Levetiracetam, Phenytoin, and Valproate Act Differently on Rat Bone Mass, Structure, and Metabolism

GNAQ/GNA11 Mosaicism Is Associated with Abnormal Serum Calcium Indices and Microvascular Neurocalcification

Mosaic mutations in genes GNAQ or GNA11 lead to a spectrum of diseases including Sturge-Weber syndrome and phakomatosis pigmentovascularis with dermal melanocytosis. The pathognomonic finding of localized "tramlining" on plain skull radiography, representing medium-sized neurovascular calcification and associated with postnatal neurological deterioration, led us to study calcium metabolism in a cohort of 42 children. In this study, we find that 74% of patients had at least one abnormal measurement of calcium metabolism, the commonest being moderately low serum ionized calcium (41%) or high parathyroid hormone (17%). Lower levels of ionized calcium even within the normal range were significantly associated with seizures, and with specific antiepileptics despite normal vitamin D levels. Successive measurements documented substantial intrapersonal fluctuation in indices over time, and DEXA scans were normal in patients with hypocalcemia. Neurohistology from epilepsy surgery in five patients revealed not only intravascular, but perivascular and intraparenchymal mineral deposition and intraparenchymal microvascular disease in addition to previously reported findings. Neuroradiology review clearly demonstrated progressive calcium deposition in individuals over time. These findings and those of the adjoining paper suggest that calcium deposition in the brain of patients with GNAQ/GNA11 mosaicism may not be a nonspecific sign of damage as was previously thought, but may instead reflect the central postnatal pathological process in this disease spectrum.

A Prospective Longitudinal Study of the Effects of Eslicarbazepine Acetate Treatment on Bone Density and Metabolism in Patients with Focal-Onset Epilepsy

BACKGROUND AND OBJECTIVES

Eslicarbazepine acetate (ESL) is a third-generation anti-seizure medication for patients with focal-onset epilepsy. There are known short-term impacts of classic enzyme-inducing drugs on bone health. For oxcarbazepine, which like ESL is a less potent inducer of cytochrome P450 (CYP450) than carbamazepine, some studies have shown that treatment is associated with increased bone metabolic parameters. The effects of ESL on bone health have not been systematically evaluated so the objective of this study was to investigate whether adverse effects of ESL on bone mineral density (BMD) could be measured after a 12-month exposure period. In addition, the effects of ESL on bone turnover were investigated using laboratory indicators of bone metabolism.

METHODS

BONAPARTE was a prospective, longitudinal, observational study that enrolled patients with focal-onset epilepsy with or without secondary generalization who started treatment with ESL, either as adjunctive treatment or monotherapy, at two tertiary epilepsy centres in Germany between February 2018 and July 2020. Standardised osteodensitometry and biochemical bone metabolism parameters at the time of ESL initiation and 1 year after continuation of therapy were assessed. Comparisons between biochemical and densitometric parameters at baseline and after 12 months of treatment were performed using the paired samples t test.

RESULTS

In total, 26 patients (15 male; mean age 41.4 ± 12.5 years) newly treated with ESL were evaluated. Six of these patients had osteopenia at baseline. The mean daily dose of ESL at the 12-month follow-up was 1438 ± 1406 mg. At the group level, there were no significant effects of treatment with ESL on laboratory markers or on BMD. Mean values of BMD in g/cm2 at baseline and after 12 months of ESL treatment were 1.17 (± 0.16) and 1.16 (± 0.16) in the lumbar spine, and 0.98 (± 0.15) and 0.96 (± 0.15) in the proximal femur, respectively. Intra-individually, two patients developed de novo osteopenia measured at the femoral neck associated with relevant changes in bone metabolic parameters.

CONCLUSION

Neither osteodensitometry nor bone metabolism parameters showed significant group effects after 1 year of treatment with ESL. Individual fluctuations were observed, however, which may warrant monitoring for longer follow-up periods. The study was registered in the German register for clinical studies under the number DRKS00010430 with the official name BONAPARTE.

Enhancing Osteoporosis Treatment through Targeted Nanoparticle Delivery of Risedronate: In Vivo Evaluation and Bioavailability Enhancement

Risedronate-loaded mPEG-coated hydroxyapatite, thiolated chitosan-based (coated) and non-coated nanoparticles were tested for their potential effects in the treatment of osteoporosis. The prepared nanoparticles were evaluated for their bone-targeting potential by inducing osteoporosis in female Wistar rats via oral administration of Dexona (dexamethasone sodium phosphate). In vivo pharmacokinetic and pharmacodynamic studies were performed on osteoporotic rat models treated with different formulations. The osteoporotic model treated with the prepared nanoparticles indicated a significant effect on bone. The relative bioavailability was enhanced for RIS-HA-TCS-mPEG nanoparticles given orally compared to RIS-HA-TCS, marketed, and API suspension. Biochemical investigations also showed a significant change in biomarker levels, ultimately leading to bone formation/resorption. Micro-CT analysis of bone samples also demonstrated that the RIS-HA-TCS-mPEG-treated group showed the best results compared to other treatment groups. Moreover, the histology of bone treated with RIS-HA-TCS-mPEG showed a marked restoration of the architecture of trabecular bone along with a well-connected bone matrix and narrow inter-trabecular spaces compared to the toxic group. A stability analysis was also carried out according to ICH guidelines (Q1AR2), and it was found that RIS-HA-TCS-mPEG was more stable than RIS-HA-TCS at 25 °C. Thus, the results of present study indicated that mPEG-RIS-HA-TCS has excellent potential for sustained delivery of RIS for the treatment and prevention of osteoporosis, and for minimizing the adverse effects of RIS typically induced via oral administration.

Risk Factors and Clinical Characteristics of Metabolic Bone Disease of Prematurity

OBJECTIVE

 The study aimed to analyze the risk factors and clinical features of metabolic bone disease of prematurity (MBDP) in premature infants compared with infants of similar gestational age and birth weight without MBDP.

STUDY DESIGN

 This retrospective case-control study was performed by comparing 81 cases of MBDP with 63 controls to identify potential risk factors. Premature infants with a gestational age ≤33 weeks and birth weight <1,500 g were included. Medical records were examined in terms of maternal conditions, potential risk factors, and clinical characteristics.

RESULTS

 Bone fractures and invasive ventilator dependence were the most common clinical features of MBDP. Duration of invasive ventilation and total mechanical ventilation days, necrotizing enterocolitis, corticosteroid use, anticonvulsive drug use, duration of dexamethasone and caffeine use, total parenteral nutrition, and length of hospitalization were significantly higher in neonates with MBDP (p < 0.05). Breastfed neonates and those receiving human milk fortifier had a lower incidence of MBDP than those premature formula or mixed feeding (p < 0.05). Anticonvulsive drug use (odds ratio: 2.935; 95% confidence interval: 1.265-6.810) was identified as a risk factor for MBDP at multiple regression analysis.

CONCLUSION

 Our results show that anticonvulsive drug use is a significant risk factor for the development of MBDP. If long-term use is not required, anticonvulsive drugs should be stopped as soon as possible. Further studies involving patients with MBDP are required to determine the risk factors and clinical features.

KEY POINTS

· MBDP is a multifactorial disorder.. · Anticonvulsive drug use is an important risk factor for the development of MBDP.. · Bone fractures and invasive ventilator dependence are the most common clinical features of MBDP..

