Anti-epileptic drugs and bone loss: Phenytoin reduces pro-collagen I and alters the electrophoretic mobility of osteonectin in cultured bone cells

Topiramate promotes osteogenic differentiation through AMPK-dependent phosphorylation of Smad1/5/9

Topiramate [2,3:4,5-bis-o-(1-methylethylidene) β-D-fructo-pyranose sulfamate; TPM] is one of the most used new-generation antiepileptic drugs. It has been reported to regulate the differentiation of human bone cells. However, the molecular mechanism of TPM in osteoblast differentiation is not fully elucidated. In the present study, we examined the effect of TPM on osteogenic differentiation of C3H10T1/2, MC3T3-E1, primary mouse calvarial cells, and primary bone marrow stem cells (BMSCs). Primary cells were isolated from mice calvaria and bone marrow respectively. Expression of the osteogenic gene was determined by RT-PCR. The osteogenic protein levels were measured by Western blot analysis. Alkaline phosphatase (ALP) staining experiment was performed to evaluate ALP activity. Alizarin red s (ARS) staining was performed to measure zebrafish caudal fin regeneration. Treatment of TPM up-regulated the osteogenic genes including distal-less homeobox 5 (Dlx5) and runt-related transcription factor 2 (Runx2). In addition, TPM also increased the Dlx5 and Runx2 protein levels, Smad1/5/9 phosphorylation, and alkaline phosphatase (ALP) activity. Furthermore, TPM activated AMPK, and inhibition of AMPK decreased TPM-induced osteogenic differentiation. In the zebrafish model, osteogenic effect of TPM was identified. TPM was increased amputated caudal fin rays of zebrafish. These results demonstrate that TPM enhances osteogenic differentiation via AMPK-mediated Smad1/5/9 phosphorylation.

Effects of antiepileptic therapy on bone mineral status evaluated by phalangeal quantitative ultrasound in pediatric patients with epilepsy and motor impairment

BACKGROUND

In epileptic patients with motor disability, it's difficult to disentangle the effects of antiepileptic drugs (AEDs) on bone health from those provoked by impaired mobility. The aim of this study was to evaluate the effects of AEDs on bone mineral status by phalangeal quantitative ultrasound (QUS), a no-radiation and non-invasive method, in pediatric patients with motor impairment and epilepsy.

METHODS

We enrolled 56 patients (31 females, 25 males) with epilepsy and motor impairment and 24 children with only motor disability (13 females, 11 males). Patients were stratified by Gross Motor Function Classification System Scale (GMFCS) in 4 groups: group A1 with epilepsy and mild motor impairment (GMFCS levels I-II), group A2 with only mild motor impairment, group B1 with epilepsy and severe motor impairment (GMFCS levels III-V), group B2 with only severe motor impairment. The bone mineral status was evaluated by phalangeal QUS and amplitude-dependent speed of sound (AD-SoS) Z-score was calculated for each patient.

RESULTS

The four groups showed no significant differences in age, gender and 25-hydroxyvitamin D levels. The group B1 had a statistically lower amplitude-dependent speed of sound Z-score as compared to group A2 (P<0.05). The multivariate analysis of independent factors revealed a significant correlation between amplitude-dependent speed of sound Z-score and Gross Motor Function Classification System levels (P=0.004). The mean Z-score value decreased by 0.53, increasing the motor impairment.

CONCLUSIONS

The bone mineral status measured as AD-SoS strongly correlates with severity of motor disability evaluated by GMFCS as compared to antiepileptic therapy and 25-hydroxyvitamin D levels.

Antiepileptic Drugs and Bone Health: Current Concepts

Chronic use of antiepileptic drugs (AEDs) can induce the development of adverse effects on bone metabolism. In epileptic patients treated with AED, the monitoring of biochemical markers of bone turnover, such as the measurement of serum 25 (OH) vitamin D, bone mineral density, before the beginning of the treatment and during the follow-up is not routinely required. In the future, monitoring of biochemical markers in epileptic patients treated with AED may help us for adequate prevention therapy.

Pharmacological modulation of cell functional activity with valproic acid and erythropoietin

Introduction: Valproic acid (VA) is carboxylic acid with a branched chain, which is used as an antiepileptic drug.

Valproic acid influence on cells in vivo: VA, which is an antiepileptic drug, is also a teratogen, which causes defects of a neural tube and an axial skeleton, although the mechanisms are not yet fully clear.

Valproic acid influence on mesenchymal stem cells (MSC) in vitro: It is shown that valproic acid reduces the intracellular level of oxygen active forms.

Valproic acid effect on tumor cells: VA inhibits tumor growth through several mechanisms, including the cell cycle stop, differentiation induction and inhibition of growth of tumor vessels.

Valproic acid influence on enzymes: It affects mainly GSK-3.

Valproic acid influence on animals’ cells: It is shown that VA can significantly improve an ability to develop in vitro and improve nuclear reprogramming of embryos.

Erythropoietin (EPO): Is an hypoxia-induced hormone and a cytokine, which is necessary for normal erythropoiesis. EPO is widely used in in vitro experiments.

Conclusion: Thus, the influence of VA and EPO on cells can be used in cell technologies.

Epilepsy and osteoporosis risk

PURPOSE OF REVIEW

It is well-recognized that individuals with epilepsy have an increased risk of vertebral and nonvertebral fractures; this increased risk has been described to be secondary to an increased bone fragility and to an increased risk of falls. Osteoporosis is the most common bone disease which has been characterized by microarchitectural deterioration of trabecula and cortical bone mass with a decrease in bone mineral density and bone strength. Specific side effects of antiepileptic drugs (AEDs) on bone metabolism have been identified; recent research publications further characterized some of the specific side effects of AEDs on bone metabolism. It is the purpose of this review to describe recent advances on the knowledge of the effects of AEDs on bone metabolism and the cause of osteoporosis in the field of epilepsy.

RECENT FINDINGS

Recent literature demonstrates that the increased risk of fractures in the epileptic patient population is likely multifactorial and includes seizure activity, injuries from falls, decreased bone strength, adverse effects from AEDs. Reviewed publications suggest that the mechanism of adverse effects on bone metabolism may differ among different AEDs. The impact of vitamin D deficiency or its metabolism in the epileptic population has also been a concern of several reviewed publications.

SUMMARY

This is a review is of the recent epilepsy and osteoporosis literature published over the past 18 months, highlighting reports and studies concerning the cause, pathogenesis, and possible preventive measures and effects of AEDs on changes of bone metabolism, bone loss, and development of osteoporosis. In addition, we also reviewed articles focusing on issues of prevention and treatment of osteoporosis in individuals with epilepsy. We utilized the search engines of PubMed and Cochrane Reviews from January 2016 to June 2017.