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PubMed1980

Effects of aging on hydroxyproline in human heart muscle.

Hydroxyproline concentration in the NaCl-soluble, TCA-soluble, and residual fractions of heart muscle was chemically determined in 40 autopsy subjects (25 men and 15 women), to study the effects of aging. In the left ventricle, the total hydroxyproline content of the endocardium and papillary muscle increased significantly in relation to age; the increase was greatest in the TCA-soluble fraction, followed by the residual fraction. Statistical analysis revealed that hydroxyproline in the residual fraction increased from the epicardium to the endocardium and then to the papillary muscle. Significant negative correlations were found between heart weight and total hydroxyproline in the epicardium and endocardium. In the right ventricle, a significant negative correlation was noted between heart weight and total hydroxyproline content. Though no correlations were evident between age and hydroxyproline content in females, significant correlations were observed between age and the total hydroxyproline content of the endocardium and papillary muscle in males. Furthermore, soluble collagen increased in most parts of the heart in females, but insoluble collagen increased in all parts of the heart in males. It is concluded that the hydroxyproline content of heart muscle increases in proportion to age and is in inverse proportion to heart weight. The increase occurs in the TCA-soluble and residual fractions, and extends from the endocardium to the papillary muscle. More profound changes in collagen metabolism are observed in males.

Adult↗
PubMed1979

Hydroxyproline metabolism in type II hyperprolinaemia.

Hydroxyproline metabolism was studied in two patients with type II hyperprolinaemia (HP II) using oral loadings of hydroxyproline or hydroxyproline-ornithine. delta 1-pyrroline-3-hydroxy-5-carboxylic acid (3 OH-PC) and delta 1-pyrroline-5-carboxylic acid (PC) were identified in the urine. The urinary excretion of both 3-OH-PC and PC increased in HP II patients but not in healthy controls during oral loading of hydroxyproline and hydroxyproline-ornithine. The plasma level of proline in patients with HP II is very high but the hydroxyproline concentration is normal or only slightly increased. Therefore one can assume that hydroxyproline is converted to pyrrole-2-carboxylic acid, which is excreted in urine as a glycine conjugate. In this study it was demonstrated that the highly elevated plasma level of proline in one of the patients with HP II decreased greatly after hydroxyproline-ornithine load; this change was followed by a 40-fold rise in urinary excretion of proline.

Adolescent↗
PubMed1977

Effect of mithramycin on hydroxyproline metabolism in Paget's disease.

Hydroxyproline was measured in the plasma and urine of six patients with symptomatic osseous Paget's disease before and after parenteral mithramycin treatment. The plasma profile data included free, peptide, and protein hydroxyproline values. Corresponding urine samples were analyzed for total hydroxyproline content and, in some instances, for free hydroxyproline. Plasma values of free and peptide hydroxyproline fell promptly toward the range of normal within 24 hr after the first intravenous injection of mithramycin. Protein hydroxyproline in the plasma was slightly but significantly lower than in the 15 normal control subjects, and this value did not change appreciably over the 4-day period during which the patients were treated. The urine excretion rate of total hydroxyproline decreased precipitously. Our results support the hypothesis that mithramycin rapidly reduces the accelerated rate of "collagenolytic" activity of osteocytes and osteoclasts in this disorder, presumably by an inhibiting effect on these bone-modeling cells. The major degradative lesion, as reflected in the plasma and urine, is characterized by the production of non-TCA-precipitable peptides containing hydroxyproline, which rapidly fell to normal levels after the administration of mithramycin.

Humans↗
PubMedDate not supplied

Semiquantitative evaluation of hepatic fibrosis by measuring tissue hydroxyproline.

