1. VEGF levels in plasma in relation to platelet activation, glycemic control, and microvascular complications in type 1 diabetesReinier O. Schlingemann, Cornelis J. F. van Noorden, Mattheus J.M. Diekman, Anna Tiller, Joost C.M. Meijers, Pieter Koolwijk, Wilmar M. Wiersinga, 2013, original scientific article Abstract: OBJECTIVE
Increased levels of vascular endothelial growth factor (VEGF) in human plasma samples have suggested that circulating VEGF is a cause of endothelial dysfunction in diabetes mellitus. However, artificial release of VEGF from platelets as a source of VEGF in plasma samples, as also occurs in serum samples, has not been ruled out in these studies.
RESEARCH DESIGN AND METHODS
We determined VEGF levels in plasma collected in both citrate and PECT, a medium that inactivates platelets, in a cross-sectional cohort of 21 healthy subjects and 64 patients with type 1 diabetes. In addition, we evaluated whether VEGF levels in both types of plasma correlated with the presence of diabetes, glycemic control, markers of in vivo or ex vivo platelet activation, and degree of diabetic retinopathy and nephropathy.
RESULTS
VEGF levels were invariably low in PECT plasma of both nondiabetic and diabetic subjects and were unrelated to any other diabetes-related variable studied. In contrast, VEGF levels in citrate plasma were 150% higher in diabetic patients than in control subjects and correlated with diabetes-related variables. Multiple linear regression analysis showed that levels of platelet factor 4, a marker for ex vivo platelet activation, and HbA1c were the independent predictors of VEGF levels in citrate plasma. Platelet activation, in vivo and ex vivo, was similar in diabetic persons and control subjects.
CONCLUSIONS
Like serum, citrate plasma is not suitable for reliable measurements of circulating VEGF. The low levels of VEGF in vivo, as represented by measurements in PECT plasma in our study, do not support a role of circulating VEGF in endothelial dysfunction in type 1 diabetes. Higher levels of VEGF in citrate plasma samples of diabetic persons do not represent the in vivo situation, but mainly originate from higher artificial ex vivo release from platelets correlating with the degree of glycemic control.
Keywords: vascular endothelial growth factor, VEGF, diabetes mellitus
Published in DiRROS: 02.08.2024; Views: 127; Downloads: 60
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3. Insulin-like growth factor 1 receptor expression in advanced non-small-cell lung cancer and its impact on overall survivalMojca Humar, Izidor Kern, Gregor Vlačić, Vedran Hadžić, Tanja Čufer, 2017, original scientific article Keywords: insulin-like growth factor 1 receptor, type 2 diabetes mellitus, advanced non-small-cell lung cancer, overall survival
Published in DiRROS: 03.06.2024; Views: 187; Downloads: 122
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4. Exploration of macromolecular phenotype of human skeletal muscle in diabetes using infrared spectroscopyBarbara Zupančič, Chiedozie Kenneth Ugwoke, Mohamed Elwy Abdelmonaem, Armin Alibegović, Erika Cvetko, Jože Grdadolnik, Anja Šerbec, Nejc Umek, 2023, original scientific article Abstract: Introduction: The global burden of diabetes mellitus is escalating, and more efficient investigative strategies are needed for a deeper understanding of underlying pathophysiological mechanisms. The crucial role of skeletal muscle in carbohydrate and lipid metabolism makes it one of the most susceptible tissues to diabetes-related metabolic disorders. In tissue studies, conventional histochemical methods have several technical limitations and have been shown to inadequately characterise the biomolecular phenotype of skeletal muscle to provide a holistic view of the pathologically altered proportions of macromolecular constituents. Materials and methods: In this pilot study, we examined the composition of five different human skeletal muscles from male donors diagnosed with type 2 diabetes and non-diabetic controls. We analysed the lipid, glycogen, and collagen content in the muscles in a traditional manner with histochemical assays using different staining techniques. This served as a reference for comparison with the unconventional analysis of tissue composition using Fourier-transform infrared spectroscopy as an alternative methodological approach. Results: A thorough chemometric post-processing of the infrared spectra using a multi-stage spectral decomposition allowed the simultaneous identification of various compositional details from a vibrational spectrum measured in a single experiment. We obtained multifaceted information about the proportions of the different macromolecular constituents of skeletal muscle, which even allowed us to distinguish protein constituents with different structural properties. The most important methodological steps for a comprehensive insight into muscle composition have thus been set and parameters identified that can be used for the comparison between healthy and diabetic muscles. Conclusion: We have established a methodological framework based on vibrational spectroscopy for the detailed macromolecular analysis of human skeletal muscle that can effectively complement or may even serve as an alternative to histochemical assays. As this is a pilot study with relatively small sample sets, we remain cautious at this stage in drawing definitive conclusions about diabetes-related changes in skeletal muscle composition. However, the main focus and contribution of our work has been to provide an alternative, simple and efficient approach for this purpose. We are confident that we have achieved this goal and have brought our methodology to a level from which it can be successfully transferred to a large-scale study that allows the effects of diabetes on skeletal muscle composition and the interrelationships between the macromolecular tissue alterations due to diabetes to be investigated.
Keywords: diabetes mellitus, skeletal muscle, metabolism, macromulecular composition, infrared spectroscopy, multivariate analysis, histochemical assays
Published in DiRROS: 11.01.2024; Views: 511; Downloads: 177
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