvestre, and zinc as an adjuvant and safe strategy to manage the lipid profiles of patients with T2DM.
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Diabetes Mellitus Tipo 1 , Hipoglucemia , Humanos , Hidroxiurea/efectos adversos , Hipoglucemia/inducido químicamente , Hipoglucemiantes/uso terapéutico , Glucosa , Insulina/uso terapéutico , Diabetes Mellitus Tipo 1/tratamiento farmacológico , Glucemia , Sistemas de Infusión de Insulina , Automonitorización de la Glucosa SanguíneaRESUMEN
Our aim was to evaluate osteomyelitis and other major lower limb safety outcomes (i.e., peripheral artery disease or PAD, ulcers, atraumatic fractures, amputations, symmetric polyneuropathy, and infections) in patients affected by type 2 diabetes mellitus (T2DM) and treated with sodium-glucose cotransporter 2 inhibitors (SGLT2-is). We thus performed a systematic review and meta-analysis of randomised controlled trials (RCTs) comparing SGLT2-is at approved doses for T2DM with a placebo or standard of care. MEDLINE, Embase, and Cochrane CENTRAL were searched through August 2022. Separate intention-to-treat analyses were implemented for each molecule to calculate Mantel-Haenszel risk ratios (RRMH) with 95% confidence intervals (CIs) through a random-effects model. We processed data from 42 RCTs for a total of 29,491 and 23,052 patients, respectively assigned to SGLT2-i and comparator groups. SGLT2-is showed a pooled neutral effect on osteomyelitis, PAD, fractures, and symmetric polyneuropathy, whereas slightly deleterious sway on ulcers (RRMH 1.39 [1.01-1.91]), amputations (RRMH 1.27 [1.04-1.55]), and infections (RRMH 1.20 [1.02-1.40]). In conclusion, SGLT2-is appear to not significantly interfere with the onset of osteomyelitis, PAD, lower limb fractures, or symmetric polyneuropathy, even though the number of these events proved consistently higher in the investigational groups; otherwise, local ulcers, amputations, and overall infections may be favoured by their employment. This study is registered with the Open Science Framework (OSF).
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Human pancreatic islets transplantation is an experimental therapeutic treatment for Type I Diabetes. Limited islets lifespan in culture remains the main drawback, due to the absence of native extracellular matrix as mechanical support after their enzymatic and mechanical isolation procedure. Extending the limited islets lifespan by creating a long-term in vitro culture remains a challenge. In this study, three biomimetic self-assembling peptides were proposed as potential candidates to recreate in vitro a pancreatic extracellular matrix, with the aim to mechanically and biologically support human pancreatic islets, by creating a three-dimensional culture system. The embedded human islets were analyzed for morphology and functionality in long-term cultures (14-and 28-days), by evaluating ß-cells content, endocrine component, and extracellular matrix constituents. The three-dimensional support provided by HYDROSAP scaffold, and cultured into MIAMI medium, displayed a preserved islets functionality, a maintained rounded islets morphology and an invariable islets diameter up to 4 weeks, with results analogues to freshly-isolated islets. In vivo efficacy studies of the in vitro 3D cell culture system are ongoing; however, preliminary data suggest that human pancreatic islets pre-cultured for 2 weeks in HYDROSAP hydrogels and transplanted under subrenal capsule may restore normoglycemia in diabetic mice. Therefore, engineered self-assembling peptide scaffolds may provide a useful platform for long-term maintenance and preservation of functional human pancreatic islets in vitro.
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Diabetes Mellitus Tipo 1 , Hipoglucemia , Humanos , Anciano , Diabetes Mellitus Tipo 1/tratamiento farmacológico , Estudios Prospectivos , Estudios de Seguimiento , Hipoglucemiantes/efectos adversos , Sistemas de Infusión de Insulina , Insulina/uso terapéutico , Glucemia , Automonitorización de la Glucosa SanguíneaRESUMEN
Skin allografts represent a milestone in burn patient treatment. However, skin procurement is still burdened by high rates of contamination, and validation procedures have not yet been standardized. In addition, it is not clear if tissue viability affects allograft skin outcomes. In 2120 skin samples from 610 donors, a retrospective analysis was performed to identify donor and procurement variables associated with bacterial contamination and tissue viability. Post-processing contamination was associated significantly with the donor type, cause of death, length of hospitalization, procurement site, surgeon, interval between procurement and banking, and decontamination method. Tissue viability appeared to be negatively associated with freezing. In two series of skin allograft recipients (155 and 195 patients), we evaluated the role of skin characteristics and procurement variables on clinical outcomes. We found that the length of hospitalization was associated significantly with donor age. Procalcitonin and PCR values in allograft recipients were correlated with the decontamination method. No significant associations were observed between tissue viability and clinical outcomes (length of hospitalization, cause of donor death, or inflammatory parameters) after allograft transplantation. In these large case series, we identified donor and procurement variables that may affect allograft skin recipients. The decontamination method appeared to be a critical step for skin allograft requiring better standardization.
