Age-related Changes in Human Bone Proteoglycan Structure: IMPACT OF OSTEOGENESIS IMPERFECTA

Proteoglycans (PGs) are a family of molecules that undergo extensive post-translational modifications that include addition of glycosaminoglycan (GAG) chains as well as N- and O-linked oligosaccharides to the protein core. PG composition and structure have been reported to alter with age. To test whether the post-translational modifications to PGs can serve as in vitro surrogate end point markers for chronological age, the extent of GAG modifications was determined for PGs derived from normal human bone cells of 14 donors (age range, fetal to 60 years). Isolated cells were steady state radiolabeled with (35)SO(4)(2-) and [(3)H]GlcN. For biglycan and decorin, iduronate content was linearly correlated with age (increased 1.5x between fetal and age 60 years). For the syndecan-like heparan sulfate PG, the N-sulfation of post-natal cells increased over 3.5-fold until reaching a plateau during the 4th decade of life. The amount of O-linked oligosaccharides was also found to decrease as a function of increasing normal donor age, whereas the specific activity of the metabolic precursor pool remained constant regardless of donor age. These age-related changes in post-translational modifications were then used to demonstrate that osteoblasts derived from patients with osteogenesis imperfecta did not exhibit facets of a pre-mature aging, but rather were arrested in a fetal-like phenotypic state. A growth matrix rich in thrombospondin altered PG metabolism in osteoblastic cells, resulting in the production and secretion of the fetal-like (rich in O-linked oligosaccharides) forms of decorin and biglycan. This effect was qualitatively different from the effect of transforming growth factor-beta, which predominantly altered GAGs rather than O-linked oligosaccharides. No other Arg-Gly-Asp protein (fibronectin, vitronectin, type I collagen, osteopontin, and bone sialoprotein) showed any detectable effect on PG metabolism in bone cells. These results indicate that a proper matrix stoichiometry is critical for metabolism of PGs

Chitotriosidase, a marker of innate immunity, is elevated in patients with primary breast cancer

BACKGROUND:Cancer progression has been associated with altered immune cell function and activation. Neopterin, which is secreted by interferon-γ stimulated macrophages, exhibits an association with multiple cancer types and metastatic disease. Chitotriosidase, which is secreted by chronically activated macrophages and granulocyte-macrophage colony-stimulating factor stimulated neutrophils has not been studied in the setting of cancer.OBJECTIVE:The goal of this discovery study was to screen chitotriosidase for diagnostic capacity in detecting cancer and compare its operating characteristics with those of neopterin.METHODS:Serum from subjects with breast (n= 66) or prostate (n= 70) cancer, and from 204 subjects free of malignant disease were studied. Chitotriosidase was measured by enzyme activity assay, while neopterin was measured by a competitive enzyme immunoassay. Statistical analyses included group comparisons by Mann Whitney U test, diagnostic capacity by receiver operating characteristics (ROC) curve analysis and biomarker associations with physiologic and clinical measures by Spearman correlation.RESULTS:Chitotriosidase activity was significantly higher in both cancer types compared with gender matched controls, though only in breast cancer was the diagnostic capacity significant (area under the ROC curve of 0.97 ± 0.01). In contrast, neopterin was significantly elevated in prostate cancer and exhibited discriminatory capacity (area under the ROC curve of 0.76 ± 0.05). Age, BMI, % body fat and metastasis were variables that correlated with neopterin, but not chitotriosidase levels.CONCLUSIONS:The operating characteristics of serum chitotriosidase were different from neopterin and further analysis of chitotriosidase as a biomarker for breast cancer is warranted.Fil: Thein, Mya Sanda. University Johns Hopkins; Estados Unidos. University of Maryland; Estados UnidosFil: Kohli, Anita. University Johns Hopkins; Estados Unidos. University of Pennsylvania; Estados UnidosFil: Ram, Rohit. University Johns Hopkins; Estados Unidos. University of Pittsburgh; Estados UnidosFil: Ingaramo, María Clara. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Agrobiotecnología del Litoral. Universidad Nacional del Litoral. Instituto de Agrobiotecnología del Litoral; ArgentinaFil: Jain, Alka. University Johns Hopkins; Estados UnidosFil: Fedarko, Neal S.. University Johns Hopkins; Estados Unido

T-Lymphocytes Expressing CC Chemokine Receptor-5 Are Increased in Frail Older Adults

OBJECTIVES: To evaluate the frequencies of T-lymphocytes expressing CC chemokine receptor-5 (CCR5(+) T-cells) and their relationship with frailty in older adults. DESIGN: Case-control study with an age-, race-, and sex-matched design. SETTING: General Clinical Research Center. PARTICIPANTS: Community-dwelling adults aged 72 and older from Baltimore, Maryland. METHODS: Frailty was determined using five validated criteria: weakness, slow walking speed, fatigue, low physical activity, and weight loss. Those meeting three or more of these five criteria were defined as frail and those with none as nonfrail. Complete blood counts were performed to obtain peripheral lymphocyte counts using an automated (Coulter) counter. Peripheral blood was collected for surface immunofluorescent staining of CCR5 and other T-cell markers. RESULTS: Twenty-six frail and matched nonfrail participants (mean age+/-standard deviation 83.8+/-5.3, range 72-94) completed the study. Frail participants had higher CCR5(+), CCR5(+)CD8(+), and CCR5(+)CD45RO(-) T-cell counts than matched nonfrail controls (349+/-160/mm(3) vs 194+/-168/mm(3), P=.02; 208+/-98/mm(3) vs 105+/-62/mm(3), P=.02; and 189+/-149/mm(3) vs 52+/-36/mm(3), P=.01; respectively). Furthermore, there was a trend toward graded increase in these T-cell counts across the frailty scores in frail participants (e.g., CCR5(+)CD8(+) counts of 123+/-52/mm(3), 248+/-115/mm(3), and 360+/-215/mm(3) for those with frailty scores of 3, 4, and 5, respectively). CONCLUSION: These initial results suggest an expansion of the CCR5(+) T-cell subpopulation in frailty. They provide a basis for further characterization of CCR5(+) T-cells and their role in frailty, with potential therapeutic implications