Publications by authors named "Anna Wendt"

Intra-islet crosstalk has become a focus area to fully understand the regulation of insulin secretion and impaired β-cell function in type 2 diabetes (T2D). Here, we put forward evidence for insulin-like growth factor binding protein 7 (IGFBP7) as a potential protein involved in autocrine and paracrine β-cell regulation. We showed presence of IGFBP7 in granules of both human α- and β-cells and measured elevated gene expression as well as IGFBP7 protein in T2D.

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  • * The lipid exchange protein, oxysterol-binding protein (OSBP), is recruited to these contact sites in response to calcium and is regulated by specific kinases and phosphatases.
  • * Disruption of the balance between OSBP and its regulatory protein Sac2 leads to increased cholesterol on insulin granules and reduces glucose-stimulated insulin secretion, highlighting the importance of lipid exchange in insulin granule maturation and secretion.
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  • Epigenetic changes in pancreatic islets may affect insulin secretion and contribute to the progression of type 2 diabetes (T2D), with 5,584 DNA methylation sites identified as altered in T2D cases.
  • Specific genes related to insulin secretion are less expressed in T2D, and one key gene, RHOT1, is found to be crucial for insulin secretion and mitochondrial function in β-cells.
  • The study suggests that individuals with T2D have epigenetic modifications tied to mitochondrial dysfunction in their pancreatic islets, and the methylation of RHOT1 in blood may predict future development of T2D.
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Glucagon is the principal glucose-elevating hormone that forms the first-line defence against hypoglycaemia. Along with insulin, glucagon also plays a key role in maintaining systemic glucose homeostasis. The cells that secrete glucagon, pancreatic α-cells, are electrically excitable cells and use electrical activity to couple its hormone secretion to changes in ambient glucose levels.

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Type 2 diabetes (T2D) is associated with low-grade inflammation. Here we investigate if the anti-inflammatory cytokine interleukin-4 (IL-4) affects glucose-stimulated insulin secretion (GSIS) in human islets from non-diabetic (ND) and type-2 diabetic (T2D) donors. We first confirmed that GSIS is reduced in islets from T2D donors.

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Aim: SYT11 and SYT13, two calcium-insensitive synaptotagmins, are downregulated in islets from type 2 diabetic donors, but their function in insulin secretion is unknown. To address this, we investigated the physiological role of these two synaptotagmins in insulin-secreting cells.

Methods: Correlations between gene expression levels were performed using previously described RNA-seq data on islets from 188 human donors.

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MicroRNAs (miRNAs) are short non-coding RNAs that regulate gene expression via mRNA targeting, playing important roles in the pancreatic islets. We aimed to identify molecular pathways and genomic regulatory regions associated with altered miRNA expression due to glycemic status, which could contribute to the development of type 2 diabetes (T2D). To this end, miRNAs were identified by a combination of differential miRNA expression and correlation analysis in human islet samples from donors with normal and elevated blood glucose levels.

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Article Synopsis
  • Diabetes involves issues with both insulin and glucagon, but glucagon has received less research focus than insulin.
  • Glucagon, produced by alpha cells in the pancreas, is crucial for raising blood sugar when it’s low and is often used in treating severe hypoglycemia.
  • There's a growing interest in therapies targeting alpha cells, especially since they can potentially be converted into insulin-secreting cells, highlighting a need for novel treatments in diabetes management.
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MicroRNAs (miRNAs) are part of deregulated insulin secretion in type 2 diabetes (T2D) development. Rodent models have suggested miR-200c to be involved, but the role and potential as therapeutic target of this miRNA in human islets are not clear. Here we report increased expression of miR-200c in islets from T2D as compared with nondiabetic (ND) donors and display results showing reduced glucose-stimulated insulin secretion in EndoC-βH1 cells overexpressing miR-200c.

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Cystic fibrosis-related diabetes mellitus (CFRD) is the most common non-pulmonary co-morbidity in cystic fibrosis (CF). CF is caused by mutations in the cystic fibrosis transmembrane conductance regulator gene (), which leads to aberrant luminal fluid secretions in organs such as the lungs and pancreas. How dysfunctional CFTR leads to CFRD is still under debate.

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Obesity is a risk factor for type 2 diabetes (T2D); however, not all obese individuals develop the disease. In this study, we aimed to investigate the cause of differential insulin secretion capacity of pancreatic islets from donors with T2D and non-T2D (ND), especially obese donors (BMI ≥30 kg/m). Islets from obese donors with T2D had reduced insulin secretion, decreased β-cell exocytosis, and higher expression of fatty acid translocase CD36.

