| 1. |
- Harlacher, Eva, et al.
(författare)
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Increased levels of a mycophenolic acid metabolite in patients with kidney failure negatively affect cardiomyocyte health.
- 2024
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Ingår i: Frontiers in cardiovascular medicine. - 2297-055X. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Chronic kidney disease (CKD) significantly increases cardiovascular risk and mortality, and the accumulation of uremic toxins in the circulation upon kidney failure contributes to this increased risk. We thus performed a screening for potential novel mediators of reduced cardiovascular health starting from dialysate obtained after hemodialysis of patients with CKD. The dialysate was gradually fractionated to increased purity using orthogonal chromatography steps, with each fraction screened for a potential negative impact on the metabolic activity of cardiomyocytes using a high-throughput MTT-assay, until ultimately a highly purified fraction with strong effects on cardiomyocyte health was retained. Mass spectrometry and nuclear magnetic resonance identified the metabolite mycophenolic acid-β-glucuronide (MPA-G) as a responsible substance. MPA-G is the main metabolite from the immunosuppressive agent MPA that is supplied in the form of mycophenolate mofetil (MMF) to patients in preparation for and after transplantation or for treatment of autoimmune and non-transplant kidney diseases. The adverse effect of MPA-G on cardiomyocytes was confirmed in vitro, reducing the overall metabolic activity and cellular respiration while increasing mitochondrial reactive oxygen species production in cardiomyocytes at concentrations detected in MMF-treated patients with failing kidney function. This study draws attention to the potential adverse effects of long-term high MMF dosing, specifically in patients with severely reduced kidney function already displaying a highly increased cardiovascular risk.
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| 2. |
- Vanholder, Raymond, et al.
(författare)
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The role of EUTox in uremic toxin research.
- 2009
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Ingår i: Seminars in dialysis. - 0894-0959 .- 1525-139X. ; 22:4, s. 323-328
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Tidskriftsartikel (refereegranskat)abstract
- In this publication, we review the activities of the European Uremic Toxin Work Group (EUTox) in the field of uremic toxin research. Founded in 1999 under the umbrella of the European Society of Artificial Organs (ESAO), and active since 2000, this group focuses essentially on questions related to solute retention and removal during chronic kidney disease, and on the deleterious impact of those solutes on biological/biochemical systems. As of January 1, 2009, the group had met 28 times; it organized the third meeting, "Uremic Toxins in Cardiovascular Disease," which took place in October 2008 in Amiens, France. The current group is composed of 25 members belonging to 23 European research institutions. As of November 1, 2008, in total 69 papers had been published to which at least two different research groups belonging to EUTox have contributed in a collaborative effort. Of these, 40 papers were on original research and eight were specific EUTox reviews or position statements. A website (http://www.eutox.info) summarizes all relevant information concerning the work group. EUTox also developed an interactive uremic toxin database, where concentrations of known toxins are displayed, to be used by researchers in the field. In the future, EUTox intends to continue its focus on bench to bedside research with specific consideration of proteomics, metabonomics, secretomics, and genomics.
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| 3. |
- Vollmer, Tino, et al.
(författare)
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An in-vitro assay using human spermatozoa to detect toxicity of biologically active substances
- 2019
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Identifying the key toxic players within an in-vivo toxic syndrome is crucial to develop targeted therapies. Here, we established a novel method that characterizes the effect of single substances by means of an ex-vivo incubation set-up. We found that primary human spermatozoa elicit a distinct motile response on a (uremic) toxic milieu. Specifically, this approach describes the influence of a bulk toxic environment (uremia) as well as single substances (uremic toxins) by real-time analyzing motile cellular behavior. We established the human spermatozoa-based toxicity testing (HSTT) for detecting single substance-induced toxicity to be used as a screening tool to identify in-vivo toxins. Further, we propose an application of the HSTT as a method of clinical use to evaluate toxin-removing interventions (hemodialysis).
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| 4. |
- Baier, Claudia, et al.
