Larry Brooks

Oxytocin attenuates NADPH-dependent superoxide activity and IL-6 secretion in macrophages and vascular cells

Oxytocin is synthesized and released in the heart and vasculature, tissues that also express oxytocin receptors. Although it has been established this intrinsic cardiovascular oxytocin system is important in normal homeostatic cardiac and vascular regulation, a role for this system in cardiovascular pathophysiology has not been investigated. The current study examined the influence of oxytocin on mechanisms in atherogenesis, oxidative stress, and inflammation in cultured human vascular cells, THP-1 monocytes, and macrophages. Oxytocin receptor protein and mRNA expression, NADPH-dependent superoxide activity, and interleukin-6 secretion were measured. Results demonstrated oxytocin receptor protein and mRNA in THP-1 monocytes and macrophages. Incubation of cells at physiological levels of oxytocin significantly decreased basal and stimulated NADPH-dependent superoxide activity in vascular cells, monocytes, and macrophages by 24-48%. Oxytocin also attenuated interleukin-6 secretion from stimulated THP-1 macrophages and endothelial cells by 56 and 26%, respectively. These findings suggest that oxytocin attenuates vascular oxidative stress and inflammation, two important pathophysiological processes in atherosclerosis. The fact that oxytocin receptors are found in monocytes and macrophages, and oxytocin decreases both superoxide production and release of a proinflammatory cytokine from these cells, suggests a potentially larger role for oxytocin in the attenuation of disease.

Assessing the progression of mild cognitive impairment to Alzheimer's disease: current trends and future directions

With the advent of advances in biomarker detection and neuropsychological measurement, prospects have improved for identifying and tracking the progression of Alzheimers disease (AD) from its earliest stages through dementia. While new diagnostic techniques have exciting implications for initiating treatment earlier in the disease process, much work remains to be done to optimize the contributions of the expanding range of tools at the disposal of researchers and clinicians. The present paper examines recent work in cerebrospinal fluid biomarkers, magnetic resonance imaging, positron emission tomography, neuropsychological measures, and functional assessment. The strengths and weaknesses of current methodologies are explored and discussed. It is concluded that AD from its mild cognitive impairment state through dementia represents a continuous process, and that progression over time can best be accomplished by interval-level variables. Biomarkers that are most sensitive to early AD may not be the most optimal for monitoring longitudinal change, and it is likely that multivariate models incorporating cognitive measures, functional variables and biomarker data will be the most fruitful avenues for future research.

Mental Health and Outcomes in Primary Total Joint Arthroplasty

A consecutive series of 640 total joint arthroplasty patients was interviewed before surgery and at a minimum of 2 years following surgery. Statistical analyses were conducted to examine the effect of psychological distress and other patient characteristics on outcomes (Western Ontario and McMaster Universities Osteoarthritis Index, Short Form 36, and Quality of Well-Being index). Before and after surgery, distressed subjects had significantly lower scores than nondistressed subjects for most dependent measures (P range, .05 ≤ .001). All mean outcomes improved by follow-up in both groups (P ≤ .001) except mental health scores of nondistressed subjects. Stepwise regression analysis found that low baseline mental health score, non-Hispanic ethnicity, and fewer years since procedure were the strongest predictors of worse Western Ontario and McMaster Universities Osteoarthritis Index scores at follow-up. Although the magnitude of improvement is similar to nondistressed subjects, distressed patients do not achieve comparable functional and psychosocial outcomes.

Oxytocin attenuates atherosclerosis and adipose tissue inflammation in socially isolated ApoE-/- Mice

Objective: To determine the effect of exogenous oxytocin (OT) administration on inflammation and atherosclerosis in socially isolated apoE−/− mice. Hyperlipidemic animals housed in isolated or stressful social environments display more extensive atherosclerosis than those in an affiliative social environment. The neurohypophyseal peptide OT may be involved in both affiliative social behavior and cardiovascular homeostasis, suggesting a role in mediating the benefits of positive social interactions on atherosclerosis. Methods: A total of 43, 12-week-old, apoE−/− mice were surgically implanted with osmotic minipumps containing OT (n = 23) or vehicle (n = 20). Blood samples were taken at baseline and after 6 weeks and 12 weeks of treatment. After 12 weeks of treatment, animals were killed, and samples of adipose tissue were dissected from a subset of OT-treated (n = 12) and vehicle-treated (n = 12) animals and incubated in culture media for 6 hours. Media samples were analyzed for interleukin (IL)-6 concentration corrected by sample dry weight. Aortas were dissected, formalin-fixed, and stained with oil-red O for en face quantification of lesion area. t tests were used to compare group means on measures of percent lesion area and IL-6 concentrations. Results: There were no group differences in plasma lipids. Adipose tissue samples taken from OT-treated animals secreted significantly less IL-6 over 6 hours (p < .01). OT-treated animals displayed significantly less atherosclerosis in the thoracic aorta (p < .05). Conclusions: These results indicate that peripheral OT administration can inhibit atherosclerotic lesion development and adipose tissue inflammation, suggesting a potential role for this neuropeptide in mediating the benefits of stable group housing on atherosclerosis. OT = oxytocin; OTR = oxytocin receptor; SNS = sympathetic nervous system.

