Increased high-density lipoprotein cholesterol in patients with epilepsy treated with carbamazepine: a gender-related study

Sex Differences in Adverse Effects of Antiseizure Medications in Adults with Epilepsy: A Systematic Review

BACKGROUND

Sex differences in epilepsy have been described in prevalence, seizure propensity and response to treatment. Therefore, taking into account sex-based differences in epilepsy is important for both diagnostic purposes and therapeutic considerations. However, little is known about sex differences in adverse effects of antiseizure medications (ASMs).

OBJECTIVES

We performed a systematic review searching for sex differences in adverse effects of ASMs in adult persons with epilepsy (PWE) as part of a wider project aimed to assess sex-based differences in efficacy and adverse effects of ASMs in PWE.

METHODS

We conducted a comprehensive literature search in the PubMed database. The search was conducted with no restriction on publication date, and all results up to April 2020 were included. We included articles written in English, Italian, Spanish, or French that evaluated adverse effects of one or more ASMs in PWE, with specific mention of the two sexes. When appropriate, Newcastle-Ottawa or Jadad scales were used to assess study quality.

RESULTS

Of 5164 identified studies, only 167 considered sex in the analysis and were therefore included. Significant sex-related differences were found in 58 of those studies. We found a consistently higher frequency of cutaneous adverse effects in females; higher risk of developing general adverse effects on different ASMs in females; stronger risk of adverse effects on bone metabolism in females, mainly on treatment with enzyme-inducing ASMs; a concordant higher risk of visual field loss was noted in males on vigabatrin; an overall worse lipid profile in males; as well as higher leptin levels and higher body mass index in females treated with various ASMs.

CONCLUSIONS

Our analysis has identified some important sex differences in the adverse effects of ASMs. Clinicians should be aware of these differences when informing patients about the risks associated with ASM treatment in PWE.

Let's talk about sex: Differences in drug therapy in males and females

Professor Henry Higgins in My Fair Lady said, 'Why can't a woman be more like a man?' Perhaps unintended, such narration extends to the reality of current drug development. A clear sex-gap exists in pharmaceutical research spanning from preclinical studies, clinical trials to post-marketing surveillance with a bias towards males. Consequently, women experience adverse drug reactions from approved drug products more often than men. Distinct differences in pharmaceutical response across drug classes and the lack of understanding of disease pathophysiology also exists between the sexes, often leading to suboptimal drug therapy in women. This review explores the influence of sex as a biological variable in drug delivery, pharmacokinetic response and overall efficacy in the context of pharmaceutical research and practice in the clinic. Prospective recommendations are provided to guide researchers towards the consideration of sex differences in methodologies and analyses. The promotion of disaggregating data according to sex to strengthen scientific rigour, encouraging innovation through the personalisation of medicines and adopting machine learning algorithms is vital for optimised drug development in the sexes and population health equity.

Impact of enzyme-inducing anti-epilepsy drugs on lipid levels in elderly patients with epilepsy

It has been speculated that patients with epilepsy in elderly is increasing. The effect of enzyme-inducing antiepileptic drugs (EIAED) on lipid metabolism is well known. However, the study in elderly subjects has been rarely conducted. Furthermore, it has not been directly assessed whether EIAED use causes the change of lipid levels from normal range to abnormal range. Adult patients with epilepsy (235 on EIAED, 213 on non-EIAED) were divided by age (20-64, 65-74 and 75 over years old). Longitudinal change (before starting AED, in 3 and 6 months after starting AED) of serum total cholesterol (TC), triglyceride (TRIG), HDL cholesterol (HDL-C), LDL cholesterol (LDL-C) and non-HDL cholesterol (non-HDL-C) were retrospectively analyzed using mixed models. The risk of change of lipid levels from normal range to abnormal range was also assessed by logistic regression analysis. Comparison between patients with EIAED use (EIAED group) and patients with non-EIAED use (non-EIAED group) revealed significant differences. non-EIAED group was set as reference. Differences in least square mean (LSM), 95 % confidence interval (CI) and P value in analysis of LDL-C and non-HDL-C levels (1 × 10^-2) were as follows: 0.23 (0.10 ∼ 0.36), P < 0.001, 0.22 (0.09 ∼ 0.33), P = 0.001 in patients with age 65-74. In patients of age over 75, those were 0.08 (0.01 ∼ 0.15), P = 0.038, 0.17 (0.07 ∼ 0.26), P < 0.001, respectively. In patients with age 65-74, odds ratios (ORs) (95 % CI) in change of TC, LDL and non-HDL-C level from normal range to abnormal range were 32.28 (1.83-567.05), 48.43 (2.69-869.05), 12.04 (1.29-111.88), respectively. In patients with age 75 over, odds ratios (ORs) (95 % CI) in change of TC, LDL and non-HDL-C level from normal range to abnormal range were 46.02 (2.77-762.89), 5.53 (1.27-23.94), 2.38 (1.01-10.76), respectively. EIAED use had significant impact on changes in lipid levels in elderly patients. Furthermore, we could assess the impact of switching AED from EIAED to levetiracetam (LEV) in 36 patients including elderly. Switching AED from EIAED to LEV had significant impact in reducing TC, TRIG, LDL-C and non-HDL-C in both younger adult and elderly patients.

