Acetate inhibition of chick bone cell proliferation and bone growth in vitro

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.

Effects of sodium acetate on rat bone-nodule formation and mineralization in vitro

Sodium acetate reportedly promotes bone atrophy by inducing resorption and inhibiting osteoprogenitor-cell proliferation, but little is known about its effects on bone-matrix deposition and mineralization by a population containing osteoprogenitor cells. The objective here was to assess the effects of 1-20 mM sodium acetate on the proliferation and differentiation of these cells and their resultant bone-nodule formation and mineralization in an in vitro assay. Exposure to 10 mM sodium acetate had no effect on cellular proliferation but significantly increased the production and mineralization of bone nodules (p < 0.01), suggesting that it affected osteoprogenitor differentiation and subsequent metabolism. However, 10 mM acetate did not increase net bone mass. Dilutions of 1-5 and 20 mM inhibited cellular proliferation and resultant bone-nodule formation and mineralization, significantly reducing the percentage bone area as compared to controls (p < 0.001). These data suggest that 1-5 and 20 mM sodium acetate significantly inhibit bone deposition, whereas 10 mM has no effects, which could contribute to iatrogenic metabolic bone disease in patients receiving either renal dialysis or total parenteral nutrition.

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.

Effects of short-chain fatty acids on growth and differentiation of the human colon-cancer cell line HT29

Short-chain fatty acids (SCFAs), namely butyrate, acetate and propionate, originate from the bacterial fermentation of dietary fibers and are the predominant anions present in the large bowel. Our study was carried out to investigate the effects of SCFAs on growth of the human adenocarcinoma cell line, HT29. The results show that, under our culture conditions, both propionate and butyrate inhibit growth of HT29 cells, whereas acetate has no significant effect. The antiproliferative effect of propionate or butyrate is associated with an inhibition of FCS-induced activation of ornithine decarboxylase (ODC), a key enzyme of polyamine metabolism. Inhibition of growth induced by either propionate or butyrate is not reversed by the addition of putrescine, which reveals that these SCFAs are not acting solely on the ODC/polyamine system. Our data show that propionate and butyrate, unlike acetate, induce an increase in alkaline phosphatase activity, which reflects a more differentiated phenotype than that of untreated control cells. Taken together, our results suggest that propionate, like butyrate, may play an important role in the physiology of the colon and could partially account for the protective effect of dietary fibers with respect to colon carcinogenesis.

Parenteral nutrition-related bone disease

Parenteral nutrition (PN)-related bone disease remains a problem in patients of all ages. Understanding of the pathogenesis of PN-related bone disease is complicated by the effect of underlying illnesses, therapeutic interventions, and pre-existing nutrition deficiencies before the initiation of PN therapy. Interrelation of various nutrients, for example, calcium, phosphorus, and vitamin D, in their effects on bone mineralization, demands simultaneous assessment of the role of multiple nutrients and increases the difficulty in defining the role of a single nutrient in the development of bone disease. However, recent reports indicate that there exist a number of factors important in the development of PN-related bone disease and some factors such as increased mineral requirement are unique to growing infants whereas other factors such as aluminum toxicity may be common to both adult and pediatric populations. Nonnutritional factors, including chronic use of potent loop diuretics and altered acid-base status, can affect urine mineral loss, cell metabolism, and bone mineralization, particularly in small, preterm infants. Current evidence indicates that the cause of PN-related bone disease is multifactorial, and the prevention of PN-related bone disease awaits better delineation of the exact sequence of pathogenic events.