Formulation development and in vitro-in vivo assessment of protransfersomal gel of anti-resorptive drug in osteoporosis treatment

Osteoporosis is a major cause of morbidity, mortality, and economic burden worldwide. Despite being an effective in combating the bone-deteriorating disorders, bisphosphonates have several shortcomings including poor and variable bioavailability, low permeability, high toxicity, etc. In this study, we developed and optimized protransfersome formulation for the drug risedronate sodium (RIS-Na) with the goal of enhancing its bioavailability and hence patient compliance. Phase separation coacervation technique was utilized for development of optimized formulation. Optimization was achieved by using three-factor, three-level Box-Behnken design combined with Response Surface Methodology (RSM). This enabled us to decipher the effect of 3 independent variables (Phospholipid, Tween-80 and Sodium Deoxycholate) on three dependent parameters (entrapment efficiency, vesicle size and transdermal flux). Optimized formulation was further evaluated for pharmacokinetic and pharmacodynamic parameters. Smooth, spherical protransfersomes with a size of 260 ± 18 nm, having entrapment efficiency and flux of 80.4 ± 4.90% and 8.41 ± 0.148 μg/cm²/h, respectively were prepared. Ex vivo studies revealed a shorter lag time of 1.21 ± 0.18 h and higher flux associated with transdermal formulation. CLSM analysis further revealed better drug penetration (220 μm) through the skin in case of protransfersomes as compared to drug solution (72 μm). Additionally, biomechanical, biochemical, and histo-pathological studies further validated the results. Thus, it was concluded that protransfersome formulation has a great potential in providing better therapeutic efficacy of risedronate than its conventional counterpart.

An insight into the implications of estrogen deficiency and transforming growth factor β in antiepileptic drugs-induced bone loss

There have been a number of reports that chronic antiepileptic drug (AEDs) therapy is associated with abnormal bone and calcium metabolism, osteoporosis/osteomalacia, and increased risk of fractures. Bony adverse effects of long term antiepileptic drug therapy have been reported for more than four decades but the exact molecular mechanism is still lacking. Several mechanisms have been proposed regarding AEDs induced bone loss; Hypovitaminosis D, hyperparathyroidism, estrogen deficiency, calcitonin deficiency. Transforming growth factor-β (TGF- β) is abundant in bone matrix and has been shown to regulate the activity of osteoblasts and osteoclasts in vitro. All isoforms of TGF- β are expressed in bone and intricately play role in bone homeostasis by modulating estrogen level. Ovariectomised animal have shown down regulation of TGF- β in bone that could also be a probable target of AEDs therapy associated bone loss. One of the widely accepted hypotheses regarding the conventional drugs induced bone loss is hypovitaminosis D which is by virtue of their microsomal enzyme inducing effect. However, despite of the lack of enzyme inducing effect of certain newer antiepileptic drugs, reduced bone mineral density with these drugs have also been reported. Thus an understanding of bone biology, pathophysiology of AEDs induced bone loss at molecular level can aid in the better management of bone loss in patients on chronic AEDs therapy. This review focuses mainly on certain new molecular targets of AEDs induced bone loss.

A Literature Review of the Potential Impact of Medication on Vitamin D Status

In recent years, there has been a significant increase in media coverage of the putative actions of vitamin D as well as the possible health benefits that supplementation might deliver. However, the potential effect that medications may have on the vitamin D status is rarely taken into consideration. This literature review was undertaken to assess the degree to which vitamin D status may be affected by medication. Electronic databases were searched to identify literature relating to this subject, and study characteristics and conclusions were scrutinized for evidence of potential associations. The following groups of drugs were identified in one or more studies to affect vitamin D status in some way: anti-epileptics, laxatives, metformin, loop diuretics, angiotensin-converting enzyme inhibitors, thiazide diuretics, statins, calcium channel blockers, antagonists of vitamin K, platelet aggregation inhibitors, digoxin, potassium-sparing diuretics, benzodiazepines, antidepressants, proton pump inhibitors, histamine H2-receptor antagonists, bile acid sequestrants, corticosteroids, antimicrobials, sulphonamides and urea derivatives, lipase inhibitors, hydroxychloroquine, highly active antiretroviral agents, and certain chemotherapeutic agents. Given that the quality of the data is heterogeneous, newer, more robustly designed studies are required to better define likely interactions between vitamin D and medications. This is especially so for cytochrome P450 3A4 enzyme (CYP3A4)-metabolized medications. Nevertheless, this review suggests that providers of health care ought to be alert to the potential of vitamin D depletions induced by medications, especially in elderly people exposed to multiple-drug therapy, and to provide supplementation if required.

Effect of levetiracetam and oxcarbazepine on 4-year fragility fracture risk among prepubertal and pubertal children with epilepsy

OBJECTIVE

The objective of this study was to determine whether two commonly prescribed antiseizure medications (ASMs), levetiracetam (LEV) and oxcarbazepine (OXC), were associated with an increased risk of fragility fracture in children with epilepsy when initiating therapy during a crucial period of bone development, namely, pre- and midpuberty.

METHODS

Claims data from January 1, 2009 to December 31, 2018 were extracted from the Optum Clinformatics Data Mart. Children aged 4-13 years at baseline with at least 5 years of continuous health plan enrollment were included to allow for a 1-year baseline (e.g., pre-ASM exposure) and 4 years of follow-up. Children with epilepsy who were ASM naïve were grouped based on whether ASM treatment initiation included LEV or OXC. The comparison group included children without epilepsy and without ASM exposure. Crude incidence rate (IR; n per 1000 person-years) and IR ratio (IRR; with 95% confidence interval [CI]) were estimated for nontrauma fracture (NTFx), a claims-based proxy for fragility fracture, for up to 4 years of follow-up. Cox proportional hazards regression estimated the hazard ratio (HR; with 95% CI) after adjusting for demographic variables, motor impairment, and baseline fracture.

RESULTS

The crude IR (95% CI) of NTFx was 21.5 (21.2-21.8) for non-ASM-users without epilepsy (n = 271 346), 19.8 (12.3-27.2) for LEV (n = 358), and 34.4 (21.1-47.7) for OXC (n = 203). Compared to non-ASM-users, the crude IRR of NTFx was similar for LEV (IRR = .92, 95% CI = .63-1.34) and elevated for OXC (IRR = 1.60, 95% CI = 1.09-2.35); the crude IRR of NTFx was elevated for OXC compared to LEV (IRR = 1.74, 95% CI = 1.02-2.99). The findings were consistent after adjusting for covariates, except when comparing OXC to LEV (HR = 1.71, 95% CI = .99-2.93), which was marginally statistically insignificant (p = .053).

SIGNIFICANCE

Initiating OXC, but not LEV, therapy among 4-13-year-olds with epilepsy is associated with an elevated risk of fragility fracture. Studies are needed to determine whether these children could benefit from adjunct bone fragility therapies.

Anticonvulsant use and bone health in a population-based study of men and women: cross-sectional data from the Geelong Osteoporosis Study

Background

Anticonvulsant use has been linked to bone deficits in specific patient populations. We studied the association between anticonvulsant use and bone health in a population-based sample of men and women.

Methods

Data from 926 men (24-73 yr) and 1070 women (21-94 yr) participating in the Geelong Osteoporosis Study were included. Bone mineral density (BMD, g/cm²) of the PA-spine and total hip was measured using dual-energy X-ray absorptiometry (Lunar). Bone quality was determined using quantitative heel ultrasound (QUS). Anthropometry was conducted and socioeconomic status was determined. Medication and lifestyle information was obtained via questionnaire. Linear regression was used to test associations between anticonvulsant use and bone health before and after adjustment for potential confounders.

