Prioriteitstelling onderzoeksvragen weidevogels

In september 2008 heeft het secretariaat van de Kenniskring aan Alterra verzocht om samen met een aantal leden van de kenniskring een beknopt overzicht te maken van de huidige kennis op het gebied van het Weidevogelonderzoek. Specifiek gewenste acties waren: het opstellen van een overzicht van de bestaande kennis, het organiseren van een bijeenkomst met deskundigen op het gebied van ecologisch weidevogelonderzoek en het opstellen van een notitie met onderzoeksonderwerpen en prioriteiten

Effects of Light-at-Night on the Rat Liver - A Role for the Autonomic Nervous System

Exposure to light at night (LAN) has been associated with serious pathologies, including obesity, diabetes and cancer. Recently we showed that 2 h of LAN impaired glucose tolerance in rats. Several studies have suggested that the autonomic nervous system (ANS) plays an important role in communicating these acute effects of LAN to the periphery. Here, we investigated the acute effects of LAN on the liver transcriptome of male Wistar rats. Expression levels of individual genes were not markedly affected by LAN, nevertheless pathway analysis revealed clustered changes in a number of endocrine pathways. Subsequently, we used selective hepatic denervations [sympathetic (Sx), parasympathetic (Px), total (Tx, i.e., Sx plus Px), sham] to investigate the involvement of the ANS in the effects observed. Surgical removal of the sympathetic or parasympathetic hepatic branches of the ANS resulted in many, but small changes in the liver transcriptome, including a pathway involved with circadian clock regulation, but it clearly separated the four denervation groups. On the other hand, analysis of the liver metabolome was not able to separate the denervation groups, and only 6 out of 78 metabolites were significantly up- or downregulated after denervations. Finally, removal of the sympathetic and parasympathetic hepatic nerves combined with LAN exposure clearly modulated the effects of LAN on the liver transcriptome, but left most endocrine pathways unaffected. Conclusion: One-hour light-at-night acutely affects the liver transcriptome. Part of this effect is mediated via the nervous innervation, as a hepatectomy modulated and reduced the effect of LAN on liver transcripts

The Constitutive Lack of α7 Nicotinic Receptor Leads to Metabolic Disorders in Mouse.

Type 2 diabetes (T2D) occurs by deterioration in pancreatic β-cell function and/or progressive loss of pancreatic β-cell mass under the context of insulin resistance. α7 nicotinic acetylcholine receptor (nAChR) may contribute to insulin sensitivity but its role in the pathogenesis of T2D remains undefined. We investigated whether the systemic lack of α7 nAChR was sufficient to impair glucose homeostasis. We used an α7 nAChR knock-out (α7 <sup>-/-</sup> ) mouse model fed a standard chow diet. The effects of the lack of α7 nAChR on islet mass, insulin secretion, glucose and insulin tolerance, body composition, and food behaviour were assessed in vivo and ex vivo experiments. Young α7 <sup>-/-</sup> mice display a chronic mild high glycemia combined with an impaired glucose tolerance and a marked deficit in β-cell mass. In addition to these metabolic disorders, old mice developed adipose tissue inflammation, elevated plasma free fatty acid concentrations and presented glycolytic muscle insulin resistance in old mice. Finally, α7 <sup>-/-</sup> mice, fed a chow diet, exhibited a late-onset excessive gain in body weight through increased fat mass associated with higher food intake. Our work highlights the important role of α7 nAChR in glucose homeostasis. The constitutive lack of α7 nAChR suggests a novel pathway influencing the pathogenesis of T2D

Invloed van pesticiden op boerenlandvogels. Is de bewijsvoering rond?

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Clinical, radiological, and patient-reported outcomes 13 years after pedicle screw fixation with balloon-assisted endplate reduction and cement injection

Purpose: In management of traumatic thoracolumbar burst fractures, short-segment pedicle screw fixation with balloon-assisted endplate reduction (BAER) and cement injection is a safe, feasible, and effective technique to maintain radiological alignment with minimum spinal segments involved. However, 20% of patients report daily discomfort despite good spinal alignment and fusion after this technique. This study provides clinical, radiological, and patient-reported outcomes after a minimum 13 years of follow-up. Methods: Eighteen patients were invited at the outpatient clinic for clinical/radiological examinations. The cohort (originally 20 patients) was treated 13–14 years earlier with pedicle screw fixation, BAER, and cement injection for traumatic thoracolumbar burst fractures. Patient-reported outcome measures were obtained at time of examinations. Current data were compared with data obtained at 6 years of follow-up. Results: Seventeen patients (median age 50; range 32–80) cooperated. No/minimal back pain was reported by 15 patients, and 12 patients returned to their previous heavy labor work. Median visual analog score of health (80%; 50–100%) was similar to results at 6 years (80%; 60–100% p = 0.259). An Oswestry Disability Index score of less than 20% (reflecting minimal disability) was reported by 14 patients, compared with 15 patients at 6 years of follow-up. No significant differences were found in wedge or Cobb angle between the time points. Intravertebral cement resorption was not observed. Conclusion: Results from this study suggest that, 13 years after pedicle screw fixation with BAER and cement injection for traumatic thoracolumbar burst fractures, functional performance, pain and radiological outcomes of the current cohort were stable or had slightly improved. Graphic abstract: These slides can be retrieved under Electronic Supplementary Material.[Figure not available: see fulltext.]

