Modulation of osteogenic properties of biodegradable polymer/extracellular matrix scaffolds generated with a flow perfusion bioreactor.

In this study, composite scaffolds consisting of both synthetic and natural components with controllable properties were generated by incorporating mineralized extracellular matrix (ECM) and electrospun poly(epsilon-caprolactone) (PCL) microfiber scaffolds. Mesenchymal stem cells (MSCs) were cultured on PCL scaffolds under flow perfusion conditions with culture medium supplemented with dexamethasone to investigate the effect of culture duration on mineralized extracellular matrix deposition. MSCs differentiated down the osteogenic lineage and produced extracellular matrix with different compositions of mineral, collagen, and glycosaminoglycan with distinct morphologies at various stages of osteogenesis. To determine whether the presence and maturity of mineralized extracellular matrix influences osteogenic differentiation in vitro, PCL/ECM constructs were decellularized to yield PCL/ECM composite scaffolds that were subsequently seeded with MSCs and cultured in the absence of dexamethasone. The presence of mineralized matrix reduced cellular proliferation while stimulating alkaline phosphatase activity with increasing amounts of calcium deposition over time. PCL/ECM composite scaffolds containing the most mature mineralized matrix resulted in the most rapid increase and highest levels of alkaline phosphatase activity and calcium deposition compared to all other scaffold groups. Therefore, we demonstrate that mineralized extracellular matrix generated under controlled flow perfusion conditions can impart osteogenic properties to an osteoconductive polymer scaffold, and that the maturity of this matrix influences osteogenic differentiation in vitro, even in the absence of dexamethasone.

The agreement between self-assessment and clinician assessment of dry eye severity.

PURPOSE: The purpose of this analysis was to measure the degree of agreement between clinicians' assessment and subjects' self-assessment of dry eye severity in a cross-sectional, observational dry eye study. A secondary purpose was to identify the role of gender and age in that concordance. METHODS: In a cross-sectional observational study, 162 dry eye subjects and 48 controls were recruited from clinical databases of ICD-9 codes in 6 clinical sites. Before examination, subjects gave a global self-assessment of the severity of their dry eye from "none" to "extremely severe." After a clinical examination that included dry eye tests, the clinician discussed the subjects' symptoms and then gave global clinician assessment of dry eye from "none" to "severe." We measured the degree of agreement in these global measures. RESULTS: Although the correlation and agreement between clinician and self-assessment was significant (r = 0.720, P = 0.000; weighted K = 0.471; 95% CI = 0.395, 0.548; P = 0.000), the clinician assessment underestimated the severity in 40.9% of the subjects by at least 1 grade compared with the subjects' self-assessment. Over 54% of subjects over age 65 and 43% of the female subjects had their condition underestimated by the clinician (P < 0.05). CONCLUSIONS: Clinicians often relatively underestimated the severity of the subjects' self-assessment of dry eye in this clinical study, especially among the elderly and women. Eye care practitioners need better, more quantitative tools for the assessment of ocular surface symptoms to improve the concordance in severity assessment and to meet the needs of this symptomatic patient population by offering them appropriate treatments.

Serine protease inhibitors modulate smoke-induced chemokine release from human lung fibroblasts.

Smoking is associated with lung inflammation and a protease-antiprotease imbalance. We previously reported that cigarette smoke extract (CSE) stimulates human lung fibroblasts to release chemotactic cytokines. We hypothesized that serine protease inhibitors might modulate lung fibroblast release of chemotactic cytokines in response to CSE. To test this hypothesis, serine protease inhibitors (FK706, alpha1-antitrypsin, methoxysuccinyl-Ala-Ala-Pro-Val chloromethyl ketone, or Nalpha-p-tosyl-L-lysine chloromethyl ketone) were evaluated for their capacity to attenuate the release of neutrophil chemotactic activity (NCA) and monocyte chemotactic activity (MCA) from human fetal lung fibroblasts by the blind-well chemotactic chamber. Metalloproteinases and cysteine proteinases were not examined in this study. Similarly, the release and gene expression of chemokines and nuclear factor-kappaB (NF-kappaB) activation were measured by means of enzyme-linked immunosorbent assay and reverse transcriptase-polymerase chain reaction. Release of NCA, MCA, chemotactic chemokines including interleukin-8, granulocyte colony-stimulating factor, monocyte chemoattractant protein-1, and granulocyte-macrophage colony-stimulating factor, and the expression of interleukin-8 and monocyte chemoattractant protein-1 mRNA were attenuated by FK706. Furthermore, FK706 suppressed NF-kappaB activation. These data suggest that serine protease inhibitors attenuate the CSE-induced release of NCA and MCA from human fetal lung fibroblasts and that the inhibitory action of antiproteases might depend on NF-kappaB signaling pathway.