Results

Seventeen (1.8%) men and 20 (1.9%) women reported anticonvulsant use. In men, anticonvulsant users had 9.1% lower adjusted mean BMD at the spine and hip compared to non-users. Body mass index was an effect modifier at the spine. Anticonvulsant users also had 1.8% lower speed of sound (SOS), 10.6% lower broadband ultrasound attenuation (BUA) and 13.7% lower stiffness index (SI) compared to non-users. In women, BMD tended to be lower at the hip compared to non-users as with the bone quality measure, BUA. No significant associations were observed at the spine or the other bone quality measures, SOS and SI.

Conclusion

Our data suggest that bone quantity and quality, assessed using BMD and QUS, are lower for men and possibly women who use anticonvulsants. While further exploration into potential mechanisms is needed, our findings suggest that monitoring bone health among users of anticonvulsants is warranted.

Effects of long-term antiepileptic polytherapy on bone biochemical markers in ambulatory children and adolescents and possible benefits of vitamin D supplementation: a prospective interventional study

PURPOSE

Our aim was to investigate any adverse effects of long-term polytherapy (VPA and add-on-therapy) on bone biochemical markers in ambulatory children and adolescents with epilepsy and the possible benefits of vitamin D supplementation on the same markers.

METHODS

In this prospective interventional study, the levels of 25(OH)D and the bone turnover markers of CrossLaps (CTX), total alkaline phosphatase (tALP), osteoprotegerin (OPG), and the receptor activator for nuclear factor kB (RANK) ligand (sRANKL) were determined in forty-two ambulatory children with epilepsy on polytherapy (valproic acid + one or more other from levetiracetam, topiramate, lamotrigine, or rufinamide). The same markers were assessed after a year's supplementation of vitamin D (400 IU/d) and were compared with those of clinically healthy controls. The respective mean (±SD) ages were 11.9 ± 4.6 and 11.4 ± 4.4 yrs.

RESULTS

The basal mean 25(OH)D levels in the patients did not differ from controls (23.9 ± 11.5 vs 27.4 ± 13.3 ng/ml), but increased significantly after the vitamin D intake (31.1 ± 13.3 ng/ml, p < 0.01). In parallel, basal serum CTX levels were found to be significantly lower in the patients than controls (0.89 ± 0.63 vs 1.22 ± 0.58 ng/ml, p < 0.02), but not tALP. Osteoprotegerin was higher in the patients (5.7 ± 7.7 pmol/L vs 2.6 ± 1.0 pmol/L, p < 0.03), while sRANKL did not differ. After vitamin D, the CTX levels increased to comparable levels in controls (0.99 ± 0.57 ng/ml), and those of OPG decreased to levels that did not differ from controls (4.9 ± 5.1 pmol/L). The ratio of OPG/sRANKL was higher in patients than controls before treatment (0.030 ± 0.045 vs 0.009 ± 0.005, p < 0.03), but decreased (0.026 ± 0.038) to comparable values in controls later.

CONCLUSIONS

These findings imply a lower bone turnover in the young patients on long-term polytherapy (VPA and add-on-therapy), but after one year's vitamin D intake, bone biochemical markers improved.

The effect of levetiracetam and oxcarbazepine monotherapy on thyroid hormones and bone metabolism in children with epilepsy: A prospective study

BACKGROUND

Long-term treatment with certain antiepileptic drugs may lead to thyroid function disturbances or alterations in bone metabolism; the data on the effects of new antiepileptic drugs on this are limited and conflicting, especially in children with epilepsy. Therefore, the aim of this study was to investigate the effects of levetiracetam and oxcarbazepine on thyroid hormone levels and bone metabolism in children with epilepsy.

METHODS

A total of 51 children with new-onset partial epilepsy were selected. They were randomly treated with either levetiracetam (n = 25), or oxcarbazepine (n = 26) monotherapy. Eight of the 51 patients were excluded for failing to take the drug continuously or failing to undergo a regular review. Thus, 43 patients were finally included (levetiracetam: 23 patients, oxcarbazepine: 20 patients). A control group consisting of age- and sex-matched healthy subjects (n = 20) was included for comparison. Serum triiodothyronine, tetraiodothyronine, free triiodothyronine, free thyroxine, thyroid-stimulating hormone, calcium, phosphorus, alkaline phosphatase, osteocalcin, parathyroid hormone, and 25-hydroxyvitamin D levels and bone mineral density values were measured before and at 6 and 12 months after therapy in all groups.

RESULTS

At baseline, thyroid hormone levels, bone metabolism index, and bone mineral density values did not differ between the control group and the drug-treated groups. Levetiracetam-treated patients showed no significant changes in thyroid hormone levels, bone metabolism, and bone mineral density during the 12-month follow-up period compared with baseline values. In the oxcarbazepine group, compared to baseline values, serum free thyroxine levels decreased after 12 months of treatment (Z = -3.115, p = 0.002), and after 6 and 12 months of treatment, calcium levels decreased (Z = -3.705, p < 0.001 and Z = -3.884, p < 0.001, respectively) and parathyroid hormone levels increased (Z = -3.698, p < 0.001 and Z = -3.921, p < 0.001, respectively); however, all other parameters did not differ from baseline values.

CONCLUSION

Our data show that levetiracetam treatment has no significant effect on thyroid function and bone metabolism in children with epilepsy. Long-term use of oxcarbazepine may reduce serum free thyroxine levels, resulting in impaired thyroid function, and may reduce serum calcium and increase parathyroid hormone levels, leading to bone metabolism disorders.

Effects of valproate, lamotrigine, and levetiracetam monotherapy on bone health in newly diagnosed adult patients with epilepsy

PURPOSE

The aim of this study was to evaluate the effects of valproate (VPA), lamotrigine (LTG), and levetiracetam (LEV) on bone turnover and bone mineral density (BMD) in newly diagnosed adult patients with epilepsy.

METHODS

Eligible adult patients who were newly diagnosed with epilepsy were treated with VPA, LTG, and LEV. The chemical indicators of bone metabolism and BMD were measured before treatment and 2 years after treatment with different antiseizure medication (ASM) monotherapies. Then, the differences in these parameters before and after treatment were analyzed.

RESULTS

One hundred twenty-four patients completed the 2 years follow-up; 43 received monotherapy with VPA, 32 received LTG, and 49 received LEV. Serum parathyroid hormone (PTH), bone alkaline phosphatase (B-ALP), and β-cross-linked C-telopeptide of type I collagen (β-CTX) levels were elevated in adult patients after 2 years of VPA administration; the serum procollagen I intact N-terminal peptide (PINP) level was noticeably higher in patients after LEV treatment than before treatment. Meanwhile, the BMD of the lumbar spine and femoral neck did not change in patients treated with VPA, LTG, and LEV.

CONCLUSIONS

Valproate altered bone turnover in adult patients with epilepsy, while LTG and LEV did not exert harmful effects on bone health in adult patients.

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.

