Methodological challenges in determining longitudinal associations between anticholinergic drug use and incident cognitive decline.

OBJECTIVES: To compare the effect of using different anticholinergic drug scales and different models of cognitive decline in longitudinal studies. DESIGN: Longitudinal cohort study. SETTING: Outpatient clinics, Quebec, Canada. PARTICIPANTS: Individuals aged 60 and older without dementia or depression (n = 102). MEASUREMENTS: Using baseline and 1-year follow-up data, four measures of anticholinergic burden (anticholinergic component of the Drug Burden Index (DBI-Ach), Anticholinergic Cognitive Burden (ACB), Anticholinergic Drug Scale (ADS), and Anticholinergic Risk Scale (ARS)) were applied. Three models of cognitive decline (worsening of raw neuropsychological test scores, Reliable Change Index (RCI), and a standardized regression based measure (SRB)) were compared in relation to Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-V) criteria for the onset of a new mild neurocognitive disorder. The consistency of associations was examined using logistic regression. RESULTS: The frequency of identifying individuals with an increase in anticholinergic burden over 1 year varied from 18% with the DBI-Ach to 23% with the ACB. The frequency of identifying cognitive decline ranged from 8% to 86% using different models. The raw change score had the highest sensitivity (0.91), and the RCI the highest specificity (0.93) against DSM-V criteria. Memory decline using the SRB method was associated with an increase in ACB (odds ratio (OR) = 5.3, 95% confidence interval (CI) = 1.1-25.8), ADS (OR = 5.7, 95% CI = 1.1-27.7), and ARS (OR = 6.5, 95% CI = 1.34-32.3). An increase in the DBI-Ach was associated with a decline on memory testing using the raw change score method (OR = 4.2, 95% CI = 1.8-15.4) and on the Trail-Making Test Part B using SRB (OR = 2.9, 95% CI = 1.1-8.0). No associations were observed using the DSM-V criteria or RCI method. CONCLUSION: The choice of different methods for defining drug exposure and cognitive decline will have a significant effect on the results of pharmacoepidemiological studies.

A systematic review of amnestic and non-amnestic mild cognitive impairment induced by anticholinergic, antihistamine, GABAergic and opioid drugs.

BACKGROUND: Mild cognitive deficits are experienced by 18% of community-dwelling older adults, many of whom do not progress to dementia. The effect of commonly used medication on subtle impairments in cognitive function may be under-recognized. OBJECTIVE: The aim of the review was to examine the evidence attributing amnestic or non-amnestic cognitive impairment to the use of medication with anticholinergic, antihistamine, GABAergic or opioid effects. METHODS: MEDLINE and EMBASE were searched for randomized, double-blind, placebo-controlled trials of adults without underlying central nervous system disorders who underwent detailed neuropsychological testing prior to and after oral administration of drugs affecting cholinergic, histaminergic, GABAergic or opioid receptor pathways. Seventy-eight studies were identified, reporting 162 trials testing medication from the four targeted drug classes. Two investigators independently appraised study quality and extracted relevant data on the occurrence of amnestic, non-amnestic or combined cognitive deficits induced by each drug class. Only trials using validated neuropsychological tests were included. Quality of the evidence for each drug class was assessed based on consistency of results across trials and the presence of a dose-response gradient. RESULTS: In studies of short-, intermediate- and long-acting benzodiazepine drugs (n = 68 trials), these drugs consistently induced both amnestic and non-amnestic cognitive impairments, with evidence of a dose-response relationship. H(1)-antihistamine agents (n = 12) and tricyclic antidepressants (n = 15) induced non-amnestic deficits in attention and information processing. Non-benzodiazepine derivatives (n = 29) also produced combined deficits, but less consistently than benzodiazepine drugs. The evidence was inconclusive for the type of cognitive impairment induced by different bladder relaxant antimuscarinics (n = 9) as well as for narcotic agents (n = 5) and antipsychotics (n = 5). Among healthy volunteers >60 years of age, low doses of commonly used medications such as lorazepam 0.5 mg, oxybutynin immediate release 5 mg and oxycodone 10 mg produced combined deficits. CONCLUSION: Non-amnestic mild cognitive deficits are consistently induced by first-generation antihistamines and tricyclic antidepressants, while benzodiazepines provoke combined amnestic and non-amnestic impairments. Risk-benefit considerations should be discussed with patients in order to enable an informed choice about drug discontinuation or substitution to potentially reverse cognitive adverse effects.