Discontinuation of carbamazepine due to concerns of long-term consequences of enzyme induction

Objective

Treatment with carbamazepine (CBZ), a potent enzyme inducer, is known to affect the lipid profile, steroid, and vitamin D metabolism. Consequently, it has been postulated that patients on CBZ should be switched to noninducing antiepileptic drugs (AEDs). However, little is known about the seizure outcome following a CBZ switch in seizure‐free patients. We aimed to address this issue using a controlled observational study design.

Methods

Fifty‐eight patients taking CBZ for focal epilepsy were assessed for discontinuing CBZ treatment due to concerns of long‐term adverse‐effects; 34 discontinued its therapy and 24 continued with CBZ. Six‐month seizure freedom was the primary end point. Furthermore, serum samples (total cholesterol (TC), low‐density lipoprotein (LDL), high‐density lipoprotein (HDL), triglycerides, sex hormone–binding globulin (SHBG), free testosterone, and 25‐hydroxyvitamin D levels from before and at least 3 months after discontinuation or continuation were obtained from all patients.

Results

Seizure‐free patients had a 5‐fold elevated odds of seizure recurrence if CBZ was discontinued (95% confidence interval [CI 0.51–49.3; p = 0.17). A significant decrease in serum levels of TC, LDL, HDL, and SHBG as well as a significant increase in that of free testosterone were found in the discontinuation group compared with those who continued CBZ. Nonsignificant changes in triglycerides and vitamin D levels were detected.

Significance

Discontinuation of CBZ in seizure‐free patients seems to carry a moderate, but legitimate, risk of relapse. Conversely, our results indicate that CBZ might have unfavorable effects on serum levels of TC, LDL, HDL, SHBG, and free testosterone.

Integrated network analysis reveals potentially novel molecular mechanisms and therapeutic targets of refractory epilepsies

Epilepsy is a complex neurological disorder and a significant health problem. The pathogenesis of epilepsy remains obscure in a significant number of patients and the current treatment options are not adequate in about a third of individuals which were known as refractory epilepsies (RE). Network medicine provides an effective approach for studying the molecular mechanisms underlying complex diseases. Here we integrated 1876 disease-gene associations of RE and located those genes to human protein-protein interaction (PPI) network to obtain 42 significant RE-associated disease modules. The functional analysis of these disease modules showed novel molecular pathological mechanisms of RE, such as the novel enriched pathways (e.g., "presynaptic nicotinic acetylcholine receptors", "signaling by insulin receptor"). Further analysis on the relationships between current drug targets and the RE-related disease genes showed the rational mechanisms of most antiepileptic drugs. In addition, we detected ten potential novel drug targets (e.g., KCNA1, KCNA4-6, KCNC3, KCND2, KCNMA1, CAMK2G, CACNB4 and GRM1) located in three RE related disease modules, which might provide novel insights into the new drug discovery for RE therapy.

Favorable change of lipid profile after carbamazepine withdrawal

OBJECTIVE

Patients treated with carbamazepine (CBZ) have increased serum levels of total cholesterol (TC), high-density lipoproteins (HDL), and low-density lipoproteins (LDL). We aimed to investigate whether these changes of serum lipids are reversible after CBZ withdrawal.