The epigenetic reader Brd4 is required for osteoblast differentiation

Transcription networks and epigenetic mechanisms including DNA methylation, histone modifications, and noncoding RNAs control lineage commitment of multipotent mesenchymal progenitor cells. Proteins that read, write, and erase histone tail modifications curate and interpret the highly intricate histone code. Epigenetic reader proteins that recognize and bind histone marks provide a crucial link between histone modifications and their downstream biological effects. Here, we investigate the role of bromodomain-containing (BRD) proteins, which recognize acetylated histones, during osteogenic differentiation. Using RNA-sequencing (RNA-seq) analysis, we screened for BRD proteins (n = 40) that are robustly expressed in MC3T3 osteoblasts. We focused functional follow-up studies on Brd2 and Brd4 which are highly expressed in MC3T3 preosteoblasts and represent "bromodomain and extra terminal domain" (BET) proteins that are sensitive to pharmacological agents (BET inhibitors). We show that small interfering RNA depletion of Brd4 has stronger inhibitory effects on osteoblast differentiation than Brd2 loss as measured by osteoblast-related gene expression, extracellular matrix deposition, and alkaline phosphatase activity. Similar effects on osteoblast differentiation are seen with the BET inhibitor +JQ1, and this effect is reversible upon its removal indicating that this small molecule has no lasting effects on the differentiation capacity of MC3T3 cells. Mechanistically, we find that Brd4 binds at known Runx2 binding sites in promoters of bone-related genes. Collectively, these findings suggest that Brd4 is recruited to osteoblast-specific genes and may cooperate with bone-related transcription factors to promote osteoblast lineage commitment and maturation.

The effect of gabapentin and pregabalin on bone turnover and bone strength: A prospective study in Wistar rats

BACKGROUND

There are limited data on the effects of GBP on bone and no data for PGB. Some data suggest that there is a significant influence of sex hormone balance on the susceptibility of bone to antiepileptic drug-induced bone loss.

METHODS

Forty-eight male Wistar rats were divided into six groups that were subjected to two surgeries, sham (noORX) or real orchidectomy (ORX), and were fed three diets, a SLD, a SLD enriched with GBP or a SLD enriched with PGB. Dual energy X-ray absorptiometry was used to measure the bone mineral density. The concentrations of bone turnover markers were assayed. The femurs were biomechanically tested.

RESULTS

Significant reductions in bone mineral density, weight and biomechanical strength were observed in ORX animals. GBP or PGB exposure did not cause significant alterations in bone mineral density or biomechanical strength. No changes in bone turnover markers were observed, except for RANKL. A significant increase was found in the ORX GBP and ORX PGB groups. Within the orchidectomized animal group, RANKL levels were significantly higher in the ORX PGB group than in the ORX GBP group.

CONCLUSIONS

Because neither GBP nor PGB affected bone mineral density or mechanical bone strength, both of these antiepileptic drugs could be considered drugs with lower risks to bone health. A shift in RANKL levels indicates that the effects of GBP and PGB on osteoclast activity may be dependent on the hormonal status of animals.

Bone Health in Rats With Temporal Lobe Epilepsy in the Absence of Anti-Epileptic Drugs

Rationale: Epilepsy patients often exhibit reduced bone mineral density and are at an increased risk of bone fracture. Whether these bone abnormalities are due to the use of anti-epileptic drugs (AED’s) or the disease itself is unknown. For example, although decreased bone health in epilepsy patients is generally attributed to the use of AED’s, seizures can also trigger a number of physiological processes that have the potential to affect bone. Therefore, to assess whether bone abnormalities occur in epilepsy in the absence of AED’s, the current study investigated mechanical characteristics and trabecular bone morphology in rats with chronic temporal lobe epilepsy.

Methods: Ten-week old male Wistar rats underwent kainic acid-induced status epilepticus (SE; n = 7) or a sham procedure (n = 9). Rats were implanted with EEG recording electrodes at nine weeks post-SE, and video-EEG was continuously recorded for one week at 10- and 22-weeks post-SE to confirm that SE rats had spontaneous seizures. Open-field testing to assess locomotion was conducted at 23-weeks post-SE. At 24-weeks post-SE, rats were euthanized and tibia were extracted to determine trabecular morphology by micro-computed tomography (µCT), while femurs were used to investigate mechanical properties via 3-point bending.

Results: All post-SE rats had spontaneous seizures at 10- and 22-weeks post-SE, while none of the sham rats had seizures. µCT trabecular analysis of tibia revealed no differences in total volume, bone volume, bone volume fraction, trabecular number, or trabecular separation between post-SE or sham rats, although post-SE rats did have increased trabecular thickness. There were also no group differences in total distance travelled in the open field suggesting that activity levels did not account for the increased trabecular thickness. In addition, no differences in mechanical properties of femurs were observed between the two groups.

Conclusion: There was a lack of overt bone abnormalities in rats with chronic temporal lobe epilepsy in the absence of AED treatment. Although further studies are still needed, these findings may have important implications towards understanding the source (e.g., AED treatments) of bone abnormalities in epilepsy patients.

An explorative literature review of the multifactorial causes of osteoporosis in epilepsy

PURPOSE

Patients with epilepsy have a greatly increased risk of osteoporosis and fractures. The literature is diverse and contradictory when dealing with the underlying pathophysiological mechanisms. Consequently, the purpose of this review was to shed light on the multifactorial causes behind the increased occurrence of metabolic bone disease in patients with epilepsy and to identify areas for future research.

METHODS

A review of the literature was performed searching PubMed with relevant Medical Subject Headings MeSH terms. The results of the search were evaluated for relevance to the review based on the title and abstract of the publication. Publications in language other than English and publications pertaining only pediatric patients were excluded. For all studies, included reference lists were evaluated for further relevant publications. In total, 96 publications were included in this explorative review.

RESULTS

The high occurrence of metabolic bone disease in patients with epilepsy is multifactorial. The causes are the socioeconomic consequences of having a chronic neurological disease but also adverse effects to antiepileptic drug treatment ranging from interference with calcium and vitamin D metabolism to hyponatremia-induced osteoporosis.

CONCLUSION

The literature supports the need for awareness of bone health in patients with epilepsy. The pathophysiological mechanisms are many and various wanting for further research in the less well-characterized areas. Furthermore, great responsibility rests on the healthcare professionals in implementing comprehensive patient care and in assuring bone protective measures in clinical practice to prevent bone loss in patients with epilepsy.

Levetiracetam Protects Against Cognitive Impairment of Subthreshold Convulsant Discharge Model Rats by Activating Protein Kinase C (PKC)-Growth-Associated Protein 43 (GAP-43)-Calmodulin-Dependent Protein Kinase (CaMK) Signal Transduction Pathway

Background

Subclinical epileptiform discharges (SEDs) are defined as epileptiform electroencephalographic (EEG) discharges without clinical signs of seizure in patients. The subthreshold convulsant discharge (SCD) is a frequently used model for SEDs. This study aimed to investigate the effect of levetiracetam (LEV), an anti-convulsant drug, on cognitive impairment of SCD model rats and to assess the associated mechanisms.

Material/Methods

A SCD rat model was established. Rats were divided into an SCD group, an SCD+ sodium valproate (VPA) group, and an SCD+ levetiracetam (LEV) group. The Morris water maze was used to evaluate the capacity of positioning navigation and space exploration. The field excitatory post-synaptic potentials (fEPSPs) were evaluated using a bipolar stimulation electrode. NCAM, GAP43, PS95, and CaMK II levels were detected using Western blot and RT-PCR, respectively. PKC activity was examined by a non-radioactive method.

Results

LEV shortens the latency of platform seeking in SCD rats in positioning navigation. fEPSP slopes were significantly lower in the SCD group, and LEV treatment significantly enhanced the fEPSP slopes compared to the SCD group (P<0.05). The NCAM and GAP-43 levels were increased and PSD-95 levels were increased in SCD rats (P<0.05), which were improved by LEV treatment. The PKC activity and CaMK II levels were decreased in SCD rats and LEV treatment significantly enhanced PKC activity and increased CaMK II levels.

