8 research outputs found
Recommended from our members
Sympathetic innervation of interscapular brown adipose tissue is not a predominant mediator of oxytocin-elicited reductions of body weight and adiposity in male diet-induced obese mice
Previous studies indicate that CNS administration of oxytocin (OT) reduces body weight in high fat diet-induced obese (DIO) rodents by reducing food intake and increasing energy expenditure (EE). We recently demonstrated that hindbrain (fourth ventricular [4V]) administration of OT elicits weight loss and elevates interscapular brown adipose tissue temperature (TIBAT, a surrogate measure of increased EE) in DIO mice. What remains unclear is whether OT-elicited weight loss requires increased sympathetic nervous system (SNS) outflow to IBAT. We hypothesized that OT-induced stimulation of SNS outflow to IBAT contributes to its ability to activate BAT and elicit weight loss in DIO mice. To test this hypothesis, we determined the effect of disrupting SNS activation of IBAT on the ability of 4V OT administration to increase TIBAT and elicit weight loss in DIO mice. We first determined whether bilateral surgical SNS denervation to IBAT was successful as noted by ≥ 60% reduction in IBAT norepinephrine (NE) content in DIO mice. NE content was selectively reduced in IBAT at 1-, 6- and 7-weeks post-denervation by 95.9 ± 2.0, 77.4 ± 12.7 and 93.6 ± 4.6% (P<0.05), respectively and was unchanged in inguinal white adipose tissue, pancreas or liver. We subsequently measured the effects of acute 4V OT (1, 5 µg ≈ 0.99, 4.96 nmol) on TIBAT in DIO mice following sham or bilateral surgical SNS denervation to IBAT. We found that the high dose of 4V OT (5 µg ≈ 4.96 nmol) elevated TIBAT similarly in sham mice as in denervated mice. We subsequently measured the effects of chronic 4V OT (16 nmol/day over 29 days) or vehicle infusions on body weight, adiposity and food intake in DIO mice following sham or bilateral surgical denervation of IBAT. Chronic 4V OT reduced body weight by 5.7 ± 2.23% and 6.6 ± 1.4% in sham and denervated mice (P<0.05), respectively, and this effect was similar between groups (P=NS). OT produced corresponding reductions in whole body fat mass (P<0.05). Together, these findings support the hypothesis that sympathetic innervation of IBAT is not necessary for OT-elicited increases in BAT thermogenesis and reductions of body weight and adiposity in male DIO mice
DOPA Decarboxylase Modulates Tau Toxicity
BACKGROUND: The microtubule-associated protein tau accumulates into toxic aggregates in multiple
neurodegenerative diseases. We found previously that loss of D2-family dopamine receptors ameliorated
tauopathy in multiple models including a Caenorhabditis elegans model of tauopathy.
METHODS: To better understand how loss of D2-family dopamine receptors can ameliorate tau toxicity, we screened a collection of C. elegans mutations in dopamine-related genes (n = 45) for changes in tau transgene–induced behavioral defects. These included many genes responsible for dopamine synthesis, metabolism, and signaling downstream of the D2 receptors.
RESULTS: We identified one dopamine synthesis gene, DOPA decarboxylase (DDC), as a suppressor of tau toxicity in tau transgenic worms. Loss of the C. elegans DDC gene, bas-1, ameliorated the behavioral deficits of tau transgenic worms, reduced phosphorylated and detergent-insoluble tau accumulation, and reduced tau-mediated neuron loss. Loss of function in other genes in the dopamine and serotonin synthesis pathways did not alter tau-induced toxicity; however, their function is required for the suppression of tau toxicity by bas-1. Additional loss of D2-family dopamine receptors did not synergize with bas-1 suppression of tauopathy phenotypes.