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The polygenic background of selectively bred diabetes models mimics the etiology of type 2 diabetes. So far, three different rodent models (Goto-Kakizaki rats, Nagoya-Shibata-Yasuda mice, and Oikawa-Nagao mice) have been established in the diabetes research field by continuous selective breeding for glucose tolerance from outbred rodent stocks. The origin of hyperglycemia in these rodents is mainly insulin secretion deficiency from the pancreatic β-cells and mild insulin resistance in insulin target organs.

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There are growing demands to ensure animal health and, from a broader perspective, animal welfare, especially for farmed animals. In addition to the newly developed welfare assessment protocols, which provide a harmonised method to measure animal health during farm visits, the question has been raised whether data from existing data collections can be used for an assessment without a prior farm visit. Here, we explore the possibilities of developing animal health scores for fattening pig herds using a) official meat inspection results, b) data on antibiotic usage and c) data from the QS (QS Qualität und Sicherheit GmbH) Salmonella monitoring programme in Germany.

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The pancreatic islets of Langerhans consist of several hormone-secreting cell types important for blood glucose control. The insulin secreting β-cells are the best studied of these cell types, but less is known about the glucagon secreting α-cells. The α-cells secrete glucagon as a response to low blood glucose.

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Cystic fibrosis-related diabetes (CFRD) is a common complication for patients with cystic fibrosis (CF), a disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR). The cause of CFRD is unclear, but a commonly observed reduction in first-phase insulin secretion suggests defects at the beta cell level. Here we aimed to examine beta- and alpha-cell function in the Cftrtm1EUR/F508del mouse model (C57BL/6J), which carries the most common human mutation in CFTR, the F508del mutation.

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Transient hepatic steatosis upon liver resection supposes functional relationships between lipid metabolism and liver regeneration. Repin1 has been suggested as candidate gene for obesity and dyslipidemia by regulating key genes of lipid metabolism and lipid storage. Herein, we characterized the regenerative potential of mice with a hepatic deletion of Repin1 (LRep1-/-) after partial hepatectomy (PH) in order to determine the functional significance of Repin1 in liver regeneration.

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Pancreatic islet hormone secretion is central in the maintenance of blood glucose homeostasis. During development of hyperglycaemia, the β-cell is under pressure to release more insulin to compensate for increased insulin resistance. Failure of the β-cells to secrete enough insulin results in type 2 diabetes (T2D).

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Failure of the β-cell to secrete enough insulin is a major contributing factor in the pathogenesis of type-2 diabetes (T2D). MicroRNAs provide an extra layer in the regulation of protein expression, and are thus involved in β-cell compensation during development of the disease. In this review, we discuss how microRNAs can regulate their target protein expression and phenotypic output, present the status of nutritional regulation of microRNA expression, and summarize work on microRNA expression in human islets.

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MicroRNAs contribute to the maintenance of optimal cellular functions by fine-tuning protein expression levels. In the pancreatic -cells, imbalances in the exocytotic machinery components lead to impaired insulin secretion and type 2 diabetes (T2D). We hypothesize that dysregulated miRNA expression exacerbates -cell dysfunction, and have earlier shown that islets from the diabetic GK-rat model have increased expression of miRNAs, including miR-335-5p (miR-335).

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To understand how extraction of different energy sources impacts water resources requires assessment of how water chemistry has changed in comparison with the background values of pristine streams. With such understanding, we can develop better water quality standards and ecological interpretations. However, determination of pristine background chemistry is difficult in areas with heavy human impact.

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The changes in life-style with increased access of food and reduced physical activity have resulted in the global epidemic of obesity. Consequently, individuals with type 2 diabetes and cardiovascular disease have also escalated. A central organ in the development of diabetes is the pancreas, and more specifically the pancreatic beta cells within the islets of Langerhans.

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Type 2 diabetic patients suffer from insulin resistance and reduced insulin secretion. Osteopontin (OPN), a versatile protein expressed in several tissues throughout the body including the islets of Langerhans, has previously been implicated in the development of insulin resistance. Here we have investigated the role of OPN in insulin secretion using an OPN knock out mouse model (OPN-/-).

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Pancreatic beta cell failure is the central event leading to diabetes. Beta cells share many phenotypic traits with neurons, and proper beta cell function relies on the activation of several neuron-like transcription programs. Regulation of gene expression by alternative splicing plays a pivotal role in brain, where it affects neuronal development, function, and disease.

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