Conclusions

Cognitive impairment in of SCD model rats may be caused by decreased PKC activity, low expression of CaMK II, and inhibition of LTP formation. LEV can improve cognitive function by activating the PKC-GAP-43-CaMK signal transduction pathway.

Harnessing the HDAC-histone deacetylase enzymes, inhibitors and how these can be utilised in tissue engineering

There are large knowledge gaps regarding how to control stem cells growth and differentiation. The limitations of currently available technologies, such as growth factors and/or gene therapies has led to the search of alternatives. We explore here how a cell's epigenome influences determination of cell type, and potential applications in tissue engineering. A prevalent epigenetic modification is the acetylation of DNA core histone proteins. Acetylation levels heavily influence gene transcription. Histone deacetylase (HDAC) enzymes can remove these acetyl groups, leading to the formation of a condensed and more transcriptionally silenced chromatin. Histone deacetylase inhibitors (HDACis) can inhibit these enzymes, resulting in the increased acetylation of histones, thereby affecting gene expression. There is strong evidence to suggest that HDACis can be utilised in stem cell therapies and tissue engineering, potentially providing novel tools to control stem cell fate. This review introduces the structure/function of HDAC enzymes and their links to different tissue types (specifically bone, cardiac, neural tissues), including the history, current status and future perspectives of using HDACis for stem cell research and tissue engineering, with particular attention paid to how different HDAC isoforms may be integral to this field.

Anti-epileptic drugs associated with fractures in the elderly: a preliminary population-based study

OBJECTIVE

Although classic anti-epileptic drugs have been associated with increased fracture risk, data are lacking on the outcomes of newer anti-epileptic drugs, such as gabapentin (GBP), levetiracetam, pregabalin, oxcarbazepine (OXC), and topiramate. This study was designed to determine fracture risks in the elderly associated with newly-developed anti-epileptic drugs.

METHODS

A total of 2,169 patients (median age = 71.01 years, SD = 11.25 years) who experienced fractures between 2006 and 2013 were selected. For each case, age-, sex-, and comorbidity-matched controls were selected. The assessed clinical outcome was any fracture, and the use of anti-epileptic drugs was used as an exposure variable.

RESULTS

There were no differences in age, sex, or comorbidities between patients and controls, but patients with fractures often lived in urban areas (odds ratio [OR] = 1.17; 95% confidence interval [CI] = 1.05-1.29) and had low income (OR = 1.14; 95% CI = 1.01-1.29) compared to controls. A significant increase in fractures was associated with OXC (OR = 3.31; 95% CI = 1.59-6.92), carbamazepine (CBZ; OR = 2.18; 95% CI = 1.31-3.61), and GBP (OR = 1.79; 95% CI = 1.01-3.18). Phenobarbital (OR = 1.97; 95%CI = 0.53-7.34), phenytoin (OR = 0.52; 95% CI = 0.23-1.16), levetiracetam (OR = 1.84; 95% CI = 0.55-6.16), valproic acid (OR = 1.01; 95% CI = 0.53-1.92), lamotrigine (OR = 1.44; 95% CI = 0.12-16.65), and topiramate (OR = 0.47; 95% CI = 0.10-2.31) were not associated with fracture risk.

CONCLUSIONS

CBZ, GBP, and OXC users have a significantly higher risk of fracture. Most recently-developed anti-epileptic drugs are not associated with an increased risk of fracture in individuals aged ≥50 years.

Levetiracetam and lamotrigine effects as mono- and polytherapy on bone mineral density in epileptic patients

OBJECTIVE

The purpose of this study was to determine the effect of lamotrigine (LTG) and levetiracetam (LEV) as mono- and polytherapy on biochemical markers of bone turnover and bone mineral density in Egyptian adult patients with epilepsy.

METHODS

Forty-eight patients were divided into four groups: two received monotherapy of either LTG or LEV, and the other two groups received polytherapy comprising (valproate [VPA] + LTG or VPA + LEV). Thirty matched healthy participants were included in the study. Participants completed a nutritional and physical activity questionnaire. Biochemical markers of bone and mineral metabolism and bone mineral density of the lumbar spine were measured at baseline and at six months.

RESULTS

In the LEV monotherapy group, the bone formation markers showed a significant decrease in serum alkaline phosphatase and serum osteocalcin levels while the bone resorption marker showed a significant increase in urinary deoxypyridinoline levels. After six months of treatment, bone mineral density showed a significant decrease in all treated groups, while among monotherapy groups, this significant decrease was more prevalent in the LEV monotherapy group compared with the LTG monotherapy group. Furthermore, there was significant negative correlation between urinary deoxypyridinoline levels and bone mineral density in the LEV monotherapy group.

CONCLUSION

Using new generation antiepileptics, LEV monotherapies and polytherapy showed harmful effects on bone but LTG did not.

Bilateral avascular necrosis of the femoral head following asynchronous postictal femoral neck fractures: a case report and review of the literature

Bilateral avascular necrosis (AVN) following postictal bilateral fracture neck of the femur is a rare occurrence. Here, we report a case of bilateral AVN of the femoral head following an asynchronous bilateral postictal fracture neck of the femur. A 16-year-old autistic boy presented with left hip pain following an episode of seizures and radiographs showed Delbet type II fracture neck of the left femur. This was treated by closed reduction and cancellous screw fixation and skeletal traction for 6 weeks. At 3 months, follow-up radiograph showed union of the fracture, but he had developed segmental AVN with collapse of the head. At 8 months, the patient presented with pain in the right hip following another episode of seizures and radiograph of the pelvis showed a fresh Delbet type II fracture neck of the right femur with established AVN of the left femoral head. He underwent closed reduction and cancellous screw fixation of the right hip and implant exit of the left hip. At the 6-month follow-up after this surgery, his radiograph of the pelvis showed AVN with collapse and extrusion of the femoral head on the right side as well. Literature review shows an increased risk of fracture neck of the femur among epileptics. The incidence of AVN is maximum in Delbet type I, followed by Delbet type II and type III in that order. Although there are no clear guidelines on the management of post-traumatic AVN of the femoral head, the majority have reported that most of them will eventually develop arthritis and will require total hip replacement at a later date. Upon extensive literature search, no case report of bilateral fracture neck of the femur with bilateral AVN was found and hence this case was reported.

HDAC inhibitor LMK‑235 promotes the odontoblast differentiation of dental pulp cells

The role of dental pulp cells (DPCs) in hard dental tissue regeneration had received increasing attention because DPCs can differentiate into odontoblasts and other tissue‑specific cells. In recent years, epigenetic modifications had been identified to serve an important role in cell differentiation, and histone deacetylase (HDAC) inhibitors have been widely studied by many researchers. However, the effects of HDAC4 and HDAC5 on the differentiation of DPCs and the precise molecular mechanisms remain unclear. The present study demonstrated that LMK‑235, a specific human HDAC4 and HDAC5 inhibitor, increased the expression of specific odontoblastic gene expression levels detected by reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) in dental pulp cells, and did not reduce cell proliferation tested by MTT assay after 3 days in culture at a low concentration. In addition, the mRNA and protein expression levels of dentin sialophosphoprotein, runt‑related transcription factor 2, alkaline phosphatase (ALP) and osteocalcin were evaluated by RT‑qPCR and western blotting, respectively. The increased gene and protein expression of specific markers demonstrated, indicating that LMK‑235 promoted the odontoblast induction of DPCs. ALP activity and mineralised nodule formation were also enhanced due to the effect of LMK‑235, detected by an ALP activity test and Alizarin Red S staining, respectively. Additionally, the vascular endothelial growth factor (VEGF)/RAC‑gamma serine/threonine‑protein kinase (AKT)/mechanistic target of rapamycin (mTOR) signalling pathway was tested to see if it takes part in the differentiation of DPCs treated with LMK‑235, and it was demonstrated that the mRNA expression levels of VEGF, AKT and mTOR were upregulated. These findings indicated that LMK‑235 may serve a key role in the proliferation and odontoblast differentiation of DPCs, and could be used to accelerate dental tissue regeneration.

