Expression of cytokines at baseline correlate/predict in the disc the outcome of surgery after disc degeneration: A 12-month follow-up study.

BACKGROUND: Low back pain (LBP) is a highly prevalent condition that comprise a large portion of outpatient practice, challenging the diagnosis and treatment. However, the diagnostic tools are limited to clinical history, physical examination and imaging. Degenerative disc disease (DDD) is a significant cause of LBP, and emerging literature confirms the elevated levels of biomarkers in the discs. These biomarkers may serve as a tool for diagnosis, but may also be useful in predicting the treatment outcome. Here, we examine the expression of various cytokines on 1-year recovery from patients with LBP. METHODS: Patient-reported outcome (PRO) in terms of pain intensity (VAS), disability (ODI), and quality of life (Eq-5D) is collected from 44 patients at baseline and 12 months after surgery to study the influence of baseline TNF-α, IL-1ß, and IL-6 mRNA expression in both annulus fibrosus (AF) and nucleus pulposus (NP). RESULTS: Between baseline and follow-up, our cohort showed improvement in VAS back pain (p < 0.001), VAS leg pain (p < 0.001), ODI (p = 0.02), and Eq-5D (p = 0.01). Baseline levels of IL-1 ß was positively correlated with VAS back pain scores in AF (p = 0.05) and NP (p = 0.01) at 1-year follow-up. TNF-α expression at baseline was also positively correlated to ODI scores (p = 0.01) at follow-up and inversely correlated to improvements in ODI score between baseline and follow-up, suggesting that high TNF-α expression at baseline is associated with poor outcomes from surgery. CONCLUSION: The results from our study support that TNF-α expression at baseline can serve as a very important predictor of treatment response from lumbar fusion surgery.

What can we learn about fish neutrophil and macrophage response to immune challenge from studies in zebrafish.

Fish rely, to a high degree, on the innate immune system to protect them against the constant exposure to potential pathogenic invasion from the surrounding water during homeostasis and injury. Zebrafish larvae have emerged as an outstanding model organism for immunity. The cellular component of zebrafish innate immunity is similar to the mammalian innate immune system and has a high degree of sophistication due to the needs of living in an aquatic environment from early embryonic stages of life. Innate immune cells (leukocytes), including neutrophils and macrophages, have major roles in protecting zebrafish against pathogens, as well as being essential for proper wound healing and regeneration. Zebrafish larvae are visually transparent, with unprecedented in vivo microscopy opportunities that, in combination with transgenic immune reporter lines, have permitted visualisation of the functions of these cells when zebrafish are exposed to bacterial, viral and parasitic infections, as well as during injury and healing. Recent findings indicate that leukocytes are even more complex than previously anticipated and are essential for inflammation, infection control, and subsequent wound healing and regeneration.

Partial volume correction of PET image data using geometric transfer matrices based on uniform B-splines.

Objective. Most methods for partial volume correction (PVC) of positron emission tomography (PET) data employ anatomical segmentation of images into regions of interest. This approach is not optimal for exploratory functional imaging beyond regional hypotheses. Here, we describe a novel method for unbiased voxel-wise PVC.Approach.B-spline basis functions were combined with geometric transfer matrices to enable a method (bsGTM) that provides PVC or alternatively provides smoothing with minimal regional crosstalk. The efficacy of the proposed method was evaluated using Monte Carlo simulations, human PET data, and murine functional PET data.Main results.In simulations, bsGTM provided recovery of partial volume signal loss comparable to iterative deconvolution, while demonstrating superior resilience to noise. In a real murine PET dataset, bsGTM yielded much higher sensitivity for detecting amphetamine-induced reduction of [11C]raclopride binding potential. In human PET data, bsGTM smoothing enabled increased signal-to-noise ratios with less degradation of binding potentials relative to Gaussian convolution or non-local means.Significance.bsGTM offers improved performance for PVC relative to iterative deconvolution, the current method of choice for voxel-wise PVC, especially in the common PET regime of low signal-to-noise ratio. The new method provides an anatomically unbiased way to compensate partial volume errors in cases where anatomical segmentation is unavailable or of questionable relevance or accuracy.

Hepcidin Reduction during Testosterone Therapy in Men with Type 2 Diabetes: A Randomized, Double-Blinded, Placebo-Controlled Study.

