Serum markers of bone metabolism in multiple myeloma: prognostic value of the carboxy-terminal telopeptide of type I collagen (ICTP)

This study was performed to evaluate the prognostic significance of serum markers of bone and collagen metabolism in multiple myeloma. Serum C-terminal telopeptide of type I collagen (ICTP) reflects degradation of bone, whereas serum osteocalcin, together with serum C-terminal propeptide of procollagen type I (PICP) and serum bone-specific alkaline phosphatase (bAP) reflect synthesis of bone matrix. The N-terminal propeptide of procollagen type III (PIIINP) in serum reflects synthesis of type III collagen. We analysed frozen sera from 109 patients with newly diagnosed multiple myeloma. Serum ICTP was elevated (>5.0μg/l) in most patients (median 6.6 μg/l, range 1.4–29.4 μg/l). Serum PIIINP was elevated (>4.2μg/l) in 46% (median 4.0 μg/l, range 1.4–20.1 μg/l). Serum PICP was generally within the reference limits, whereas serum osteocalcin and serum bAP were elevated in 19% and 37%, respectively. Serum ICTP correlated with serum PIIINP, serum β₂-microglobulin (β₂m), serum calcium, performance status, and stage. In univariate analysis, the test variables serum ICTP ( P =0.026) and serum osteocalcin ( P =0.036) were found to be of prognostic value, but PIIINP, PICP, or bAP in serum were not. Serum ICTP and serum β₂m had a similar prognostic value. In multivariate analysis, serum calcium showed the highest prognostic significance, and serum β₂m was the only other variable of independent prognostic value. However, in normocalcaemic patients, serum ICTP showed the highest prognostic significance, followed by serum osteocalcin. Thus, the serum levels of ICTP and osteocalcin seem related to bone turnover and calcium metabolism, and provide further information about myeloma activity, particularly in normocalcaemic patients.     

Prognostic value of serum markers of bone metabolism in untreated multiple myeloma patients

Bone involvement is a central feature of multiple myeloma (MM). We investigated whether serum markers of osteoblastic and osteoclastic activity correlate with the presence of bone disease and survival in 313 MM patients enrolled in a phase III trial (E9486). Five markers were measured, including osteocalcin (OC), carboxy-terminal propeptide of type I collagen (PICP), bone alkaline phosphatase (BAP), carboxy-terminal telopeptide of type I collagen (ICTP) and tartrate-resistant acid phosphatase (TRAP). We analysed the relationship between serum levels of these markers and the presence of bone manifestations, and survival. Serum levels of ICTP and BAP correlated significantly with bone pain, lesions and fractures. Serum level of ICTP was also higher in stage II-III compared with stage I disease. The serum level of ICTP was significantly associated with shortened survival in the univariate analysis. The median survival times were 4.1 and 3.5 years for low and high ICTP respectively (P = 0.02). There was a strong relationship between ICTP and beta-2-micrgolobulin (B2M). ICTP stands out as a significant marker of bone disease. Incorporation of these markers into clinical trials assessing the use of bisphosphonates in MM is needed to determine whether they might serve as indicators of effectiveness of these agents.     

Bone resorption parameters [carboxy-terminal telopeptide of type-I collagen (ICTP), amino-terminal collagen type-I telopeptide (NTx), and deoxypyridinoline (Dpd)] in MGUS and multiple myeloma

