Abstract

Endemic fluorosis is a serious problem in public health, affecting thousands of people. Abnormal proliferation and activation of osteoblasts in skeletal fluorosis lesions play a leading role and osteoblast proliferation is finely regulated by the cell cycle. There are a few reports on fluoride-induced DNA methylation. However, the role of DNA methylation of the cyclin/cyclin-dependent kinase (CDK)/cyclin-dependent kinase inhibitor (CKI) regulatory network in skeletal fluorosis has not been investigated. We used a population study and in vitro experiment to explore the relationship between the pathogenesis of skeletal fluorosis and methylation of Cyclin d1/CDK4/p21. The results showed a positive relationship between fluoride exposure and expression of Cyclin d1/CDK4, and a negative relationship between fluoride exposure and expression of P21. Hypermethylation of p21 was found in the fluoride-exposed population, and low expression of p21 attributed to promoter hypermethylation was confirmed in vitro. However, no changes in methylation levels of Cyclin d1 and CDK4 genes were observed in the population exposed to fluoride and NaF-treated osteoblasts. These results show that methylation of p21 gene has a significant impact on the proliferation of osteoblasts during the development of skeletal fluorosis. The present study was a first attempt to link the methylation of the Cyclin d1/CDK4/p21 regulatory network with osteoblast proliferation in skeletal fluorosis.

• Related Studies :

  • Suppression of Sclerostin and Dickkopf-1 levels in patients with fluorine bone injury

    Evidence has been accumulating for the role of Sclerostin and Dickkopf-1 as the antagonists of Wnt/B-Catenin signaling pathway, which suppresses bone formation through inhibiting osteoblastic function. To get deep-inside information about the expression of the antagonists in patients with fluorine bone injury, a case-control study was conducted in two counties

  • Experimental fluorosis in rats: NaF induced changes of bone and bone marrow

    The results of our experiments suggest that increased doses of NaF cause more extensive osteosclerosis due to the decrease in number and/or activity of osteoclasts. Therefore oateosclerosis is caused primarily, not by increased bone formation but, by the inhibition of bone resorption. This view is supported by the fact that

  • [A study of the genetic basis of susceptibility to occupational fluorosis in aluminum industry workers of Siberia].

    The phenotype frequency distributions of several classical blood genetic markers and dermatoglyphic characters were analyzed in workers of Siberian aluminum plants who had occupational fluorosis. Comparison with healthy workers revealed significant differences in frequencies of several markers. Phenotypes B (AB0), D (Rh), MN (MN), P1 (P), Le a (Lewis), Gc

  • [Qualitative and quantitative variation of serum proteins in fluorosis patients].

    Comparison between patients with occupational fluorosis, a group of healthy workers, and a sample from the general population revealed differences in concentrations of some polymorphic serum proteins. These differences depended on phenotypes of patients. TF 1-2, PI 1-2, and HP 2-1 patients exhibited a decreased concentration of transferrin (TF), a

  • Fluoride's effects on the formation of teeth and bones, and the influence of genetics.

    Fluorides are present in the environment. Excessive systemic exposure to fluorides can lead to disturbances of bone homeostasis (skeletal fluorosis) and enamel development (dental/enamel fluorosis). The severity of dental fluorosis is also dependent upon fluoride dose and the timing and duration of fluoride exposure. Fluoride's actions on bone cells predominate

• Related FAN Content :

  • Factors which increase the risk for skeletal fluorosis

    The risk for developing skeletal fluorosis, and the course the disease will take, is not solely dependent on the dose of fluoride ingested. Indeed, people exposed to similar doses of fluoride may experience markedly different effects. While the wide range in individual response to fluoride is not yet fully understood, the following are some of the factors that are believed to play a role.

  • Skeletal Fluorosis & Individual Variability

    One of the common fallacies in the research on skeletal fluorosis is the notion that there is a uniform level of fluoride that is safe for everyone in the population. These "safety thresholds" have been expressed in terms of (a) bone fluoride content, (b) daily dose, (c) water fluoride level, (d) urinary fluoride level, and (e) blood fluoride level. The central fallacy with each of these alleged safety thresholds, however, is that they ignore the wide range of individual susceptibility in how people respond to toxic substances, including fluoride.

  • Fluoridation, Dialysis & Osteomalacia

    In the 1960s and 1970s, doctors discovered that patients receiving kidney dialysis were accumulating very high levels of fluoride in their bones and blood, and that this exposure was associated with severe forms of osteomalacia, a bone-softening disease that leads to weak bones and often excruciating bone pain. Based on

  • Mayo Clinic: Fluoridation & Bone Disease in Renal Patients

    The available evidence suggests that some patients wtih long-term renal failure are being affected by drinking water with as little as 2 ppm fluoride. The finding of adverse effects in patients drinking water with 2 ppm of fluoride suggests that a few similar cases may be found in patients imbibing 1 ppm, especially if large volumes are consumed, or in heavy tea drinkers. The finding of adverse effects in patients drinking water with 2 ppm of fluoride suggests that a few similar cases may be found in patients imbibing 1 ppm, especially if large volumes are consumed, or in heavy tea drinkers and if fluoride is indeed the cause. It would seem prudent, therefore, to monitor the fluoride intake of patients with renal failure living in high fluoride areas.

  • Fluoride & Osteoarthritis

    While the osteoarthritic effects that occurred from fluoride exposure were once considered to be limited to those with skeletal fluorosis, recent research shows that fluoride can cause osteoarthritis in the absence of traditionally defined fluorosis. Conventional methods used for detecting skeletal fluorosis, therefore, will fail to detect the full range of people suffering from fluoride-induced osteoarthritis.