IGF-1 and G-CSF complement each other in BMSC migration towards infarcted myocardium in a novel in vitro model

Stem cell capability enhanced with cytokine administration is a promising treatment for myocardial infarction. Bone marrow stem cells (BMSCs) were isolated from C57BL/6 mice (8-12 weeks old) expressing GFP and characterized with c-kit and CD34. Infarcted heart tissue fragments were placed into dishes with BMSCs and medium supplemented with G-CSF, SCF, IGF-1 or combinations thereof were given to the BMSC-infarcted myocardium in vitro model. The IGF-1-G-CSF group showed significantly higher migration (67.7% ± 2.6) of c-kit⁺ BMSCs towards the ischemic tissue and expressed MEF-2 (43.7% ± 1.7). Of the single treatment groups, the G-CSF group demonstrated significantly higher migration of c-kit⁺ BMSCs (60.5 ± 2.7) with MEF-2 expression (38.7 ± 1.4). IGF-1 complements G-CSF and was relatively more significant in its effects on BMSC migration and cardiac lineage commitment towards ischemic heart tissue.     

Stem cell- and scaffold-based tissue engineering approaches to osteochondral regenerative medicine

In osteochondral tissue engineering, cell recruitment, proliferation, differentiation, and patterning are critical for forming biologically and structurally viable constructs for repair of damaged or diseased tissue. However, since constructs prepared ex vivo lack the multitude of cues present in the in vivo microenvironment, cells often need to be supplied with external biological and physical stimuli to coax them toward targeted tissue functions. To determine which stimuli to present to cells, bioengineering strategies can benefit significantly from endogenous examples of skeletogenesis. As an example of developmental skeletogenesis, the developing limb bud serves as an excellent model system in which to study how osteochondral structures form from undifferentiated precursor cells. Alongside skeletal formation during embryogenesis, bone also possesses innate regenerative capacity, displaying remarkable ability to heal after damage. Bone fracture healing shares many features with bone development, driving the hypothesis that the regenerative process generally recapitulates development. Similarities and differences between the two modes of bone formation may offer insight into the special requirements for healing damaged or diseased bone. Thus, endogenous fracture healing, as an example of regenerative skeletogenesis, may also inform bioengineering strategies. In this review, we summarize the key cellular events involving stem and progenitor cells in developmental and regenerative skeletogenesis, and discuss in parallel the corresponding cell- and scaffold-based strategies that tissue engineers employ to recapitulate these events in vitro.     

Field Validation of Helium as a Tracer Gas During Soil Vapor Sample Collection

This paper reports the results of a field study to evaluate the use of helium as a tracer gas during soil vapor sampling. The authors found that the helium tracer method recommended in regulatory guidance can detect atmospheric leakage. However, the degree of leakage can be underestimated due to: 1) losses of helium from the tracer reservoir during sampling; 2) the entry of atmospheric air from an area outside the tracer reservoir; 3) temporal variability of leakage; and 4) flow-related reduction in helium detector response. Frequent leakage was observed in soil vapor probes installed using conventional direct push techniques. Probes installed at a depth of 8 ft exhibited less leakage than those installed at 4 ft. Probes installed in glacial till exhibited greater and more frequent leakage than those installed in sandy loam. Based on the frequency of observed leakage, refinement and standardization of tracer methods, with routine incorporation of tracers and in-line pressure and flow monitoring, is recommended.     

Hommes modernes en Asie septentrionale

The huge asiatic area does not show clear cut traditions but only fundamental tendencies proper to the human mind considered in its whole evolution mechanism. These tendencies are both clear and powerful: lightness of the skulls, technical blanks lighter, bone tools, pendants, and high mobility. The cultural European categories cannot be applied as such since the anthropological units were fuzzy, just like the huge steppes where they have developed. Europe just represents marginal caricatures and fixed of these general movements acting like waves perpetual and powerful.     

史前人类对动物骨骼油脂的开发和利用

动物骨骼油脂的开发和利用是史前人类生存活动的重要组成部分。西方学者的研究表明,这一过程可能包含了敲骨取髓和骨脂提取两种不同的人类行为。相较于敲骨取髓,骨脂提取更为复杂,不仅要将骨骼砸碎成较小尺寸,还要加水煮沸骨骼碎片,过程中不断添冷水使水保持温和沸腾的状态,才能获得浮于水面的骨脂。目前,国内学者在此领域的研究多关注于前一行为而对后者鲜有论述。本文通过对相关科学文献的全面梳理,系统介绍了史前人类骨脂提取行为的鉴定分析手段和方法,进而探讨了这一行为在古人类资源利用程度、流动性、用火方式和烹饪技术等方面的指示意义与价值。     

Characterization of the growth plate-bone interphase region using cryo-FIB SEM 3D volume imaging

The interphase region at the base of the growth plate includes blood vessels, cells and mineralized tissues. In this region, cartilage is mineralized and replaced with bone. Blood vessel extremities permeate this space providing nutrients, oxygen and signaling factors. All these different components form a complex intertwined 3D structure. Here we use cryo-FIB SEM to elaborate this 3D structure without removing the water. As it is challenging to image mineralized and unmineralized tissues in a hydrated state, we provide technical details of the parameters used. We obtained two FIB SEM image stacks that show that the blood vessels are in intimate contact not only with cells, but in some locations also with mineralized tissues. There are abundant red blood cells at the extremities of the vessels. We also documented large multinucleated cells in contact with mineralized cartilage and possibly also with bone. We observed membrane bound mineralized particles in these cells, as well as in blood serum, but not in the hypertrophic chondrocytes. We confirm that there is an open pathway from the blood vessel extremities to the mineralizing cartilage. Based on the sparsity of the mineralized particles, we conclude that mainly ions in solution are used for mineralizing cartilage and bone, but these are augmented by the supply of mineralized particles.     

