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9 result(s) for "Lytrivi, Maria"
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Real-world performance of an AI system for diabetic retinopathy screening
Diabetic retinopathy (DR) is a leading cause of preventable blindness, and the growing global burden of diabetes is placing increasing pressure on ophthalmic services. Artificial intelligence (AI)–based retinal image analysis offers a promising strategy to scale up DR screening while reducing reliance on specialist graders. We assessed the performance of an AI-based DR screening system implemented in a real-world endocrinology clinic at the Erasmus Hospital, Belgium. Adult patients with diabetes underwent non-mydriatic fundus photography, and images were analyzed by the AI system for referable DR and diabetic macular edema. All images were independently graded by a retinal specialist using the Early Treatment Diabetic Retinopathy Study (ETDRS) classification as the reference standard. Of 405 patients screened, 353 (86.7%) were included in the primary analysis. The AI system achieved an area under the curve of 96.5%, sensitivity of 88.9%, specificity of 98.7%, and high predictive values for referable DR detection. Subgroup analyses showed consistently high accuracy across demographic and clinical strata. Multivariate analysis identified higher HbA1c at diagnosis and longer diabetes duration as significant predictors of referable DR for both AI and human grading. These findings support the robustness, generalizability and operational feasibility of this AI system for DR screening in routine clinical care.
Combined transcriptome and proteome profiling of the pancreatic β-cell response to palmitate unveils key pathways of β-cell lipotoxicity
Background Prolonged exposure to elevated free fatty acids induces β-cell failure (lipotoxicity) and contributes to the pathogenesis of type 2 diabetes. In vitro exposure of β-cells to the saturated free fatty acid palmitate is a valuable model of lipotoxicity, reproducing features of β-cell failure observed in type 2 diabetes. In order to map the β-cell response to lipotoxicity, we combined RNA-sequencing of palmitate-treated human islets with iTRAQ proteomics of insulin-secreting INS-1E cells following a time course exposure to palmitate. Results Crossing transcriptome and proteome of palmitate-treated β-cells revealed 85 upregulated and 122 downregulated genes at both transcript and protein level. Pathway analysis identified lipid metabolism, oxidative stress, amino-acid metabolism and cell cycle pathways among the most enriched palmitate-modified pathways. Palmitate induced gene expression changes compatible with increased free fatty acid mitochondrial import and β-oxidation, decreased lipogenesis and modified cholesterol transport. Palmitate modified genes regulating endoplasmic reticulum (ER) function, ER-to-Golgi transport and ER stress pathways. Furthermore, palmitate modulated cAMP/protein kinase A (PKA) signaling, inhibiting expression of PKA anchoring proteins and downregulating the GLP-1 receptor. SLC7 family amino-acid transporters were upregulated in response to palmitate but this induction did not contribute to β-cell demise. To unravel critical mediators of lipotoxicity upstream of the palmitate-modified genes, we identified overrepresented transcription factor binding sites and performed network inference analysis. These identified LXR, PPARα, FOXO1 and BACH1 as key transcription factors orchestrating the metabolic and oxidative stress responses to palmitate. Conclusions This is the first study to combine transcriptomic and sensitive time course proteomic profiling of palmitate-exposed β-cells. Our results provide comprehensive insight into gene and protein expression changes, corroborating and expanding beyond previous findings. The identification of critical drivers and pathways of the β-cell lipotoxic response points to novel therapeutic targets for type 2 diabetes.
GLP-1R agonists demonstrate potential to treat Wolfram syndrome in human preclinical models
Aims/hypothesis Wolfram syndrome is a rare autosomal recessive disorder caused by pathogenic variants in the WFS1 gene. It is characterised by insulin-dependent diabetes mellitus, optic nerve atrophy, diabetes insipidus, hearing loss and neurodegeneration. Considering the unmet treatment need for this orphan disease, this study aimed to evaluate the therapeutic potential of glucagon-like peptide 1 receptor (GLP-1R) agonists under wolframin (WFS1) deficiency with a particular focus on human beta cells and neurons. Methods The effect of the GLP-1R agonists dulaglutide and exenatide was examined in Wfs1 knockout mice and in an array of human preclinical models of Wolfram syndrome, including WFS1-deficient human beta cells, human induced pluripotent stem cell (iPSC)-derived beta-like cells and neurons from control individuals and individuals affected by Wolfram syndrome , and humanised mice. Results Our study shows that the long-lasting GLP-1R agonist dulaglutide reverses impaired glucose tolerance in WFS1-deficient mice, and that exenatide and dulaglutide improve beta cell function and prevent apoptosis in different human WFS1-deficient models including iPSC-derived beta cells from people with Wolfram syndrome. Exenatide improved mitochondrial function, reduced oxidative stress and prevented apoptosis in Wolfram syndrome iPSC-derived neural precursors and cerebellar neurons. Conclusions/interpretation Our study provides novel evidence for the beneficial effect of GLP-1R agonists on WFS1-deficient human pancreatic beta cells and neurons, suggesting that these drugs may be considered as a treatment for individuals with Wolfram syndrome. Graphical abstract
Is there still a role for thyroid scintigraphy in the workup of a thyroid nodule in the era of fine needle aspiration cytology and molecular testing? version 1; peer review: 3 approved
Thyroid scintigraphy is now rarely used in the work-up of a thyroid nodule except in the presence of a low TSH value. Therefore, autonomously functioning thyroid nodules (AFTNs) with a normal TSH value are diagnosed only in the rare medical centers that continue to use thyroid scan systematically in the presence of a thyroid nodule. In this review, we discuss the prevalence of AFTN with a normal TSH level and the possible consequences of performing fine needle aspiration cytology (FNAC) in an undiagnosed AFTN. We also discuss the risk of malignant AFTN which may be higher than previously stated.