CONCLUSIONS: Loss of the DDC bas-1 reduced tau-induced toxicity in a C. elegans model of tauopathy, while loss of no other dopamine or serotonin synthesis genes tested had this effect. Because loss of activity upstream of DDC could reduce suppression of tau by DDC, this suggests the possibility that loss of DDC suppresses tau via the combined accumulation of dopamine precursor levodopa and serotonin precursor 5-hydroxytryptophan.This work was supported by Department of Veterans Affairs Merit Review Grant No. 1147891 (to BCK), Bright Focus Foundation Grant No. A2014438S (BCK), and National Institutes of Health National Institute of General Medical Sciences Medical Genetics Postdoctoral Training Program Grant No. T32-GM-007454 (to RLK)
DOPA Decarboxylase Modulates Tau Toxicity
BACKGROUND: The microtubule-associated protein tau accumulates into toxic aggregates in multiple
neurodegenerative diseases. We found previously that loss of D2-family dopamine receptors ameliorated
tauopathy in multiple models including a Caenorhabditis elegans model of tauopathy.
METHODS: To better understand how loss of D2-family dopamine receptors can ameliorate tau toxicity, we screened a collection of C. elegans mutations in dopamine-related genes (n = 45) for changes in tau transgene–induced behavioral defects. These included many genes responsible for dopamine synthesis, metabolism, and signaling downstream of the D2 receptors.
RESULTS: We identified one dopamine synthesis gene, DOPA decarboxylase (DDC), as a suppressor of tau toxicity in tau transgenic worms. Loss of the C. elegans DDC gene, bas-1, ameliorated the behavioral deficits of tau transgenic worms, reduced phosphorylated and detergent-insoluble tau accumulation, and reduced tau-mediated neuron loss. Loss of function in other genes in the dopamine and serotonin synthesis pathways did not alter tau-induced toxicity; however, their function is required for the suppression of tau toxicity by bas-1. Additional loss of D2-family dopamine receptors did not synergize with bas-1 suppression of tauopathy phenotypes.
CONCLUSIONS: Loss of the DDC bas-1 reduced tau-induced toxicity in a C. elegans model of tauopathy, while loss of no other dopamine or serotonin synthesis genes tested had this effect. Because loss of activity upstream of DDC could reduce suppression of tau by DDC, this suggests the possibility that loss of DDC suppresses tau via the combined accumulation of dopamine precursor levodopa and serotonin precursor 5-hydroxytryptophan.This work was supported by Department of Veterans Affairs Merit Review Grant No. 1147891 (to BCK), Bright Focus Foundation Grant No. A2014438S (BCK), and National Institutes of Health National Institute of General Medical Sciences Medical Genetics Postdoctoral Training Program Grant No. T32-GM-007454 (to RLK)
Chronic Hypopituitarism Associated with Increased Postconcussive Symptoms Is Prevalent after Blast-Induced Mild Traumatic Brain Injury
The most frequent injury sustained by US service members deployed to Iraq or Afghanistan is mild traumatic brain injuries (mTBI), or concussion, by far most often caused by blast waves from improvised explosive devices or other explosive ordnance. TBI from all causes gives rise to chronic neuroendocrine disorders with an estimated prevalence of 25–50%. The current study expands upon our earlier finding that chronic pituitary gland dysfunction occurs with a similarly high frequency after blast-related concussions. We measured circulating hormone levels and accessed demographic and testing data from two groups of male veterans with hazardous duty experience in Iraq or Afghanistan. Veterans in the mTBI group had experienced one or more blast-related concussion. Members of the deployment control (DC) group encountered similar deployment conditions but had no history of blast-related mTBI. 12 of 39 (31%) of the mTBI participants and 3 of 20 (15%) veterans in the DC group screened positive for one or more neuroendocrine disorders. Positive screens for growth hormone deficiency occurred most often. Analysis of responses on self-report questionnaires revealed main effects of both mTBI and hypopituitarism on postconcussive and posttraumatic stress disorder (PTSD) symptoms. Symptoms associated with pituitary dysfunction overlap considerably with those of PTSD. They include cognitive deficiencies, mood and anxiety disorders, sleep problems, diminished quality of life, deleterious changes in metabolism and body composition, and increased cardiovascular mortality. When such symptoms are due to hypopituitarism, they may be alleviated by hormone replacement. These findings suggest consideration of routine post-deployment neuroendocrine screening of service members and veterans who have experienced blast-related mTBI and are reporting postconcussive symptoms