Skeletal morbidity is a major problem in multiple myeloma. Histomorphometric studies have demonstrated that increased bone resorption can be present even in the absence of radiographic abnormalities. To overcome diagnostic problems in estimating the activity of bone resorption, new laboratory parameters that reflect bone metabolism accurately are urgently needed. We analyzed three parameters of osteoclastic bone destruction, i.e. deoxypyridinoline (Dpd) and amino-terminal collagen type-I telopeptide (NTx) in urine and carboxy-terminal telopeptide of type-I collagen (ICTP) in serum, of 75 patients with multiple myeloma (n = 57) or monoclonal gammopathy of undetermined significance (MGUS, n = 18) by ELISA/RIA techniques. Serum ICTP and urinary Dpd levels increased parallel to the stage of the disease and differed significantly (P < 0.001 for ICTP and P = 0.03 for Dpd) between MGUS, myeloma stage I, and myeloma in stages II and III according to Salmon and Durie. ICTP and Dpd were significantly elevated in patients with multiple myeloma in stage I compared to individuals with MGUS, while no significant difference was found for NTx. In this first study comparing the prognostic relevance of ICTP, NTx, and Dpd in multiple myeloma patients, ICTP was found to be a prognostic factor for overall survival in the Kaplan-Meier analysis (log-rank test: P < 0.03). Urinary NTx showed borderline significance (P = 0.05), and Dpd had no prognostic value in the survival analysis. Our data show that serum ICTP and urinary Dpd levels increase in parallel to advanced disease stages, and gives the first report on a significant difference in the bone resorption parameters ICTP and Dpd between individuals with MGUS and patients with myeloma in stage I. Among the bone resorption parameters studied serum ICTP was found to be the best prognostic factor for survival in multiple myeloma.     

Increased degradation of type I collagen in patients with inflammatory bowel disease.

To assess the mechanisms of osteopenia in inflammatory bowel disease (IBD), the serum markers of bone formation (osteocalcin and carboxyterminal propeptide of type I procollagen (PICP)) and bone degradation (carboxyterminal telopeptide of type I collagen (ICTP)), the bone mineral density (BMD) of the lumbar spine and the proximal femur and calcium intake of 150 unselected IBD patients and 73 healthy controls were investigated. The patients had higher ICTP values (3.69 (SD 1.40) microgram/l) than the healthy controls (3.25 (1.00) microgram/l, p = 0.035), but no differences in serum PICP and osteocalcin between these groups were detected. In the patients, the ICTP, PICP, and osteocalcin values did not have any significant correlation with BMD, but the patients with ICTP values above 3.6 microgram/l had significantly lower Z scores than those with lower ICTP. In the controls, however, a positive correlation between serum ICTP and BMD was found. The ulcerative colitis patients with total colitis had higher values of ICTP (3.96 (1.58) microgram/l) than those with a left sided disease (3.04 (0.86) micrograms/l, p = 0.009). The patients with a history of clinically active disease (n = 20) had higher ICTP (4.58 (1.55) microgram/l) and osteocalcin (12.56 (5.64) microgram/l) values than the patients (n = 130) with quiescent disease (ICTP 3.56 (1.33), p = 0.002, and osteocalcin 9.76 (3.62), p = 0.017). Increased serum osteocalcin, PICP, and ICTP concentrations and reduced BMD Z scores were found in a subgroup of Crohn's disease patients with a history of an active disease (n = 11). Raised serum ICTP and normal values of osteocalcin and PICP in IBD patients show increased breakdown of type I collagen without a compensatory increase in its synthesis suggesting an increased rate of bone degradation as a probable mechanism for osteopenia in IBD. Raised ICTP values are related to reduced bone mineral densities.     

Osteoclastic function is accelerated in male patients with type 2 diabetes mellitus: the preventive role of osteoclastogenesis inhibitory factor/osteoprotegerin (OCIF/OPG) on the decrease of bone mineral density

To clarify the pathogenesis of altered bone metabolism in diabetic state and its underlying mechanisms, the bone mineral content and fasting levels of serum intact parathyroid hormone (i-PTH), intact osteocalcin (i-OC), tartrate-resistant acid phosphatase (TRAP) and osteoclastgenesis inhibitory factor/osteoprotegerin (OCIF/OPG) were measured in male type 2 diabetic patients and their age-matched controls. In addition, urine levels of osteoclastic markers, C-telopeptide of type I collagen (CTx), deoxypyridinoline (DPD), and N-telopeptide of type I collagen (NTx) were simultaneously determined. Serum levels of i-PTH and i-OC in diabetic patients were significantly lower than those in the controls. Conversely, serum concentrations of TRAP were significantly elevated in diabetic patients. However, no clear correlation was observed between serum i-OC and TRAP. It was also observed that urinary excretion of CTx, DPD, and NTx was significantly increased in the diabetics as compared with the controls. Unexpectedly, serum levels of OCIF/OPG tended to be higher in the diabetic group, and these values exhibited a significantly positive correlation with those of serum TRAP. There was found a significantly negative correlation between serum TRAP and bone mineral density (BMD) and also between serum OCIF/OPG and bone mineral density. It seems probable that OCIF/OPG has a suppressive role on the increased bone resorption to prevent further loss of the skeletal bone mass in type 2 diabetic patients.     