The Histone-Deacetylase-Inhibitor Suberoylanilide Hydroxamic Acid Promotes Dental Pulp Repair Mechanisms Through Modulation of Matrix Metalloproteinase-13 Activity

Direct application of histone-deacetylase-inhibitors (HDACis) to dental pulp cells (DPCs) induces chromatin changes, promoting gene expression and cellular-reparative events. We have previously demonstrated that HDACis (valproic acid, trichostatin A) increase mineralization in dental papillae-derived cell-lines and primary DPCs by stimulation of dentinogenic gene expression. Here, we investigated novel genes regulated by the HDACi, suberoylanilide hydroxamic acid (SAHA), to identify new pathways contributing to DPC differentiation. SAHA significantly compromised DPC viability only at relatively high concentrations (5 μM); while low concentrations (1 μM) SAHA did not increase apoptosis. HDACi-exposure for 24 h induced mineralization-per-cell dose-dependently after 2 weeks; however, constant 14d SAHA-exposure inhibited mineralization. Microarray analysis (24 h and 14 days) of SAHA exposed cultures highlighted that 764 transcripts showed a significant >2.0-fold change at 24 h, which reduced to 36 genes at 14 days. 59% of genes were down-regulated at 24 h and 36% at 14 days, respectively. Pathway analysis indicated SAHA increased expression of members of the matrix metalloproteinase (MMP) family. Furthermore, SAHA-supplementation increased MMP-13 protein expression (7 d, 14 days) and enzyme activity (48 h, 14 days). Selective MMP-13-inhibition (MMP-13i) dose-dependently accelerated mineralization in both SAHA-treated and non-treated cultures. MMP-13i-supplementation promoted expression of several mineralization-associated markers, however, HDACi-induced cell migration and wound healing were impaired. Data demonstrate that short-term low-dose SAHA-exposure promotes mineralization in DPCs by modulating gene pathways and tissue proteases. MMP-13i further increased mineralization-associated events, but decreased HDACi cell migration indicating a specific role for MMP-13 in pulpal repair processes. Pharmacological inhibition of HDAC and MMP may provide novel insights into pulpal repair processes with significant translational benefit. J. Cell. Physiol. 231: 798-816, 2016. © 2015 Wiley Periodicals, Inc.

Osteochondral alteration in a child treated with levetiracetam: a rare case of juvenile osteochondritis dissecans of the talar head

Levetiracetam is a relatively novel antiepileptic drug used for the treatment of partial and generalized seizures in adult and children. Several animal studies describe a possible drug adverse effect on skeletal growth and metabolism. We present a case report of a 10-year-old female child who underwent a prolonged 7-year treatment with levetiracetam for sporadic secondary convulsions secondary to enterovirus encephalitis at the age of 15 months. This patient developed an osteochondritis dissecans lesion (OCD) of the talar head well treated conservatively. Only a few cases have been described of this rare type of OCD. We hypothesize a possible association between levetiracetam therapy and OCD development, suggesting the importance of long-term control of bone growth in levetiracetam-treated pediatric populations.

Bone Mineral Changes in Epilepsy Patients During Initial Years of Antiepileptic Drug Therapy

Antiepileptic drug (AED) therapy is associated with decreased bone mineral density; however, the time course for this development is unclear. The aim of this study was to evaluate bone mineral changes during the initial years of AED therapy in AED-naive, newly diagnosed epilepsy patients compared with non-AED users. In 49 epilepsy patients newly started on AEDs and in 53 non-AED users of both genders, bone mineral density (BMD) and bone mineral content were measured using dual-energy X-ray absorptiometry at baseline (within the first year of therapy) and at least 1 yr later. Bone changes between the 2 assessments, adjusted for age, height, and weight, were calculated as the annual rate of change. The median duration of AED therapy was 3.5 mo at baseline and 27.6 mo at follow-up. No overall difference was found in mean BMD and bone mineral content measures between user and nonuser cohorts in both cross-sectional baseline and the annual rate of change (p > 0.05). However, users on carbamazepine monotherapy (n = 11) had an increased annual rate of total hip (-2.1% vs -0.8%, p = 0.020) and femoral neck BMD loss (-2.1% vs -0.6%, p = 0.032) compared to nonusers. They also had a marginally higher rate of femoral neck BMD loss (-2.1%, p = 0.049) compared with valproate (-0.1%, n = 13) and levetiracetam users (+0.6%, n = 13). During the initial years of AED treatment for epilepsy, no difference was found in bone measures between AED users as a group and nonuser cohorts. However, the data suggested that carbamazepine monotherapy was associated with increased bone loss at the hip regions, compared to users of levetiracetam or valproate and nonusers. Larger studies of longer duration are warranted to better delineate the bone effects of specific AEDs, with further consideration of the role of early dual-energy X-ray absorptiometry scanning and careful AED selection in potentially minimizing the impact on bone health in these patients.

Epigenetic Mechanisms in Bone Biology and Osteoporosis: Can They Drive Therapeutic Choices?

Osteoporosis is a complex multifactorial disorder of the skeleton. Genetic factors are important in determining peak bone mass and structure, as well as the predisposition to bone deterioration and fragility fractures. Nonetheless, genetic factors alone are not sufficient to explain osteoporosis development and fragility fracture occurrence. Indeed, epigenetic factors, representing a link between individual genetic aspects and environmental influences, are also strongly suspected to be involved in bone biology and osteoporosis. Recently, alterations in epigenetic mechanisms and their activity have been associated with aging. Also, bone metabolism has been demonstrated to be under the control of epigenetic mechanisms. Runt-related transcription factor 2 (RUNX2), the master transcription factor of osteoblast differentiation, has been shown to be regulated by histone deacetylases and microRNAs (miRNAs). Some miRNAs were also proven to have key roles in the regulation of Wnt signalling in osteoblastogenesis, and to be important for the positive or negative regulation of both osteoblast and osteoclast differentiation. Exogenous and environmental stimuli, influencing the functionality of epigenetic mechanisms involved in the regulation of bone metabolism, may contribute to the development of osteoporosis and other bone disorders, in synergy with genetic determinants. The progressive understanding of roles of epigenetic mechanisms in normal bone metabolism and in multifactorial bone disorders will be very helpful for a better comprehension of disease pathogenesis and translation of this information into clinical practice. A deep understanding of these mechanisms could help in the future tailoring of proper individual treatments, according to precision medicine's principles.

The Impact of Anti-Epileptic Drugs on Growth and Bone Metabolism

Epilepsy is a common neurological disorder worldwide and anti-epileptic drugs (AEDs) are always the first choice for treatment. However, more than 50% of patients with epilepsy who take AEDs have reported bone abnormalities. Cytochrome P450 (CYP450) isoenzymes are induced by AEDs, especially the classical AEDs, such as benzodiazepines (BZDs), carbamazepine (CBZ), phenytoin (PT), phenobarbital (PB), and valproic acid (VPA). The induction of CYP450 isoenzymes may cause vitamin D deficiency, hypocalcemia, increased fracture risks, and altered bone turnover, leading to impaired bone mineral density (BMD). Newer AEDs, such as levetiracetam (LEV), oxcarbazepine (OXC), lamotrigine (LTG), topiramate (TPM), gabapentin (GP), and vigabatrin (VB) have broader spectra, and are safer and better tolerated than the classical AEDs. The effects of AEDs on bone health are controversial. This review focuses on the impact of AEDs on growth and bone metabolism and emphasizes the need for caution and timely withdrawal of these medications to avoid serious disabilities.