Blood plasma model predictions for the proposed bone-seeking radiopharmaceutical [Sn]Sn(IV)-N,N′,N′-trimethylenephosphonate-poly(ethyleneimine)

In an attempt to elucidate the in vivo stability of the prospective radiopharmaceutical [^117mSn]Sn(IV)-PEI-MP, where PEI-MP stands for N,N′,N′-trimethylenephosphonate-polyethyleneimine, glass electrode potentiometry was used to determine the stability constants of the Sn⁴⁺ ion as complexed with a variety of physiological amino acids. In addition, linear free energy relationship (LFER) correlation plots were used to extrapolate the constants of the major blood plasma ligands, based on data from Cu²⁺, Pb²⁺, and Zn²⁺. In so doing, a thermodynamic model of blood plasma was established for Sn⁴⁺ from which the complexation tendencies of Sn⁴⁺ were predicted in the event of the intravenous administration of such a drug. It was found that the Sn(IV)-PEI-MP could succumb to competition by the glutamine amino acid, which forms more stable complex(es), whilst the PEI-MP gets taken up largely by Ca²⁺. Also, this study shows the value of the in vitro experiments and modeling performed for radiopharmaceutical research and for attempts to reduce the number of animal experiments.     

Adenoviral transduction of hTGF-β1 enhances the chondrogenesis of bone marrow derived stromal cells

TGF-β1 plays a necessary and important role in the induction of chondrogenic differentiation of bone marrow stromal cells (BMSCs). In this study, porcine BMSCs were infected with a replication-deficient adenovirus expression vector carrying the hTGF-β1 gene. The transduced BMSCs were cultured as pelleted micromasses in vitro for 21 days, seeded onto disk-shaped PGA scaffolds for 3 days and subsequently implanted into the subcutaneous tissue of mice. BMSCs transduced with AdhTGF-β1 expressed and secreted more hTGF-β1 protein in vitro than those of the control group. Histological and immunohistological examination of the pellets revealed robust chondrogenic differentiation. Tissues made from cells transduced with AdhTGF-β1 exhibited neocartilage formation after 3 weeks in vivo. The neocartilage occupied 42 ± 5% of the total tissue volume which was significantly greater than that of the control group. Furthermore, there was extensive staining for sulfated proteoglycans and type II collagen in the AdhTGF-β1 group compared to controls, and quantification of GAG content showed significantly greater amounts of GAG in experimental groups. The results demonstrate that transfer of hTGF-β1 into BMSCs via adenoviral transduction can induce chondrogenic differentiation in vitro and enhance chondrogenesis in vivo.     

Subcutaneous graft of D1 mouse mesenchymal stem cells leads to the formation of a bone-like structure

Mesenchymal stem cells (MSC) are capable of both self-renewal and multi-lineage differentiation into mesoderm-type cells such as osteoblasts, chondrocytes, adipocytes and myocytes. Together the multipotent nature of MSCs and the facility to expand them in vitro make these cells ideal resources for regenerative medicine, particularly for bone reconstruction, and therefore research efforts focused on defining efficient protocols for directing their differentiation into the requisite lineage. Despite much progress in identifying mechanisms and factors that direct and control in vitro osteogenic differentiation of MSCs, a rapid and simple model to evaluate in vivo tissue formation is still lacking. Here, we describe the unique capacity of the murine bone marrow-derived D1 MSC cell line, which differentiates in vitro into at least three cell lineages, to form in vivo a structure resembling bone. This bone-like structure was obtained after subcutaneous grafting of D1 cells into immunocompetent mice without the need of neither an osteogenic factor nor scaffold material. These data allow us to propose this cell model as a tool for exploring in vivo the mechanisms and/or factors that govern and potentially regulate osteogenesis.     

Multiparametric comparison of mesenchymal stromal cells obtained from trabecular bone by using a novel isolation method with those obtained by iliac crest aspiration from the same subjects

Trabecular bone fragments from femoral heads are sometimes used as bone grafts and have been described as a source of mesenchymal progenitor cells. Nevertheless, mesenchymal stromal cells (MSC) from trabecular bone have not been directly compared with MSC obtained under standard conditions from iliac crest aspiration of the same patients. This is the ideal control to avoid inter-individual variation. We have obtained MSC by a novel method (grinding bone fragments with a bone mill without enzymatic digestion) from the femoral heads of 11 patients undergoing hip replacement surgery and compared them with MSC obtained by standard iliac crest aspiration of bone marrow from the same patients. We have shown that trabecular bone MSC obtained by mechanically fragmented femoral heads fulfil the immunophenotypic and multilineage (adipogenic, osteogenic and chondrogenic) differentiation criteria used to define MSC. We have also differentially compared cellular yields, growth kinetics, cell cycle assessment, and colony-forming unit-fibroblast content of MSC from both sources and conclude that these parameters do not significantly differ. Nevertheless, the finding of slight differences, such as a higher expression of the immature marker CD90, a lower expansion time through the different passages, and a higher percentage of cycling cells in the trabecular bone MSC, warrants further studies with the isolation method proposed here in order to gain further knowledge of the status of MSC in this setting. The present study was partially supported by grant HUS01B07 from the Consejería de Educación and by grant SAN196/SA13/07 from the Consejería de Sanidad, Junta de Castilla y León, Spain.