Abnormal bone turnover in monoclonal gammopathy of undetermined significance: analyses of type I collagen telopeptide,osteocalcin, bone-specific alkaline phosphatase and propeptides of type I and type III procollagens

Abstract: The main difference between monoclonal gammopathy of undetermined significance (MGUS) and multiple myeloma (MM) is the presence of lytic bone destructions in the latter. About 20% of MGUS patients develop MM, and histomorphometric studies have shown disturbed bone turnover rates in some of these patients. This study was performed in order to evaluate whether serum analyses of the C-terminal telopeptide of type I collagen (ICTP), as a reflector of bone degradation, and of osteocalcin, bone-specific alkaline phosphatase (bAP) and the C-terminal propeptide of type I procollagen (PICP), as markers of bone formation, might give information on disturbancies of bone metabolism in MGUS. Furthermore, serum N-terminal propeptide of procollagen III (PIIINP) might give information on disturbances in collagen III metabolism in the bone marrow. In the 35 patients examined, serum ICTP was elevated in 12 patients (34%), serum PIIINP elevated in 6 patients (17%), serum osteocalcin elevated in 11 patients (31%), serum bAP elevated in 6 patients (17%), and serum PICP elevated in 4 patients (11%). Serum ICTP correlated significantly with PIIINP (r=0.72, p<0.001), and with serum osteocalcin (r=0.57, p<0.001) and serum bAP (r=0.51, p=0.002). These findings indicate disturbancies of bone turnover and affected collagen metabolism in some MGUS patients. Follow-up observation may reveal any prognostic value of these findings.     

Comparison of five biochemical markers of bone resorption in multiple myeloma: elevated pre-treatment levels of S-ICTP and U-Ntx are predictive for early progression of the bone disease during standard chemotherapy

Increased osteoclastic bone resorption is the major causal factor of bone disease in multiple myeloma. Recently, non-invasive methods have been developed for the estimation of bone resorptive activity. To evaluate the biological sensitivity and clinical usefulness of five biochemical assays for measuring the C-terminal telopeptide of collagen I (ICTP) in serum (beta-Crosslaps ELISA and ICTP radioimmunoassay) and urinary creatinine-adjusted excretions of pyridinoline (PYR), deoxypyridinoline (DPD) and N-terminal telopeptide of collagen I (Ntx), we performed a study of 34 consecutive newly diagnosed myeloma patients. Serum and morning-fasting, second-void urine samples were taken before the start of treatment. In total, 40 age- and sex-adjusted healthy individuals served as controls. Results were expressed as Z-scores. All test variables were highly significantly elevated in the patients (P < 0.001). Serum (S)-ICTP was elevated (Z-score > 2) in most patients (85%) and showed significantly higher Z-score values than the other markers. S-ICTP remained more sensitive than the urinary assays when patients with impaired renal function were excluded from analysis. S-ICTP and the urinary metabolites correlated significantly with skeletal morbidity. S-beta-Crosslaps correlated with the bone morbidity only when patients with renal insufficiency were excluded from the analysis. High levels of S-ICTP and urinary (U)-Ntx correlated with an increased risk for early progression of bone lesions during standard melphalan-prednisolone treatment. U-Ntx and S-ICTP are sensitive tools for estimating the increased bone resorption in multiple myeloma and are clinically useful for identifying patients with increased risk of early progression of bone disease.     

