Endosomal TLRs play an important role in innate immune response as well as in autoimmune processes. In the therapy of systemic lupus erythematosus, antimalarial drugs chloroquine, hydroxychloroquine, ...and quinacrine have been used for a long time. Their suppression of endosomal TLR activation has been attributed to the inhibition of endosomal acidification, which is a prerequisite for the activation of these receptors. We discovered that chloroquine inhibits only activation of endosomal TLRs by nucleic acids, whereas it augments activation of TLR8 by a small synthetic compound, R848. We detected direct binding of antimalarials to nucleic acids by spectroscopic experiments and determined their cellular colocalization. Further analysis revealed that other nucleic acid-binding compounds, such as propidium iodide, also inhibited activation of endosomal TLRs and colocalized with nucleic acids to endosomes. We found that imidazoquinolines, which are TLR7/8 agonists, inhibit TLR9 and TLR3 even in the absence of TLR7 or TLR8, and their mechanism of inhibition is similar to the antimalarials. In contrast to bafilomycin, none of the tested antimalarials and imidazoquinolines inhibited endosomal proteolysis or increased the endosomal pH, confirming that inhibition of pH acidification is not the underlying cause of inhibition. We conclude that the direct binding of inhibitors to nucleic acids mask their TLR-binding epitope and may explain the efficiency of those compounds in the treatment of autoimmune diseases.
The stem cell theory of aging postulates that stem cells become inefficient at maintaining the original functions of the tissues. We, therefore, hypothesized that transplanting young bone marrow (BM) ...to old recipients would lead to rejuvenating effects on immunity, followed by improved general health, decreased frailty, and possibly life span extension. We developed a murine model of non-myeloablative heterochronic BM transplantation in which old female BALB/c mice at 14, 16, and 18(19) months of age received altogether 125.1 ± 15.6 million nucleated BM cells from young male donors aged 7-13 weeks. At 21 months, donor chimerism was determined, and the immune system's innate and adaptive arms were analyzed. Mice were then observed for general health and frailty until spontaneous death, when their lifespan, post-mortem examinations, and histopathological changes were recorded. The results showed that the old mice developed on average 18.7 ± 9.6% donor chimerism in the BM and showed certain improvements in their innate and adaptive arms of the immune system, such as favorable counts of neutrophils in the spleen and BM, central memory Th cells, effector/effector memory Th and Tc cells in the spleen, and B1a and B1b cells in the peritoneal cavity. Borderline enhanced lymphocyte proliferation capacity was also seen. The frailty parameters, pathomorphological results, and life spans did not differ significantly in the transplanted vs. control group of mice. In conclusion, although several favorable effects are obtained in our heterochronic non-myeloablative transplantation model, additional optimization is needed for better rejuvenation effects.
Objective
Hematopoietic stem and progenitor cells (HSPCs) can be used as a vector for gene therapies. In order to predict the number of HSPCs cells necessary to achieve the target level of chimerism ...in an autologous setting, syngeneic male bone marrow (BM) cells were transplanted into 35 non‐conditioned female BALB/c mice.
Method
The resulting chimerism was determined at 6‐53 weeks using qPCR, cell subpopulation sorting, and colony‐forming units (CFU) analysis.
Results
After the transplantation of 125.8 ± 2.5 million nucleated BM cells, the BM of recipients contained 20.0 ± 2.8% donor cells, representing a chimerism of 0.16 ± 0.02% per one million transplanted nucleated BM cells. Chimerism levels in the BM, neutrophils, and B cells were comparable, whereas in T cells it was lower, and in CFU was approximately twice greater than in BM.
Conclusion
By extrapolating our murine data, and data from some previous studies to a human non‐conditioned autologous CD34+ HSPC transplantation setting, we conclude that approximately 44 million CD34+ HSPCs would be needed to achieve 20% donor chimerism in a 70‐kg human, which could serve as a starting point for the future use of HSCPs in gene and cell therapy.
Background
Stem cell therapy is a promising new approach to wound healing. Stromal vascular fraction is a heterogeneous collection of cells, including adipose-derived stem cells, which are ...traditionally isolated using a manual collagenase-based technique. To our knowledge, this is the first human study that histologically assesses the potential of intraoperative intradermal injection of stromal vascular fraction on skin regeneration.
Methods
In this controlled study, 20 patients undergoing deep inferior epigastric perforator flap breast reconstruction and bilateral flank liposuction were included. Stromal vascular fraction was injected intradermally into one side of the abdominal suture line, while the other side served as a control. Outcome measures included analysis of stromal vascular fraction by flow cytometry, histological analysis of scar tissue, and scar photography.
Results
Cell yield for application and cell viability were 55.9 ± 28.5 × 10
6
and 75.1% ± 14.5%, respectively. Age and body mass index were positively correlated with the number of cells for application and adipose-derived stem cells. Mean vascular density, elastic fiber content, collagen maturity (scar index), epidermal thickness, and number of rete ridges all showed higher values on the treated side. Furthermore, the injected number of adipose-derived stem cells and pericytes positively correlated with vascular density.
Conclusions
It is safe to speculate that intradermal stromal vascular fraction injection at the beginning of the healing process increases vascular density, collagen maturity and organization, elastic fiber content, epidermal thickness, epidermal–dermal anchoring of the scarring skin and is therefore responsible for improved skin regeneration. It is a viable and safe method that can be used as an adjunctive treatment in plastic surgery procedures where suboptimal wound healing is anticipated.
Level of Evidence IV
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