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Quemaduras , Humanos , Estudios Retrospectivos , Quemaduras/cirugía , Piel , Trasplante Homólogo , Aloinjertos , Resultado del TratamientoRESUMEN
PURPOSE: Our aim was to investigate the involvement of posterior pole structures in eyes affected by keratoconus (KC). Optical coherence tomography (OCT) and OCT angiography (OCTA) were used to determine the status of lamina cribrosa (LC), peripapillary retinal nerve fiber layer (RNFL), macular and peripapillary microvasculature. DESIGN: Observational, cross-sectional, case-control analysis. METHODS: Single-center investigation involving patients with KC and healthy control subjects. Enrolled subjects underwent anterior segment OCT combined with Placido-disk topography, macular and optic nerve head swept-source OCT and swept-source OCTA scans, and 3D wide glaucoma module for peripapillary RNFL thickness measurement. The LC curvature index was used to express the degree of LC posterior bowing. We calculated the vessel density and vessel length density at the macular superficial capillary plexus, deep capillary plexus, choriocapillaris, and nerve radial peripapillary capillary plexus. RESULTS: Overall, 32 eyes with KC and an equal number of age- and axial length-matched control eyes were included in the analysis. Almost all (97%) of eyes with KC were classified as early stage. KC displayed a reduction in peripapillary RNFL thickness (104.8 ± 11.9 µm vs 110.7 ± 10.5 µm; P = .039) and nerve radial peripapillary capillary plexus vessel density (46.31% ± 3% vs 43.82% ± 4%; P = .006) when compared with control subjects; these differences were more evident in the temporal sector and were associated with a higher LC curvature index (9.9% ± 2.6% vs 8.48% ± 1.7%; P = .012). Mean macular superficial capillary plexus vessel density was 3 percentage points lower in eyes with KC than in healthy controls (P < .001). CONCLUSION: Early-stage KC may be characterized by a posterior bowing of the LC along with a subtle peripapillary RNFL thinning and vascular impairment. These findings support the hypothesis that KC may be a corneal manifestation of a more generalized "eye collagen disease."
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Queratocono , Humanos , Queratocono/diagnóstico , Estudios Transversales , Vasos Retinianos/fisiología , Campos Visuales , Células Ganglionares de la Retina , Tomografía de Coherencia Óptica/métodos , Fibras Nerviosas , Perfusión , Angiografía con Fluoresceína/métodosRESUMEN
Purpose: To evaluate the impact of vitamin D (Vit D) supplementation on systemic biomarkers of collagen degradation, inflammation, oxidative stress, and copper metabolism in adolescent patients with keratoconus (KC). Methods: This was a prospective observational pilot study. Twenty patients (age range, 16-19 years) presenting KC and Vit D insufficiency (<30 ng/mL) were included. Vit D supplementation was prescribed by their general practitioner as per the standard of care. Patients were followed up for 12 months. At each visit, best spectacle-corrected visual acuity (BSCVA), maximal keratometry (Kmax), and thinnest corneal thickness (TCT) were evaluated. The primary outcome of the study was the proportion of patients with Kmax progression of less than 1 D throughout the 12-month follow-up time. Blood samples were collected at different time points to evaluate Vit D levels and systemic markers of collagen degradation, inflammation, oxidative stress, and copper metabolism by ELISA or RT-PCR. Results: Lower Vit D levels in the plasma were correlated with higher levels of systemic biomarkers of collagen degradation. Vit D supplementation increased the cell availability of copper. Moreover, stabilization of KC progression was found in 60% of patients (72% of eyes) after 12 months with Vit D supplementation. BSCVA, Kmax, and TCT rates remained stable during the observation period. Conclusions: Our findings support that Vit D administration could affect ocular and systemic biomarkers in KC and illuminate a possible mechanism that can be used to develop new treatment alternatives. Translational Relevance: Although KC therapy currently relies exclusively on surgical procedures, Vit D supplementation may offer a non-invasive and inexpensive alternative with minimal associated side effects.
