Urinary hydroxyproline and plasma mucoprotein as an indication of the presence of bone metastases

Urinary Hydroxyproline in Multiple Myeloma: Correlation with Clinical Stages and Bone Disease

Twenty-four-hour urinary hydroxyproline excretion (HOP) (normal values: 6–22 mg/day/m2) was measured by the Hypronosticon test in 50 untreated patients with plasma cell myeloma. At diagnosis, HOP was elevated in 36 of 50 patients (72 %) with a mean value of 35.9 mg/day/m2. Extent of bone lesions and clinical stage were accurately assessed in all patients. Higher HOP values were found in patients with a higher degree of bone lesions (multiple lytic areas and/or destruction of skeletal segments). According to clinical stages, HOP was very elevated only in stage III (mean value: 43.7); in stages I and II the mean value (25.2) was just above the normal range. Our data indicate that HOP in multiple myeloma at diagnosis is closely related to the extension of skeletal lesions and that during the clinical course it may be useful in the follow-up of bone disease.

Hydroxyproline and Bone Metastases for Breast Cancer

The urinary excretion of Hydroxyproline (OH-P), evaluated as OH-P/creatinine ratio, has been examined in the follow up of 142 breast cancer patients. The mean value obtained in the women with bone lytic lesions, prior to treatment, was 5.3 ± 1.9 (min. 3, max. 9), whereas in the women without bone metastases it was 1.7 + 0.5 (min. 0.6, max. 3), similar to the control group. The patients affected by osteoplastic lesions had a normal OH-P/creatinine ratio. The highest values of OH-P/creatinine ratio were found in women with bone marrow infiltration, ascertained by bone needle biopsy. In the group of patients with bone lytic metastases, a good correlation between changes of OH-P/creatinine ratio and response to hormonal or chemotherapeutic treatment has been observed. Therefore the OH-P/creatinine ratio could be effectively useful, with other clinical parameters, in the follow up of breast cancer patients.

The postabsorptive hydroxyproline in the long-term evaluation of patients with breast cancer

The postabsorptive urinary hydroxyproline excretion test (Spot-HYPRO) was evaluated for its usefulness in reflecting the presence or absence of bone metastasis in 75 women with breast cancer. A comparison was made between the Spot-HYPRO values and bone disease, as documented by bone scanning supported by skeletal x-rays. Breast cancer patients with skeletal metastasis had 3-4-fold elevations in Spot-HYPRO above the control values (P less than 0.001). Mild elevations were noted in breast cancer patients without skeletal metastasis (P less than 0.025). Thirty patients received serial Spot-HYPRO and bone scans for 6 to 48 months (average, 24 months). There was a 90% correlation between changes in Spot-HYPRO and simultaneous changes on bone scan. Elevations in Spot-HYPRO preceded changes found on bone scan by an average of 3 months. The authors conclude that the Spot-HYPRO is a simple, convenient, and accurate method of documenting and following bone metastasis in patients with breast cancer.

Study of hydroxyproline excretion in patients with prostatic cancer

Urinary hydroxproline concentrations were measured in 36 prostatic cancer patients. Metastases were ruled out by radiography in 24, and confirmed in 12 cases.14 patients with no malignant disease served as controls. In patients with no metastases excretion was similar to that in the controls, in some of them it was higher. In the patients with higher values the studies were repeated six months later: deposits were found in all cases but one. In the group in which deposits had been present at the outset the values of the untreated patients were significantly higher than in the controls, whereas in the treated patients no consistent values were found.

[The action of calcium on the step of collagen metabolism, catalyzed by procollagen-proline hydroxylase]

Calcium effects on procollagen-proline-hydroxylase activity of chick embryo tibias was studied. Serial preincubation of the natural substrate, the enzymatic preparation or the mixture of both with and without calcium showed that calcium decreased procollagen-prolin-hydroxylase affinity for procollagen, decreased the maximum velocity of the reaction by binding to the substrate and by increasing the thermosensitivity of the enzyme -- substrate complex. Calcium could also increase the maximum velocity by dissociation of an enzyme -- inhibitor ligand complex. The resulting decrease of the overall reaction rate has been discussed in the context of the relationship between collagen metabolism and calcium fixation during calcification.