Systematic review and meta-analysis: do clinical trials testing antimuscarinic agents for overactive bladder adequately measure central nervous system adverse events?

Experimental studies in healthy volunteers suggest that some antimuscarinic agents confer a risk of cognitive impairment, yet clinical trials of people with overactive bladder report only rare central nervous system (CNS) side effects. A lack of systematic measurement and reporting of CNS outcomes in clinical trials may partially explain this discrepancy. The purpose of this review and meta-analysis was to ascertain the reporting bias associated with adverse CNS events in clinical drug trials of younger and older adults with overactive bladder. Articles were identified from MEDLINE and EMBASE databases until 2010 using the search terms "clinical trial" AND (one of) "oxybutynin, tolterodine, fesoterodine, propiverine, solifenacin, darifenacin, and trospium." Eligibility criteria included original randomized trials involving adults with overactive bladder; standard doses of medication; reports of confusion, somnolence, sedation, dizziness, drowsiness, asthenia, insomnia, and vertigo; no evidence of dementia at baseline; and trials in English. Seventy-seven percent (242/314) of eligible trials identified in the search neither measured nor reported CNS outcomes. Of the remaining 23%, it was difficult to distinguish whether CNS adverse events were systematically measured or spontaneously reported. Only one of 72 trials that were retained objectively measured changes in cognitive performance (Mini-Mental State Examination). Dizziness was the most frequently reported side effect, in 3% of oxybutynin, 3.2% of propiverine, and 1.8% of tolterodine users, compared with 1.6% with placebo. Confusion was reported in fewer than 1% of cases. Age-stratified analyses of CNS outcomes from trials in adults aged 65 and older with overactive bladder were found in only eight publications. Meta-analyses were conducted with 33 randomized, double-blind, placebo-controlled trials to determine the effect of each drug and dose on different CNS outcomes. Study heterogeneity, dosing inconsistency, and reporting bias limited interpretation of the findings from the meta-analyses. More-detailed standardized measurement of age-stratified CNS outcomes in clinical trials is required to better inform patients and clinicians about CNS risks associated with antimuscarinic agents.

Resistance training attenuates fat mass regain after weight loss in ovariectomized rats.

OBJECTIVE: The aim of the present study was to investigate the effects of maintaining only one of the two components of a food restriction (FR)+resistance training (RT) regimen on the regain of body weight and fat mass (liver and adipocytes) in ovariectomized (Ovx) rats. METHODS: Five week Ovx rats were submitted to a weight loss program consisting of a 26% FR combined with RT (OvxFR+RT) for 8 weeks. RT consisted of climbing a 1.5m vertical grid with a load attached to the tail, 20-40 times with progressively increasing loads 4 times/week. Following this weight loss intervention, OvxFR+RT rats were sub-divided into 3 groups for an additional 5 weeks: 2 groups went back to a normal ad libitum feeding with or without RT and the other group kept only FR. RESULTS: Combined FR+RT program in Ovx rats led to lower body mass gain, liver triacylglycerol (TAG) levels, and fat mass gain compared to sedentary normally fed Ovx rats (P<0.01). Stopping both FR and RT over a 5 week period resulted in the regain of body weight, intra-abdominal fat pad weight and liver TAG (P<0.01). When only FR was maintained, the regain of body and fat pad weight as well as liver and plasma TAG concentrations was completely prevented. However, when only RT was maintained, regain in the aforementioned parameters was attenuated but not prevented (P<0.05). CONCLUSION: It is concluded that following a FR+RT weight loss program, continuation of only RT constitutes an asset to attenuate body weight and fat mass regain in Ovx rats; although the impact is less than the maintaining FR alone. These results suggest that, in post-menopausal women, RT is a positive strategy to reduce body weight and fat mass relapse.