Biochemical markers of bone turnover in diagnosis of myeloma bone disease

This study was designed to explore the value of markers of bone turnover, macrophage inflammatory protein-1alpha (MIP-1alpha), and osteopontin (OPN) in the diagnosis of myeloma bone disease. Twenty-five patients with newly diagnosed and untreated multiple myeloma (MM), and 22 age-, sex-, and bone mineral density-matched control subjects were enrolled. Levels of MIP-1alpha, OPN, carboxy-terminal telopeptide of Type-1 collagen (C-telopeptide or Ctx), deoxypyridinoline (DPD), Type-1 collagen propeptide (T1Pro), and bone-specific alkaline phosphatase (BALP) were assessed in both groups. Twenty-two of the patients had bone involvement documented by skeletal surveys and lumbar spinal magnetic resonance imaging. Levels of serum Ctx, OPN, MIP-1alpha, and urine DPD were significantly higher in MM patients with bone disease than in controls (P<0.01). Serum Ctx levels were elevated in 90.9% of patients with MM and 40.9% of controls (P<0.001). Urine DPD levels were elevated in 90.4% of the patients and 31.8% of the controls (P<0.001). The serum OPN and MIP-1alpha levels of the patients were significantly correlated with beta2-microglobulin and lactate dehydrogenase levels (P<0.05). Our study indicates that Ctx and DPD are sensitive markers of bone disease in MM, and higher than normal values suggest presence of bone disease rather than benign osteoporosis in MM. The utility of OPN and MIP-1alpha needs to be further investigated.     

Serum concentrations of interleukin 6, osteocalcin, intact parathyroid hormone, and markers of bone resorption in patients with rheumatoid arthritis.

OBJECTIVE: To analyze serum concentrations of interleukin 6 (IL-6), osteocalcin, intact parathyroid hormone (PTH), and type 1 collagen carboxyterminal telopeptide (ICTP) as well as the urinary concentrations of crosslinked N-telopeptides of type 1 collagen (NTx) and deoxypyridinoline (Dpd) in patients with rheumatoid arthritis (RA) to investigate their role in the etiology of the osteopenia in this disease. METHODS: Using ELISA and radioimmunoassay methods, we estimated serum concentrations of IL-6, osteocalcin, ICTP, intact PTH, and spot urine concentrations of NTx and Dpd in 25 female patients with active RA, 25 female patients with suppressed disease, and 25 age matched healthy female controls. RESULTS: Patients with active RA had significantly higher (p < 0.001) concentrations of IL-6 (94.0+/-12.1 pg/ml) compared to patients with suppressed disease (13.2+/-0.8 pg/ml) and healthy controls (12.3+/-0.8 pg/ml). Serum osteocalcin was significantly lower (p < 0.001) in patients with active RA (1.9+/-0.2 ng/ml) compared to patients with suppressed disease (2.7+/-0.2 ng/ml) and the controls (2.9+/-0.2 ng/ml). Similarly, serum intact PTH was significantly lower (p < 0.001) in patients with active disease (29.9+/-1.5 ng/ml) compared to patients with suppressed RA (38.0+/-1.6 ng/ml) and controls (49.8+/-2.4 ng/ml). Serum ICTP was also significantly higher (p < 0.01) in patients with active RA (9.5+/-0.3 microg/l) versus patients with suppressed disease (4.1+/-0.2 microg/l) and controls (3.4+/-0.2 microg/l). In patients with active disease, spot urine concentrations of NTx (123.1+/-5.1 nmol bone collagen equivalent/mmol creatinine) and Dpd (15.1+/-0.7 nmol/mmol creatinine) were significantly higher (p < 0.001) than in patients with suppressed disease (58.4+/-2.5 nmol bone collagen equivalent/mmol creatinine and 10.1+/-0.5 nmol/mmol creatinine, respectively) and healthy controls (53.4+/-2.1 nmol bone collagen equivalent/mmol creatinine and 9.7+/-0.5 nmol/mmol creatinine, respectively). There were no significant correlations between serum IL-6 and serum ICTP (r = 0.2357, p = 0.257) or urinary NTx (r = 0.1436, p = 0.494) or between serum intact PTH and ICTP (r = 0.0206, p = 0.922) in patients with active RA. CONCLUSION: There are no significant correlations between bone resorption markers and serum IL-6 and intact PTH in patients with RA.     