The Effect of Social Environment on Markers of Vascular Oxidative Stress and Inflammation in the Watanabe Heritable Hyperlipidemic Rabbit

Objective: Previous research demonstrated that social environment can influence progression of atherosclerosis in the Watanabe Heritable Hyperlipidemic (WHHL) rabbit. This study examined the effect of social environment on markers of oxidative stress and inflammation to clarify the physiological pathways potentially responsible for the influence of social environment on disease. Methods and Results: WHHL rabbits were assigned to 1 of 3 social groups: an unstable group, in which unfamiliar rabbits were paired daily, with the pairing switched each week; a stable group, in which littermates were paired daily; and an individually-caged group. The stable group engaged in more affiliative social behavior than the unstable group. The unstable group showed more agonistic behavior compared with the stable group and higher C-reactive protein levels than the individually caged group. The individually caged group was behaviorally sedentary, had higher 24-hour urinary catecholamine levels than the other groups, and exhibited higher NAD(P)H-oxidase activity in the aortic arch relative to the stable group. Conclusions: The results suggest that social environment creates distinct behavioral contexts that can affect markers of inflammation and oxidative stress early in the development of atherosclerosis. Specifically, physical inactivity associated with individual caging affects indices of oxidative stress and inflammation. These pathophysiological markers may help to explain behaviorally related differences in the extent of atherosclerosis observed in prior studies. ANG II = angiotensin II; ACE = angiotensin-converting-enzyme; CRP = c-reactive protein; HDL = high-density lipoprotein; IL = interleukin; LDL = low-density lipoprotein; ROS = reactive oxygen species; TNF = tumor necrosis factor; WHHL = Watanabe Heritable Hyperlipidemic.

An investigation of PreMCI: Subtypes and longitudinal outcomes

To investigate the clinical features and rates of progression of conditions that are not considered to be normal, but do not fulfill criteria for mild cognitive impairment (MCI).

Venlafaxine extended-release for depression following spinal cord injury a randomized clinical trial

IMPORTANCE Depression is prevalent and associated with negative outcomes in individuals with spinal cord injury (SCI). Antidepressants are used routinely to treat depression, yet no placebo-controlled trials have been published in this population to our knowledge. OBJECTIVE To determine the efficacy and tolerability of venlafaxine hydrochloride extended-release (XR) for major depressive disorder (MDD) or dysthymic disorder in persons with chronic SCI. DESIGN, SETTING, AND PARTICIPANTS Multisite, randomized (1:1), double-blind, placebo-controlled Project to Improve Symptoms and Mood After SCI (PRISMS) trial. All research staff conducting screening, intervention, and outcome procedures were blinded to randomization status. We screened 2536 patients from outpatient clinics at 6 SCI treatment centers in the United States and randomized 133 participants into the trial. Participants were 18 to 64 years old and at least 1 month after SCI, with MDD or dysthymic disorder. Seventy-four percent of participants were male, and participants were on average 40 years old and 11 years after SCI. Forty-seven percent had cervical injuries, 53.4% had American Spinal Injury Association injury severity A (complete injury) SCI, 24.1% had at least 2 prior MDD episodes, and 99.2% had current MDD. Common comorbidities included chronic pain (93.9%), significant anxiety (57.1%), and history of substance dependence (44.4%). INTERVENTIONS Twelve-week trial of venlafaxine XR vs placebo using a flexible-dose algorithm. MAIN OUTCOMES AND MEASURES The Hamilton Depression Rating Scale (HAM-D 17-item version and Maier subscale, which focuses on core depression symptoms and excludes somatic symptoms) over 12 weeks. RESULTS Mixed-effects models revealed a significant difference between the venlafaxine XR and placebo groups in improvement on the Maier subscale from baseline to 12 weeks (treatment effect, 1.6; 95% CI, 0.3-2.9; P = .02) but not on the HAM-D 17-item version (treatment effect, 1.0; 95% CI, -1.4 to 3.4; P = .42). Participants receiving venlafaxine XR reported significantly less SCI-related disability on the Sheehan Disability Scale at 12 weeks compared with placebo (treatment effect, 4.7; 95% CI, 1.5-7.8; P = .005). Blurred vision was the only significantly more common new or worsening adverse effect in the venlafaxine XR group compared with the placebo group over 12 weeks. CONCLUSIONS AND RELEVANCE Venlafaxine XR was well tolerated by most patients and an effective antidepressant for decreasing core symptoms of depression and improving SCI-related disability. Further research is needed to determine the optimal treatment and measurement approaches for depression in chronic SCI. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00592384.

