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- Heiskanen, Annamari, et al.
(författare)
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N-glycolylneuraminic acid xenoantigen contamination of human embryonic and mesenchymal stem cells is substantially reversible.
- 2007
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Ingår i: Stem cells (Dayton, Ohio). - : Oxford University Press (OUP). - 1066-5099 .- 1549-4918. ; 25:1, s. 197-202
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Tidskriftsartikel (refereegranskat)abstract
- Human embryonic and mesenchymal stem cell therapies may offer significant benefit to a large number of patients. Recently, however, human embryonic stem cell lines cultured on mouse feeder cells were reported to be contaminated by the xeno-carbohydrate N-glycolylneuraminic acid (Neu5Gc) and considered potentially unfit for human therapy. To determine the extent of the problem of Neu5Gc contamination for the development of stem cell therapies, we investigated whether it also occurs in cells cultured on human feeder cells and in mesenchymal stem cells, what are the sources of contamination, and whether the contamination is reversible. We found that N-glycolylneuraminic acid was present in embryonic stem cells cultured on human feeder cells, correlating with the presence of Neu5Gc in components of the commercial serum replacement culture medium. Similar contamination occurred in mesenchymal stem cells cultured in the presence of fetal bovine serum. The results suggest that the Neu5Gc is present in both glycoprotein and lipid-linked glycans, as detected by mass spectrometric analysis and monoclonal antibody staining, respectively. Significantly, the contamination was largely reversible in the progeny of both cell types, suggesting that decontaminated cells may be derived from existing stem cell lines. Although major complications have not been reported in the clinical trials with mesenchymal stem cells exposed to fetal bovine serum, the immunogenic contamination may potentially be reflected in the viability and efficacy of the transplanted cells and thus bias the published results. Definition of safe culture conditions for stem cells is essential for future development of cellular therapies.
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| 2. |
- Matilainen, Johanna, et al.
(författare)
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Increased secretion of adipocyte-derived extracellular vesicles is associated with adipose tissue inflammation and the mobilization of excess lipid in human obesity
- 2024
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Ingår i: JOURNAL OF TRANSLATIONAL MEDICINE. - 1479-5876. ; 22:1
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundObesity is a worldwide epidemic characterized by adipose tissue (AT) inflammation. AT is also a source of extracellular vesicles (EVs) that have recently been implicated in disorders related to metabolic syndrome. However, our understanding of mechanistic aspect of obesity's impact on EV secretion from human AT remains limited.MethodsWe investigated EVs from human Simpson Golabi Behmel Syndrome (SGBS) adipocytes, and from AT as well as plasma of subjects undergoing bariatric surgery. SGBS cells were treated with TNF alpha, palmitic acid, and eicosapentaenoic acid. Various analyses, including nanoparticle tracking analysis, electron microscopy, high-resolution confocal microscopy, and gas chromatography-mass spectrometry, were utilized to study EVs. Plasma EVs were analyzed with imaging flow cytometry.ResultsEVs from mature SGBS cells differed significantly in size and quantity compared to preadipocytes, disagreeing with previous findings in mouse adipocytes and indicating that adipogenesis promotes EV secretion in human adipocytes. Inflammatory stimuli also induced EV secretion, and altered EV fatty acid (FA) profiles more than those of cells, suggesting the role of EVs as rapid responders to metabolic shifts. Visceral AT (VAT) exhibited higher EV secretion compared to subcutaneous AT (SAT), with VAT EV counts positively correlating with plasma triacylglycerol (TAG) levels. Notably, the plasma EVs of subjects with obesity contained a higher number of adiponectin-positive EVs than those of lean subjects, further demonstrating higher AT EV secretion in obesity. Moreover, plasma EV counts of people with obesity positively correlated with body mass index and TNF expression in SAT, connecting increased EV secretion with AT expansion and inflammation. Finally, EVs from SGBS adipocytes and AT contained TAGs, and EV secretion increased despite signs of less active lipolytic pathways, indicating that AT EVs could be involved in the mobilization of excess lipids into circulation.ConclusionsWe are the first to provide detailed FA profiles of human AT EVs. We report that AT EV secretion increases in human obesity, implicating their role in TAG transport and association with adverse metabolic parameters, thereby emphasizing their role in metabolic disorders. These findings promote our understanding of the roles that EVs play in human AT biology and metabolic disorders.
