Enhancing Human Treg Cell Induction through Engineered Dendritic Cells and Zinc Supplementation.

Regulatory T (Treg) cells hold promise for the ultimate cure of immune-mediated diseases. However, how to effectively restore Treg function in patients remains unknown. Previous reports suggest that activated dendritic cells (DCs) de novo synthesize locally high concentrations of 1,25-dihydroxy vitamin D, i.

A segmental defect adaptation of the mouse closed femur fracture model for the analysis of severely impaired bone healing.

Objective: To better characterize nonunion endochondral bone healing and evaluate novel therapeutic approaches for critical size defect healing in clinically challenging bone repair, a segmental defect model of bone injury was adapted from the three-point bending closed fracture technique in the murine femur.

Methods: The mouse femur was surgically stabilized with an intramedullary threaded rod with plastic spacers and the defect adjusted to different sizes. Healing of the different defects was analyzed by radiology and histology to 8 weeks postsurgery.

Changes in ephrin gene expression during bone healing identify a restricted repertoire of ephrins mediating fracture repair.

To identify the repertoire of ephrin genes that might regulate endochondral bone fracture repair, we examined changes in ephrin ligand and receptor (Eph) gene expression in fracture callus tissues during bone fracture healing. Ephrin and Eph proteins were then localized in the fracture callus tissues present when changes in gene expression were observed. Ephrin gene expression was widespread in fracture tissues, but the repertoire of ephrin genes with significant changes in expression that might suggest a regulatory role in fracture callus development was restricted to the ephrin A family members Epha4, Epha5 and the ephrin B family member Efnb1.

Potential Role of DARC-Chemokine Interaction in the Recruitment of Osteoclast Precursors in Response to Bacterial Lipopolysaccharide Challenge.

Duffy antigen receptor for chemokines (DARC) binds to a number of pro-inflammatory chemokines, and since chemokines are known to regulate trafficking of osteoclast (OC) precursors, we predicted that DARC would regulate OC recruitment to sites of inflammation by modulating chemokine activity. To test this hypothesis, we evaluated the mRNA expression of Darc and the chemokines known to bind to DARC, in endothelial cells treated with bacterial lipopolysaccharide (LPS). The mRNA expression of Mcp-1, Rantes, Darc and Ccr5 was significantly increased in endothelial cells in response to LPS treatment.

Microarray Analysis of Gene Expression Reveals that Cyclo-oxygenase-2 Gene Therapy Up-regulates Hematopoiesis and Down-regulates Inflammation During Endochondral Bone Fracture Healing.

Background: Cyclo-oxygenase-2 (Cox-2) is an inflammatory mediator that is necessary for the tissue repair, including bone fracture healing. Although the application of Cox-2 gene therapy to a murine closed femoral fracture has accelerated bony union, but the beneficial effect was not observed until the endochondral stage of bone repair that is well after the inflammatory stage normally subsides.

Methods: To identify the molecular pathways through which Cox-2 regulates fracture healing, we examined gene expression profile in fracture tissues in response to Cox-2 gene therapy during the endochondral bone repair phase.

Duffy antigen receptor for chemokines regulates post-fracture inflammation.

There is now considerable experimental data to suggest that inflammatory cells collaborate in the healing of skeletal fractures. In terms of mechanisms that contribute to the recruitment of inflammatory cells to the fracture site, chemokines and their receptors have received considerable attention. Our previous findings have shown that Duffy antigen receptor for chemokines (Darc), the non-classical chemokine receptor that does not signal, but rather acts as a scavenger of chemokines that regulate cell migration, is a negative regulator of peak bone density in mice.

Urokinase plasminogen activator gene deficiency inhibits fracture cartilage remodeling.

Urokinase plasminogen activator (uPA) regulates a proteolytic cascade of extracellular matrix degradation that functions in tissue development and tissue repair. The development and remodeling of the skeletal extracellular matrix during wound healing suggests that uPA might regulate bone development and repair. To determine whether uPA functions regulate bone development and repair, we examined the basal skeletal phenotype and endochondral bone fracture repair in uPA-deficient mice.

Fracture healing in mice deficient in plasminogen activator inhibitor-1.

To evaluate the role of plasminogen activator inhibitor (PAI)-1, a key negative regulator of the plasmin system of extracellular matrix proteases in developmental bone growth and fracture repair, the bone phenotype of male adult PAI-1-deficient mice was determined and femoral fracture healing was compared with that of age- and sex-matched wild-type C57BL/6J control mice. Regarding bone phenotype, the length and size (but not cortical thickness) of the femur of male PAI-1-deficient mice were smaller than those of wild-type controls. Although the total bone mineral content of PAI-1-deficient mice was not significantly different from that of wild-type mice, the total bone area in PAI-1-deficient mice was smaller, leading to an increase in total bone mineral density.

Bax deficiency in mice increases cartilage production during fracture repair through a mechanism involving increased chondrocyte proliferation without changes in apoptosis.

This study sought to determine the role of the pro-apoptotic gene, Bax, in fracture healing by comparing femoral fracture healing in Bax knockout (KO) and wild-type C57BL/6J (background strain) mice. Bax KO fractures were larger, had more bone mineral content, had approximately 2-fold larger cartilage area per callus area in the first and second weeks of fracture healing, and showed an increased osteoclast surface area in the third and fourth weeks of fracture healing compared to C57BL/6J fractures. The increased cartilage area in the Bax KO fracture callus was due to increases in number of both pre-hypertropic and hypertropic chondrocytes.