Serine protease inhibitors modulate chemotactic cytokine production by human lung fibroblasts in vitro.

Chemotactic chemokines can be released from lung fibroblasts in response to interleukin (IL)-1beta and tumor necrosis factor (TNF)-alpha. An imbalance between proteases and antiproteases has been observed at inflammatory sites, and, therefore, protease inhibitors might modulate fibroblast release of chemotactic cytokines. To test this hypothesis, serine protease inhibitors (FK-706, alpha(1)-antitrypsin, or N(alpha)-p-tosyl-L-lysine chloromethyl ketone) were evaluated for their capacity to attenuate the release of neutrophil chemotactic activity (NCA) or monocyte chemotactic activity (MCA) from human fetal lung fibroblasts (HFL-1). Similarly, the release of the chemoattractants IL-8, granulocyte colony-stimulating factor, monocyte chemoattractant protein-1, macrophage colony-stimulating factor, and granulocyte/macrophage colony-stimulating factor, from HFL-1, were evaluated in response to IL-1beta and TNF-alpha. NCA, MCA, and chemotactic cytokines were attenuated by FK-706. However, matrix metalloproteinase inhibitors were without effect, and cysteine protease inhibitors only slightly attenuated chemotactic or cytokine release. These data suggest that IL-1beta and TNF-alpha may stimulate lung fibroblasts to release NCA and MCA by a protease-dependent mechanism and that serine protease inhibitors may attenuate the release.

Peroxynitrite enhances interleukin-10 reduction in the release of neutrophil chemotactic activity.

Peroxynitrite, formed by nitric oxide and superoxide, has been shown to nitrate and reduce the function of proinflammatory proteins such as interleukin (IL)-8, monocyte chemoattractant protein-1, and eotaxin, but in contrast, to enhance the function of the anti-inflammatory cytokine IL-10 in reducing IL-1 release from blood monocytes. However, the effect of nitrated IL-10 on release of proinflammatory cytokines from lung epithelial cells is unknown. We hypothesized that peroxynitrite would enhance the capacity of human IL-10 to reduce inflammatory mediators released by epithelial cells. To test this hypothesis, recombinant human IL-10 was evaluated for its capacity to attenuate the release of neutrophil chemotactic activity and IL-8 from a human epithelial cell line in response to IL-1 beta and tumor necrosis factor-alpha. Neutrophil chemotactic activity and IL-8 in lung epithelial culture supernatant fluids were significantly lower after culture with nitrated human IL-10 compared with non-nitrated human IL-10 controls (P < 0.05). Consistent with these results, nitrated human IL-10 attenuated IL-8 mRNA expression more than non-nitrated human IL-10 controls (P < 0.05). These data demonstrate that peroxynitrite exposed human IL-10 has enhanced anti-inflammatory activity and suggest that nitration may play a critical role in the regulation of inflammation within the lower respiratory tract.

Enhanced activity of human IL-10 after nitration in reducing human IL-1 production by stimulated peripheral blood mononuclear cells.

Nitric oxide and superoxide form the unstable compound, peroxynitrite, which can nitrate proteins and compromise function of proinflammatory cytokines at sites of inflammation. Reduced function of proinflammatory proteins such as IL-8, macrophage inflammatory protein-1alpha, and eotaxin suggest an anti-inflammatory effect of nitration. The effects of nitration on anti-inflammatory cytokines such as IL-10 are unknown. We hypothesized that peroxynitrite would modify the function of anti-inflammatory cytokines like IL-10. To test this hypothesis, the capacity of recombinant human IL-10 to inhibit production of human IL-1beta (IL-1) from LPS-stimulated human PBMC was evaluated. Human IL-10 was nitrated by incubation with peroxynitrite or by incubation with 3-morpholinosydnonimine, a peroxynitrite generator, for 2 h and then incubated with LPS-stimulated PBMC for 6 h, and IL-1 was measured in the culture supernatant fluids. Human IL-1 production was significantly lower in the peroxynitrite- or 3-morpholinosydnonimine-nitrated IL-10 group than in the IL-10 controls (p < 0.05, all comparisons). This finding demonstrates that although peroxynitrite inhibits proinflammatory cytokines, it may augment anti-inflammatory cytokines and further point to an important role for peroxynitrite in the regulation of inflammation.