Is there any therapeutic value for the use of histone deacetylase inhibitors for chronic pain?

Chronic pain is a complex clinical condition that reduces the quality of life for billions of people. In recent years, the role of epigenetic modulation in the control of long-term neuronal plasticity has attracted the attention of pain researchers. The epigenetic mechanisms include covalent modifications of DNA and/or histone proteins. Mounting evidence suggests that the activity of histone deacetylases (HDACs) and levels of histone acetylation are dynamic and that these enzymes modulate pain-related synaptic plasticity. Therefore, HDACs play essential roles in chronic pain development and maintenance. In this mini review, we will discuss the role of HDACs in the pathogenesis of chronic pain and will consider the therapeutic value of HDAC inhibitors in treating chronic pain.

Epigenetic Mechanisms Regulating Mesenchymal Stem Cell Differentiation

Human Mesenchymal Stem Cells (hMSCs) have emerged in the last few years as one of the most promising therapeutic cell sources and, in particular, as an important tool for regenerative medicine of skeletal tissues. Although they present a more restricted potency than Embryonic Stem (ES) cells, the use of hMCS in regenerative medicine avoids many of the drawbacks characteristic of ES cells or induced pluripotent stem cells. The challenge in using these cells lies into developing precise protocols for directing cellular differentiation to generate a specific cell lineage. In order to achieve this goal, it is of the upmost importance to be able to control de process of fate decision and lineage commitment. This process requires the coordinate regulation of different molecular layers at transcriptional, posttranscriptional and translational levels. At the transcriptional level, switching on and off different sets of genes is achieved not only through transcriptional regulators, but also through their interplay with epigenetic modifiers. It is now well known that epigenetic changes take place in an orderly way through development and are critical in the determination of lineage-specific differentiation. More importantly, alteration of these epigenetic changes would, in many cases, lead to disease generation and even tumour formation. Therefore, it is crucial to elucidate how epigenetic factors, through their interplay with transcriptional regulators, control lineage commitment in hMSCs.

Challenges in the pharmacological management of epilepsy and its causes in the elderly

Epilepsy represents the third most common neurological disorders in the elderly after cerebrovascular disorders and dementias. The incidence of new-onset epilepsy peaks in this age group. The most peculiar aetiologies of late-onset epilepsy are stroke, dementia, and brain tumours. However, aetiology remains unknown in about half of the patients. Diagnosis of epilepsy may be challenging due to the frequent absence of ocular witnesses and the high prevalence of seizure-mimics (i.e. transient ischemic attacks, syncope, transient global amnesia or vertigo) in the elderly. The diagnostic difficulties are even greater when patients have cognitive impairment or cardiac diseases. The management of late-onset epilepsy deserves special considerations. The elderly can reach seizure control with low antiepileptic drugs (AEDs) doses, and seizure-freedom is possible in the vast majority of patients. Pharmacological management should take into account pharmacokinetics and pharmacodynamics of AEDs and the frequent occurrence of comorbidities and polytherapy in this age group. Evidences from double-blind and open-label studies indicate lamotrigine, levetiracetam and controlled-release carbamazepine as first line treatment in late-onset epilepsy.

Preliminary evidence for gender effects of levetiracetam monotherapy duration on bone health of patients with epilepsy

Enzyme-inducing antiepileptic drugs AEDs have adverse effects on bone mineral density (BMD), whereas studies on levetiracetam (LEV), a nonenzyme-inducing agent, have showed conflicting results. The aim of this study was to further elucidate the role of LEV in bone health. A sample of forty-six patients with epilepsy (mean age: 35.7 years, range: 20.2-64.2 years, 39.1% males) on LEV monotherapy for at least one year (range: 1.5-14.5 years, median 5.5 years) underwent femoral neck (FN) and lumbar spine (LS) BMD measurements. The T- and Z-scores were calculated. Results showed that 15.2% of the patients were identified with osteopenia and none with osteoporosis. Pearson's correlations revealed a negative but not significant association of LEV duration with bone-related measurements (range of rhos: from -0.004 to -0.23), except for LS T-scores. In terms of FN BMD measurements, Z-scores, and T-scores, longer LEV therapy duration had adverse but not significant effects on bone health after adjusting for age and gender. With regard to LS BMD measurements, Z-scores, and T-scores, men taking LEV for at least 5.5 years had better, although not significant, bone health compared with men with shorter LEV exposure, after adjusting for age. The opposite was found in women, although differences did not reach significance. These preliminary results are indicative of a differential effect of LEV therapy duration in men and women, which could presumably account for the incongruity of the already published studies. Also, LS assessments were more sensitive to these gender differences. Future larger studies should validate these results.

Effects of Oxcarbazepine and Levetiracetam on Calcium, Ionized Calcium, and 25-OH Vitamin-D3 Levels in Patients with Epilepsy

Objective

The primary objective of the present study was to further elucidate the effects of oxcarbazepine (OXC) and levetiracetam (LEV) monotherapies on the bone health status of patients with epilepsy.

Methods

This study included 48 patients who attended our epilepsy outpatient clinic, had a diagnosis of epilepsy, and were undergoing either OXC or LEV monotherapy and 42 healthy control subjects. The demographic and clinical features of the patients, including gender, age, onset of disease, daily drug dosage, and duration of disease, were noted. Additionally, the calcium, ionized calcium, and 25-OH vitamin-D3 levels of the participants were prospectively evaluated.

Results

The 25-OH vitamin-D3, calcium, and ionized calcium levels of the patients taking OXC were significantly lower than those of the control group. These levels did not significantly differ between the patients taking LEV and the control group, but there was a significant negative relationship between daily drug dose and ionized calcium levels in the LEV patients.

Conclusion

In the present study, anti-epileptic drugs altered the calcium, ionized calcium, and 25-OH vitamin-D3 levels of epilepsy patients and resulted in bone loss, abnormal mineralization, and fractures. These findings suggest that the calcium, ionized calcium, and 25-OH vitamin-D3 levels of patients with epilepsy should be regularly assessed.

Impact of antiepileptic drugs on bone health: Need for monitoring, treatment, and prevention strategies

Epilepsy is the most common neurological disorder affecting approximately 50 million people worldwide. In India, overall prevalence of epilepsy is reported to be 5.59/1000 population. Antiepileptic drugs (AEDs) constitute the main-stay of treatment with a large number of AEDs available in the market. High incidence of adverse effects is a major limitation with AEDs. One of the major concerns is significant metabolic effects on the bone. However, little attention has been paid to this issue because most of the bone effects remain subclinical for a long time and may take years to manifest clinically. The main effects include hypocalcemia, hypophosphatemia, reduced serum levels of Vitamin D, increase in parathormone (PTH) levels, and alterations in bone turnover markers. The CYP450 enzyme-inducing AEDs such as phenytoin, phenobarbital, carbamazepine, and primidone are the most common AEDs associated with bone disorders while the data regarding the effect of valproate and newer AEDs such as lamotrigine, gabapentin, vigabatrin, levetiracetam, and topiramate on bone metabolism and bone density are scanty and controversial. Deficiency of Vitamin D is commonly described as a cause for the bone loss in epileptic patients while others being decreased absorption of calcium, increased PTH levels, and inhibition of calcitonin secretion, etc. However, there are no formal practical guidelines for the management of bone disease among those taking AEDs. Evidence-based strategies regarding monitoring, prevention, and treatment of bone diseases in patients on AED therapy are needed.

