HIV, metabolic syndrome X, inflammation, oxidative stress, and coronary heart disease risk : role of protease inhibitor exposure

Differences on measures of metabolic syndrome X and coronary heart disease (CHD) risk, as well as potential pathophysiological mediators, inflammation, and oxidative stress, were examined as a function of HIV serostatus and highly active antiretroviral therapy (HAART) regimen with and without protease inhibitors (PIs). Data from 164 men and women, aged 18 to 55 yr, were used to compare 82 HIV+ subjects who were free of hepatitis C virus and were on a stable HAART regimen for >/=6 mo, with 82 seronegative subjects matched on age, sex, body mass index, and ethnicity. For the HIV+ subjects, after controlling for diabetes status and HIV disease progression, PI exposure was associated with greater oxidative stress, triglyceridemia, and lipidemia than it was for non-PI-exposed HIV+ subjects, and the risk of a future myocardial infarction was up to 56% greater in PI-exposed than in non-PI-exposed subjects and 129% greater than in controls. Although it is likely that the greatest proportion of CHD risk in the HIV+ subjects may be accounted for by pathological conditions linked to HIV infection in interaction with mediating processes such as inflammation, central obesity, and dyslipidemia, which was greater than in controls, it appears that PI medications may exacerbate oxidative stress and hypertriglyceridemia to enhance this risk.

Cost-effective screening for the metabolic syndrome in patients treated with second-generation antipsychotic medications

OBJECTIVE

Despite concerns about the adverse effects of second-generation antipsychotics on weight regulation and glucose and lipid metabolism, little is known about the relationship between these agents and the metabolic syndrome. Because the metabolic syndrome is more strongly associated with cardiovascular morbidity and mortality than its individual components, attention to the full syndrome is important. The authors' goal was to explore the relationship between second-generation antipsychotics and the metabolic syndrome.

METHOD

They assessed the prevalence of metabolic syndrome in a nearly consecutive group of 89 acutely admitted psychiatric inpatients treated with at least one second-generation antipsychotic for different psychiatric disorders. Patients' waist circumference and blood pressure were measured as well as their fasting blood glucose and lipid levels.

RESULTS

Twenty-six (29.2%) of the 89 patients fulfilled criteria for the metabolic syndrome. Presence of the syndrome was associated with older age, higher body mass index, and higher values for each individual criterion of the metabolic syndrome but not with specific diagnoses or antipsychotic treatment regimens. Presence of abdominal obesity was most sensitive (92.0%), while fasting glucose >110 mg/dl was most specific (95.2%) in correctly identifying the presence of metabolic syndrome. Combining abdominal obesity and elevated fasting blood glucose had 100% sensitivity.

CONCLUSIONS

The measurement of both abdominal obesity and fasting blood glucose is a simple, cost-effective screening test to detect patients at high risk for future cardiovascular morbidity.

Tolerability profiles of atypical antipsychotics in the treatment of bipolar disorder

Atypical antipsychotics have unequivocally advanced the pharmacotherapy of bipolar disorder. These broad-spectrum medications offer efficacy against core symptoms of mania, and evidence supports the use of several agents as treatment options in depressed and maintenance phases of the disorder. Atypical antipsychotics also have a reduced propensity for provoking acute or tardive neurologic adverse events compared with their therapeutic predecessors, the conventional antipsychotics. These agents are not, however, a panacea and are associated with several problematic tolerability and safety concerns. Although classified together, atypical antipsychotics are heterogeneous in their tolerability and safety profiles, an issue that is relevant to individualizing treatment selection. This article reviews relevant adverse events attributable to the use of atypical antipsychotic agents, with particular consideration of the bipolar disorder population.