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Queratocono , Fotoquimioterapia , Adolescente , Humanos , Adulto Joven , Adulto , Queratocono/tratamiento farmacológico , Queratocono/metabolismo , Fármacos Fotosensibilizantes , Fotoquimioterapia/métodos , Cobre/uso terapéutico , Agudeza Visual , Rayos Ultravioleta , Riboflavina , Estudios Prospectivos , Estudios de Seguimiento , Topografía de la Córnea , Colágeno , Inflamación , Vitamina D/uso terapéutico , Suplementos DietéticosRESUMEN
BACKGROUND AND AIMS: Sodium-glucose co-transporter-2 inhibitors (SGLT2i) may have important benefits for the elderly with type 2 diabetes (T2D), however some safety concerns still limit their use in patients over 70 years of age. The SOLD study (SGLT2i in Older Diabetic patients) is a multicenter study, aimed to evaluate the effectiveness and safety of SGLT2i in the older diabetic patients in a real-life setting. MATERIALS AND METHODS: We analyzed a population of 739 adults (mean age 75.4 ± 3.9 years, M/F 420/319) with T2D, which started a SGLT2i-based treatment after the age of 70, with at least one year of follow-up. Data were collected at baseline, at 6 and 12 months of follow-up. RESULTS: SGLT2i (37.5% Empagliflozin, 35.7% Dapagliflozin, 26.1% Canagliflozin, 0.7% Ertugliflozin) were an add-on therapy to Metformin in 88.6%, to basal insulin in 36.1% and to other antidiabetic drugs in 29.6% of cases. 565 subjects completed the follow up, while 174 (23.5%) discontinued treatment due to adverse events which were SGLT2i related. A statistically significant reduction of glycated hemoglobin (baseline vs 12 months: 7.8 ± 1.1 vs 7.1 ± 0.8%, p < 0.001) and body mass index values (baseline vs 12 months: 29.2 ± 4.7 vs 28.1 ± 4.5 kg/m2, p < 0.001) were evident during follow-up. Overall, estimated glomerular filtration rate remained stable over time, with significant reduction of urinary albumin excretion. In the subgroup of patients which were ≥ 80 years, a significant improvement in glycated hemoglobin values without renal function alterations was evident. Overall discontinuation rate during the follow-up period was different across age groups, being urinary tract infections and worsening of renal function the most common cause. CONCLUSION: SGLT2i are well-tolerated and safe in the elderly and appear as an effective therapeutic option, though some caution is also suggested, especially in more fragile subjects.
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Diabetes Mellitus Tipo 2 , Inhibidores del Cotransportador de Sodio-Glucosa 2 , Anciano , Anciano de 80 o más Años , Canagliflozina/efectos adversos , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Hemoglobina Glucada/metabolismo , Humanos , Hipoglucemiantes/efectos adversos , Seguridad del Paciente , Transportador 2 de Sodio-Glucosa , Inhibidores del Cotransportador de Sodio-Glucosa 2/efectos adversosRESUMEN
AIM: Pregnancies of women with pregestational diabetes are at risk of after-meal glucose peaks and late after-meal hypoglycemia, particularly at breakfast. We aimed to explore the effectiveness of a specific feature of insulin pump therapy called superbolus in preventing these glucose swings. METHODS: In this retrospective observational study, we analyzed continuous glucose monitoring data of patients with type 1 diabetes in pregnancy who were advised to use superbolus to manage their breakfast. Some of the postprandial basal insulin delivery was partially reduced and delivered instead as additional insulin bolus on top of a normal bolus. Outcomes of interest were one hour after breakfast glucose levels, the time in glucose range for after breakfast period, the number of late hypoglycemic episodes. RESULTS: Overall, 21 consecutive pregnant women with type 1 diabetes (mean age 34.3 ± 5.5 years, mean pregestational body mass index 23.7 ± 4.7 kg/m2, HbA1c levels during pregnancy 6.1 ± 0.6%) were studied. Superbolus reduced after breakfast glucose peaks (one hour after breakfast glucose levels 130 ± 17 mg/dL vs 123 ± 10 mg/dL before and after superbolus use, respectively, P = .01), improved the time in glucose range for after breakfast period (70.4% vs 50.8%, P = .001), and reduced the number of late hypoglycemic episodes (3 [1-5] vs 1 [0-2], P< .0001). CONCLUSION: Superbolus was effective in avoiding after-meal glucose peaks, increased postprandial glucose time in target, without late hypoglycemia occurrence. It represents a valid option for the treatment of pregnant women with type 1 diabetes using insulin pump.