YIPF5 mutations cause neonatal diabetes and microcephaly through endoplasmic reticulum stress
Neonatal diabetes is caused by single gene mutations reducing pancreatic β cell number or impairing β cell function. Understanding the genetic basis of rare diabetes subtypes highlights fundamental biological processes in β cells. We identified 6 patients from 5 families with homozygous mutations in the YIPF5 gene, which is involved in trafficking between the endoplasmic reticulum (ER) and the Golgi. All patients had neonatal/early-onset diabetes, severe microcephaly, and epilepsy. YIPF5 is expressed during human brain development, in adult brain and pancreatic islets. We used 3 human β cell models (YIPF5 silencing in EndoC-βH1 cells, YIPF5 knockout and mutation knockin in embryonic stem cells, and patient-derived induced pluripotent stem cells) to investigate the mechanism through which YIPF5 loss of function affects β cells. Loss of YIPF5 function in stem cell-derived islet cells resulted in proinsulin retention in the ER, marked ER stress, and β cell failure. Partial YIPF5 silencing in EndoC-βH1 cells and a patient mutation in stem cells increased the β cell sensitivity to ER stress-induced apoptosis. We report recessive YIPF5 mutations as the genetic cause of a congenital syndrome of microcephaly, epilepsy, and neonatal/early-onset diabetes, highlighting a critical role of YIPF5 in β cells and neurons. We believe this is the first report of mutations disrupting the ER-to-Golgi trafficking, resulting in diabetes.
Recessive TMEM167A variants cause neonatal diabetes, microcephaly, and epilepsy syndrome
Understanding the genetic causes of diseases that affect pancreatic β cells and neurons can give insights into pathways essential for both cell types. Microcephaly, epilepsy, and diabetes syndrome (MEDS) is a congenital disorder with two known etiological genes, IER3IP1 and YIPF5. Both genes encode proteins involved in endoplasmic reticulum (ER) to Golgi trafficking. We used genome sequencing to identify 6 individuals with MEDS caused by biallelic variants in the potentially novel disease gene TMEM167A. All had neonatal diabetes (diagnosed at <6 months) and severe microcephaly, and 5 also had epilepsy. TMEM167A is highly expressed in developing and adult human pancreas and brain. To gain insights into the mechanisms leading to diabetes, we silenced TMEM167A in EndoC-βH1 cells and knocked-in one patient's variant, p.Val59Glu, in induced pluripotent stem cells (iPSCs). Both TMEM167A depletion in EndoC-βH1 cells and the p.Val59Glu variant in iPSC-derived β cells sensitized β cells to ER stress. The p.Val59Glu variant impaired proinsulin trafficking to the Golgi and induced iPSC-β cell dysfunction. The discovery of TMEM167A variants as a genetic cause of MEDS highlights a critical role of TMEM167A in the ER to Golgi pathway in β cells and neurons.
