Modulation of proteoglycan and collagen profiles in human dermal fibroblasts by high density micromass culture and treatment with lactic acid suggests change to a chondrogenic phenotype.

Cartilage formation during embryonic development and in fracture healing in adult animals involves chondrogenic differentiation of mesenchymal precursors. Here we describe an in vitro model whereby human dermal fibroblasts, considered to be restricted to a fibroblast lineage, are apparently redirected toward a chondrogenic phenotype by high density micromass culture in the presence of lactic acid. Micromass cultures treated with 40 mM lactate exhibited increased levels of Alcian blue staining and sulfate incorporation, indicative of elevated sulfated glycosaminoglycan synthesis. Northern analysis revealed an up-regulation of chondroitin sulfate proteoglycan 1 (aggrecan) and transforming growth factor-beta 1 mRNA and a decrease in type I collagen expression. Type II collagen was detected by reverse transcription-PCR only in experimental cultures. Although the observed changes in biosynthesis and gene expression were consistent with differentiating chondrocytes, the cells displayed an elongated, fibroblast-like morphology. These findings suggest that dermal fibroblasts may be committed to differentiate along a chondrogenic pathway by in vitro culture under specific forcing conditions.

Design of biomimetic habitats for tissue engineering with P-15, a synthetic peptide analogue of collagen.

In tissues, collagen forms the scaffold for cell attachment and migration, and it modulates cell differentiation and morphogenesis by mediating the flux of chemical and mechanical stimuli. We are constructing biomimetic environments by immobilizing a collagen-derived high-affinity cell-binding peptide P-15 in three-dimensional (3-D) templates. The cell-binding peptide can be expected to transduce mechanical forces. In their physiological environment, periodontal ligament fibroblasts (PDLF) are subject to significant mechanical forces. We have examined the behavior of human PDLF in culture on particulate bovine anorganic bone mineral (ABM) coated with P-15 (ABM-P-15). Greater numbers of cells associated with ABM-P-15 compared to ABM alone. Higher levels of incorporation of radiolabeled precursors in DNA and protein were consistent with the presence of larger numbers of cells on ABM-P-15 compared to ABM cultures. Scanning electron microscopic examination showed that cultures on ABM-P-15 generated highly oriented 3-D colonies of elongated cells and formed copious amounts of fibrous as well as membranous matrix reminiscent of ligamentous structures. PDLF cultured on ABM formed sparse monolayers with little order and a meager matrix. Alizarin Red stained the matrix of particle associated cells and inter-particle cellular bridges in P-15-associated cultures, indicating mineralization. 3-D colony formation and ordering of cells along with increased mineralization suggests that the coupling of cells to the ABM matrix through P-15 may provide a biomimetic environment permissive for cell differentiation and morphogenesis. Our studies suggest that ABM-P-15 templates may be effective as endosseous grafts, and, when seeded with PDLF, these matrices may serve as tissue engineered substitutes for autologous bone grafts.

[The influence of heart infarction on the concentration of aminoterminal type III procollagen peptide in blood serum]. / Wplyw zawalu miesnia sercowego na stezenie aminoterminalnego peptydu prokolagenu typu III w surowicy krwi.

UNLABELLED: The reconstructive processes in a heart infarction pertain also the fibrous tissue sceleton, of which the main element are collagen fibres. The aim of the study was determination of variability of a specific collagen synthesis marker, i.e. the serum aminoterminal type III procollagen peptide (PIIINP) and its correlation with hydroxyproline (HP), hydroxylysin (HL) concentration as well as activity of creatine kinase (CK) and aspartate aminotransferase (AspAT) in serum after heart infarction. The investigations were carried out in 30 patients with a heart infarction with Q wave (group I), in 20 subjects with a heart infarction without Q wave (group II) and in 30 healthy subjects, comprising the C group. All these parameters were determined on the 1st, 2nd, 3rd, 5th and 10th day after onset of infarction. In comparison to the C group, in group I on the 1st day the PIIINP concentration was 3-fold higher and in group II it 2 1/2-fold higher (C = 4.3 +/- 1.8; I = 14.2 +/- 3.9; II = 10.4 +/- 2.0 micrograms/l; p < 0.001). In group I even on the 10th day the concentration did not return to normal values, instead in group II it reached the values x + SD in C group after 5 days. There was no significant correlation between concentration of PIIINP and all other examined parameters stated. Heart infarction with a Q wave caused a relatively highest (% of mean values in C group) increase in CK and AspAT activity, PIIINP held a medial position, while HP and HL the lowest. After infarction without a Q wave the relative elevation of PIIINP concentration was near to the AspAT and HP increase. CONCLUSIONS: 1. the differences of serum PIIINP concentration are probably resulted by the magnitude of heart infarction. 2. During 10 days after the onset of heart infarction the serum concentration of PIIINP does not show any correlation with HP, HL and enzymatic heart infarct markers. 3. The results indirectly show, that the scar formation after heart infarction begins already on the first day.

[Effect of heart infarction on levels of type I procollagen carboxyterminal peptide in blood serum]. / Wplyw zawalu miesnia sercowego na stezenie karboksyterminalnego peptydu prokolagenu typu I w surowicy krwi.

The aim of the study was determination of the influence of heart infarction on the blood serum level of type I procollagen carboxyterminal peptide (PICP) and its covariability with concentration of hydroxyproline (HP) and hydroxylysine (HL) as well as activity of creatine kinase (CK) and aspartate transferase (AspAT). The investigations were carried out in 30 patients with a heart infarction with Q wave (group I) and in 20 subjects with a heart infarction without Q wave. The control group comprised 30 healthy subjects. The determination of all parameters was performed on the 1st, 2nd, 3rd, 5th and 10th day after the infarct onset. On the 1st day of heart infarction, the concentration of PICP in serum was (x +/- SD): gr. I-235 +/- 33, gr. II-209 +/- 8, gr. C-65 +/- 17 micrograms/l. There was no co-variability of PICP concentration and the values of all other determined parametres. The authors conclude: 1. the increase of serum PICP concentration is connected probably with the magnitude of heart infarction, 2. the reconstruction process of the heart fibrous tissue and scar formation begins already on the first day of infarction onset, 3. during 10 days after infarction onset the serum PICP concentration does not correlate with HP, HL as well as the enzymatic heart infarct indices, namely CK and AspAT.

[Collagen metabolism disturbances with experimentally increased pulmonary flow--experimental model of left to right shunt with congenital heart defects in children]. / Zaburzenia metabolizmu kolagenu w doswiadczalnie wywolanym zwiekszonym przeplywie plucnym--model eksperymentalny przeciekowych wad wrodzonych serca u dzieci.

The studies carried out on young piglets were to demonstrate that experimentally increased pulmonary flow resulted in collagen hyperproduction in the pulmonary tissue. In 14 piglets a modified Blalock-Taussig anastomosis was performed, 9 animals constituted the controls. The survivors included 9 experimental and 8 control piglets. In direct lung biopsies the biochemical collagen content was assessed, whereas histopathology confirmed the development of vascular lesions characteristic for pulmonary hypertension. A significant increase of collagen level in the pulmonary tissue was demonstrated in experimental animals. Determinations were also made of serum and urine hydroxyproline values. A significant increase was observed in serum and urine hydroxyproline values in experimental animals in comparison to the controls when determinations were made 7 days to 3 months after the anastomosis had been performed (p < 0.01). The authors showed that an increase of pulmonary flow in piglets results in collagen metabolism disturbances which are seen both in an increased collagen level in the tissue and in increased serum and hydroxyproline levels.