Metabolic syndrome and cardiovascular disease in patients with human immunodeficiency virus

Use of highly active antiretroviral therapy (HAART) for the treatment of human immunodeficiency virus (HIV) infection is associated with the development of cardiovascular risk factors, including dyslipidemia, insulin resistance, fat redistribution, and hypertension. The results of the Data Collection on Adverse Events of Anti-HIV Drugs study showed that HAART therapy is associated with a 26% relative risk increase in the rate of myocardial infarction per year of HAART exposure. A number of studies have shown that insulin resistance often precedes lipodystrophy, suggesting that insulin resistance may be a primary feature of the metabolic syndrome in this population. The rate-limiting step in the uptake of glucose is glucose transport, and the predominant glucose transporter (GLUT) in muscle and fat is GLUT-4. Specific protease inhibitors (PIs) have been associated with decreased GLUT-4-mediated glucose transport and insulin resistance both in vitro and in vivo, whereas newer protease inhibitors may have fewer effects on insulin sensitivity. Data also suggest that endothelial dysfunction, impaired fibrinolysis, and excess inflammation may contribute to increased cardiovascular risk in the population infected with HIV. Moreover, recent data suggest that evidence for coronary atherosclerotic disease can be revealed by means of carotid intimal medial thickness (IMT) assessments in specific groups of HIV patients. Pharmacologic strategies for the prevention and/or treatment of HAART-induced dyslipidemia and abnormal glucose homeostasis include 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins), resins, nicotinic acid, fibrates, and insulin-sensitizing agents. However, newer PIs such as atazanavir may result in less insulin resistance and dyslipidemia and, as part of a HAART regimen, use of atazanavir may reduce the metabolic complications associated with HAART.

Metabolic issues and cardiovascular disease in patients with psychiatric disorders

Individuals with psychiatric disorders tend to have excessive morbidity. They typically have high rates of respiratory illnesses, infectious diseases, substance abuse (including smoking), obesity, diabetes mellitus, and cardiovascular disease (CVD). Persons with schizophrenia and affective disorders also have a high prevalence of risk factors for CVD, such as diabetes and obesity, which are on the order of 1.5 to 2.0 times higher than in the general population; this translates into increased mortality rates due to CVD. The use of certain psychotropics results in metabolic sequelae, such as obesity, dyslipidemia, glucose dysregulation, and the metabolic syndrome. These sequelae exacerbate the already elevated risk of CVD and diabetes in this group of people. Therefore, the use of psychotropic agents that result in, for example, excessive weight gain not only add another complication for physicians managing a patient with schizophrenia but also may have serious prognostic and cost implications with respect to treatment-related diabetes and coronary disease incidence. The recent American Diabetes Association (ADA) Consensus Panel concluded that some agents are associated with greater diabetes risk than others. The current review describes the prevalence of the metabolic syndrome in people with affective disorders and schizophrenic populations, its prognostic relevance, and its exacerbation among patients treated with particular psychotropic agents, including certain atypical antipsychotics, selective serotonin reuptake inhibitors, and mood stabilizers. The costs associated with the treatment of the metabolic syndrome, diabetes, and coronary heart disease in populations with schizophrenia are also described.

Improvement in Highly Active Antiretroviral Therapy--Induced Metabolic Syndrome by Treatment with Pioglitazone but Not with Fenofibrate: A 2 x 2 Factorial, Randomized, Double-Blinded, Placebo-Controlled Trial

We designed a 2 x 2 factorial, randomized, double-blinded, placebo-controlled trial to evaluate the effects of treatment with pioglitazone and/or fenofibrate in patients with highly active antiretroviral therapy (HAART)-induced metabolic syndrome. We found that the administration of pioglitazone, but not fenofibrate, improved insulin resistance, blood pressure, and lipid profile over a 12-month period.

Activities of antioxidant enzymes in two stages of pathology development in sucrose-fed rats

The activities of catalase in liver, heart and kidney as well as glutathione peroxidase and superoxide dismutase in liver, heart, kidney, and serum from hypertriglyceridemic and hypertensive female and male rats were measured at 3 and 8 months of daily administration of sucrose in their drinking water. This treatment induces high levels of serum triglycerides, central obesity, moderate hypertension, hyperinsulinemia, and an increase in lipoper oxida tion, among other alterations. The experimental periods were chosen on the basis of previous observations: at 3 months the level of serum triglycerides increases significantly above the normal value and remains without major changes thereafter, but the blood pressure only rises significantly at about 4 months in males and 5 months in females. So, at 8 months the rats have been subjected to abnormal conditions for 3–4 months. The effect of these and the influence of sex on levels of antioxidant enzymes were investigated. Both factors, sucrose treatment and sex, were conducive to significant changes in those variables.Key words: antioxidant enzymes, gender influence, hypertriglyceridemia, hypertension, sucrose-fed rats.