BACKGROUND/AIMS: It is important to evaluate the degree of hepatic fibrosis when diagnosing and treating hepatic cirrhosis. We focused on hydroxyproline, which is detected specifically in collagen, which plays a major role in hepatic fibrosis. The correlations between liver tissue hydroxyproline residue levels and the degree of hepatic fibrosis were examined in dogs with dimethylnitrosamine-induced fibrotic livers. METHODOLOGY: Dimethylnitrosamine was administered to dogs to establish experimental hepatic fibrosis. Paraffinized sections of liver specimens, stained with hematoxylin-eosin and azan, were examined and the degree of hepatic fibrosis was graded. About three-milligram samples of liver tissue were loaded onto a fully automated liquid chromatograph and the levels of hydroxyproline residues were measured. RESULTS: The liver tissue hydroxyproline appeared to reflect the degree of hepatic fibrosis. The liver tissue hydroxyproline levels and pathological hepatic fibrosis grades correlated significantly (p<0.05). CONCLUSIONS: Tissue hydroxyproline appears to be a more useful fibrosis marker, because hydroxyproline is influenced less by other factors. Furthermore, our results demonstrate that a very small amount of liver tissue (wet weight 3 mg) was enough to enable the levels of hydroxyproline residues to be measured by an automated amino acid analyzer (JLC-3000) and hepatic fibrosis is expressed as the numerical value by this analysis.

Animals↗
PubMed1991

Synthesis and characterization of magnetically responsive albumin microspheres containing cis-hydroxyproline for scar inhibition.

Magnetically responsive albumin microspheres containing the proline analog, cis-hydroxyproline, were synthesized and their in-vitro physical properties were characterized. These microspheres have an average size of 1.1 +/- 0.3 microns with 94% of the microspheres less than 2.0 microns. They are uniformly spherical and contain 67% albumin, 22% magnetite, and 8% cis-hydroxyproline. The cis-hydroxyproline is releasable during a 72-h period and demonstrates a slow, releasable pool that constitutes approximately 50% of the incorporated drug. cis-Hydroxyproline is neither chemically nor biologically altered during its incorporation into the microsphere. cis-Hydroxyproline release from microspheres results in the in vitro inhibition of collagen secretion, which is indistinguishable from unincorporated cis-hydroxyproline. In a rat-tail animal model these microspheres were selectively targeted using an external magnetic field applied to a 1.5-2.0-cm target site. Fifty to 80% of the infused microspheres were localized to this site, whereas without a magnetic field only 15-20% of the microspheres are localized to this site. cis-Hydroxyproline microspheres resulted in a 16% decrease in collagen content in a scar model when compared with untreated animals (p less than 0.05). With further refinement of this method of drug delivery, clinically useful inhibition of scar formation may result.

Animals↗
PubMed1977

Hydroxyproline fractions in serum and urine of rats during wound healing.

Total hydroxyproline in urine and free hydroxyproline, free and peptide hydroxyproline and protein bound hydroxyproline in serum are measured during wound healing in rats. The free and free+peptide fractions vary in concert with each other and with urine hydroxyproline. Protein bound hydroxyproline fractions take a very different course and behave as an acute phase reactant. The results suggest that protein bound hydroxyproline does not mirror collagen turnover but may be more relevant to C1q or complement metabolism.

Animals↗
PubMed1995

A simple and automated HPLC method for determination of total hydroxyproline in urine. Comparison with excretion of pyridinolines.

An HPLC method for measuring total hydroxyproline in human urine was validated. Hydroxyproline derivatization was achieved with 9-fluorenylmethyl chloroformate after blocking primary amino acids with orthophthaldialdehyde. The derivatives (hydroxyproline and internal standard) were separated by reversed phase high-performance liquid chromatography and detected by absorbance at 254 nm. Duplicate measurements of hydroxyproline have a coefficient of variation of 3.9% and the recovery in spiked urine samples is between 99.5 and 100.8%. We have compared the HPLC procedure with a commercial colorimetric assay. Analytical criteria of these methods are identical. Regression analysis, involving 50 samples, shows an excellent correlation between hydroxyproline chromatographic (y) and colorimetric (x) procedures: y = 0.989x + 2.99 (r = 0.976). Hydroxyproline excretion was determined in urine samples from 76 women more than 5 years post-menopause. The mean hydroxyproline/creatinine ratio in this group was 19.3 +/- 5.6 mumol/mmol (range 10.6-34.7). Finally, we compared in the same urinary samples hydroxyproline excretion with pyridinoline excretion (hydroxylysylpyridinoline and lysylpyridinoline), a new marker of bone resorption. The values show a significant correlation, with r = 0.417 for hydroxylysylpyridinoline and r = 0.443 for lysylpyridinoline.

Aged↗
PubMed1984

Hydroxyproline excretion in urine of smokers and passive smokers.