Serum osteocalcin concentrations in patients with multiple myeloma--correlation with disease stage and survival.

Multiple myeloma affects bone, and enhanced bone resorption is a characteristic finding. In the present study the serum concentration of osteocalcin, serum bone gla-protein, which is a protein specific for bone turnover and reflects osteoblast activity, was analysed at diagnosis in 48 patients with multiple myeloma. At that time there was a significant relationship between disease stage (Durie-Salmon) and osteocalcin levels, lower levels being found in patients with more advanced disease. No relationship was found between osteocalcin and serum calcium levels. To date, 33 patients have died. There was a significant correlation between initial osteocalcin levels and patient survival. These findings suggest that serum osteocalcin could be a marker of prognostic significance for survival in multiple myeloma.     

The role of markers of bone remodeling in multiple myeloma

Osteolytic bone disease is a frequent complication of multiple myeloma, resulting in skeletal complications that are a significant cause of morbidity and mortality. A characteristic feature of myeloma bone disease is that the lesions rarely heal and bone scans are often negative in myeloma patients who have extensive lytic lesions, offering very little in the follow-up of bone disease. X-rays are also of limited value in monitoring bone destruction during anti-myeloma or anti-resorptive treatment. Biochemical markers of bone turnover, such as N- and C-terminal cross-linking telopeptide of type I collagen (NTX, CTX/ICTP, respectively), and newer ones such as the tartrate resistant acid phosphatase isoform 5b, provide information on bone dynamics that in turn may reflect disease activity in bone. Several studies have shown bone markers to be elevated in myeloma patients and reflect the extent of bone disease, while in some of them bone resorption markers correlate with survival. These markers may also be helpful in identifying those patients likely to respond to bisphosphonate treatment, and monitoring the effectiveness of bisphosphonate therapy in the management of myeloma bone disease. This review attempts to summarize the existing data for the role of markers of bone remodeling in assessing the extent of bone destruction in myeloma and monitoring bone turnover during specific anti-myeloma treatment. We also discuss some novel markers that may be of particular interest in the near future.     

Biochemical markers of bone disease in asymptomatic early stage multiple myeloma. A study on their role in identifying high risk patients

BACKGROUND AND OBJECTIVES: Skeletal involvement is typical of multiple myeloma (MM) and its occurrence increases with the progression of the disease. We performed a study to evaluate the clinical importance of osteocalcin (bone gla-protein, BGP) and bone alkaline phosphatase (b-AP) as indices of osteoblastic activity, and deoxypyridoline (DPD) as a marker of bone resorption. DESIGN AND METHODS: Fifty-two MM patients, 39 patients with monoclonal gammopathy of undetermined significance (MGUS), and 30 normal controls entered the study. Of the 52 MM patients, 10 showed lytic lesions at standard X-rays and 42 did not; 21 were untreated and 31 had been treated with chemotherapy (combined with bisphophonates in 15). Of these last, 12 had progressive disease and 19 were in plateau phase. RESULTS: DPD levels were higher in MM patients than in patients with MGUS or healthy controls (p = 0.0001 and p = 0.0008, respectively). No statistical differences were seen between patients with MGUS and healthy controls. BGP serum levels were significantly lower in MM patients than in MGUS patients (p = 0.001) or healthy controls (p = 0.001). b-AP was significantly higher in MGUS patients than in MM patients (p = 0.04). Biochemical parameters were analyzed in a continuous fashion and after dichotomization into low and high values with respect to normal ones. Abnormal high values of DPD showed statistically significant correlations with presence of osteolysis (p = 0.008), advanced stage (p = 0.03) and abnormal beta2-microglobulin (beta2M) values (p = 0.03), while DPD as a continuous variable correlated significantly only with the presence of osteolysis (p = 0.02). In contrast, neither BGP nor b-AP showed statistical correlations with the presence of lytic lesions, or with other clinical or laboratory parameters. In 15 patients followed with serial controls, modifications of DPD levels reflected bone disease status well. Of the 42 patients without radiologic evidence of skeletal lesions, 15 had abnormal DPD values. Spinal magnetic resonance imaging (MRI) showed initial lytic lesions in 10 of them. INTERPRETATION AND CONCLUSIONS: Biochemical markers of bone metabolism are useful in evaluating and monitoring skeletal involvement in MM patients. They may help clinicians to identify: 1) from among patients without radiologic evidence of lytic lesions, those who deserve more accurate radiologic examinations (namely MRI); 2) from among asymptomatic patients, and in association with spinal MRI, those patients at higher risk of progression who might benefit from early treatment.     