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PURPOSE: To assess the accuracy of different corneal powers for intraocular (IOL) power calculation in combined Descemet membrane endothelial keratoplasty (DMEK) and cataract surgery and investigate whether preoperative parameters correlate to the prediction error (PE). METHODS: This prospective case series involved patients with Fuchs endothelial dystrophy receiving combined DMEK and cataract surgery. Preoperatively, patients underwent optical biometry and anterior segment OCT (AS-OCT). AS-OCT measurements were repeated 6 months postoperatively, when final refraction was assessed. The PE was calculated using the preoperative average keratometry (Kave) measured by the optical biometer and User Group for Laser Interference Biometry (ULIB) constants. It was also calculated, after constant optimization, using the preoperative Kave from both devices and the total corneal power (TCP) measured by AS-OCT, as well as the postoperative Kave and TCP measured by AS-OCT. RESULTS: ULIB constants resulted in the highest hyperopic PE (P < .0001). Constant optimization improved the results, because the PE was zeroed out and the absolute PEs decreased. No significant difference was found among the Barrett Universal II, Emmetropia Verifying Optical 2.0, Haigis, Hoffer Q, Holladay 1, Kane, and SRK/T formulas. Further improvement was achieved with the postoperative Kave and TCP, although the accuracy remained moderate. The PE based on preoperative corneal measurements was correlated to the amount of corneal flattening; the latter could be predicted by multiple linear regression accounting for anterior and posterior corneal radii (P = .0002) and was correlated to the preoperative anterior/posterior ratio. CONCLUSIONS: Constant optimization is beneficial for combined DMEK and phacoemulsification. Predicting postoperative corneal flattening may improve the results of IOL power accuracy. [J Refract Surg. 2022;38(7):435-442.].
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Catarata , Trasplante de Córnea , Lentes Intraoculares , Facoemulsificación , Biometría/métodos , Lámina Limitante Posterior , Humanos , Óptica y Fotónica , Facoemulsificación/métodos , Refracción Ocular , Estudios RetrospectivosRESUMEN
The use of a televisit service complying with efficiency and safety regulatory parameters was effective in significantly improving HbA1c levels of people with T1D after a one-year follow-up period. No acute diabetes-related complications occurred. Patients were highly satisfied with the service. Televisit is a valid option for diabetes management.
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Complicaciones de la Diabetes , Diabetes Mellitus Tipo 1 , Telemedicina , Diabetes Mellitus Tipo 1/terapia , Estudios de Seguimiento , Humanos , Estudios RetrospectivosRESUMEN
BACKGROUND AND AIMS: The new advanced hybrid closed loop insulin infusion systems have the potential to significantly improve glycaemic control. The aim of this study was to evaluate the effectiveness of the Minimed 780G system in 59 patients with type 1 diabetes. METHODS AND RESULTS: Glucose control obtained by using the system in automatic mode at 1-2 months of activation, at 2-4 months, at 4-6 months, and beyond 6 month was compared with those obtained with the system in manual mode. A significant improvement in time-in-range and in time-above-range throughout the follow-up was observed, as well as a significant reduction in time-below-range (<54 mg/dl) after 6 months, a significant reduction of the glucose variability and of HbA1c. After switching the mode, all target percentages lied on the average within the recommended ranges by literature consensus and no severe hypoglycemia nor ketoacidosis episodes were recorded. CONCLUSION: The Minimed 780G allowed a rapid and progressive improvement of the overall glucose control.