(författare)
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Hyaluronan is organized into fiber-like structures along migratory pathways in the developing mouse cerebellum
- 2007
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Ingår i: Matrix Biology. - : Elsevier BV. - 1569-1802 .- 0945-053X. ; 26:5, s. 348-358
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Tidskriftsartikel (refereegranskat)abstract
- Hyaluronan is a free glycosaminoglycan which is abundant in the extracellular matrix of the developing brain. Although not covalently linked to any protein it can act as a backbone molecule forming aggregates with chondroitin sulfate proteoglycans of the lectican family and link proteins. Using neurocan-GFP as a direct histochemical probe we analyzed the distribution and organization of hyaluronan in the developing mouse cerebellum, and related its fine structure to cell types of specified developmental stages. We observed a high affinity of this probe to fiber-like structures in the prospective white matter which are preferentially oriented parallel to the cerebellar cortex during postnatal development suggesting a specially organized form of hyaluronan. In other layers of the cerebellar cortex, the hyaluronan organization seemed to be more diffuse. During the second postnatal week, the overall staining intensity of hyaluronan in the white matter declined but fiber-like structures were still present at the adult stage. This type of hyaluronan organization is different from perineuronal nets e.g. found in deep cerebellar nuclei. Double staining experiments with cell type specific markers indicated that these fiber-like structures are predominantly situated in regions where motile cells such as Pax2-positive inhibitory interneuron precursors and MBP-positive oligodendroglial cells are located. In contrast, more stationary cells such as mature granule cells and Purkinje cells are associated with lower levels of hyaluronan in their environment. Thus, hyaluronan-rich fibers are concentrated at sites where specific neural precursor cell types migrate, and the anisotropic orientation of these fibers suggests that they may support guided neural migration during brain development. (c) 2007 Elsevier B.V./International Society of Matrix Biology. All rights reserved.
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| 5. |
- Holmar, Jana, et al.
(författare)
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An Optical Method for Serum Calcium and Phosphorus Level Assessment during Hemodialysis
- 2015
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Ingår i: Toxins. - BASEL, SWITZERLAND : MDPI AG. - 2072-6651. ; 7:3, s. 719-727
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Tidskriftsartikel (refereegranskat)abstract
- Survival among hemodialysis patients is disturbingly low, partly because vascular calcification (VC) and cardiovascular disease are highly prevalent. Elevated serum phosphorus (P) and calcium (Ca) levels play an essential role in the formation of VC events. The purpose of the current study was to reveal optical monitoring possibilities of serum P and Ca values during dialysis. Twenty-eight patients from Tallinn (Estonia) and Linköping (Sweden) were included in the study. The serum levels of Ca and P on the basis of optical information, i.e., absorbance and fluorescence of the spent dialysate (optical method) were assessed. Obtained levels were compared in means and SD. The mean serum level of Ca was 2.54 ± 0.21 and 2.53 ± 0.19 mmol/L; P levels varied between 1.08 ± 0.51 and 1.08 ± 0.48 mmol/L, measured in the laboratory and estimated by the optical method respectively. The levels achieved were not significantly different (p = 0.5). The Bland-Altman 95% limits of agreement between the two methods varied from -0.19 to 0.19 for Ca and from -0.37 to 0.37 in the case of P. In conclusion, optical monitoring of the spent dialysate for assessing the serum levels of Ca and P during dialysis seems to be feasible and could offer valuable and continuous information to medical staff.
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| 6. |
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| 7. |
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| 8. |
- Mischak, Harald, et al.
(författare)
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Implementation of proteomic biomarkers : making it work
- 2012
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Ingår i: European Journal of Clinical Investigation. - : Wiley. - 0014-2972 .- 1365-2362. ; 42:9, s. 1027-1036
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Tidskriftsartikel (refereegranskat)abstract
- While large numbers of proteomic biomarkers have been described, they are generally not implemented in medical practice. We have investigated the reasons for this shortcoming, focusing on hurdles downstream of biomarker verification, and describe major obstacles and possible solutions to ease valid biomarker implementation. Some of the problems lie in suboptimal biomarker discovery and validation, especially lack of validated platforms with well-described performance characteristics to support biomarker qualification. These issues have been acknowledged and are being addressed, raising the hope that valid biomarkers may start accumulating in the foreseeable future. However, successful biomarker discovery and qualification alone does not suffice for successful implementation. Additional challenges include, among others, limited access to appropriate specimens and insufficient funding, the need to validate new biomarker utility in interventional trials, and large communication gaps between the parties involved in implementation. To address this problem, we propose an implementation roadmap. The implementation effort needs to involve a wide variety of stakeholders (clinicians, statisticians, health economists, and representatives of patient groups, health insurance, pharmaceutical companies, biobanks, and regulatory agencies). Knowledgeable panels with adequate representation of all these stakeholders may facilitate biomarker evaluation and guide implementation for the specific context of use. This approach may avoid unwarranted delays or failure to implement potentially useful biomarkers, and may expedite meaningful contributions of the biomarker community to healthcare.