MATERIAL AND METHODS

We used a prospective, randomized double-blinded design. A total of 160 patients who had been seizure free on anti-epileptic drug monotherapy for more than 2 years were included and randomized to withdrawal or not. The intervention was completed by 150 (80 females, 53%) patients. Serum samples from before and 4 months after completed withdrawal or no withdrawal were obtained from 130 patients (63 females, 48%). Of these, 84 were treated with CBZ, 28 with valproate, nine with phenytoin, four with phenobarbital, and five with lamotrigine. Of the patients who had been treated with CBZ, 47 were randomized to the withdrawal group, and 37 were randomized to the non-withdrawal group.

RESULTS

Among the CBZ-treated patients, a significant decrease in serum levels of TC, LDL, and apolipoprotein B (ApoB) were found in the withdrawal group compared with the non-withdrawal group. Mean differences in change were as follows: TC 0.68 mmol/l (P = 0.005, CL - 1.15 to -0.21); LDL - 0.67 mmol/l (P = 0.001, CL - 1.03 to -0.29); ApoB - 0.13 g/l (P = 0.02, CL - 0.23 to -0.03). No significant changes in HDL, apolipoprotein A, and C-reactive protein were detected.

CONCLUSION

Our results indicate that CBZ may have unfavorable effects on serum levels of TC, LDL, and ApoB. However, these changes seem to be reversible even after years of treatment.

Metabolic syndrome and anticonvulsants: A comparative study of valproic acid and carbamazepine

PURPOSE

The aim of this study was to compare the risk of metabolic syndrome (MS) and evaluate related factors for MS among people with epilepsy treated with valproate (VPA) or carbamazepine (CBZ).

METHODS

A total of 213 adult patients with epilepsy treated with VPA (n=118) or CBZ (n=95) monotherapy were included in the study. Participants were evaluated for the presence of MS, diagnosed according to the National Cholesterol Education Program Adult Treatment Panel III criteria.

RESULTS

In the multiple logistic regression analysis, the risk of MS in CBZ- and VPA-treated patients was similar (odds ratio [OR]=0.99; 95% confidence interval [CI], 0.43-2.26; P=0.979). A lower proportion of CBZ-treated patients had abnormally low levels of high-density lipoprotein cholesterol (OR=0.10; 95% CI, 0.02-0.42; P=0.002), whereas a lower proportion of VPA-treated patients had abnormally high concentrations of fasting blood glucose (OR=0.30; 95% CI, 0.13-0.69; P=0.004). Females treated with VPA tended to have a higher risk of MS (OR=1.48; 95% CI, 0.50-4.41; P=0.485) compared to males (OR=0.74; 95% CI, 0.28-1.96; P=0.551), although this difference was not statistically significant.

CONCLUSION

Although the overall risk of MS was similar in patients with epilepsy who were treated with VPA or CBZ, the distribution of MS components differed between treatment groups. Patients treated with CBZ or VPA less frequently had decreased high-density lipoprotein cholesterol levels or increased blood glucose concentrations, respectively. Females on VPA treatment could be at higher risk of MS than males.

Possible Induction of Cholinesterase in Epileptic Patients Treated With Anticonvulsant Drugs: Relationship With Lipoprotein Levels

The effect of enzyme-inducing anticonvulsant drugs on the serum concentrations of lipoproteins has been widely studied. However, there is little agreement between the results with regard to the possible development of a lipoprotein profile related to an increased or decreased cardiovascular risk. It has been suggested that cholinesterase (ChE) could be induced by these drugs, something of undeniable interest as ChE appears to have a relation to the metabolism of lipoproteins. The serum activity of ChE was determined in a group of 90 adult epileptic patients (56 male and 34 female) treated with phenobarbital, phenytoin, and carbamazepine. The liver enzyme induction produced by these drugs was then evaluated by determining serum gamma-glutamyltranspherase activity and urinary excretion of D-glucaric acid. A significant increase of serum ChE (p < 0.005) was found in the group of patients compared to a control group (n = 49) with a similar distribution for age and sex. A significant correlation was found for both male and female patients between ChE and concentrations of triglycerides, phospholipids, cholesterol, low-density lipoprotein (LDL) phospholipids, LDL-cholesterol, and apolipoprotein B (p < 0.01). Similarly, in female patients, ChE had a significant correlation with the total cholesterol/high-density lipoprotein (HDL) cholesterol and LDL-cholesterol/HDL-cholesterol ratios (p < 0.01). The ChE/HDL-cholesterol relationship, which has been proposed as a marker for cardiovascular risk, presented significant correlations with the total cholesterol/HDL-cholesterol and LDL-cholesterol/HDL-cholesterol ratios in patients of both sexes (p < 0.001). In the case of epileptic patients treated with enzyme-inducing anticonvulsant drugs, there may be an association between the possible induction of ChE and the metabolism of lipoproteins containing apolipoprotein B.