Combined transcriptome and proteome profiling of the pancreatic beta-cell response to palmitate unveils key pathways of beta-cell lipotoxicity
Prolonged exposure to elevated free fatty acids induces [beta]-cell failure (lipotoxicity) and contributes to the pathogenesis of type 2 diabetes. In vitro exposure of [beta]-cells to the saturated free fatty acid palmitate is a valuable model of lipotoxicity, reproducing features of [beta]-cell failure observed in type 2 diabetes. In order to map the [beta]-cell response to lipotoxicity, we combined RNA-sequencing of palmitate-treated human islets with iTRAQ proteomics of insulin-secreting INS-1E cells following a time course exposure to palmitate. Crossing transcriptome and proteome of palmitate-treated [beta]-cells revealed 85 upregulated and 122 downregulated genes at both transcript and protein level. Pathway analysis identified lipid metabolism, oxidative stress, amino-acid metabolism and cell cycle pathways among the most enriched palmitate-modified pathways. Palmitate induced gene expression changes compatible with increased free fatty acid mitochondrial import and [beta]-oxidation, decreased lipogenesis and modified cholesterol transport. Palmitate modified genes regulating endoplasmic reticulum (ER) function, ER-to-Golgi transport and ER stress pathways. Furthermore, palmitate modulated cAMP/protein kinase A (PKA) signaling, inhibiting expression of PKA anchoring proteins and downregulating the GLP-1 receptor. SLC7 family amino-acid transporters were upregulated in response to palmitate but this induction did not contribute to [beta]-cell demise. To unravel critical mediators of lipotoxicity upstream of the palmitate-modified genes, we identified overrepresented transcription factor binding sites and performed network inference analysis. These identified LXR, PPAR[alpha], FOXO1 and BACH1 as key transcription factors orchestrating the metabolic and oxidative stress responses to palmitate. This is the first study to combine transcriptomic and sensitive time course proteomic profiling of palmitate-exposed [beta]-cells. Our results provide comprehensive insight into gene and protein expression changes, corroborating and expanding beyond previous findings. The identification of critical drivers and pathways of the [beta]-cell lipotoxic response points to novel therapeutic targets for type 2 diabetes.
YIPF5 mutations cause neonatal diabetes and microcephaly through endoplasmic reticulum stress
Neonatal diabetes is caused by single gene mutations reducing pancreatic [beta] cell number or impairing [beta] cell function. Understanding the genetic basis of rare diabetes subtypes highlights fundamental biological processes in [beta] cells. We identified 6 patients from 5 families with homozygous mutations in the YIPF5 gene, which is involved in trafficking between the endoplasmic reticulum (ER) and the Golgi. All patients had neonatal/early-onset diabetes, severe microcephaly, and epilepsy. YIPF5 is expressed during human brain development, in adult brain and pancreatic islets. We used 3 human [beta] cell models (YIPF5 silencing in EndoC-[beta]H1 cells, YIPF5 knockout and mutation knockin in embryonic stem cells, and patient-derived induced pluripotent stem cells) to investigate the mechanism through which YIPF5 loss of function affects [beta] cells. Loss of YIPF5 function in stem cell-derived islet cells resulted in proinsulin retention in the ER, marked ER stress, and p cell failure. Partial YIPF5 silencing in EndoC-[beta]H1 cells and a patient mutation in stem cells increased the [beta] cell sensitivity to ER stress-induced apoptosis. We report recessive YIPF5 mutations as the genetic cause of a congenital syndrome of microcephaly, epilepsy, and neonatal/early-onset diabetes, highlighting a critical role of YIPF5 in [beta] cells and neurons. We believe this is the first report of mutations disrupting the ER-to-Golgi trafficking, resulting in diabetes.
Unilateral Adrenalectomy Could Be a Valid Option for Primary Nodular Adrenal Disease: Evidence From Twins
Primary pigmented nodular adrenal disease (PPNAD) accounts for <1% of ACTH-independent Cushing syndrome. We describe the case of twin female patients with PPNAD who both had sustainable disease control after unilateral adrenalectomy, which corroborates current evidence in favor of unilateral adrenalectomy for a subset of patients with PPNAD. Patient A presented with a 10-kg weight gain over the past year and facial plethora. Diagnostic evaluation revealed abolition of normal cortisol rhythm with suppressed ACTH levels, normal adrenal CT and MRI imaging and a slightly left-predominant adrenal uptake on 131I iodomethyl norcholesterol scintigraphy coupled with single-photon emission CT/CT. PPNAD was confirmed after genetic testing revealed a known pathogenic PRKA1A mutation (c.709 (-7-2) del6). At that time, her twin sister (patient B) was asymptomatic. Patient A underwent successful unilateral adrenalectomy and histology confirmed PPNAD. Two years after initial onset of symptoms in patient A, patient B was seen for the same subtle symptoms of progressive weight gain. Diagnostic test results were identical, revealing the same clinical features and mutational status as patient A. Patient B also underwent unilateral adrenalectomy with a favorable outcome. Follow-up 3 years after surgery for patient A and 18 months for patient B showed sustained disease control without recurrence and uncompromised quality of life, with no adrenal insufficiency having occurred. Unilateral adrenalectomy can be a successful therapeutic approach for patients with PPNAD with a mild phenotype without the risk and the inconvenience of subsequent adrenal insufficiency, which alters quality of life.