Publications by authors named "Aleksandra Mieczkowska"

The main aim of this work was to study the chemical composition of eighteen ground coffees from different countries and continents with regard to the content of hazardous substances as radioactive elements (K, Ra, Ra, U, U and Cs), metals, including heavy metals, aluminum and some microelements (V, Cr, Mn, Fe, Co, Ni, Cu, Zn) as well as substances that have a positive effect on human health and well-being (polyphenols, proteins, fats and caffeine). The tests were carried out before and after the brewing process using the following techniques: gamma and beta spectrometry, a microwave-induced plasma optical emission spectrometer (MIP-OES), gravimetric method, UV-Vis spectrophotometry as well as thin-layer chromatography. The leaching percentage of certain elements/compounds in coffee infusions was also measured.

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The extensive characterization of tissue mineralization in the context of bone regeneration represents a significant challenge, given the numerous modalities that are currently available for analysis. Here, we propose a workflow for a comprehensive evaluation of new bone formation using a relevant large animal osseous ex vivo explant. A bone defect (diameter = 3.

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Enzymatic cross-linking of the bone collagen is important to resist to crack growth and to increased flexural strength. In the present study, we proposed a new method for assessment of enzymatic cross-link based on Fourier transform infrared (FTIR) microspectroscopy that takes into account secondary structure of type I collagen. Briefly, femurs were collected from sham or ovariectomized mice and subjected either to high-performance liquid chromatography-mass spectrometry or embedded in polymethylmethacrylate, cut and analyzed by FTIR microspectroscopy.

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Bisphenol A (BPA) exposure may impair gonadal steroidogenesis, although the underlying mechanism is not well known. Hereby, we assessed BPA action on human primary granulosa (hGC) and mouse Leydig cells (BLTK-1) proliferation, cytotoxicity, hormone secretion, and steroidogenic enzyme/receptor gene profile. hGC and BLTK-1 cells were stimulated with increasing concentrations of BPA (10 M to 10 M for cell proliferation assay, 10 M to 10 M for LDH-cytotoxicity assay, and 10 M to 10 M for hormone secretion and genes expression analysis).

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Bone tissue is organized at the molecular level to resist fracture with the minimum of bone material. This implies that several modifications of the extracellular matrix, including enzymatic collagen crosslinking, take place. We previously highlighted the role of several gut hormones in enhancing collagen maturity and bone strength.

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The aim of this study is to compare head-to-head the effects of dapagliflozin and liraglutide on bone strength and bone material properties in a pre-clinical model of diabetes-obesity. Combined low-dose streptozotocin and high fat feeding were employed in mice to promote obesity, insulin resistance, and hyperglycaemia. Mice were administered daily for 28 days with saline vehicle, 1 mg/kg dapagliflozin or 25 nmol/kg liraglutide.

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Receptors to glucose-dependent insulinotropic polypeptide (GIP), have been identified on bone and GIP receptor (GIPr) knockout mice exhibit reduced bone strength and quality. Despite this, little is known on the potential beneficial bone effects of exogenous GIP on bone physiology. The aim of the present study was to assess whether stable GIP analogues were capable of ameliorating bone strength in mice with diet-induced obesity.

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Type 2 diabetes mellitus (T2DM) has recently been recognized as a significant risk factor for bone fragility. Careful investigations of bone mechanical properties in human studies suggested possible alterations of bone composition, although this axis has poorly been investigated. The main aim of this study was to evaluate the impact of high fat diet-induced diabetes and therapy using the clinically approved GLP-1 receptor agonist, exenatide, on tissue bone mechanical properties and compositional parameters.

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Type 2 diabetes mellitus is recognized as a significant risk factor for fragility of bone. Among the newer anti-diabetic agents, dipeptidyl peptidase-4 inhibitors (DPP4i) have been reported to decrease the occurrence of bone fractures although the reason is unclear. The main aim of this study was to evaluate the impact of sitagliptin treatment on tissue bone strength and compositional parameters in the high-fat-fed mouse model.