Clinical usefulness of serum pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (ICTP) for diagnosis of bone metastasis in patients with primary lung cancer]

Pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (ICTP) is a metabolite of type I collagen representing more than 90% of organic substances in bone and expected to be one of the markers reflecting bone resorption. We measured ICTP to evaluate its clinical usefulness for diagnosis of bone metastasis from primary lung cancer by comparing serum alkaline phosphatase (ALP), a bone formation marker, which was simultaneously measured. In addition, using the receiver operating characteristic (ROC) curve, we calculated the cut-off value of ICTP from which the diagnostic accuracy serves as best. The subjects were 87 patients with primary lung cancer including 21 patients with bone metastasis. ICTP was significantly higher in patients with bone metastasis than in the group without bone metastasis. On the other hand, in the serum ALP there was no significant difference between the two group. The result suggested that measurement of serum ICTP is worthwhile as a diagnosis method of bone metastasis from lung cancer. The calculated cut-off value was 6.4 ng/ml, higher than the 4.5 ng/ml indicated by the appending document which was from patients with lung, breast and prostate cancer. It is possible that the reason for the style of bone metastasis from lung cancer is mainly a osteolytic process.     

Bone remodelling markers and serum cytokines in patients with hyperthyroidism

OBJECTIVE: This study was designed in order to evaluate bone turnover with bone formation and resorption markers in hyperthyroidism and its possible relationship with serum cytokines interleukin 6 (IL-6) and tumour necrosis-alpha (TNF-alpha), levels of thyroid hormones and thyroid autoantibodies. DESIGN AND PATIENTS: Twenty-six hyperthyroid patients including nine with Graves' disease, 14 with toxic multi-nodular disease and three toxic adenoma were studied. Twenty normal subjects served as the control group. MEASUREMENTS: Serum calcium, phosphorus, total and bone-specific alkaline phosphatase, procollagen type 1-C peptide (PICP), osteocalcin, IL-6 and TNF-alpha measurements were performed and deoxypyridinoline (free DPD), calcium, phosphorus and creatinine levels were measured in fasting morning urine specimens of all hyperthyroid patients and all controls. Also, serum total and free T3 and T4 and TSH were analysed and thyroid antiperoxidase and antithyroglobulin antibodies were determined in sera of hyperthyroid patients. Patients with hyperthyroidism received propylthiouracil treatment until the achievement of euthyroidism and then serum cytokine levels were remeasured. RESULTS: Mean serum values of osteocalcin, total and bone-specific alkaline phosphatase were all significantly higher in hyperthyroid patients than in normal controls. PICP levels were not significantly different between these two groups. Urinary deoxypyridinoline levels were markedly elevated in hyperthyroid patients compared to the control group. There was a significant positive correlation between urinary free DPD levels and serum free T3, free T4 and T4 levels. Serum free T4 levels also correlated with urinary calcium levels. Serum IL-6 values were significantly higher in hyperthyroid patients compared to control group. TNF-alpha levels were slightly lower in patients with hyperthyroidism. No significant correlation was found between bone remodelling markers and serum cytokines. Serum Il-6 levels were correlated positively with age. After the treatment period both IL-6 and TNF-alpha returned to levels comparable with euthyroid controls. CONCLUSION: Bone turnover is increased in favour of resorption and the rate of resorption is associated with the levels of thyroid hormones in hyperthyroidism. The increase in the levels of serum IL-6 in hyperthyroidism is not related directly with bone resorption seen in hyperthyroidism.     

