potassium-titanate and Inflammation

Among the crystal forms of calcium carbonate, aragonite has needle-like shape. Although materials with needle-shaped crystals are associated with pulmonary toxicity, the toxic activity of aragonite is unclear. Therefore, proinflammatory potential of aragonite, neutralized aragonite and potassium titanate whisker was evaluated. The cellular effects of aragonite were weaker than those of potassium titanate whisker. Aragonite treatment induced the expression of chemokines in A549 cells and macrophages. Although aragonite exhibited proinflammatory effects in vitro, pulmonary inflammation was not observed in vivo after intratracheal administration of aragonite in mice. We did not observe the induction of inflammatory cytokine secretion or tissue lesion in the lungs of mice after administration of aragonite. Potassium titanate whisker treatment induced chemokine secretion in vitro. An increase in the number of neutrophils was observed in the mice lung tissue after administration of potassium titanate whisker. Aragonite and neutralized aragonite both induced an increase in the levels of intracellular calcium, but the levels were significantly higher in cells treated with aragonite than in cells treated with neutralized aragonite. These results suggested that intracellular calcium release mediates the cellular effects of aragonite. The toxicity of aragonite based on its needle-like structure was also not observed.

Topics: A549 Cells; Animals; Calcium; Calcium Carbonate; Chemokines; Humans; Inflammation; Macrophages; Male; Mice; Mice, Inbred C57BL; Neutrophils; Titanium

Phagocytosis is a physiological process used by immune cells such as macrophages to actively ingest and destroy foreign pathogens and particles. It is the cellular process that leads to the failure of drug delivery carriers because the drug carriers are cleared by immune cells before reaching their target. Therefore, clarifying the mechanism of particle phagocytosis would have a significant implication for both fundamental understanding and biomedical engineering. As far as we know, the effect of particle shape on biological response has not been fully investigated. In the present study, we investigated the particle shape-dependent cellular uptake and biological response of differentiated THP-1 macrophages by using calcium carbonate (CaCO

Topics: Animals; Calcium; Calcium Carbonate; Cell Line; Cytokines; Humans; Inflammation; Macrophages; Male; Mice, Inbred C57BL; Particle Size; Phagocytosis; Phosphates; Titanium

We compared in vivo biological effects, focusing on lung inflammatory responses after a single intratracheal administration of two types of well-characterized whiskers: potassium octatitanate and potassium hexatitanate, which have similar fiber sizes and chemical compositions, except their surface morphology. The geometrical mean of length (microm), width (microm), and geometric standard deviation (GSD) are: K(2)Ti(8)O(17) (PT1), 6.0[2.0], 0.35[1.51], having rough surface; K(2)Ti(6)O(13) (PT2), 5.0[2.18], 0.31[1.63], having smooth surface. Sixty male Wistar rats (8 wk old) under anesthesia were injected intratracheally with 2 doses of fibers (0.2 mg/0.5 ml/rat, 1.0 mg/0.5 ml/rat) or the same amount of saline solution (group C). Animals were sacrificed on days 1, 3, and 7 after fiber administration, and then the lung tissue and bronchoalveolar lavage (BAL) were collected. There were no obvious differences among the three groups in the yield of BAL fluid. Total protein concentration in BAL increased significantly from day 1; BAL fucose level increased significantly from day 3 in a dose-dependent manner, which gradually recovered by day 7 in groups PT1 and PT2. BAL total protein and fucose in group PT1 increased significantly compared with those in group PT2 at a dose level of 1.0 mg. A dose-independent increase of beta-glucuronidase activity and decrease of superoxide dismutase activity were observed in both fibers. BAL tumor necrosis factor-alpha (TNF-alpha) increased significantly in animals treated with 1.0 mg dosage of PT1 and PT2 on day 1. However, BAL IL-1beta did not show any marked change during the experimental period in animals treated with both fibers. On day 1, BAL cytokine-induced neutrophil attractants (CINC)/growth-related gene product (GRO) increased significantly in the PT1 group treated with 0.2 and 1.0 mg dosage. On day 3, the group treated with 1.0 mg PT1 showed significant increase of CINC/GRO compared with the group treated with 1.0 mg PT2, which recovered to the control level on day 7. Expression of various chemokine mRNAs (MCP-3, MIP-1alpha, RANTES, and eotaxin) increased in rats treated with PT1 or PT2 on day 1 and/or day 3. Increase of gene expression in the PT1 group was greater than that of the PT2 group at 0.2 mg dosage level. These results suggest that differences in the surface morphology of the whisker fibers of similar length and diameter, density, and chemical composition appear to be related to the facilitation of macropha

Topics: Animals; Bronchoalveolar Lavage Fluid; Cytokines; Dose-Response Relationship, Drug; Gene Expression Regulation; Inflammation; Inhalation Exposure; Lung; Male; Manufactured Materials; Phagocytes; Rats; Rats, Wistar; Titanium; Trachea