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Glucose-dependent insulinotropic polypeptide (GIP) has been recognized in the last decade as an important contributor of bone remodelling and is necessary for optimal bone quality. However, GIP receptors are expressed in several tissues in the body and little is known about the direct vs indirect effects of GIP on bone remodelling and quality. The aims of the present study were to validate two new GIP analogues, called [d-Ala2]-GIP-Tag and [d-Ala2]-GIP1-30, which specifically target either bone or whole-body GIP receptors, respectively; and to ascertain the beneficial effects of GIP therapy on bone in a mouse model of ovariectomy-induced bone loss.

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A role for glucose-dependent insulinotropic polypeptide (GIP) in controlling bone resorption has been suspected. However uncertainty remains to identify whether GIP act directly on osteoclasts. The aim of the present study were (i) to identify in different osteoclast differentiation models (human peripheral blood mononuclear cells-PBMC, murine bone marrow macrophage-BMM and murine Raw 264.

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Obesity and type 2 diabetes mellitus (T2DM) progress worldwide with detrimental effects on several physiological systems including bone tissue mainly by affecting bone quality. Several gut hormones analogues have been proven potent in ameliorating bone quality. In the present study, we used the leptin receptor-deficient db/db mice as a model of obesity and severe T2DM to assess the extent of bone quality alterations at the organ and tissue levels.

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Type 1 diabetes mellitus is associated with a high risk for bone fractures. Although bone mass is reduced, bone quality is also dramatically altered in this disorder. However, recent evidences suggest a beneficial effect of the glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide 1 (GLP-1) pathways on bone quality.

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Type 1 diabetes mellitus (T1DM) is a severe disorder characterized by hyperglycemia and hypoinsulinemia. A higher occurrence of bone fractures has been reported in T1DM, and although bone mineral density is reduced in this disorder, it is also thought that bone quality may be altered in this chronic pathology. Vibrational microscopies such as Fourier transform infrared microspectroscopy (FTIRM) represent an interesting approach to study bone quality as they allow investigation of the collagen and mineral compartment of the extracellular matrix in a specific bone location.

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Glucose-dependent insulinotropic polypeptide (GIP) is absolutely crucial in order to obtain optimal bone strength and collagen quality. However, as the GIPR is expressed in several tissues other than bone, it is difficult to ascertain whether the observed modifications of collagen maturity, reported in animal studies, were due to direct effects on osteoblasts or indirect through regulation of signals originating from other tissues. The aims of the present study were to investigate whether GIP can directly affect collagen biosynthesis and processing in osteoblast cultures and to decipher which molecular pathways were necessary for such effects.

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Bone remodeling is under complex regulation from nervous, hormonal and local signals, including gut hormones. Among the gut hormones, a role for the glucose-dependent insulinotropic polypeptide (GIP) has been suggested. However, the rapid degradation of GIP in the bloodstream by the ubiquitous enzyme dipeptidyl peptidase-4 (DPP-4) precludes therapeutic use.

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Background: Patients with type 2 diabetes mellitus (T2DM) are at a higher risk of bone fractures independent of the use of antidiabetic medications. Furthermore, antidiabetic medications could directly affect bone metabolism. Recently, the use of dipeptidyl peptidase-4 inhibitors has been associated with a lower rate of bone fracture.

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Bone is permanently remodeled by a complex network of local, hormonal, and neuronal factors that affect osteoclast and osteoblast biology. Among these factors, a role for gastrointestinal hormones has been proposed based on the evidence that bone resorption dramatically falls after a meal. Glucagon-like peptide-1 (GLP1) is one of these gut hormones, and despite several reports suggesting an anabolic effect of GLP1, or its stable analogs, on bone mass, little is known about the effects of GLP1/GLP1 receptor on bone strength.

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Bone is permanently remodeled by a complex network of local, hormonal and neuronal factors that affect osteoclast and osteoblast biology. In this context, a role for gastro-intestinal hormones has been proposed based on evidence that bone resorption dramatically falls after a meal. Glucose-dependent insulinotropic polypeptide (GIP) is one of the candidate hormones as its receptor, glucose-dependent insulinotropic polypeptide receptor (GIPR), is expressed in bone.

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Thiazolidinediones (TZDs) represent an interesting treatment of type 2 diabetes mellitus. However, adverse effects such as heart problems and bone fractures have already been reported. Previously, we reported that pioglitazone and rosiglitazone induce osteocyte apoptosis and sclerostin up-regulation; however, the molecular mechanisms leading to such effects are unknown.

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