Metabolic syndrome: epidemiology and consequences

Psychiatry is constantly faced with challenges related to the medical status of its patients and comorbid effects of pharmacologic treatment for psychiatric disorders. Other articles in this supplement review how obesity, diabetes, and dyslipidemia play a role in the treatment of schizophrenia, but these issues are by no means limited to schizophrenia. As the population of the United States becomes more obese and sedentary over time, risk factors for cardiovascular disease and diabetes are increasing in prevalence and affect the treatment of any psychiatric condition. As our understanding of how metabolic factors contribute to disease grows, it has become clear that a clustering of individual dysmetabolic factors, now known as metabolic syndrome, can contribute to significant morbidity and mortality and should be accounted for in the treatment of psychiatric conditions.

Abnormalities of glucose metabolism associated with atypical antipsychotic drugs

The introduction of atypical antipsychotic drugs has provided a clear benefit for many schizophrenia patients, with less risk for the extrapyramidal side effects associated with conventional antipsychotics. However, some antipsychotics are associated with an increased risk of adverse metabolic outcomes, including weight gain, dyslipidemia, and hyperglycemia. Increases in adiposity and disturbances in glucose and lipid metabolism represent a serious health risk in a patient that may be predisposed to these metabolic conditions. The increased risk for diabetes with certain antipsychotics may be associated with the risk of treatment-induced weight gain. However, other mechanisms, including effects on central neurotransmitters and direct effects on glucose metabolism, may contribute to the development of disordered glucose metabolism. The purpose of this article is to review the association between antipsychotic medications and obesity, insulin resistance, and diabetes, including the mechanisms through which these changes might be effected.

Glucose metabolism in patients with schizophrenia treated with atypical antipsychotic agents: a frequently sampled intravenous glucose tolerance test and minimal model analysis

BACKGROUND

While the incidence of new-onset diabetes mellitus may be increasing in patients with schizophrenia treated with certain atypical antipsychotic agents, it remains unclear whether atypical agents are directly affecting glucose metabolism or simply increasing known risk factors for diabetes.

OBJECTIVE

To study the 2 drugs most clearly implicated (clozapine and olanzapine) and risperidone using a frequently sampled intravenous glucose tolerance test.

DESIGN

A cross-sectional design in stable, treated patients with schizophrenia evaluated using a frequently sampled intravenous glucose tolerance test and the Bergman minimal model analysis.

SETTING

Subjects were recruited from an urban community mental health clinic and were studied at a general clinical research center. Patients Fifty subjects signed informed consent and 41 underwent the frequently sampled intravenous glucose tolerance test. Thirty-six nonobese subjects with schizophrenia or schizoaffective disorder, matched by body mass index and treated with either clozapine, olanzapine, or risperidone, were included in the analysis.

MAIN OUTCOME MEASURES

Fasting plasma glucose and fasting serum insulin levels, insulin sensitivity index, homeostasis model assessment of insulin resistance, and glucose effectiveness.

RESULTS

The mean +/- SD duration of treatment with the identified atypical antipsychotic agent was 68.3 +/- 28.9 months (clozapine), 29.5 +/- 17.5 months (olanzapine), and 40.9 +/- 33.7 (risperidone). Fasting serum insulin concentrations differed among groups (F(33) = 3.35; P = .047) (clozapine>olanzapine>risperidone) with significant differences between clozapine and risperidone (t(33) = 2.32; P = .03) and olanzapine and risperidone (t(33) = 2.15; P = .04). There was a significant difference in insulin sensitivity index among groups (F(33) = 10.66; P<.001) (clozapine<olanzapine<risperidone), with subjects who received clozapine and olanzapine exhibiting significant insulin resistance compared with subjects who were treated with risperidone (clozapine vs risperidone, t(33) = -4.29; P<.001; olanzapine vs risperidone, t(33) = -3.62; P = .001 [P<.001]). The homeostasis model assessment of insulin resistance also differed significantly among groups (F(33) = 4.92; P = .01) (clozapine>olanzapine>risperidone) (clozapine vs risperidone, t(33) = 2.94; P = .006; olanzapine vs risperidone, t(33) = 2.42; P = .02). There was a significant difference among groups in glucose effectiveness (F(30) = 4.18; P = .02) (clozapine<olanzapine<risperidone) with significant differences between clozapine and risperidone (t(30) = -2.59; P = .02) and olanzapine and risperidone (t(30) = -2.34, P = .03).