Urinary hydroxyproline excretion was investigated in 125 male cigarette smokers, 194 male pipe and/or cigar smokers, and 24 male nonsmokers. Hydroxyproline excretion was calculated either as hydroxyproline/creatinine ratio or as body surface-standardized amounts of hydroxyproline excreted in urine sampled during day, during night, or over 24 hr. The association of hydroxyproline excretion with smoke uptake variables such as daily cigarette consumption, carboxyhemoglobin, serum cotinine, and nicotine in urine and with self-reported passive smoking exposure in nonsmokers was analyzed. The hydroxyproline/creatinine ratio was found to be unsuitable as a measure of hydroxyproline excretion since creatinine urine concentrations correlate inversely with smoke uptake in cigarette and pipe/cigar smokers. The amount of hydroxyproline excreted in 24-hr urine and standardized for body surface was not significantly associated with smoke uptake in pipe/cigar smokers or exposure to passive smoking in nonsmokers. In cigarette smokers the situation appeared similar, although the results were less clear-cut. The data do not favor the premise that measuring urinary hydroxyproline excretion is an accurate method of investigating a lung-damaging effect of smoking, passive smoking, or air pollution.

Adult↗
PubMed1981

tuberous sclerosis: hydroxyproline content in urine and tissues.

To elucidate the nature of an overabundance of collagen seen on microscopic examination in tuberous sclerous (TS), the hydroxyproline content in tissues and urine was determined. TS tissues of 5 patients were obtained on necropsy or plastic surgery. Urine was collected from 10 patients with TS and 19 controls. Tumors in kidney, pancreas, lung and heart but not brain contained more hydroxyproline than the surrounding tissues. In brain with the lowest hydroxyproline content, the tumor showed reduced hydroxyproline compared to normal. Collagen sheet in TS skin and shagreen patch showed the same hydroxyproline content as control skin. Th urinary hydroxyproline: creatinine ratios of the patients with TS were all higher than those in age-matched controls with or without anticonvulsant treatment except for congenital muscular dystrophy. The higher content of hydroxyproline in several affected tissues and urine of patients with TS might indicate that an increase in collagen synthesis occurs in TS.

Adolescent↗
PubMed1990

Differentiation of hydroxyproline isomers and isobars in peptides by tandem mass spectrometry.

The isomeric 3- and 4-hydroxyprolines are isobaric with the isomers leucine and isoleucine, and all four have, therefore, the same "residue mass" of 113. Secondary fragmentation processes were found that differentiate the hydroxyproline isomers from each other and from the leucines. Variants of synthetic bradykinin containing one or two hydroxyproline moieties were prepared by using manual Edman degradation and/or enzymatic methods. The tandem mass spectra of these peptides were recorded. The C-terminal wn fragment ions allow the differentiation of 4-hydroxyproline from the 3-isomer and isoleucine, while the N-terminal an ions containing 4-hydroxyproline undergo H2O elimination to differentiate this amino acid from the 3-isomer and leucine. Lys-C digestion of a mussel adhesive protein produced a set of decapeptides varying in the degree of hydroxylation of proline and tyrosine. Heterogeneity with respect to 3-hydroxyproline and 4-hydroxyproline at a certain position in these peptides was assessed by tandem mass spectrometry based on the wn ion series in the CID spectra of these Lys-C peptides. Some N-terminal ions further allow for the differentiation of these two isomeric species.

Hydroxyproline↗
PubMed1995

Determination of free hydroxyproline and proline in human serum by high-performance liquid chromatography using 4-(5,6-dimethoxy-2-phthalimidinyl)phenylsulfonyl chloride as a pre-column fluorescent labelling reagent.

A fluorescent labelling reagent, 4-(5,6-dimethoxy-2-phthalimidinyl)phenylsulfonyl chloride, was designed for the determination of amines by precolumn HPLC and was applied to the simultaneous determination of hydroxyproline and proline in serum. The reagent reacted with hydroxyproline and proline at 30 degrees C for 10 min to produce the fluorescent derivatives, which were separated on a reversed-phase column by gradient elution with phosphate buffer (1 mmol l-1, pH 7) and acetonitrile and detected by fluorescence measurement at 315 nm (excitation) and 385 nm (emission). The detection limits (signal-to-noise ratio = 3) for both hydroxyproline and proline were 10 fmol per injection. The within-day (n = 10) and day-to-day (n = 5) relative standard deviations using human sera were less than 2.16% and 2.75%, respectively, for hydroxyproline and less than 2.30% and 3.25%, respectively, for proline. The concentrations of free hydroxyproline and proline in normal human sera (n = 13) were 5.6-18.0 and 137.6-252.6 mumol l-1, respectively. The proposed method was also applied to the determination of hydroxyproline and proline in sera from patients with chronic renal failure. The mean concentrations of hydroxyproline and proline in chronic renal failure were about 2.6 and 1.6 times higher, respectively, than those in normal human sera.