Screening for neuropathic pain after spinal cord injury with the Spinal Cord Injury Pain Instrument (SCIPI): A preliminary validation study

Study design:Cross-sectional.Objective:To preliminarily evaluate the validity of an interview-based spinal cord injury (SCI) neuropathic pain screening instrument.Setting:Six university-based SCI centers in the United States.Methods:Clinician diagnoses of neuropathic pain (NP) and non-neuropathic pain subtypes were collected independently of descriptions of the pain characteristics provided by the persons with SCI by using the Spinal Cord Injury Pain Instrument (SCIPI); SCIPI information and physician diagnoses for 82 pain sites of which they were most confident were subsequently compared.Results:Four of the SCIPI items correlated significantly with the NP subtype as determined by the clinician. The best cutoff score for identifying NP was an endorsement of two or more of these four items. Using this cutoff, sensitivity of the SCIPI was 78%, specificity was 73% and overall diagnostic accuracy was 76%.Conclusion:In this preliminary study, the SCIPI, which can be administered by a nonclinician, appears to have good sensitivity, specificity and diagnostic accuracy in a SCI population; it may have a role as a screening tool for NP after SCI. Further study is needed.

Efficacy of venlafaxine XR for the treatment of pain in patients with spinal cord injury and major depression: a randomized, controlled trial.

OBJECTIVES To (1) determine the efficacy of venlafaxine XR for the treatment of pain (secondary aim) in individuals with spinal cord injury (SCI) enrolled in a randomized controlled trial (RCT) on the efficacy of venlafaxine XR for major depressive disorder (MDD) (primary aim); and (2) test the hypothesis that venlafaxine XR would be effective for both neuropathic and nociceptive pain. DESIGN Multisite, double-blind, randomized (1:1) controlled trial with subjects block randomized and stratified by site, lifetime history of substance abuse, and prior history of MDD. SETTING Six Departments of Physical Medicine and Rehabilitation in university-based medical schools. PARTICIPANTS Individuals (N=123) with SCI and major depression between 18 and 64 years of age, at least 1 month post-SCI who also reported pain. INTERVENTION Twelve-week trial of venlafaxine XR versus placebo using a flexible titration schedule. OUTCOME MEASURES A 0-to-10 numeric rating scale for pain, pain interference items of the Brief Pain Inventory; 30% and 50% responders. RESULTS The effect of venlafaxine XR on neuropathic pain was similar to that of placebo. However venlafaxine XR resulted in statistically significant and clinically meaningful reductions in nociceptive pain site intensity and interference even after controlling for anxiety, depression, and multiple pain sites within the same individual. For those who achieved a minimally effective dose of venlafaxine XR, some additional evidence of effectiveness was noted for those with mixed (both neuropathic and nociceptive) pain sites. CONCLUSIONS Venlafaxine XR could complement current medications and procedures for treating pain after SCI and MDD that has nociceptive features. Its usefulness for treating central neuropathic pain is likely to be limited. Research is needed to replicate these findings and determine whether the antinociceptive effect of venlafaxine XR generalizes to persons with SCI pain without MDD.

A randomized controlled trial of venlafaxine XR for major depressive disorder after spinal cord injury: Methods and lessons learned

Abstract Context/objective We describe the rationale, design, methods, and lessons learned conducting a treatment trial for major depressive disorder (MDD) or dysthymia in people with spinal cord injury (SCI). Design A multi-site, double-blind, randomized (1:1) placebo controlled trial of venlafaxine XR for MDD or dysthymia. Subjects were block randomized and stratified by site, lifetime history of substance dependence, and prior history of MDD. Setting Six SCI centers throughout the United States. Participants Across participating centers, 2536 subjects were screened and 133 were enrolled into the trial. Subjects were 18–64 years old and at least 1 month post-SCI. Interventions Twelve-week trial of venlafaxine XR versus placebo using a flexible titration schedule. Outcome measures The primary outcome was improvement in depression severity at 12 weeks. The secondary outcome was improvement in pain. Results This article includes study methods, modifications prompted by a formative review process, preliminary data on the study sample and lessons learned. We describe common methodological and operational challenges conducting multi-site trials and how we addressed them. Challenges included study organization and decision making, staff training, obtaining human subjects approval, standardization of measurement and treatment, data and safety monitoring, subject screening and recruitment, unblinding and continuity of care, database management, and data analysis. Conclusions The methodological and operational challenges we faced and the lessons we learned may provide useful information for researchers who aim to conduct clinical trials, especially in the area of medical treatment of depression in people with SCI.