elastin and histidinohydroxylysinonorleucine

We have developed a novel chromatographic analytical method for the simultaneous quantitation of collagen crosslinks. Seven non-derivatised crosslinks could be separated on a Cogent Diamond Hydride HPLC column using either isocratic or gradient conditions then detected by mass spectrometry. The total run time was less than 10min which is significantly shorter than that previously reported. This is the first method in which histidinohydroxylysinonorleucine (HHL) and histidinohydroxymero-desmosine (HHMD) were separated and identified by mass spectrometry without the need for pre- or post-column derivatization. The CVs of the retention times of all seven crosslinks were less than 1% and the limit of detection (LOD) and the limits of quantitation (LOQ) were 0.07-0.13pmol/μL and 0.20-0.38pmol/μL, respectively. This novel method was used for the routine analysis and quantitation of crosslinks in different animal skins in which potential new collagen crosslinks were identified that are as yet undocumented.

Topics: Animals; Chemistry Techniques, Analytical; Chromatography, Liquid; Collagen; Desmosine; Dipeptides; Elastin; Histidine; Limit of Detection; Skin; Spectrometry, Mass, Electrospray Ionization

In an attempt to identify potential staging markers of effective healing, changes in connective tissue properties were measured in a human skin excisional wound healing model in which tissue was re-excised at intervals up to 6 months after injury. The proportion of collagen III relative to collagen I increased significantly (p<0.001) up to 6 weeks after initial injury and remained elevated up to 6 months, at which time the proportion of collagen III was 70% above baseline values. Extractability of biopsy tissue collagen by pepsin increased significantly throughout the study (baseline, 32.8+/-6.8%; 6 months, 89.1+/-8.9%), with inverse changes in the mature skin cross-link, histidinohydroxylysinonorleucine (baseline, 1.18+/-0.11 mol/mol collagen; 6 months, 0.27+/-0.09 mol/mol collagen). Pyridinoline content increased over the period of the study, although remaining at relatively low concentrations (baseline, 0.037+/-0.011; 6 months, 0.063+/-0.014 mol/mol collagen), and the pyridinoline/deoxypyridinoline ratio was significantly higher (baseline, 3.5+/-0.6; 6 months, 10.3+/-2.2). Elastin content, measured as desmosine cross-links, decreased significantly in the first 3 weeks and continued to decline over the period of study. Overall, the data suggest that remodeling of the wound tissue continues at least up to 6 months after injury. The close inverse correlation between histidinohydroxylysinonorleucine concentrations and extractability by pepsin (r2=0.89, p<0.0001) suggests a causal relationship, consistent with the likely effects of a substantial network of mature, inter-helical bonds in collagen.

Topics: Adult; Amino Acids; Collagen; Collagen Type I; Collagen Type III; Dipeptides; Elastin; Histidine; Humans; Male; Skin; Time Factors; Wound Healing; Wounds, Penetrating