TNF-related weak inducer of apoptosis (TWEAK) is a potent skeletal muscle-wasting cytokine.

TWEAK cytokine has been implicated in several biological responses including inflammation, angiogenesis, and osteoclastogenesis. We have investigated the role of TWEAK in regulating skeletal muscle mass. Addition of soluble TWEAK protein to cultured myotubes reduced the mean myotube diameter and enhanced the degradation of specific muscle proteins such as CK and MyHCf.

New quantitative trait loci that regulate wound healing in an intercross progeny from DBA/1J and 129 x 1/SvJ inbred strains of mice.

Wound healing/regeneration mouse models are few, and studies performed have mainly utilized crosses between MRL/MPJ (a good healer) and SJL/J (a poor healer) or MRL/lpr (a good healer) and C57BL/6J (a poor healer). Wound healing is a complex trait with many genes involved in the expression of the phenotype. Based on data from previous studies that common and additional quantitative trait loci (QTL) were identified using different crosses of inbred strains of mice for various complex traits, we hypothesized that a new cross would identify common and additional QTL, unique modes of inheritance, and interacting loci, which are responsible for variation in susceptibility to fast wound healing.

Progress toward skeletal gene therapy.

Skeletal gene therapy is an attractive new approach to the treatment of bone disorders. Impressive advances in our knowledge of the molecular genetic basis of skeletal disorders and fracture healing have led to the development of novel therapeutics based on ectopic expression of one or more genes in patient cells that can influence repair or regenerative processes in bone. Although still a relatively immature field, proof-of-principle for enhanced bone formation through skeletal gene therapy has already been established.

Effects of short-term calcium depletion and repletion on biochemical markers of bone turnover in young adult women.

The skeletal responses to calcium depletion and repletion in rodents have been well characterized, but those in humans are poorly understood. The present study sought to evaluate the effects of short term dietary calcium depletion and repletion on biochemical markers of bone turnover in 15 young Caucasian women (age, 21-30 yr). The study contained 3 phases: 1) 5 days of a regular diet containing more than 800 mg/day calcium to establish baseline values (baseline phase), 2) 22 days of a restricted diet containing less than 300 mg/day calcium (depletion phase), and 3) 7 days of a normal diet containing more than 800 mg/day calcium (repletion phase).

Focus formation of C3H/10T1/2 cells and exposure to a 836.55 MHz modulated radiofrequency field.

Disruption of communication between transformed cells and normal cells is involved in tumor promotion. We have tested the hypothesis that exposures to radiofrequency (RF) fields using a form of digital modulation (TDMA) and a chemical tumor promoter, 12-O-tetradecanoylphorbol-13-acetate (TPA), are copromoters that enhance focus formation of transformed cells in coculture with parental C3H/10T1/2 murine fibroblasts. RF field exposures did not influence TPA's dose-dependent promotion of focus formation in coculture.

Exposure of nerve growth factor-treated PC12 rat pheochromocytoma cells to a modulated radiofrequency field at 836.55 MHz: effects on c-jun and c-fos expression.

Rat PC12 pheochromocytoma cells have been treated with nerve growth factor and then exposed to athermal levels of a packet-modulated radiofrequency field at 836.55 MHz. This signal was produced by a prototype time-domain multiple-access (TDMA) transmitter that conforms to the North American digital cellular telephone standard.

Comparison of the clinical anticaries efficacy of an 1100 NaF silica-based dentifrice containing triclosan and a copolymer to an 1100 NaF silica-based dentifrice without those additional agents: a study on adults in California.

Recent years have seen much work in the development of dentifrices containing the antimicrobial agent triclosan, a broad spectrum antibacterial agent manufactured for use in oral products by the Ciba-Geigy Corporation. Studies have shown that the incorporation of this agent into dental products, in combination with a PVM/MA copolymer (the non-proprietary designation for a polyvinylmethyl ether/maleic acid copolymer), can provide several important dental therapeutic benefits, including an antigingivitis effect. Much research on the therapeutic benefits of such dentifrices has been reported in the literature.

60 Hz magnetic field acts as co-promoter in focus formation of C3H/10T1/2 cells.

Disruption of communication between transformed cells and normal cells is involved in tumor promotion. We have tested the hypothesis that 60 Hz electromagnetic (EM) field exposures and a chemical tumor promoter, 12-O-tetradecanoylphorbol-13-acetate (TPA) are co-promoters that enhance focus formation of transformed cells in co-culture with normal cells. EM field exposures alone did not affect the growth curves of parental C3H/10T1/2 fibroblasts or daughter mutant cells, UV-TDTx10e.

Carbon dioxide and oxygen partial pressure in expiratory water condensate are equivalent to mixed expired carbon dioxide and oxygen.

This study was to determine whether the PCONCO2 and PCONO2 which collect in the expiratory trap of a ventilator circuit are equivalent to PECO2 and PEO2. Fifty studies were performed in 34 mechanically ventilated male patients. Five milliliters of condensate fluid were collected and PECO2 and PEO2 were measured.