Multi-Parameter Analysis of Biobanked Human Bone Marrow Stromal Cells Shows Little Influence for Donor Age and Mild Comorbidities on Phenotypic and Functional Properties

Heterogeneous populations of human bone marrow-derived stromal cells (BMSC) are among the most frequently tested cellular therapeutics for treating degenerative and immune disorders, which occur predominantly in the aging population. Currently, it is unclear whether advanced donor age and commonly associated comorbidities affect the properties of ex vivo-expanded BMSCs. Thus, we stratified cells from adult and elderly donors from our biobank (n = 10 and n = 13, mean age 38 and 72 years, respectively) and compared their phenotypic and functional performance, using multiple assays typically employed as minimal criteria for defining multipotent mesenchymal stromal cells (MSCs). We found that BMSCs from both cohorts meet the standard criteria for MSC, exhibiting similar morphology, growth kinetics, gene expression profiles, and pro-angiogenic and immunosuppressive potential and the capacity to differentiate toward adipogenic, chondrogenic, and osteogenic lineages. We found no substantial differences between cells from the adult and elderly cohorts. As positive controls, we studied the impact of in vitro aging and inflammatory cytokine stimulation. Both conditions clearly affected the cellular properties, independent of donor age. We conclude that in vitro aging rather than in vivo donor aging influences BMSC characteristics

Metal‐Specific Biomaterial Accumulation in Human Peri‐Implant Bone and Bone Marrow

Metallic implants are frequently used in medicine to support and replace degenerated tissues. Implant loosening due to particle exposure remains a major cause for revision arthroplasty. The exact role of metal debris in sterile peri‐implant inflammation is controversial, as it remains unclear whether and how metals chemically alter and potentially accumulate behind an insulating peri‐implant membrane, in the adjacent bone and bone marrow (BM). An intensively focused and bright synchrotron X‐ray beam allows for spatially resolving the multi‐elemental composition of peri‐implant tissues from patients undergoing revision surgery. In peri‐implant BM, particulate cobalt (Co) is exclusively co‐localized with chromium (Cr), non‐particulate Cr accumulates in the BM matrix. Particles consisting of Co and Cr contain less Co than bulk alloy, which indicates a pronounced dissolution capacity. Particulate titanium (Ti) is abundant in the BM and analyzed Ti nanoparticles predominantly consist of titanium dioxide in the anatase crystal phase. Co and Cr but not Ti integrate into peri‐implant bone trabeculae. The characteristic of Cr to accumulate in the intertrabecular matrix and trabecular bone is reproducible in a human 3D in vitro model. This study illustrates the importance of updating the view on long‐term consequences of biomaterial usage and reveals toxicokinetics within highly sensitive organs.BMBF, 01EC1402B, Erkennung und individualisiertes Management der früh beginnenden Osteoporos

Morphological pictures of HUVEC/HUASMC co-cultures upon physiological FSS conditions.

<p>(<b>A</b>) Scanning electron microscopy picture of the homogenously colonized inside of a hollow fiber with confluently grown and characteristically cobblestone shaped human primary endothelial cells upon the application of low laminar FSS (0.1 N/m²) for 24 h (magnification: 1∶500). (<b>B</b>) Scanning electron microscopy picture of HUASMCs on the hollow fiber outside with their typical cell cytoskeletal structure and morphology upon 0.1 N/m² applied for 24 h (magnification: 1∶400). (<b>C</b>) Confocal microscopic immunolocalization of Cadherin-5 in co-cultivated HUVECs exposed to low laminar FSS (0.1 N/m²) over a period of five days (magnification: 1∶400). (<b>D</b>)Cadherin-5 in HUVECs upon high laminar FSS (3 N/m²) (magnification: 1∶400). (<b>E</b>) Confocal microscopic immunolocalization of α-smooth-muscle-actin in co-cultivated HUASMCs upon 3 N/m² luminally applied for a five day period (magnification: 1∶400). (<b>F</b>) α-smooth-muscle-actin in co-cultivated HUASMCs upon high laminar FSS (3 N/m²) (magnification: 1∶400).</p

Hoechst 33342 staining of human primary cell nuclei colonized onto polypropylene hollow fiber membranes.

<p>(<b>A</b>) Longitudinal section of the inside of a hollow fiber membrane confluently colonized with HUVECs and stained with Hoechst 33342 after 0.1 N/m² applied for 24 h (magnification: 1∶100). (<b>B</b>) Longitudinal section of the outside of a HUASMC mono-culture module stimulated with low laminar FSS for 24 h (magnification: 1∶100). (<b>C</b>) Cross-section of a polypropylene hollow fiber co-colonized with HUVECs and HUASMCs. In focus are HUVECs on the inside upon 0.1 N/m² applied for five days (magnification: 1∶100). (<b>D</b>) Cross-section of a co-culture module showing HUASMCs on the outside of a hollow fiber after low laminar FSS stimulation for five days (magnification: 1∶100).</p

Validation of the “<i>artificial artery</i>” as <i>in vitro</i> co-culture system with arterial functional characteristics mimicking <i>in vivo</i> conditions of the vasculature.

<p>Semi-quantitative RT-PCR analysis showing the total VWF mRNA expression in co-colonized HUVECs and HUASMCs. RNA of both cell types was isolated separately. The expression of VWF in 0.1 N/m² stimulated HUVECs was taken as reference. (<b>A</b>) MALDI mass spectrum from supernatants of the “<i>artificial artery”</i> after each day. Randomly selected peptides show constant molecular mass-signal intensities over a period of five days (abscissa: relative molecular mass m/z, z = 1; ordinate: relative intensity, arbitrary units). (<b>B</b>) MALDI mass spectrum of the supernatant of endothelial cells after stimulation with 3.0 N/m² (upper spectrum) and without stimulation (0.1 N/m²) (lower spectrum) (abscissa: relative molecular mass, m/z, z = 1; ordinate: relative intensity, arbitrary units). (<b>C</b>) Relative mass-signal intensities of Up₄A in secretomes isolated from HUVECs, HUASMCs, and HUVEC/HUASMC co-cultures in the “<i>artificial artery</i>” after stimulating with 3 N/m² for five days. (<b>D</b>) Semi-quantitative RT-PCR analyses showing the total mRNA expression of KLF2, TIMP1, and CCND1 in co-colonized HUVECs exposed to 3 N/m² for five days. The expression of each gene in 0.1 N/m² stimulated HUVECs was taken as reference. (<b>E</b>) Semi-quantitative RT-PCR analysis showing the total EDN1 mRNA expression in co-colonized HUVECs (0.1 N/m² vs. 3 N/m²) and HUASMCs (0.1 N/m² vs. 3 N/m²). The expression of END1 in 0.1 N/m² stimulated HUVECs was taken as reference.</p