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| 9. |
- Vanholder, Raymond, et al.
(författare)
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A bench to bedside view of uremic toxins.
- 2008
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Ingår i: Journal of the American Society of Nephrology : JASN. - 1533-3450. ; 19:5, s. 863-70
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Tidskriftsartikel (refereegranskat)abstract
- Reviewing the current picture of uremic toxicity reveals its complexity. Focusing on cardiovascular damage as a model of uremic effects resulting in substantial morbidity and mortality, most molecules with potential to affect the function of a variety of cell types within the vascular system are difficult to remove by dialysis. Examples are the larger middle molecular weight molecules and protein-bound molecules. Recent clinical studies suggest that enhancing the removal of these compounds is beneficial for survival. Future therapeutic options are discussed, including improved removal of toxins and the search for pharmacologic strategies blocking responsible pathophysiologic pathways.
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| 10. |
- Wollenhaupt, Julia, et al.
(författare)
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Pro-oxidative priming but maintained cardiac function in a broad spectrum of murine models of chronic kidney disease
- 2022
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Ingår i: Redox Biology. - : Elsevier BV. - 2213-2317. ; 56
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Tidskriftsartikel (refereegranskat)abstract
- Aims: Patients with chronic kidney disease (CKD) have an increased risk of cardiovascular events and exhibit myocardial changes including left ventricular (LV) hypertrophy and fibrosis, overall referred to as 'uremic cardiomyopathy'. Although different CKD animal models have been studied for cardiac effects, lack of consistent reporting on cardiac function and pathology complicates clear comparison of these models. Therefore, this study aimed at a systematic and comprehensive comparison of cardiac function and cardiac pathophysiological characteristics in eight different CKD models and mouse strains, with a main focus on adenine-induced CKD. Methods and results: CKD of different severity and duration was induced by subtotal nephrectomy or adenine-rich diet in various strains (C57BL/6J, C57BL/6 N, hyperlipidemic C57BL/6J ApoE(-/-), 129/Sv), followed by the analysis of kidney function and morphology, blood pressure, cardiac function, cardiac hypertrophy, fibrosis, myocardial calcification and inflammation using functional, histological and molecular techniques, including cardiac gene expression profiling supplemented by oxidative stress analysis. Intriguingly, despite uremia of variable degree, neither cardiac dysfunction, hypertrophy nor interstitial fibrosis were observed. However, already moderate CKD altered cardiac oxidative stress responses and enhanced oxidative stress markers in each mouse strain, with cardiac RNA sequencing revealing activation of oxidative stress signaling as well as anti-inflammatory feedback responses. Conclusion: This study considerably expands the knowledge on strain-and protocol-specific differences in the field of cardiorenal research and reveals that several weeks of at least moderate experimental CKD increase oxidative stress responses in the heart in a broad spectrum of mouse models. However, this was insufficient to induce relevant systolic or diastolic dysfunction, suggesting that additional "hits " are required to induce uremic cardiomyopathy. Translational perspective: Patients with chronic kidney disease (CKD) have an increased risk of cardiovascular adverse events and exhibit myocardial changes, overall referred to as 'uremic cardiomyopathy'. We revealed that CKD increases cardiac oxidative stress responses in the heart. Nonetheless, several weeks of at least moderate experimental CKD do not necessarily trigger cardiac dysfunction and remodeling, suggesting that additional "hits " are required to induce uremic cardiomyopathy in the clinical setting. Whether the altered cardiac oxidative stress balance in CKD may increase the risk and extent of cardiovascular damage upon additional cardiovascular risk factors and/or events will be addressed in future studies.
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