Effects of ovariectomy on PPAR alpha, SREBP-1c, and SCD-1 gene expression in the rat liver.

OBJECTIVE: To investigate whether estrogen deficiency modifies the expression of important genes involved in hepatic lipid regulation, PPAR alpha, SREBP-1c, and SCD-1, in association with fat accumulation in the liver of ovariectomized rats. DESIGN: Thirty female Sprague-Dawley rats were divided into three groups: sham-operated (n = 12), ovariectomized (n = 12), and ovariectomized with 17beta-estradiol replacement (n = 6). All animals were killed 8 weeks after surgery. In addition to liver triacylglycerol determination, transcripts levels and protein content of peroxisome proliferator-activated receptor alpha, liver sterol regulatory element-binding protein 1c, and stearoyl coenzyme Adesaturase 1 were quantified by quantitative real-time polymerase chain reaction and Western blot, respectively. RESULTS: As expected, liver triacylglycerol levels were higher (51%; 21.9 +/- 2.6 vs 14.5 +/- 1.2 mg/g; P < 0.01) in ovariectomized compared with sham-operated rats. Peroxisome proliferator-activated receptor alpha mRNA levels were 66% lower (P < 0.01), whereas sterol regulatory element-binding protein 1 and stearoyl coenzyme A desaturase 1 transcript levels were 80% and 41% higher (P < 0.05), respectively, after estrogen removal. Our data on gene expression obtained with quantitative real-time polymerase chain reaction for peroxisome proliferator-activated receptor alpha and sterol regulatory element-binding protein 1c were confirmed by Western blots. All the effects of ovariectomy were prevented by 17beta-estradiol replacement, indicating a role for estrogens in the prevention of hepatic fat accumulation. CONCLUSIONS: Our results suggest that a reduction in lipid oxidation and an increase in lipogenesis are defective mechanisms leading to lipid accumulation in the liver of ovariectomized rats. We conclude that estrogen deficiency induced by ovariectomy changes the expression of genes that favor the development of a steatotic phenotype.

Resistance training prevents liver fat accumulation in ovariectomized rats.

BACKGROUND: Menopause is associated with increased lipid deposition in the liver and fat accumulation in the abdomen. OBJECTIVE: The purpose of the present study was to determine the effects of adding a resistance training program (RT) to a restrictive diet (RD) on liver lipid accumulation and abdominal fat depots in ovariectomized (Ovx) rats. METHODS: One group of sham-operated and three groups of Ovx rats were compared. Five weeks after surgery, Ovx rats were either submitted to an approximately 25% RD with or without RT for 3 or 8 weeks, while a third group of Ovx rats were fed ad libitum and remained sedentary. The RT program consisted of climbing a 6m vertical metal grill five times a week with an increasing load up to 75% of body weight attached to the tail. The number of repetitions increased from two to four sets of 10 repetitions. RESULTS: Ovariectomy resulted in significantly higher (P<0.01) body weight, energy intake, intra-abdominal fat depots, plasma leptin levels (P<0.05), and liver triacylglycerol concentrations. All of these responses were (P<0.01) reduced in Ovx rats following the RD with the exception of liver lipid infiltration. The addition of RT to the RD treatment synergistically reduced abdominal fat deposition and plasma-free fatty acid levels. Moreover, liver lipid infiltration was completely prevented by the addition of the RT program. Muscle mass relative to body weight was significantly increased in Ovx-RD-RT compared to all other groups. CONCLUSION: It is concluded that RT is an asset to minimize the deleterious effects of ovarian hormone withdrawal on liver lipid accumulation and abdominal fat accumulation in Ovx rats.