CONCLUSIONS

Both nonobese clozapine- and olanzapine-treated groups displayed significant insulin resistance and impairment of glucose effectiveness compared with risperidone-treated subjects. Patients taking clozapine and olanzapine must be examined for insulin resistance and its consequences.

[A new atypical antipsychotic with partial dopamine agonist effect (aripiprazole)]

Aripiprazole act as a partial agonist on the D2 receptors in contrast to the other antipsychotic agents which exert a pure antagonist action. In the autoreceptors with large receptor reserve aripiprazole shows primarily agonistic action, while postsynaptically its antagonistic action becomes predominant. In addition aripiprazole is an antagonist at the 5-HT2A, receptor and a partial agonist on the 5-HT1 receptor. On the basis of these receptor actions it is suggested that aripiprazole works as a stabilizer of both the dopaminergic and serotoninergic systems. Probably due to this dual stabilizing effect aripiprazole ameliorates positive and negative as well as anxiety and cognitive symptoms. Especially the very rare extrapyramidal symptoms, prolactine level elevation, QT-interval lengthening and absence of severe body weight increase and metabolic disturbances are noteworthy, which all seriously impair the health condition, the quality of life and the therapy adherence of the patients. Due to the very low affinity of aripiprazole to the H1 and muscarinic receptors aripiprazole practically does not lead to increase of body weight. The significant clinical efficacy coupled with good tolerability assures high level clinical effectiveness for aripiprazole in the broad clinical practice.

Randomized, controlled, double-blind multicenter comparison of the efficacy and tolerability of ziprasidone and olanzapine in acutely ill inpatients with schizophrenia or schizoaffective disorder

OBJECTIVE

Limited randomized, controlled trial data exist on possible differences between atypical antipsychotics in efficacy, overall tolerability, and important indices of health status. The authors compared the efficacy and tolerability of ziprasidone and olanzapine in the treatment of acutely ill inpatients with schizophrenia or schizoaffective disorder.

METHOD

In this 6-week, multicenter, double-blind, parallel-design, flexible-dose trial, patients were randomly assigned to receive ziprasidone (N=136) or olanzapine (N=133). Primary efficacy measures were improvement in Brief Psychiatric Rating Scale and Clinical Global Impression (CGI) severity scale scores; secondary measures were scores on the CGI improvement scale, Positive and Negative Syndrome Scale, and Calgary Depression Scale for Schizophrenia. Tolerability assessments included fasting lipid profiles, fasting glucose and insulin measurements, electrocardiography, and monitoring of vital signs and body weight.

RESULTS

The overall mean daily doses were 129.9 mg (SD=27.3) for ziprasidone and 11.3 mg (SD=2.8) for olanzapine. Both antipsychotics were efficacious in improving symptoms and global illness severity. The two treatment groups did not differ significantly in primary or secondary efficacy measures at endpoint or in by-visit analysis. Both agents were well tolerated. Body weight, total cholesterol, triglycerides, and low-density lipoprotein cholesterol significantly increased with olanzapine but not with ziprasidone; all between-group comparisons of these variables were significant and favored ziprasidone. Olanzapine, but not ziprasidone, was associated with significant increases in fasting insulin level. No patient in either group exhibited a corrected QT interval >/=500 msec.

CONCLUSIONS

During 6 weeks' treatment, ziprasidone and olanzapine demonstrated comparable antipsychotic efficacy. Differences favoring ziprasidone were observed in metabolic parameters.

Treatment of the metabolic disturbances caused by antipsychotic drugs: focus on potential drug interactions

The risk of excessive bodyweight gain, glucose dysregulation and hyperlipidaemia is differentially increased by conventional and atypical antipsychotic drugs. Switching or combining agents may be sufficient in some cases, but in many instances additional drug treatment will be required. This includes oral antidiabetics, insulin and agents to treat hyperlipidaemia, hypertension and platelet dysfunction, among others. Numerous pharmacokinetic and pharmacodynamic interactions with the antipsychotics are possible, although few have been tested in formal studies. After reviewing the literature, the authors provide preliminary guidelines to assist clinicians in drug selection for this complex and fragile clinical population.