Cardiovascular risk factors in epilepsy patients taking levetiracetam, carbamazepine or lamotrigine

OBJECTIVES

The aim of the study was to investigate risk factors for cardiovascular disease in patients with epilepsy using the new antiepileptic drug levetiracetam (LEV), compared with patients taking carbamazepine (CBZ) or lamotrigine (LTG).

METHODS

Two hundred and twelve patients and 80 controls (age: 18-45 years) of both genders were included. The patients had been treated with either LEV (n = 52), CBZ (n = 87) or LTG (n = 73) monotherapy for at least 6 months. Total cholesterol (TC), low-density lipoprotein (LDL) and high-density lipoprotein (HDL) were measured. Smoking, drinking habits and physical activity were recorded and body mass index (BMI) was calculated.

RESULTS

Neither LEV nor LTG altered TC, LDL or HDL. Both men and women using CBZ had higher TC, HDL and LDL than controls. LDL/HDL and TC/HDL ratios were unchanged. Women on CBZ and LTG had a greater BMI when compared with the control group. Patients with epilepsy recorded less physical activity and lower alcohol use than the controls.

CONCLUSIONS

Neither LEV nor LTG affected blood lipid levels, while patients treated with CBZ have higher cholesterol, HDL and LDL than controls. The patients were less physically active, and women on CBZ and LTG had higher BMI.

Lipid levels in female patients with affective disorders

The role of serum lipids [total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG)] in the pathophysiology of mood disorders is not clear. The aim of this study was to determine lipid profiles in patients with affective disorders. The study included medication-free female subjects (41 patients with bipolar disorder, 22 in a manic and 19 in a depressive phase), 34 patients with major depression, and 50 healthy controls. Serum lipid levels were determined using standard laboratory tests. All patients had significantly lower HDL-C values than control subjects. Increased TG levels were found in patients with bipolar disorder compared with healthy subjects. The changes in lipid profiles persisted when data were adjusted for age, smoking and menopausal status. The results revealed no differences in cholesterol and LDL-C levels and body mass index, but significant differences in the ratios of cholesterol/HDL-C and LDL-C/HDL-C (atherogenic index) among groups. Our results suggest that low HDL-C levels and a high atherogenic index might be a hallmark of affective disorders. Since low HDL-C levels could be a risk factor for the development of coronary heart disease, further investigation of lipid metabolism in affective disorders is warranted.

Lipid profile, apolipoproteins A and B in children with epilepsy

In this study, lipid profile was assessed, and the intimal wall thickness of both carotid arteries in children with idiopathic epilepsy was measured. The study comprised 22 children with idiopathic epilepsy on either carbamazepine or valproate. A profile including triglycerides, total cholesterol, low-density and high-density lipoproteins cholesterol, apolipoproteins AI and B, and Duplex estimation of intimal wall thickness of carotid arteries were performed. Patients on carbamazepine showed increase in total cholesterol, low-density and high-density lipoproteins cholesterol, and decrease in apolipoprotein AI levels compared with controls. Levels of total cholesterol, low-density lipoproteins cholesterol, and apolipoprotein AI were reduced in patients receiving valproate compared with controls, whereas total cholesterol, high-density lipoproteins cholesterol, and apolipoprotein AI were reduced compared with those receiving carbamazepine. Carotid arteries intimal wall thickness was not significantly changed in any of the studied groups. Although atherogenic ratios are not changed, the lowered apolipoprotein AI levels may suggest an increased risk for coronary heart disease.

Platelet serotonin and serum lipids in psychotic mania

BACKGROUND

The role of serotonergic system and lipid status in the etiology of mania and its subtypes is not clear. The aims of the study were to determine platelet serotonin (5-HT) concentration, platelet monoamine oxidase (MAO) activity, and serum total cholesterol, high-density lipoprotein cholesterol (HDL), low-density lipoprotein cholesterol (LDL) and triglycerides (TG) in patients with psychotic and nonpsychotic subtypes of mania and in healthy control subjects.

