Serum markers of bone formation in parenteral nutrition patients

Whole-blood-free choline and choline metabolites in infants who require chronic parenteral nutrition therapy

BACKGROUND AND AIM

Choline deficiency is associated with hepatic dysfunction. Parenteral nutrition (PN) and lipid emulsions contain phosphatidylcholine (PtdCho) but insignificant free choline (FCho). PtdCho is sequentially degraded to glycerolphosphocholine (GPCho), phosphocholine (PCho), and finally to FCho. Biosynthesis of FCho may be insufficient during PN therapy. The aim of the study was to examine the status of FCho and related metabolites in infants on prolonged (> or =4 weeks) PN.

METHODS

Whole blood concentrations of FCho, PtdCho, GPCho, and PCho were measured and compared in infants on PN and infants on enteral feeds (controls).

RESULTS

Infants on PN (n = 14) had higher birth weight but same postnatal age as controls (n = 14) (mean +/- standard deviation) 8.3 +/- 3.9 versus 7.4 +/- 3.6 weeks. Parenteral nutrition was associated with increased PtdCho 1761 +/- 452 versus 1471 +/- 221 nmol/mL, P = 0.04. Mean whole blood FCho, GPCho, and PCho concentrations did not differ significantly in PN versus controls: 40.0 +/- 15.4 versus 50.8 +/- 49.7, 16.4 +/- 14.5 versus 25.2 +/- 29.3, and 15.3 +/- 13.5 versus 22.0 +/- 14.8 nmol/mL, respectively. However, PCho was positively correlated with GPCho in controls (r = 0.91, P < 0.01) but not PN (r = 0.24, P = NS), and infants receiving >90% of daily energy intake from PN (n = 6) had decreased PCho, 5.7 +/- 4.1 nmol/mL, compared with those receiving <90% of daily energy intake (n = 8) 22.5 +/- 13.7 nmol/mL, P < 0.05, and controls, 22.0 +/- 14.8 nmol/mL, P < 0.01.

CONCLUSIONS

Decreased whole-blood concentrations of choline suggest possible evidence of choline deficiency as illustrated by decreased whole-blood PCho. Choline supplementation should be investigated in infants who require prolonged PN, and whole-blood PCho can be used to monitor response.

Effect of cyclical intravenous clodronate therapy on bone mineral density and markers of bone turnover in patients receiving home parenteral nutrition

BACKGROUND

Patients receiving home parenteral nutrition (HPN) because of intestinal failure are at high risk of developing osteoporosis.

OBJECTIVE

We studied the effect of the bisphosphonate clodronate on bone mineral density (BMD) and markers of bone turnover in HPN patients.

DESIGN

A 12-mo, double-blind, randomized, placebo-controlled trial was conducted to study the effect of 1500 mg clodronate, given intravenously every 3 mo for 1 y, in 20 HPN patients with a bone mass T score of the hip or lumbar spine of less than -1. The main outcome measure was the difference in the mean percentage change in the BMD of the lumbar spine measured by dual-energy X-ray absorptiometry. Secondary outcome measures included changes in the BMD of the hip, forearm, and total body and biochemical markers of bone turnover, ie, serum osteocalcin, urinary pyridinoline, and urinary deoxypyridinoline.

RESULTS

The mean (+/-SEM) BMD of the lumbar spine increased by 0.8 +/- 2.0% in the clodronate group and decreased by 1.6 +/- 2.0% in the placebo group (P = 0.43). At all secondary skeletal sites (ie, hip, total body, and distal forearm), we observed no changes or small increases in the BMD of the clodronate group and decreases in the BMD of the placebo group. In the clodronate group, biochemical markers of bone resorption decreased significantly (P < 0.05).

CONCLUSIONS

Clodronate significantly inhibits bone resorption as assessed by changes in biochemical markers of bone turnover. Although the mean BMD increased in the clodronate group, cyclic clodronate therapy failed to increase spinal BMD significantly at 12 mo.

Complications of long-term home total parenteral nutrition: their identification, prevention and treatment

The purpose of this review is to describe the most common complications of home total parenteral nutrition, their identification, treatment and prevention. Data sources were manuscripts and abstracts published in the English literature since 1968. Studies were selected for summarization in this review on the basis of clinical relevance to the practicing clinician. Home total parenteral nutrition is a relatively safe, life-saving method for nutrient delivery in patients with compromised gastrointestinal function. However, numerous complications, with associated morbidity and mortality, involving the delivery system and the gastrointestinal, renal, and skeletal systems may develop. Catheter-related complications are often preventable and treatable when they occur, although renal and bone abnormalities have elusive etiologies.

Bone turnover in short-term and long-term home parenteral nutrition for benign disease

6 mo afterward. Long-HPN was assessed only at baseline. In short-HPN, there was a hyperkinetic turnover at baseline. At follow-up, OC was similar to baseline, whereas cross-links, urinary calcium and magnesium decreased (P < 0.03), and parathyroid hormone increased (P < 0.001). The variation of urinary calcium correlated with that of cross-links (r = 0.73, P < 0.04). In long-HPN, OC was low or low-normal in almost all the patients, and cross-links were normal. Mean OC was lower than that of short-HPN both at baseline (P < 0. 003) and at follow-up (P < 0.002). The results suggest that in the early period of HPN bone metabolism improved from a hyperkinetic turnover to a positive balance. A low bone-formation rate appeared to be a characteristic feature of long-term HPN.