Effects of fish oil on hypertension, plasma lipids, and tumor necrosis factor-α in rats with sucrose-induced metabolic syndrome

Dietary fish oil rich in (n-3) fatty acids plays an important role in reducing abnormalities associated with the metabolic syndrome and mortality from coronary heart disease. We investigated the effects of dietary fish oil on the metabolic syndrome in a high-sucrose-fed rat model. The model was achieved by the administration of 30% sucrose in drinking water in male Wistar rats during 21 weeks. After the metabolic syndrome rat model was established, fish oil was administered during 6 weeks. The metabolic syndrome rats showed significant increases in body weight, systolic blood pressure, serum insulin, total lipids, triacylglycerols, cholesterol, free fatty acids, LDL, total proteins, albumin, and serum tumor necrosis factor-alpha (TNF-alpha). They also presented abdominal and epididymal fat accumulation and fatty liver. After fish oil diet administration, metabolic syndrome rats had a significant reduction in blood pressure, serum insulin, triacylglycerols, cholesterol, free fatty acids, and total lipids, but no change was observed in TNF-alpha concentration or fat accumulation. In conclusion, fish oil reversed the alterations on metabolic parameters and blood pressure exerted by sucrose administration, although it had no effect on TNF-alpha production and adiposity. This confirms the theory that the molecular etiology of the metabolic syndrome is multifactorial, as is the effect of n-3 polyunsaturated fatty acids (PUFAs) upon it, having complex and multifaceted actions.

Development of an atherogenic metabolic risk factor profile associated with the use of atypical antipsychotics

BACKGROUND

It is important to assess cardiovascular risk factors to properly verify the potential consequences of atypical antipsychotic-related weight gain. The objective of the present study was to evaluate whether 2 atypical antipsychotics differ regarding their impact on the cardiovascular disease risk profile compared with a reference group.

METHOD

We conducted a cross-sectional, multicenter study to assess anthropometric indices of obesity and to obtain a comprehensive fasting metabolic risk profile. Either risperidone or olanzapine had to be prescribed as the first and only antipsychotic for a minimum of 6 months. Patients were compared with a reference group of nondiabetic men. Data were collected from August 1999 to August 2001.

RESULTS

Eighty-seven patients treated with olanzapine (N = 42) or risperidone (N = 45) were evaluated. Olanzapine-treated patients had significantly higher plasma triglyceride concentrations (2.01 +/-1.05 vs. 1.34 +/-0.65 mmol/L, p < or =.05), lower high-density lipoprotein (HDL)-cholesterol levels (0.92 +/-0.17 vs. 1.04 +/- 0.21 mmol/L, p < or =.05), higher cholesterol/HDL-cholesterol ratios (5.62 +/-1.70 vs. 4.50 +/- 1.44, p < or =.05), higher apolipoprotein B levels (1.07 +/- 0.35 vs. 0.92 +/- 0.27 g/L, p < or =.05), smaller low-density lipoprotein peak particle diameters (252.6 +/-4.1 vs. 255.2 +/-4.3 A, p <.01), and higher fasting insulin concentrations (103.9 +/- 67.6 vs. 87.5 +/- 56.1 pmol/L, p < or =.05) than risperidone-treated patients. Moreover, 33% of olanzapine-treated patients were carriers of 3 atherogenic features of the metabolic syndrome as opposed to a prevalence of only 11% of risperidone-treated patients.

CONCLUSION

These results suggest that olanzapine-treated patients are characterized by a more deteriorated metabolic risk factor profile compared with risperidone-treated patients. These observations raise concerns about the potential differential long-term deleterious effects of some antipsychotics, such as olanzapine, on cardiovascular health.

Metabolic effects associated with atypical antipsychotic medications

Despite the plethora of evidence that demonstrates the efficacy of novel antipsychotic medications, there are mounting concerns about their side effects. Major concerns are data that link some agents with metabolic effects, such as obesity, type 2 diabetes, and CVD. For these reasons, patients receiving novel antipsychotic medications must be closely monitored for metabolic side effects and treated to reduce risk factors associated with CVD.