Serum osteocalcin concentrations in Paget's disease of bone

Total body scintiscans, serum alkaline phosphatase estimations, and serum osteocalcin radioimmunoassays were performed in 49 consecutive patients with Paget's disease of bone. Eleven were receiving calcitonin (salmon synthetic) at the time of the study. The serum alkaline phosphatase activities were elevated in all but one patient, with the highest value almost 50 times the upper limit of the reference range. Serum osteocalcin concentrations were elevated in 53% of patients and normal in the rest. The highest serum osteocalcin value was 4.2 times the upper limit of the reference range. The correlation coefficient between the extent of skeletal involvement and serum osteocalcin level was .70, while that between skeletal involvement and serum alkaline phosphatase level was .55. In spite of the better correlation between bone scintiscans and serum osteocalcin level, osteocalcin measurements are diagnostically less useful than serum alkaline phosphatase estimations in patients with Paget's disease of bone.     

胰岛素、胰岛素原对胰岛素抵抗状态下HepG2细胞PAI-1分泌的影响

目的研究胰岛素、胰岛素原对胰岛素抵抗状态下ＨｅｐＧ２细胞ＰＡＩ１分泌的影响。方法选择在合成ＰＡＩ１方面与肝细胞相似的ＨｅｐＧ２细胞，以高浓度胰岛素诱导胰岛素抵抗后，分别用生理浓度的胰岛素、胰岛素原刺激２４小时，以观察胰岛素抵抗状态下ＰＡＩ１活性的变化。结果基础状态下胰岛素抵抗ＨｅｐＧ２细胞与非胰岛素抵抗ＨｅｐＧ２细胞相比，ＰＡＩ１活性差异不明显；胰岛素、胰岛素原刺激后，胰岛素抵抗ＨｅｐＧ２细胞ＰＡＩ１活性明显高于非胰岛素抵抗ＨｅｐＧ２细胞。当培液中同时加入１０－４Ｍ二甲双胍后，胰岛素、胰岛素原介导的ＰＡＩ１过量分泌得到明显抑制。结论在胰岛素抵抗状态下，胰岛素、胰岛素原刺激后ＨｅｐＧ２细胞ＰＡＩ１活性明显增加，而二甲双胍可明显抑制此现象。     

Biochemical markers of bone turnover as tools in the evaluation of skeletal involvement in patients with type 1 Gaucher disease

Gaucher disease is caused by the inherited deficiency of glucocerebrosidase, a lysosomal enzyme responsible for the cleavage of glucosylceramide. In addition to organomegaly and hematological abnormalities, type 1 (nonneuronopathic) disease is characterized by insidiously progressive and often severe skeletal involvement. We investigated the applications of biochemical markers of bone turnover in the evaluation of skeletal lesions in type 1 Gaucher disease patients. Serum osteocalcin, a marker of osteoblastic bone formation, and type I collagen C-terminal telopeptide, a marker of osteoclastic bone resorption, were measured in 16 type 1 Gaucher disease patients and in 29 age-matched controls. Our results indicate a significant decrease of both osteocalcin (11.13 +/- 2.27 ng/ml) and type I collagen C-terminal telopeptide (3617.62 +/- 536.69 ng/ml) values in patients with Gaucher disease, compared to the unaffected controls (38.67+/-6.24 ng/ml and 6808.57 ng/ml +/- 865.66, respectively). These low values were observed in all patients, irrespective of their age, indicating a marked failure of both osteoblastic and osteoclastic functions in Gaucher disease. Significant differences in the mean serum values of biochemical bone turnover markers were found in different evolutional stages of bone involvement. We conclude that measurement of serum biochemical markers of bone turnover can be used as an auxiliary tool in the diagnosis, staging, and monitoring the skeletal lesions in Gaucher disease, in conjunction with imaging methods and bone densitometry measurements.     