Time course of liver lipid infiltration in ovariectomized rats: impact of a high-fat diet.

OBJECTIVES: The present study was undertaken to determine the time course of liver lipid infiltration in ovariectomized (Ovx) rats and the impact of high-fat (HF; 42% kJ) feeding on this response. METHODS: In a first step, Ovx rats were compared to Sham-operated (Sham) and Ovx rats supplemented with 17beta-estradiol (OvxE2) to evaluate the effect of estrogen removal. In a second time, Ovx rats fed a HF diet (OvxHf) were compared with normally fed Ovx rats. Animals were killed after 3, 8, and 13 weeks of their respective treatment (n=8 rats/group). We measured liver triacylglycerol (TAG) content, fat pad mass, and several other plasma parameters. RESULTS: Ovariectomy resulted in the typical increase in energy intake and body weight. Liver TAG accumulation was 35, 43, and 99% higher in Ovx than in Sham rats after 3, 8, and 13 weeks, respectively. The ovariectomy-induced liver lipid infiltration was completely prevented by estrogen replacement. On the opposite, plasma TAG concentrations were lower in Ovx than in Sham and OvxE2 rats. HF feeding in Ovx rats resulted in a significant (P<0.05; 38 versus 22 mg/g at 13-week) accumulation of fat in liver as compared to normally fed Ovx rats. CONCLUSIONS: Ovariectomy results in a progressive accumulation of fat in liver over a 13-week period. In addition, HF feeding in Ovx rats lead to an even more severe liver lipid infiltration. These data indicate that the absence of estrogens in rat favours fat accretion in liver, which is highly amplified by a HF diet.

Specific adaptations of estrogen receptor alpha and beta transcripts in liver and heart after endurance training in rats.

Estrogens exert their biological roles mainly through estrogen receptors (ER) that function as ligand-activated transcription factors. ER content in a cell is regulated by many factors and is decisive for estrogen action. The purpose of the present study was to investigate the influence of an 8-wk endurance training program on ER expression in the liver, right atrium (RA), and left ventricle (LV) of intact and ovariectomized (Ovx) rats. We measured ERalpha and ERbeta mRNA content by reverse transcription-polymerase chain reaction (RT-PCR). We found an important increase in ERalpha mRNA levels in the liver (300%; P < 0.01) and in ERbeta mRNA levels in the RA (200%; P < 0.05), and a marked decrease in ERalpha (80%; P < 0.01) and ERbeta (40%; P < 0.05) transcripts content in the LV of intact rats after endurance training. On the other hand, ERalpha mRNA levels were depressed by 50% (P < 0.01) in the liver, and increased by 60% (P < 0.01) in LV of Ovx rats after exercise training. These results first indicate that endurance training is associated with modifications of ER transcripts levels in the liver, LV, and RA of female rats. More specifically, these effects are tissue and isoform-specific and the direction of the response (increase or decrease) is different in intact and Ovx rats. It is suggested that some of the adaptations to endurance training in liver and heart may be mediated by an ER-dependent mechanism.

Effect of exercise training on cardiac oxytocin and natriuretic peptide systems in ovariectomized rats.