METHODS

The serum lipids, platelet 5-HT and MAO were determined in 40 (17 psychotic, 23 nonpsychotic) drug free male inpatients with type I bipolar affective disorder, current episode mania (DSM-IV criteria), and in 32 healthy male subjects.

RESULTS

Platelet 5-HT levels in manic patients were similar to the values in healthy controls. Serum cholesterol and LDL values were significantly lower in manic patients than in healthy controls. Patients with psychotic features had increased platelet 5-HT concentrations and decreased levels of cholesterol and LDL as compared to the nonpsychotic manic patients and healthy controls. There was no significant difference in age, body mass index, platelet MAO activity, serum levels of TG and HDL between psychotic and nonpsychotic manic patients and healthy subjects.

LIMITATION

Data on physical activity, dietary habits and alcohol consumption before hospitalization were not collected.

CONCLUSION

The results of the present study suggest that biological differences between subtypes of mania might depend upon the presence of the psychotic symptoms. Our data confirm our previous results showing the increased platelet 5-HT concentration in psychotic disorders across the different diagnoses.

Evolution of serum lipids and lipoprotein (a) levels in epileptic children treated with carbamazepine, valproic acid, and phenobarbital

The concentration levels of serum lipids and lipoprotein (a) were measured in 20 children receiving carbamazepine, 25 children receiving valproic acid, and 5 children receiving phenobarbital at the following times: (1) during chronic treatment while eating a normal diet, (2) during chronic treatment while eating a low-fat diet (children treated with carbamazepine and phenobarbital with high levels of total cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol), and (3) 3 months after the end of treatment with antiepileptic drugs. Patients during chronic treatment and eating a normal diet revealed significant changes in lipids, but when we reevaluated the groups of children treated with carbamazepine and phenobarbital when they were eating a low-fat diet and reevaluated the three groups of children 3 months after the end of treatment, a complete return to normal of all parameters was observed. These data demonstrate that the changes induced by these drugs are transient, reversible, and influenced by a low-fat diet. (J Child Neurol 2006;21:48-53).

Serum thyroid hormone balance and lipid profile in patients with epilepsy

PURPOSE

Patients with epilepsy may exhibit changes in thyroid hormone balance, lipids and lipoproteins concentrations. The suggestion that lipid abnormalities are associated with subclinical thyroid dysfunction remains controversial. The aim of this study was to analyze whether thyroid dysfunction encountered in patients with epilepsy would also be associated with abnormal lipid profile.

METHODS

Eighty-eight patients with epilepsy and 30 control subjects were included in the study. A fasting blood sample for thyroid hormones, lipid profile and GGT determination was obtained.

RESULTS

The serum levels of FT3 was elevated in 10.2% of patients, FT4 was low in 28.4%, TSH was high in 4.6% and low in 2.3%. 13.6% of patients had high TC, 17.1% had high LDL-c, 60.2% had marked reduction of HDL-c levels (P<0.0001) and only 2.3% had high TG levels. Abnormalities were predominated in CBZ-treated patients. 27.3% patients with abnormal hormones had abnormal lipid profile. Significant association was identified between the serum TC, LDL-c, TG, GGT and EIAEDs and between the duration of illness and TG (r=-0.411; P=0.017), and FT4 (r=-0.412; P=0.018). HDL was higher in women than men (r=0.416; P<0.002). However, changes in HDL-c levels associated neither with duration of illness, type or serum levels of AEDs nor with age or degree of control on AEDs.

CONCLUSIONS

Our results support that (1) altered lipid metabolism might be associated but not solely influenced by thyroid hormones and (2) enzyme induction is not the main or only reason for altered thyroid function or HDL-c among patients with epilepsy. Hypothalamic/pituitary dysregulation by precisely mechanism caused by epilepsy itself or AEDs seems possible and (3) it is important to recognize that patients with epilepsy are at great risk for atherosclerosis, hence monitoring and correction of the culprit risks are mandatory.