Metabolic bone disease in gut diseases

A wide spectrum of gastrointestinal illnesses impairs bone health and can result in bone pain, demineralization, and fracture. This article summarizes current knowledge of the skeletal pathology exhibited in patients with diseases of the liver, biliary tree, pancreas, and bowel. Mechanisms responsible for these syndromes and treatment options are discussed. This article enhances the practicing gastroenterologist's knowledge of the implications of gastrointestinal illness for bone.

Bone turnover in patients on home parenteral nutrition: alongitudinal observation by biochemical markers

In order to characterize biochemical markers of bone turnover in home parenteral nutrition(HPN) patients, 8 adult patients on HPN for benign intestinal failure were studied at 0, 6 and 12 months by evaluating serum osteocalcin (bone formation marker), urinary hydroxylysyl pyridinoline, lysyl pyridinoline and beta-galactosyl hydroxylysine (bone resorption markers), serum PTH, Calcitonin, 25 vitD, 1-25vitD, serum and urinary minerals, body weight, rehabilitation degree and HPN characteristics. Three patients entered the study 2-3 months after the beginning of HPN. Their features of bone turnover were homogeneous, characterized by increased resorption associated with normal or increased formation, at baseline, and normalization of resorption associated with an increase or a parallel decrease of formation, at 6 months. At 12 months, the patterns were similar to those observed at 6 months. The patients were not of the same sex and age and had different underlying diseases and types of intestinal failure, HPN composition and serum vitamin D levels. They had weight gain that was already present at baseline and the positive outcomes of the rehabilitation and clinical status in common. Five patients entered the study more than 1 year after the beginning of HPN. They showed heterogeneous features of bone turnover that were stable throughout the study, characterized by increased resorption associated with low or normal formation in two cases, low normal resorption associated with low or normal formation in three. In one patient, who had increased resorption and low formation, the bone turnover appeared to be explained by the nutritional and clinical outcomes, which were negative. These results appeared consistent with those obtained in previous studies by bone histomorphometry, indicating that bone turnover of short-term HPN patients differed from that of long-term patients, and suggesting that the early months of HPN were associated with increased bone resorption.

Serum alkaline phosphatase, calcium, and phosphate levels following clinical use of natural coral. Case reports

Measurement of alkaline phosphatase enzymatic activity is the most commonly used serum marker to assess bone formation. In this present study serum alkaline phosphatase, calcium, and phosphate were measured in 12 patients where natural coral was implanted in surgical bony defects. Blood samples were obtained preoperatively which served as control, and at 1, 7, 15, and 30 days. No statistically significant increase in serum alkaline phosphatase, calcium, and phosphate was observed.

Total parenteral nutrition and its effects on bone metabolism

Total parenteral nutrition (TPN) may affect bone metabolism in a variety of ways. These may include potential indirect effects such as on gastrointestinal hormone secretion, liver function, especially cytochrome P450 isoenzymes, metabolic biorhythms where established, and the continuous compared with the intermittent supply of nutrients. More substantial evidence exists for the reduction of bone formation, parathyroid hormone secretion, and calcitriol production in TPN patients along with high urinary calcium excretion. This review considers both aluminum loading and vitamin D sensitivity as etiologic factors and suggests that aluminum may have played a primary role in the pathogenesis of these abnormalities in bone and mineral metabolism, but that vitamin D may have potentiated the deleterious actions of aluminum. While the sources of aluminum contamination of TPN solutions have been identified and efforts are under way to reduce its contamination of TPN solutions, the persistence of low bone mass measurement in TPN patients is a problem that has been identified repeatedly, does not have a current explanation, and requires further study.

Metabolic bone disease in adults receiving long-term parenteral nutrition: longitudinal study with regional densitometry and bone biopsy

A syndrome of bone pain and fractures has been described in patients receiving long-term support from parenteral nutrition containing large quantities of aluminium or vitamin D2. Whether this same syndrome occurs in patients supported by current therapeutic regimens is controversial. In this study, bone health was longitudinally evaluated over 7 to 61 months in 14 subjects maintained on long-term parenteral nutrition. The parameters of bone health evaluated included bone mass as measured by single and dual photon absorptiometry and quantitative histomorphometry of bone biopsies. There was a striking heterogeneity in baseline measures of bone health. Mean bone density of parenteral nutrition patients was significantly below expected values on entry into the study at both the distal radius (z score = -0.76 +/- 0.27) and the lumbar spine (z score = -1.17 +/- 0.27). Mean areal density at the forearm was less severely depressed (z score = -0.62 +/- 0.34). The longitudinal changes in bone density and morphology were heterogeneous, with some subjects showing deterioration, others improvement, and still others no change. We conclude that patients already established on parenteral nutrition frequently have osteopenia. The group as a whole did not demonstrate normalization of the osteopenia, but our results also suggest that current parenteral nutrition formulations low in aluminum and vitamin D2 do not necessarily cause worsening of bone health. The etiology of this clinical syndrome merits additional study.