Markers of bone turnover in patients with epilepsy and their relationship to management of bone diseases induced by antiepileptic drugs

Data from cross-sectional and prospective studies revealed that patients with epilepsy and on long-term treatment with antiepileptic drugs (AEDs) are at increased risk for metabolic bone diseases. Bone diseases were reported in about 50% of patients on AEDs. Low bone mineral density, osteopenia/osteoporosis, osteomalacia, rickets, altered concentration of bone turnover markers and fractures were reported with phenobarbital, phenytoin, carbamazepine, valproate, oxcarbazepine and lamotrigine. The mechanisms for AEDs-induced bone diseases are heterogeneous and include hypovitaminosis D, hypocalcemia and direct acceleration of bone loss and/or reduction of bone formation. This article reviews the evidence, predictors and mechanisms of AEDs-induced bone abnormalities and its clinical implications. For patients on AEDs, regular monitoring of bone health is recommended. Prophylactic administration of calcium and vitamin D is recommended for all patients. Treatment doses of calcium and vitamin D and even anti-resorptive drug therapy are reserved for patients at high risk of pathological fracture.

The bone mineral content alterations in pediatric patients medicated with levetiracetam, valproic acid, and carbamazepine

AIM

The negative effect of antiepileptic drugs on bone health has been previously documented. However, which antiepileptic drug is safer in regard to bone health is still questionable. Our aims were to investigate the bone mineral density alterations in pediatric patients who receive antiepileptic medication for a minimum of two years and to compare the results of these drugs.

MATERIALS AND METHODS

Fifty-nine patients (32 males, 27 females; mean age: 8.6±4.6years) and a control group (13 males, 7 females; mean age: 7.6±3.3years) were included in the study. The patients were receiving necessarily the same antiepileptic drugs (AEDs) for at least two years, and none of the patients had mental retardation or cerebral palsy. The patients were divided into three groups: group 1 (patients receiving levetiracetam (LEV), n=20), group 2 (patients receiving carbamazepine (CBZ), n=11), and group 3 (patients receiving valproic acid (VPA), n=28). Plasma calcium (Ca), phosphorus (P), parathyroid hormone (PTH), alkaline phosphatase (ALP), vitamin D levels, and bone mineral density (BMD) values of femur and vertebras (L1-4) and z-scores (comparative results of BMD values of the patients with the age- and gender-matched controls in device database) of the groups were compared.

RESULTS

The differences between P, PTH, ALP and age, Ca and BMD results, and vitamin D levels of the patients in all four groups was not statistically significant according to Kruskal-Wallis test (p>0.05). The z-score levels of all the patient and control groups were also not statistically significantly different compared with each other.

CONCLUSION

In contrast to previous reports in pediatric patients, our study has documented that there is not a considerable bone loss in patients receiving long-term AED medication. Although levetiracetam has been proposed as bone-protecting medication, we did not observe any difference between AEDs regarding bone mineral density after two years of treatment.

Epigenetic modulation of dental pulp stem cells: implications for regenerative endodontics

Dental pulp stem cells (DPSCs) offer significant potential for use in regenerative endodontics, and therefore, identifying cellular regulators that control stem cell fate is critical to devising novel treatment strategies. Stem cell lineage commitment and differentiation are regulated by an intricate range of host and environmental factors of which epigenetic influence is considered vital. Epigenetic modification of DNA and DNA-associated histone proteins has been demonstrated to control cell phenotype and regulate the renewal and pluripotency of stem cell populations. The activities of the nuclear enzymes, histone deacetylases, are increasingly being recognized as potential targets for pharmacologically inducing stem cell differentiation and dedifferentiation. Depending on cell maturity and niche in vitro, low concentration histone deacetylase inhibitor (HDACi) application can promote dedifferentiation of several post-natal and mouse embryonic stem cell populations and conversely increase differentiation and accelerate mineralization in DPSC populations, whilst animal studies have shown an HDACi-induced increase in stem cell marker expression during organ regeneration. Notably, both HDAC and DNA methyltransferase inhibitors have also been demonstrated to dramatically increase the reprogramming of somatic cells to induced pluripotent stem cells (iPSCs) for use in regenerative therapeutic procedures. As the regulation of cell fate will likely remain the subject of intense future research activity, this review aims to describe the current knowledge relating to stem cell epigenetic modification, focusing on the role of HDACi on alteration of DPSC phenotype, whilst presenting the potential for therapeutic application as part of regenerative endodontic regimens.

Histone deacetylase inhibition destabilizes the multi-potent state of uncommitted adipose-derived mesenchymal stromal cells

Human adipose-derived mesenchymal stromal cells (AMSCs) grown in platelet lysate are promising agents for therapeutic tissue regeneration. Here, we investigated whether manipulation of epigenetic events by the clinically relevant histone deacetylase inhibitor suberoylanilide hydroxamic acid (SAHA) alters differentiation of AMSCs. The multipotency of AMSCs was validated by their ability to differentiate into osteogenic, chondrogenic, and adipogenic lineages. High-throughput RNA sequencing and RT-qPCR established that human histone deacetylases (HDAC1 to HDAC11, and SIRT1 to SIRT7) are differentially expressed in AMSCs. SAHA induces hyper-acetylation of histone H3 and H4, stimulates protein expression of the HDAC-responsive gene SLC9A3R1/NHERF1 and modulates the AKT/FOXO1 pathway. Biologically, SAHA interferes with osteogenic, chondrogenic and adipogenic lineage commitment of multipotent AMSCs. Mechanistically, SAHA-induced loss of differentiation potential of uncommitted AMSCs correlates with multiple changes in the expression of principal transcription factors that control mesenchymal or pluripotent states. We propose that SAHA destabilizes the multi-potent epigenetic state of uncommitted human AMSCs by hyper-acetylation and perturbation of key transcription factor pathways. Furthermore, AMSCs grown in platelet lysate may provide a useful biological model for screening of new HDAC inhibitors that control the biological fate of human mesenchymal stromal cells.

Phenytoin and sodium valproate but not levetiracetam induce bone alterations in female mice

Adverse effects on the bone are amongst the potentially adverse clinical consequences with antiepileptic drugs (AEDs). This study compared the effects of 3 AEDs (phenytoin (PHT), sodium valproate (SVP), and levetiracetam (LTM)) on the bones of a Swiss strain of albino female mice. Drugs were administered daily for 4 months at doses that produced plasma concentrations corresponding to the clinically relevant therapeutic ranges. PHT and SVP (but not LTM) significantly lowered the bone mineral density (BMD) of lumbar vertebrae (L2–L4) as evaluated by dual-energy X-ray absorptiometry (DEXA) scan. The findings were supported by histopathology of vertebral (lumbar) bone and analysis of bone turnover markers. While both PHT and SVP reduced alkaline phosphatase (ALP) and hydroxyproline (HxP) in lumbar vertebrae, and elevated tartarate-resistant acid phosphatase (TRAP) and urinary excretion of calcium, LTM did not affect any of these markers of bone turnover, indicating that the drug might be a safer option in female epileptic patients prone to bone changes.