Chromatography, High Pressure Liquid↗
PubMed1981

Urinary total hydroxyproline excretion in patients with Turner's syndrome and Klinefelter's syndrome.

Urinary total hydroxyproline excretion in patients with Turner's syndrome and Klinefelter's syndrome was studied. Among the patients with Turner's syndrome hydroxyproline excretion was relatively low in girls 11-14 years old and somewhat increased in 14-17 age groups. Above 17 years of age urinary total hydroxyproline excretion was significantly higher than in the control. In patients with Klinefelter's syndrome at the age below 11 and above 17 years normal hydroxyproline values were observed. In 3 sixteen-year-old boys with 47, XXY karyotype, excretion of hydroxyproline with urine was significantly lower than in the control. Relatively low values of total hydroxyproline in urine of 11-14 year-old girls with Turner's syndrome and decreased in boys with Klinefelter's syndrome result, most probably, from the absence of hormonal changes typical for the puberty. However, concentration of hydroxyproline in urine does not correlate with serum FSH and LH levels. It is not affected by the enhancement of changes in the bone system either. The presented data encourage further studies on the connective tissue biochemistry in the patients with numerical aberrations sex chromosomes.

Adolescent↗
PubMed1969

The quantitative relationship of urinary peptide hydroxyproline excretion to collagen degradation.

To determine the quantitative relationship of urinary hydroxyproline peptide excretion to collagen breakdown, known quantities of radioactive hydroxyproline peptides were administered to unlabeled animals and excertion of radioactivity in respiratory carbon dioxide, urine, and feces was measured. The major routes of excretion of collagen peptide metabolites were respiratory carbon dioxide (75%) and urine, as hydroxyproline-containing peptides (25%). Since the predominant urine hydroxyproline peptide linkage is proly-hydroxyproline, L-prolyl-L-hydroxyproline-(3)H was administered to unlabeled animals. Greater than 80% of the administered dipeptide was excreted in urine, suggesting that this peptide linkage is not hydrolyzed to a significant extent in vivo. These data suggest that urinary hydroxyproline excretion is a "fairly" sensitive indicator of collagen breakdown and can be used at the clinical level to quantitate changes in collagen breakdown.

Animals↗
PubMedDate not supplied

Elevated plasma hydroxyproline. A possible risk factor associated with connective tissue injuries during overuse.

Basal plasma hydroxyproline was measured in 104 male Navy Seal candidates 1 week into their intense physical training program, which lasted 7 weeks, and correlated to the incidence of connective tissue injuries incurred later in the training program. Eleven subjects (10.6%) were diagnosed as having connective tissue injuries. Those subjects with connective tissue injuries had a significantly higher (P less than 0.05) mean plasma hydroxyproline value (4.02 micrograms/ml) than subjects without injury (3.10 micrograms/ml). The majority of graduates (75%) had plasma hydroxyproline values less than 3.3 micrograms/ml. These graduates represented the strongest and most enduring injury-free subjects. Of the subject pool who incurred connective tissue injuries, only 27% had plasma hydroxyproline values less than 3.3 micrograms/ml. The majority of the injured subjects (73%) had plasma hydroxyproline values greater than or equal to 3.3 micrograms/ml. In conclusion, there is a relationship between initial training basal plasma hydroxyproline levels and connective tissue injuries later incurred in an intense physical training program. These data suggest that elevated plasma hydroxyproline levels may represent a risk factor associated with connective tissue injuries.

Adolescent↗
PubMed1999

Effects of Sho-saiko-to extract on liver fibrosis in relation to the changes in hydroxyproline and retinoid levels of the liver in rats.