The High Atherosclerotic Risk Among Epileptics: the Atheroprotective Role of Multivitamins

Neurologists have little concern about the high atherosclerotic risk among epileptics. Recent evidences mount that chronic epilepsy and prolonged use of antiepileptic drugs (AEDs) are associated with multiple risk factors that are critically implicated in pathobiology and dysfunction of the vessel wall through complex molecular mechanisms that promote atherogenesis. This review is concerned with three metabolic alterations, which are attributed as major risk factors for atherosclerosis among epileptics: altered metabolism of a) homocysteine (Hcy), b) lipids and lipoproteins, and c) uric acid. Most conventional AEDs reduce folic acid levels, thereby raising Hcy levels. Hyperhomosysteinemia is recently believed to induce endothelial dysfunction and promote atherosclerosis through complex oxidative and excitatory neurotoxic molecular mechanisms. However, Hcy itself is a convulsing substance with increased seizure recurrence and intractability to antiepileptic medications. AEDs can disturb lipid metabolism with resultant hypercholestrolemia and dyslipidemia, common recognized risks for atherosclerosis. Altered uric acid metabolism is common among epileptics. Uric acid has been implicated in endothelial cell damage and decreased endothelial nitric oxide bioavailability. In the presence of atherosclerotic milieu, uric acid interacts with other substrate toxicities and increased reactive oxygen species, accelerating atherosclerosis. The above information forms the rationale for future routine screening and correction of such metabolic alterations in epileptics. A convincing argument now develops that routine polyvitamin supplementation (folic acid, vitamin B12, vitamin B6, vitamin C, vitamin E, and beta-carotene) becomes increasingly important for women and men receiving AEDs at all ages. The atheroprotective effect of multivitamins is through their antioxidant and anti-inflammatory effects together with their lipid and Hcy lowering effects.

Interictal EEG discharges, reproductive hormones, and menstrual disorders in epilepsy

We evaluated reproductive endocrine function in women with unilateral temporolimbic epilepsy and normal control subjects to assess the effects of epilepsy, epilepsy laterality, and antiepileptic drug use on the cerebral regulation of hormonal secretion. The findings indicate that reproductive endocrine function differs between women with epilepsy and normal control subjects. Significant differences exist at all levels of the reproductive neuroendocrine axis, that is, hypothalamus, pituitary, and peripheral gland. Differences show significant relationships to the epilepsy itself as well as to medication use. Reproductive neuroendocrine changes occur in a stochastic manner such that the laterality of unilateral temporolimbic discharges is associated with predictable directional changes in hormonal secretion at all levels of the reproductive neuroendocrine axis. These directional changes are consistent with the finding that different reproductive disorders may develop in relation to left- and right-sided temporolimbic epilepsy. Hormonal changes can show close temporal relationship to the occurrence of interictal epileptiform discharges and may vary in relation to the laterality of the discharges. Antiepileptic drugs differ in their effects on reproductive hormone levels. There are notable differences between enzyme-inducing and noninducing drugs. Menstrual disorders are more common among women with interictal discharges as well as women with abnormal hormonal findings.

Lipoprotein(a) concentration increases during treatment with carbamazepine

PURPOSE

Treatment with carbamazepine (CBZ) is known to affect apolipoprotein B-containing lipoprotein concentrations in serum. However, little is known about the effects of anticonvulsant drugs (AEDs) on lipoprotein(a) [Lp(a)], although Lp(a) has been characterized as independent cardiovascular risk factor. We investigated prospectively the effect of CBZ on lipoprotein(a) concentration in normolipidemic healthy adults.

METHODS

Twenty male volunteers were included in the study. Lp(a) levels were determined before and 69 +/- 19 days after CBZ administration by using an enzyme-linked immunoassay.

RESULTS

CBZ (mean plasma concentration, 6.6 +/- 0.6 microg/ml) caused a significant increase in Lp(a) concentrations, with a median change of +19.5% (95% CI: +8.2, +53.3; p < 0.001). Total cholesterol, low density lipoprotein (LDL) cholesterol, and triglycerides also increased significantly.

CONCLUSIONS

Although the precise mechanism of action of CBZ on Lp(a) elevation remains uncertain, it might be related to its enzyme-inducing properties. During treatment with CBZ, special focus should be given to elevated LDL cholesterol and Lp(a) concentrations with regard to increased risk for atherosclerotic vascular diseases.