Cost-Effectiveness of perioperative Vaginally Administered estrogen in postmenopausal women undergoing prolapse surgery (EVA trial):study protocol for a multicenter double-blind randomized placebo-controlled trial
BACKGROUND: Surgery for pelvic organ prolapse (POP) is associated with high recurrence rates. The costs associated with the treatment of recurrent POP are huge, and the burden from women who encounter recurrent POP, negatively impacts their quality of life. Estrogen therapy might improve surgical outcome for POP due to its potential beneficial effects. It is thought that vaginal estrogen therapy improves healing and long-term maintenance of connective tissue integrity. Hence, this study aims to evaluate the cost-effectiveness of perioperative vaginal estrogen therapy in postmenopausal women undergoing POP surgery. METHODS: The EVA trial is a multi-center double-blind randomized placebo-controlled trial conducted in the Netherlands comparing the effectiveness and costs-effectiveness of vaginal estrogen therapy. This will be studied in 300 postmenopausal women undergoing primary POP surgery, with a POP-Q stage of ≥ 2. After randomization, participants administer vaginal estrogen cream or placebo cream from 4 to 6 weeks preoperative until 12 months postoperative. The primary outcome is subjective improvement of POP symptoms at 1 year follow-up, measured with the Patient Global Impression of Improvement (PGI-I) scale. Secondary outcomes are POP-Q anatomy in all compartments, re-interventions, surgery related complications, general and disease specific quality of life, sexual function, signs and complaints of vaginal atrophy, vaginal pH, adverse events, costs, and adherence to treatment. Follow up is scheduled at 6 weeks, 6 months and 12 months postoperative. Data will be collected using validated questionnaires and out-patient visits including gynecological examination performed by an independent gynecologist. DISCUSSION: This study investigates whether perioperative vaginal estrogen will be cost-effective in the surgical treatment of POP in postmenopausal women. It is hypothesized that estrogen therapy will show a reduction in recurrent POP symptoms and a reduction in reoperations for POP, with subsequent improved quality of life among women and cost savings. Trial registrationNetherlands Trial Registry: NL6853; registered 19-02-2018, https://www.trialregister.nl/trial/6853. EudraCT: 2017-003144-21; registered: 24-07-2017. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12905-021-01587-9
Cost-effectiveness of pessary therapy versus surgery for symptomatic pelvic organ prolapse: an economic evaluation alongside a randomised non-inferiority controlled trial
Objective To evaluate the cost-effectiveness of pessary therapy as an initial treatment option compared with surgery for moderate to severe pelvic organ prolapse (POP) symptoms in secondary care from a healthcare and a societal perspective.Design Economic evaluation alongside a multicentre randomised controlled non-inferiority trial with a 24-month follow-up.Setting 21 hospitals in the Netherlands, recruitment conducted between 2015 and 2022.Participants 1605 women referred to secondary care with symptomatic prolapse stage ≥2 were requested to participate. Of them, 440 women gave informed consent and were randomised to pessary therapy (n=218) or to surgery (n=222) in a 1:1 ratio stratified by hospital.Interventions Pessary therapy and surgery.Primary and secondary outcome measures The Patient Global Impression of Improvement (PGI-I), a 7-point scale dichotomised into successful versus unsuccessful, with a non-inferiority margin of −10%; quality-adjusted life-years (QALYs) measured by the EQ-5D-3L; healthcare and societal costs were based on medical records and the institute for Medical Technology Assessment questionnaires.Results For the PGI-I, the mean difference between pessary therapy and surgery was −0.05 (95% CI −0.14; 0.03) and −0.03 (95% CI −0.07; 0.002) for QALYs. In total, 54.1% women randomised to pessary therapy crossed over to surgery, and 3.6% underwent recurrent surgery. Healthcare and societal costs were significantly lower in the pessary therapy (mean difference=−€1807, 95% CI −€2172; −€1446 and mean difference=−€1850, 95% CI −€2349; −€1341, respectively). The probability that pessary therapy is cost-effective compared with surgery was 1 at willingness-to-pay thresholds between €0 and €20 000/QALY gained from both perspectives.Conclusions Non-inferiority of pessary therapy regarding the PGI-I could not be shown and no statistically significant differences in QALYs between interventions were found. Due to significantly lower costs, pessary therapy is likely to be cost-effective compared with surgery as an initial treatment option for women with symptomatic POP treated in secondary care.Trial registration number NTR4883