To examine the effects of Sho-saiko-to extract on liver fibrosis, the drug was administered to rats with dimethylnitrosamine-induced liver-injury at various doses. Hydroxyproline and retinoid levels in the liver were measured as indicators of liver function. In liver-injured rats, the hydroxyproline level in the liver (957+/- 154nmol g(-1)) was about 4.16-times that found in normal liver (230+/-11 nmol g(-1)), but administration of Sho-saiko-to extract (0.75%, 1.5% or 3%) reduced the hydroxyproline level significantly (554+/-58, 356+/-51, 374+/-66nmol g(-1), P<0.01). Single administration of the active constituents of Sho-saiko-to extract, glycyrrhizin, baicalin or baicalein, decreased the hydroxyproline level significantly compared with the ordinary food group (P < 0.05), but the decrease was smaller compared with the Sho-saiko-to extract group. The liver retinoid level was higher in the Sho-saiko-to extract group than the ordinary food group and the value increased dose-dependently. A significant negative correlation, r=-0.814 (P<0.001) was detected between the hydroxyproline level and retinoid level in the liver of liver-injured rats. Significant negative correlations, r =-0.728 (P < 0.001) and r= -0.873 (P < 0.001), were also detected between the liver hydroxyproline level and the liver concentrations of the active constituents (glycyrretic acid, baicalin and baicalein) in the liver-injured rats. From these findings, it was considered that the liver concentrations of hydroxyproline and retinoid as well as the active constituents were involved in the improvement of liver fibrosis in the liver-injured rats administered Sho-saiko-to extract. Administration of Sho-saiko-to extract inhibited collagen production while an increase in retinoid level inhibited activation of Ito cells leading to inhibition and prevention of liver fibrosis.

Administration, Oral↗
PubMed1982

[The influence of diet on the urinary excretion of total, free and conjugated non-dialysable hydroxyproline in the normal adult (author's transl)].

Having established reference values for the different forms of urinary excretion of hydroxyproline on the basis of the results obtained in 12 normal subjects aged from 20 to 43 years, the authors studied the influence of three diets on the excretion of total, free and conjugated hydroxyproline. Urinary levels of total and peptide dialysable hydroxyprolines were found to be highly sensitive to the dietary collagen content, whilst free hydroxyproline increased only when the dietary collagen intake was very high. Peptide non-dialysable hydroxyproline, corresponding to peptides of molecular weight 6000-8000 was not influenced by diet. The ratio dialysable hydroxyproline/non-dialysable hydroxyproline varied from reference values if the diet was loaded with collagen. Only the ratio free hydroxyproline/non-dialysable hydroxyproline seemed to be independent of diet in the subjects studied.

Adult↗
PubMed1994

Spectroscopic study of hydroxyproline transport in rat kidney mitochondria.

Hydroxyproline uptake by rat kidney mitochondria is here first shown by monitoring the reduction of the intramitochondrial pyridine nucleotides which occurs as a result of metabolism of imported hydroxyproline via hydroxyproline oxidase and 3-hydroxy-pyrroline-5-carboxylate dehydrogenase. Widely used criteria for demonstrating the occurrence of carrier-mediated transport were applied to this process. Hydroxyproline uptake shows saturation features (Km and Vmax values, measured at 20 degrees C and at pH 7.20, were found to be about 1.4 mM and 5 nmoles/min x mg mitochondrial protein, respectively) and proves to be inhibited by the impermeable compound phenylsuccinate, but insensitive to externally added methylglutamate. Difference found in the Km and Vmax values, a different inhibitor sensitivity and the failure of hydroxyproline to cause efflux of glutamate from the mitochondria show that hydroxyproline enters mitochondria by means of a translocator different from those which transport proline.

Animals↗
PubMed1978

[Analysis of the hydroxyproline containing serum proteins in connective tissue diseases (author's transl)].

The serum proteins were fractionated on Sephadex G 200, their hydroxyproline content determined. Three protein peaks (I-III) containing different hydroxyproline concentrations could be separated. In connective tissue disorders accompanied by increased collagen synthesis or collagen degradation, an elevation of hydroxyproline was found in peak II. An increase of hydroxyproline always was associated with an increase of the serum proteins in the same fractions. Hydroxyproline serum levels above normal obviously are due to a certain capacity of the serum proteins binding free hydroxyproline and collagen metabolites.

Blood Proteins↗