Towards Personalized Treatment in Haemophilia: The Role of Genetic Factors in Iron and Heme Control to Identify Patients at Risk for Haemophilic Arthropathy

The treatment landscape for haemophilia is changing rapidly, creating opportunities for personalized treatment. As major morbidity is still caused by haemophilic arthropathy, understanding the factors affecting joint damage and joint damage progression might lead to more individualized treatment regimens. We investigated the association of HFE mutations or HMOX1 polymorphisms affecting iron/heme handling with radiographic joint damage in 252 haemophilia patients (severe and moderate). Although iron levels and transferrin saturation were significantly increased in the 95 patients with an HFE mutation, neither carrying this mutation nor the HMOX1 polymorphism was associated with radiographic joint damage, and the same was true after adjustment for well-known factors associated with arthropathy. In conclusion, this study does not support the hypothesis that HFE mutations or HMOX1 polymorphisms can be used to predict the development of haemophilic arthropathy

A Major Role for Perifornical Orexin Neurons in the Control of Glucose Metabolism in Rats

OBJECTIVE-The hypothalamic neuropeptide orexin influences (feeding) behavior as well as energy metabolism. Administration of exogenous orexin-A into the brain has been shown to increase both food intake and blood glucose levels. In the present study, we investigated the role of endogenous hypothalamic orexin release in glucose homeostasis in rats. RESEARCH DESIGN AND METHODS-We investigated the effects of the hypothalamic orexin system on basal endogenous glucose production (EGP) as well as on hepatic and peripheral insulin sensitivity by changing orexinergic activity in the hypothalamus combined with hepatic sympathetic or parasympathetic denervation, two-step hyperinsulinemic-euglycemic clamps, immunohistochemistry, and RT-PCR studies. RESULTS-Hypothalamic disinhibition of neuronal activity by the gamma-aminobutyric acid receptor antagonist bicuculline (BIC) increased basal EGP, especially when BIC was administered in the perifornical area where orexin-containing neurons but not melanocortin-concentrating hormone-containing neurons were activated. The increased BIC-induced EGP was largely prevented by intracerebroventricular pretreatment with the orexin-1 receptor antagonist. Intracerebroventricular administration of orexin-A itself caused an increase in plasma glucose and prevented the daytime decrease of EGP. The stimulatory effect of intracerebroventricular orexin-A on EGP was prevented by hepatic sympathetic denervation. Plasma insulin clamped at two or six times the basal levels did not counteract the stimulatory effect of perifornical BIC on EGP, indicating hepatic insulin resistance. RT-PCR showed that stimulation of orexin neurons increased the expression of hepatic glucoregulatory enzymes. CONCLUSIONS-Hypothalamic orexin plays an important role in EGP, most likely by changing the hypothalamic output to the autonomic nervous system. Disturbance of this pathway may result in unbalanced glucose homeostasis. Diabetes 58:1998-2005, 200

The prevalence of vertebral fractures in diffuse idiopathic skeletal hyperostosis and ankylosing spondylitis: A systematic review and meta-analysis

Background: Subjects with ankylosing spinal disorders, including diffuse idiopathic skeletal hyperostosis (DISH) and ankylosing spondylitis (AS) are more prone to vertebral fractures and frequently present with neurological deficit compared to the patients without an ankylosed spine. Moreover, prevalent vertebral fractures are an important predictor for subsequent fracture risk. However, the pooled fracture prevalence for DISH is unknown and less recent for AS. We aimed to systematically investigate the prevalence and risk of vertebral fractures in DISH and AS populations. Methods: Publications in Medline and EMBASE were searched from January 1980 until July 2023 for cohort studies reporting vertebral fractures in AS and DISH. Data on prevalence were pooled with random effects modeling after double arcsine transformation. Heterogeneity was assessed with I2 statistics and we performed subgroup analysis and meta-regression to explore sources of heterogeneity. Results: We included 7 studies on DISH (n = 1,193, total fractures = 231) with a pooled vertebral fracture prevalence of 22.6% (95%CI: 13.4%–33.4%). For AS, 26 studies were included (n = 2,875, total fractures = 460) with a pooled vertebral fracture prevalence of 15.2% (95%CI: 11.6%–19.1%). In general, fracture prevalence for AS remained similar for several study-level and clinically relevant characteristics, including study design, diagnostic criteria, spine level, and patient characteristics in subgroup analysis. AS publications from 2010 to 2020 showed higher fracture prevalence compared to 1990 to 2010 (18.6% vs. 11.6%). Fractures in DISH were most common at the thoracolumbar junction, whereas for AS, the most common location was the mid-thoracic spine. Conclusions: Vertebral fractures are prevalent in AS and DISH populations. Differences in fracture distribution along the spinal axis exist between the 2 disorders. Additional longitudinal studies are needed for incident fracture assessment in patients with ankylosing spinal disorders