Three-dimensional AFM picture (top) and NMR-TOCSY spectra (middle, bottom) of collagen hydroylsates.

<p>The AFM picture (Fig. 2 top) shows the amorphous crystal-like structures in the presented 25 square micrometer area (0 to 5 micrometer) with a high resolution in the third dimension (0 to 150 nanometer), demonstrating that no higher-ordered collagen structures (eg, triple-helical collagen fragments) are present in the collagen hydrolysate preparation (RDH) from Rousselot. The highly resolved proton-NMR signals are displayed along the F1 and the F2 axes according to their ppm values (Fig. 2 middle and bottom). F1 is frequency axis one, F2 is the second frequency axis. The ppm values on both frequency axes correspond to the ppm values of the one-dimensional NMR spectrum. Depending on the relation of the magnetization transfer (via the bonds: TOCSY, via space: NOESY), an assignment of the signals to the protons is possible and thus leads to a characteristic fingerprint pattern of the collagen hydrolysate investigated (Fig. 2 middle and bottom). The TOCSY spectra (Fig. 2 middle and bottom) show, for example, one obvious difference in their signal patterns–namely, the characteristic cross-peak at F1: 1.5 ppm/F2: 7.2 ppm, highlighted as a grey circle in the TOCSY spectrum of RDH (Fig. 2 middle), is missing in the TOCSY spectrum of RDH-N (Fig. 2 bottom). This observation makes it clear that the fragments that belong to this cross-peak are missing in the sample RDH-N (Fig. 2 bottom). Thus, one change in the cross-peak signal pattern is already enough to distinguish between different collagen hydrolysates.</p

Effect of collagen hydrolysates on the collagen synthesis of OA cartilage.

<p>Incorporation of [³H]-proline and [¹⁴C]-proline into collagen of human cartilage explants was determined by measuring the radioactivity found in hydroxyproline. The [¹⁴C/³H]-incorporation ratio was then calculated and is expressed as percent of untreated control (100%) in the presence of 0.1, 0.5, 1, 2, and 10 mg/ml of RDH, RDH-N, or CH-Alpha®. Each experiment was done with explants removed from the lateral condyle of 6 patients graded with a Collins score of <1.5 and another 6 patients who presented lateral condyles with a Collin score between 1.5 and 3. Thus, explants from a total of 12 patients were used. Data shown are the mean±standard deviation (N = 12). Statistically significant different from untreated controls: **0.001</p

Compositional differences of collagen hydrolysates as determined by MALDI-TOF-MS.

<p>Mass spectra obtained in the (<b>A–C</b>) linear and (<b>D–F</b>) reflector mode reveal differences between (<b>A,D</b>) CH-Alpha®, (<b>B,E</b>) RDH, and (<b>C,F</b>) RDH-N with respect to peptide composition, as represented by the molecular weight distribution of the peptides, and the average molecular weight of each collagen hydrolysate preparation.</p

Concentration-dependent effect of collagen hydrolysates on the synthesis and/or release of MMP-1, MMP-3, and MMP-13.

<p>MMPs were determined within nutrient media of cultured human articular cartilage. Following stabilization of explant metabolism for 4–6 days, explants were treated for additional 6 days with 0–10 mg/ml collagen hydrolysate. MMPs were determined with ELISA, and data are expressed as mean±standard deviation (N = 5). Statistically significant different from untreated controls: *0.01</p