A prospective study of impairment in glucose control caused by clozapine without changes in insulin resistance

OBJECTIVE

This prospective study examines the effect of clozapine on glucose control and insulin sensitivity.

METHOD

Glucose homeostasis was measured in nine female and 11 male patients with schizophrenia (mean age=30.5 years, SD=7.4) before clozapine treatment and after a mean of 2.5 months (SD=0.95) of clozapine treatment. Oral glucose tolerance and insulin levels were measured. Insulin resistance level was measured by the homeostasis model assessment.

RESULTS

Eleven (55%) of the patients developed abnormal glucose control; the mean age of these patients was 30.2 (SD=7.1), and five were women. Patients' insulin resistance at baseline (mean insulin resistance level=3.88, SD=2.93) was unaffected by clozapine. Mean fasting and 2-hour glucose levels significantly increased by 0.55 mmol/liter and 1.4 mmol/liter, respectively. There was no correlation between change in body mass index and change in fasting glucose levels.

CONCLUSIONS

Clozapine impairs glucose control within 4 months of treatment, independent of changes in insulin sensitivity and body mass index.

Obesity, diabetes, and the metabolic syndrome: new challenges in antipsychotic drug therapy

Obesity and diabetes continue to be national health epidemics. Greater than 50% of adults in the United States are overweight, and >17 million people have diabetes--one third of whom are not diagnosed. Diabetes ranks number 1 in direct health care costs of any disease category. Patients who suffer from schizophrenia may be at twice the risk of developing diabetes compared with the general population. Some new antipsychotic agents are among several types of medications that may potentially impair glucose metabolism. For example, studies have shown that people treated with clozapine and olanzapine have developed elevated fasting serum insulin levels, suggestive of insulin resistance. Insulin resistance may be a result of irregularities in the insulin action sequence and it may occur long before overt diabetes. The further study of the effects of medications on glucose metabolism and their mechanisms, therefore, is essential to developing better treatment regimens that minimize insulin resistance and avoid associated health risks such as obesity and diabetes.

[The HIV protease inhibitor-induced insulin resistance syndrome]

BACKGROUND

HIV protease inhibitors improve the morbidity and mortality of HIV infection, however, this therapy also initiates insulin resistance that is associated with an increasing development of disturbances in glucose and lipid metabolism. Similar to the common insulin resistance syndrome, treated patients also suffer from an increased cardiovascular risk.

PATHOGENESIS

Studies based on animal or cell models suggest that HIV protease inhibitors induce short-term effects on GLUT4 glucose transport and longterm effects on insulin signal transduction.

CONCLUSION

Therapy with HIV protease inhibitors should include regular monitoring of metabolic alterations and cardiovascular damage. Particularly patients with genetic or traditional risk factors for type 2 diabetes should be monitored frequently.

[The effect of analysed hypotensive drugs on certain metabolic parameters]

The aim of this study was to assess the influence of 3 hypotensive drugs on the metabolic disorders: dyslipidemia, insulin resistance, hyperuricemia. There were 39 patients aged 20-55, with mild-to-moderate essential hypertension. The patients with other serious diseases or treated earlier with cholesterol or uric acid lowering drugs were excluded. Patients were divided into 3 groups, each was treated during 8 weeks with one drug: gr 1--trandolapril (T), gr 2--felodipine ER (F), gr 3--rilmenidine (R). Glucose and insulin in oral glucose tolerance test, I/G proportion, serum lipids and uric acid were tested before and after therapy. The therapy did not influence lipid parameters: LDL, HDL, triglyceride. In the T group there could be observed a significant reduction of total cholesterol value. Examined drugs did not induce changes in serum carbohydrate. The significant reduction of serum uric acid could be observed only after F therapy. Analysed drugs are very useful in therapy of hypertension with metabolic disorders.

The metabolic syndrome: psychopharmacologists should weigh the evidence for weighing the patient

We are in the midst of a North American epidemic of obesity and type 2 diabetes. Since patients with psychiatric disorders who receive psychopharmacologic treatments may be at even greater risk than the general population for weight gain, dyslipidemia, and diabetes and their complications, psychopharmacologists now need standards for how to monitor and manage these risks.