Carbamazepine increases atherogenic lipoproteins: mechanism of action in male adults

Treatment with carbamazepine (CBZ) affects cholesterol concentrations, but little is known about the precise nature and underlying mechanisms of changes in lipoprotein metabolism. We investigated prospectively the effects of CBZ on lipid metabolism in normolipemic adults. In 21 healthy males, lipoprotein and noncholesterol sterol concentrations were measured before and during treatment with CBZ for 70 +/- 18 days. Thirteen subjects underwent kinetic studies of apolipoprotein-B (ApoB) metabolism with the use of endogenous stable isotope labeling. Lipoprotein kinetic parameters were calculated by multicompartmental modeling. Significant increases in total cholesterol, in ApoB-containing lipoproteins [very-low-density lipoprotein (VLDL), intermediate density lipoprotein (IDL), and low-density lipoprotein (LDL)], and in triglycerides, but not in high-density lipoprotein (HDL), were observed. Lipoprotein particle composition remained unchanged. Mean fractional catabolic and production rates of ApoB-containing lipoproteins were not significantly different, although mean production rates of VLDL and IDL were substantially increased (+46 +/- 139% and +30 +/- 97%, respectively), whereas mean production of LDL remained unchanged (+2.1 +/- 45.6%). Cholestanol in serum increased significantly but not the concentrations of plant sterols (campesterol, sitosterol) and the cholesterol precursors (lathosterol, mevalonic acid). There was a significant correlation between the decrease in free thyroxine and the increase in IDL cholesterol. Treatment with CBZ increases mainly ApoB-containing lipoproteins. CBZ seems not to influence endogenous cholesterol synthesis or intestinal absorption directly. The increase is neither related to increased ApoB production nor to decreased catabolism but is rather due to changes in the conversion cascade of IDL particles, most likely as an indirect effect through a decrease in thyroid hormones.

Brain sterols in the AY-9944 rat model of atypical absence seizures

PURPOSE

The AY-9944 (AY)-treated rat is a reproducible and clinically relevant animal model of atypical absence seizures. AY inhibits cholesterol synthesis, but the relation between brain sterol levels and the spontaneously recurrent absence seizures has not been determined.

METHODS

Long-Evans hooded rats were treated every 6 days from postnatal day (P)2 to P20 with AY (7.5 mg/kg, s.c.) or saline. Electrodes were permanently implanted under pentobarbital anesthesia at P50. Spike-and-wave discharge (SWD) duration and amplitude were quantified at P55. Changes in brain sterols after AY were examined in three different experiments, looking at brain regions (experiment 1), recovery after stopping AY (experiment 2), or gender differences (experiment 3).

RESULTS

Experiment 1: AY caused spontaneously recurrent slow SWD that lasted 59 times longer and had a 3.2-fold higher amplitude than that in controls. At P55, brain cholesterol was reduced and 7-dehydrocholesterol was increased in all brain regions (p < 0.0001). Experiment 2: Four hundred days after stopping AY-9944 treatment (P420), brain sterol levels had returned to normal levels, but the AY-induced SWD lasted twice as long as at P55. Experiment 3: At P55, AY-induced changes in plasma and liver (but not brain) sterols were significantly more severe in females compared with males.

CONCLUSIONS

AY-induced seizures appear to be related to AY-induced changes in brain sterols but persisted long after the sterols had returned to normal after the last AY injection. Hence, there appears to be a critical developmental window during which the AY must be given but after which the AY-induced change in brain sterols is no longer essential to sustaining the seizures.

Drug-Induced lipid changes: a review of the unintended effects of some commonly used drugs on serum lipid levels

Many drugs besides lipid-lowering drugs affect serum lipid levels in either a potentially harmful or beneficial way, and may therefore increase or decrease the risk of cardiovascular disease. Diuretics, beta-blocking agents, progestogens, combined oral contraceptives containing 'second generation' progestogens, danazol, immunosuppressive agents, protease inhibitors and enzyme-inducing anticonvulsants adversely affect the lipid profile. They increase total cholesterol, low density lipoprotein cholesterol and triglycerides by up to 40, 50 and 300%, respectively, and decrease high density lipoprotein cholesterol by a maximum of 50%. Conversely, alpha-blocking agents, estrogens, hormone replacement therapy, combined oral contraceptives containing 'third generation' progestogens, selective estrogen receptor modulators, growth hormone and valproic acid show mostly beneficial effects on the lipd profile. Some drugs, for example, isotretinoin, acitretin and antipsychotics, mainly elevate triglyceride levels. Adverse or beneficial effects on serum cholesterol levels do not always translate into a higher or lower, respectively, incidence of cardiovascular disease. because these drugs may influence cardiovascular risk through multiple pathways. In some cases, excessive cholesterol levels occur, for example, with protease inhibitor therapy, and several cases of pancreatitis attributable to drug-induced hypertriglyceridaemia have been reported. Some general guidelines on the management of drug-induced dyslipidaemia can be given. Replacement of the dyslipidaemia-inducing drug by an equivalent alternative therapy is preferred. However, such alternatives are often difficult to find. If there is no equivalent alternative and treatment with the dyslipidaemia-inducing drug must be initiated, monitoring of serum lipid levels is important. If drug use is expected to be long term, the existing guidelines for the management of dyslipidaemia in the general population can be applied to drug-induced dyslipidaemia. In cases of extreme hyperlipidaemia, medication use should be reassessed.