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| 3. |
- Mirastschijski, Ursula, et al.
(författare)
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Ectopic localization of matrix metalloproteinase-9 in chronic cutaneous wounds.
- 2002
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Ingår i: Human Pathology. - : Elsevier BV. - 1532-8392 .- 0046-8177. ; 33:3, s. 355-364
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Tidskriftsartikel (refereegranskat)abstract
- It has been hypothesized that excessive activity of matrix metalloproteinases (MMPs), in particular the gelatinases MMP-9 and MMP-2, contributes to poor healing of chronic skin ulcers. We compared MMP-9 and MMP-2 in wound margin biopsies of standardized acute partial-thickness wounds in healthy volunteers (n = 6) and in venous leg ulcer patients (n = 12) with those of chronic wounds of different etiologies (n = 34) by a combination of specific analyses of activity and protein localization. We also studied MMP-14 by immunohistochemistry and in situ hybridization in parallel. Neither MMP-9 (P =.814) nor MMP-2 (P =.742) endogenous activities differed significantly between acute and chronic wound tissues. Acute wound healing was characterized by induction of MMP-9 in the advancing epithelium. In chronic wounds, prominent MMP-9 immunostaining was seen in neutrophils and macrophages in the ulcer bed, but virtually no MMP-9 was detected in wound edge keratinocytes. MMP-2 was increased and activated with acute wound age. MMP-2 was found abundantly in dermal fibroblasts and endothelial cells beneath, but not in new epithelium of acute and chronic wounds. MMP-14 mRNA or protein was detected solely in the stroma of both acute and chronic wounds. In conclusion, the overall activity of gelatinases MMP-9 and MMP-2 was not increased in chronic wounds compared to normally healing wound tissues. Chronic nonhealing wounds may not be caused by excessive gelatinase activity, but are distinguished from healing wounds by an unfavorable distribution and persistance of MMP-9.
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| 4. |
- Mirastschijski, Ursula, et al.
(författare)
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Matrix metalloproteinase inhibitor BB-3103 unlike the serine proteinase inhibitor aprotinin abrogates epidermal healing of human skin wounds ex vivo.
- 2002
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Ingår i: Journal of Investigative Dermatology. - : Elsevier BV. - 1523-1747 .- 0022-202X. ; 118:1, s. 55-64
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Tidskriftsartikel (refereegranskat)abstract
- Several matrix metalloproteinases and serine proteinases are upregulated in migrating keratinocytes during cutaneous wound repair. Single cell culture studies indicate the necessity for matrix metalloproteinases but not for serine proteinases in keratinocyte locomotion. To account for epithelial-mesenchymal interactions, an ex vivo human skin wound model was used to investigate the contribution of matrix metalloproteinases and serine proteinases to wound healing by treatment with broad-spectrum inhibitors of matrix metalloproteinases (BB-3103) or serine proteinases (aprotinin). Human skin explants with circular 3 mm superficial defects were incubated in culture medium without (controls) or with the proteinase inhibitors for 7 d. BB-3103 abrogated epithelialization (p < 0.001), whereas aprotinin-treated wounds and controls were covered with new epithelium. Lack of epithelialization was unlikely due to cytotoxicity because the matrix metalloproteinase inhibitor did neither influence viability of cultured epidermal keratinocytes nor apoptosis in wounds. Involvement of specific matrix metalloproteinases in epithelialization was analyzed by gelatin zymography, western blotting, immunohistochemistry, and in situ hybridization. Wound healing was accompanied by active matrix metalloproteinase-1 and increased active matrix metalloproteinase-2 but irrespectively of active matrix metalloproteinase-9. BB-3103 blocked activation of matrix metalloproteinase-2 and matrix metalloproteinase-9 but not of matrix metalloproteinase-1. Active matrix metalloproteinase-2 localized solely to the dermis, whereas matrix metalloproteinase-9 was consistently found in new epithelium. Membrane-type 1 matrix metalloproteinase was undetectable in wound keratinocytes. BB-3103 and aprotinin reduced tumor necrosis factor-alpha in media but did not appreciably alter amounts of other soluble regulators of matrix metalloproteinases and epithelialization. Our findings demonstrate that keratinocyte migration is associated with active matrix metalloproteinase-2 but occurs independently of serine proteinases and active matrix metalloproteinase-9 in fibrin-deficient skin wound healing.
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