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Diabetes Mellitus Tipo 1 , Glucemia , Automonitorización de la Glucosa Sanguínea , Diabetes Mellitus Tipo 1/diagnóstico , Diabetes Mellitus Tipo 1/tratamiento farmacológico , Humanos , Hipoglucemiantes/efectos adversos , Insulina/efectos adversos , Sistemas de Infusión de InsulinaRESUMEN
Islet cell surface autoantibodies were previously found in subjects with type 1 diabetes mellitus (T1DM), but their target antigens and pathogenic mechanisms remain elusive. The glutamate transporter solute carrier family 1, member 2 (GLT1/EAAT2) is expressed on the membrane of pancreatic ß-cells and physiologically controls extracellular glutamate concentrations thus preventing glutamate-induced ß-cell death. We hypothesized that GLT1 could be an immunological target in T1DM and that autoantibodies against GLT1 could be pathogenic. Immunoprecipitation and ELISA experiments showed that sera from T1DM subjects recognized GLT1 expressed in brain, pancreatic islets, and GLT1-transfected COS7-cell extracts. We validated these findings in two cohorts of T1DM patients by quantitative immunofluorescence assays. Analysis of the combined data sets indicated the presence of autoantibodies against GLT1 in 32 of the 87 (37%) T1DM subjects and in none of healthy controls (n = 64) (p < 0.0001). Exposure of pancreatic ßTC3 cells and human islets to purified IgGs from anti-GLT1 positive sera supplemented with complement resulted in plasma membrane ruffling, cell lysis and death. The cytotoxic effect was prevented when sera were depleted from IgGs. Furthermore, in the absence of complement, 6 out of 16 (37%) anti-GLT1 positive sera markedly reduced GLT1 transport activity in ßTC3 cells by inducing GLT1 internalization, also resulting in ß-cell death. In conclusion, we provide evidence that GLT1 is a novel T1DM autoantigen and that anti-GLT1 autoantibodies cause ß-cell death through complement-dependent and independent mechanisms. GLT1 seems an attractive novel therapeutic target for the prevention of ß-cell death in individuals with diabetes and prediabetes.
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Sistema de Transporte de Aminoácidos X-AG , Diabetes Mellitus Tipo 1 , Autoanticuerpos , Diabetes Mellitus Tipo 1/terapia , Ácido Glutámico/metabolismo , Humanos , Neuroglía/metabolismoRESUMEN
Loss of pancreatic beta cells is a central feature of type 1 (T1D) and type 2 (T2D) diabetes, but a therapeutic strategy to preserve beta cell mass remains to be established. Here we show that the death receptor TMEM219 is expressed on pancreatic beta cells and that signaling through its ligand insulin-like growth factor binding protein 3 (IGFBP3) leads to beta cell loss and dysfunction. Increased peripheral IGFBP3 was observed in established and at-risk T1D/T2D patients and was confirmed in T1D/T2D preclinical models, suggesting that dysfunctional IGFBP3/TMEM219 signaling is associated with abnormalities in beta cells homeostasis. In vitro and in vivo short-term IGFBP3/TMEM219 inhibition and TMEM219 genetic ablation preserved beta cells and prevented/delayed diabetes onset, while long-term IGFBP3/TMEM219 blockade allowed for beta cell expansion. Interestingly, in several patients' cohorts restoration of appropriate IGFBP3 levels was associated with improved beta cell function. The IGFBP3/TMEM219 pathway is thus shown to be a physiological regulator of beta cell homeostasis and is also demonstrated to be disrupted in T1D/T2D. IGFBP3/TMEM219 targeting may therefore serve as a therapeutic option in diabetes.
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Regulación de la Expresión Génica , Homeostasis/genética , Proteína 3 de Unión a Factor de Crecimiento Similar a la Insulina/genética , Células Secretoras de Insulina/metabolismo , Proteínas de la Membrana/genética , Transducción de Señal/genética , Adulto , Animales , Células Cultivadas , Diabetes Mellitus Tipo 1/genética , Diabetes Mellitus Tipo 1/metabolismo , Diabetes Mellitus Tipo 1/patología , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/patología , Femenino , Humanos , Immunoblotting , Proteína 3 de Unión a Factor de Crecimiento Similar a la Insulina/metabolismo , Masculino , Proteínas de la Membrana/metabolismo , Ratones Endogámicos C57BL , Ratones Endogámicos NOD , Ratones Noqueados , Ratones Transgénicos , Persona de Mediana Edad , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
A 48-year-old deaf-mute man attending our outpatient clinic for long-term severely decompensated type 1 diabetes (mean glycated haemoglobin over 100 mmol/mol) has proved to be the best candidate for the beneficial implant of a next-generation closed loop insulin pump featuring a new refined auto-correction algorithm. The patient had already worn a stand-alone real-time continuous glucose monitoring (rt-CGM) device for 2 years, but his haemoglobin A1c (HbA1c) remained out of target with ample glucose variability. Then, we decided to use a novel advanced hybrid closed-loop insulin pump (the MiniMed 780G) coupled with his CGM device. After only 4 months this system led to a significant improvement in mean daily glucose levels (201±100 mg/dL vs 141±57 mg/dL), time in glucose range (43% vs 78%), percentage of time spent in hyperglycaemia (52% vs 20%), glucose variability (Coefficient of Variation 46% vs 38%), and HbA1c levels (121 mmol/mol vs 56 mmol/mol). The patient was highly satisfied.