Smith-Lemli-Opitz syndrome and other sterol disorders among Finns with developmental disabilities

Smith-Lemli-Opitz syndrome (SLOS) is an inherited disorder of cholesterol metabolism in which 7- and 8-dehydrocholesterols are accumulated in blood and tissues. Diagnosis of SLOS and other disorders in cholesterol metabolism (eg, cerebrotendinous xanthomatosis, phytosterolemia, desmosterolosis, and X-linked dominant Conradi-Hünermann-Happle syndrome) can be performed by gas-liquid chromatographic analysis of serum sterols. To elucidate their involvement in developmental disability, we evaluated serum sterols in two study groups: developmentally disabled subjects in long-term care (N = 322) and newborns and young children (N = 49) with features of SLOS in the Finnish population of 5 million. Only 1 SLOS case (type II) was found from among the 49 children. Seven additional adult cases (type I) with a wide range of clinical features and the serum sterol abnormalities characteristic of SLOS were detected from among the developmentally disabled subjects. The frequency of SLOS in the latter group was relatively high (7 in 322). No other hereditary sterol disorders were found, but two subgroups with low serum cholesterol precursor sterols and high serum plant sterols were identified. Several subjects, including the 7 SLOS patients, used ample medication and had abnormalities in serum sterol concentrations. Thus, among the subjects taking melperone, a high serum delta8-cholestenol level suggests an interference by the drug with cholesterol synthesis. Our results emphasize the importance of analyzing the serum sterols of developmentally disabled subjects to diagnose SLOS and of finding putative undiagnosed disorders in sterol metabolism associated with these clinical conditions.

The effects on lipid and apolipoprotein serum levels of long-term carbamazepine, valproic acid and phenobarbital therapy in children with epilepsy

The aim of the present study was to assess the effect of long-term carbamazepine (CBZ), valproic acid (VPA) and phenobarbital (PB) treatment on serum lipids and apolipoproteins in epileptic children. Serum levels of total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), very low-density lipoprotein cholesterol (VLDL-C) and triglycerides (TGs) were measured and the LDL-C/HDL-C and TC/HDL-C ratios were calculated in 320 children and adolescents (129 receiving CBZ, 127 receiving VPA and 64 receiving PB) suffering from various types of epilepsy. Additionally, in a subgroup of 181 children (68 CBZ; 78 VPA; 35 PB) apolipoprotein A-I (apoA-I), apolipoprotein B (apoB), HDL2-C and HDL3-C were measured and apoA-I/apoB and HDL2-C/HDL3-C ratios were calculated. Results of the measurements were compared with those of 169 age-and sex-matched healthy controls. None of the variables considered was significantly correlated with time elapsed since start of treatment or with drug concentration in serum. TC and LDL-C serum levels were high in children receiving CBZ or PB and low in those treated with VPA. Serum LDL-C level exceeded 130 mg/dl in 27.9% of CBZ-group, 31.8% of the subjects receiving PB, but only in 7% of those receiving VPA and in 11.8% of control group subjects. CBZ-treated children also showed high HDL-C and HDL3-C values. In the group receiving VPA, HDL2-C, HDL2-C/HDL3-C ratio and apo B were significantly lower than in the control group. Mean apoA-I levels were low in all treated groups: by contrast, in neither group did TGs, VLDL-C levels and TC/HDL-C or LDL-C/HDL-C ratios differ significantly from the corresponding control group. Our results suggest that the effects of long-term AED therapy on lipid profile and, particularly, on apolipoprotein serum levels increase risk of atherosclerosis-related disease. Moreover, these results confirm our previously reported increased risk in CBZ and PB-treated patients.