Exercise training results in cardiovascular and metabolic adaptations that may be beneficial in menopausal women by reducing blood pressure, insulin resistance, and cholesterol level. The adaptation of the cardiac hormonal systems oxytocin (OT), natriuretic peptides (NPs), and nitric oxide synthase (NOS) in response to exercise training was investigated in intact and ovariectomized (OVX) rats. Ovariectomy significantly augmented body weight (BW), left ventricle (LV) mass, and intra-abdominal fat pad weight and decreased the expression of oxytocin receptor (OTR), atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and guanylyl cyclase-A (GC-A), in the right atrium (RA) and LV, indicating estrogenic control of these genes. These effects of ovariectomy were counteracted by 8-wk-long exercise training which decreased fat pad weight (33.4 +/- 2.3 to 23.4 +/- 3.1 g, n = 8, P < 0.05), plasma free fatty acids (0.124 +/- 0.033 to 0.057 +/- 0.010 mM, n = 8, P < 0.01), and plasma triacylglycerol (0.978 +/- 0.174 to 0.588 +/- 0.115 mM, n = 8, P < 0.05). Chronic exercise tended to decrease BW and stimulated ANP (4- to 5-fold) and OTR gene expression in the LV and RA and BNP and inducible NOS (iNOS) mRNA in the LV. In sham-operated rats, exercise augmented ANP expression in the RA, downregulated GC-A mRNA in the LV and RA, but increased its expression threefold in the RA of OVX animals. Endothelial NOS and iNOS expression was enhanced in the left atrium of sham-operated rats. Altogether, these data indicate that in OVX animals, chronic exercise significantly enhances cardiac OT, NPs, and NOS, thus implicating all three hormonal systems in the beneficial effects of exercise training.

Effects of ingesting a high-fat diet upon exercise-training cessation on fat accretion in the liver and adipose tissue of rats.

The purpose of the present study was to determine if exercise trained rats might benefit from protection against fat accumulation in response to an obesity stimulus initiated upon training cessation. Two groups of female rats were either treadmill trained for 8 weeks (DTr) or remained sedentary (Sed). They were then submitted either to a high-fat diet (HF; 42 E%) or kept on a standard diet (SD; 12.5 E% lipids) for another 6 weeks while remaining sedentary. Fat accumulation in liver and adipocytes along with fat-cell diameter and plasma free fatty acid (FFA) levels were measured 0, 2, and 6 weeks after training cessation. Immediately after the training period (t = 0), DTr rats exhibited similar body mass and higher dietary intake but smaller body fat content (4 fat pads) compared with Sed rats. DTr rats, under both diets, exhibited higher gains in body fat than Sed rats (DTr vs. Sed, 71% vs. 8% and 132% vs. 55% for SD and HF, respectively), such that fat mass in all 4 depots was similar to Sed rats 6 weeks after training cessation. Despite higher adipocyte fat accretion, liver lipid infiltration was not increased in DTr animals and plasma FFA levels were lower throughout the detraining period. In addition, plasma leptin levels remained lower in DTr animals throughout the detraining period under the HF diet condition. The present results indicate that previously exercise trained rats are not protected against adipocyte fat accumulation whether they ingest a standard or a high-fat diet.

Effects of alternations (10 days) of high-fat with normal diet on liver lipid infiltration, fat gain, and plasma metabolic profile in rats.

The purpose of the present study was to test the hypothesis that short-term alternations of high-fat with normal chow feeding result in higher fat accumulation in liver than continuous intake of the same high-fat diet. Male Sprague-Dawley rats (7 weeks of age) were divided into 3 groups according to diet composition: standard chow (SD; 12,5% kcal as fat), high-fat (HF; 42% kcal as fat), and food cycles (FC) consisting of 10-day alternations between HF and SD diets beginning with the high-fat diet. Rats in each of these 3 groups were sacrificed after 10, 30, and 50 days (n = 10 rats/sub-groups). Energy intake, body weight, liver and muscle relative weights were not significantly (P > 0.05) different between FC- and HF-fed rats. Using the total energy intake for the 50-day period, it was calculated that approximately 30% less calories as fat was ingested in the FC- compared to the HF-fed rats. In spite of this, liver lipid infiltration as well as fat accretion in abdominal adipose tissues were increased (P < 0.01) similarly in FC- and HF-fed rats. Plasma FFA and insulin levels depicted strong tendencies (P < 0.07) to be higher in FC- than in continuous HF-fed rats at the end of the 50-day period. These results indicate that, despite a 30% reduction in ingested lipids, alternations of HF with normal chow diet compared to the continuous hyperlipidic diet caused the same level of infiltration of lipids in the liver and in the abdominal adipose tissues and, to a certain extent, may even result in a larger deterioration of the metabolic profile.