Serum osteocalcin in rheumatoid arthritis and other inflammatory arthritides: relation between inflammatory activity and the effect of glucocorticoids and remission inducing drugs.

Osteocalcin, a vitamin K dependent protein synthesised by osteoblasts, was measured in serum by radioimmunoassay in patients with rheumatoid arthritis (n = 36) and seronegative spondyloarthropathies (n = 23). The serum osteocalcin levels were decreased in both patient groups compared with the levels measured in age and sex matched healthy controls. We found no relation between serum osteocalcin and the disease duration or inflammatory activity of the patients who were without drug treatment at the first examination. After administration of glucocorticoids (20 mg prednisolone a day) circulating osteocalcin decreased significantly after one week of treatment. During gradual reduction of the steroid dosage osteocalcin returned to pretreatment values. Treatment with non-steroidal anti-inflammatory drugs (NSAIDs) did not influence circulating osteocalcin. During treatment with chloroquine or penicillamine serum osteocalcin increased significantly, concomitant with a reduction of the acute phase reactants. Controversy persists about the abnormality of bone turnover in rheumatic diseases, but our data suggest that the overall bone turnover is decreased in patients with rheumatoid arthritis and other inflammatory arthritides.     

Assessment of bone metabolism in obese women

OBJECTIVE: To evaluate the bone metabolism in obese women by the estimation of selected markers of bone formation. METHODS: The concentration of plasma parathyroid hormone (PTH) and selected markers of bone formation [osteocalcin (BGP) in plasma, carboxyterminal propeptide of type I procollagen (PICP) and alkaline phosphatase (AP) activity in blood serum] and bone resorption [cross-linked carboxyterminal telopeptide of type I collagen (ICTP) in blood serum and urinary excretion of calcium (Ca)] in 18 extremely obese women (BMI>40 kg/m2) with android phenotype (WHR>0.8) and in 20 healthy women with normal body weight. The age range of all subjects was 25 to 42 years (mean: 36.82 + 3.95). RESULTS: All obese women showed significantly increased concentration of plasma PTH, BGP and serum PICP, ICTP and elevated urinary excretion of Ca. CONCLUSIONS: The obtained results show that in extremely obese women with android phenotype bone metabolism disturbances may occur pointing at increased bone formation and resorption.     

Serum osteocalcin levels in diabetes mellitus: analysis of the type of diabetes and microvascular complications

Summary Recent studies indicate that serum levels of osteocalcin, a 49-aminoacid bone matrix protein, are a biochemical marker of bone formation. In order to study bone metabolism in diabetes mellitus, in 28 patients with Type 1 (insulin-dependent) diabetes mellitus, in 38 patients with Type 2 (non-insulin-dependent) diabetes mellitus and two control groups, matched for Type 1 and Type 2 diabetic patients, respectively, serum levels of osteocalcin, parathyroid hormone and 25 hydroxy vitamin D were measured by radioimmunoassay. Whereas in Type 1 diabetic patients and control subjects serum levels of osteocalcin and 25 hydroxy vitamin D were not statistically different, serum osteocalcin and 25 hydroxy vitamin D levels were significantly decreased in Type 2 diabetic patients when compared with corresponding control subjects (p<0.03 and p<0.001, respectively). Independent of the type of diabetes, serum parathyroid hormone levels were comparable in diabetic patients and matched control subjects. Serum osteocalcin levels were significantly lower in Type 1 diabetic patients with retinopathy and/or proteinuria than in Type 1 diabetic patients without microangiopathy (p<0.05). Whereas serum parathyroid hormone levels in Type 2 diabetic patients with retinopathy and/or proteinuria were significantly increased (p<0.02), 25 hydroxy vitamin D levels were decreased (p<0.02) when compared with Type 2 diabetic patients without microangiopathy. Our data give evidence of a vitamin D deficiency and a decreased bone formation in patients with Type 2 diabetes mellitus. In Type 1 diabetes mellitus bone formation as reflected by serum osteocalcin levels is influenced by the presence or absence of microangiopathic complications.