High hepcidin is linked to low-grade inflammation and lower iron levels. The consequences of testosterone replacement therapy (TRT) on inflammation and the risk of cardiovascular disease (CVD) are undetermined. We investigate the effect of TRT on the inflammatory cardiovascular risk markers hepcidin-iron, fibroblast growth factor 23 (FGF23)-phosphate-klotho, and calprotectin pathways. METHODS: A randomized, placebo-controlled, double-blinded study at an academic tertiary-care medical center. Interventions were testosterone gel (TRT, n = 20) or placebo gel (n = 19) for 24 weeks. We included 39 men (50-70 years) with type 2 diabetes (T2D) on metformin monotherapy with bioavailable testosterone levels <7.3 nmol/L. Body composition was assessed with DXA- and MRI-scans; the main study outcomes were serum hepcidin-iron, FGF23, phosphate, klotho, and calprotectin. RESULTS: Hepcidin levels decreased during TRT (ß = -9.5 ng/mL, p < 0.001), lean body mass (ß = 1.9 kg, p = 0.001) increased, and total fat mass (ß = -1.3 kg, p = 0.009) decreased compared to placebo. Delta hepcidin was not associated with changes in lean body mass or fat mass. Iron and the pathways of FGF23-phosphate-klotho and calprotectin were unchanged during TRT. CONCLUSIONS: During TRT, the reduction in hepcidin was not associated with circulating iron levels, lean body mass, or fat mass; these findings suggested a direct anti-inflammatory effect of TRT and no indirect effect mediated through these factors.

Acute immune responses in zebrafish and evasive behavior of a parasite - who is winning?

The protozoan parasite Ichthyophthirius multifiliis is an economically important parasite for the aquaculture- and ornamental fish industry. The parasite is abundant worldwide and infects the skin, gills and fins of freshwater fish species. For approximately the last fifty years the innate and protective immune mechanisms induced by I. multifiliis have been in focus in different fish hosts. By utilizing transgenic zebrafish, new tools to investigate this have emerged. The aim of this study was therefore to elucidate early immune responses in zebrafish larvae by using gene expression and in vivo imaging of neutrophil and macrophage behavior during infection. For the first time, zebrafish larvae were infected with the parasite and infection dynamics, parasite size and host-parasite interactions were investigated. Results showed that the larvae responded with mild inflammation and that the 12 compared to 5 days post fertilization larvae were significantly less susceptible. It was furthermore observed that neutrophils and macrophages were attracted to the parasites and that neutrophils reacted with neutrophil extracellular traps (NETs) when fighting the parasite. The parasite was rotating vigorously, presumably to impede the neutrophils and macrophages from attaching to it but on rare occasions, neutrophils and macrophages were able to kill the parasite. Based on these observations, we concluded that the parasite uses the rotation as an immune evasive strategy and that the zebrafish larvae respond with high activity from neutrophils and macrophages locally but systemically only with mild inflammation.

Heritability and circulating concentrations of pregnancy-associated plasma protein-A and stanniocalcin-2 in elderly monozygotic and dizygotic twins.

Introduction: Pregnancy-associated plasma protein-A (PAPP-A) is an IGF-activating enzyme suggested to influence aging-related diseases. However, knowledge on serum PAPP-A concentration and regulation in elderly subjects is limited. Therefore, we measured serum PAPP-A in elderly same-sex monozygotic (MZ) and dizygotic (DZ) twins, as this allowed us to describe the age-relationship of PAPP-A, and to test the hypothesis that serum PAPP-A concentrations are genetically determined. As PAPP-A is functionally related to stanniocalcin-2 (STC2), an endogenous PAPP-A inhibitor, we included measurements on STC2 as well as IGF-I and IGF-II. Methods: The twin cohort contained 596 subjects (250 MZ twins, 346 DZ twins), whereof 33% were males. The age ranged from 73.2 to 94.3 (mean 78.8) years. Serum was analyzed for PAPP-A, STC2, IGF-I, and IGF-II by commercial immunoassays. Results: In the twin cohort, PAPP-A increased with age (r=0.19; P<0.05), whereas IGF-I decreased (r=-0.12; P<0.05). Neither STC2 nor IGF-II showed any age relationship. When analyzed according to sex, PAPP-A correlated positively with age in males (r=0.18; P<0.05) and females (r=0.25; P<0.01), whereas IGF-I correlated inversely in females only (r=-0.15; P<0.01). Males had higher levels of PAPP-A (29%), STC2 (18%) and IGF-I (19%), whereas serum IGF-II was 28% higher in females (all P<0.001). For all four proteins, within-pair correlations were significantly higher for MZ twins than for DZ twins, and they demonstrated substantial and significant heritability, which after adjustment for age and sex averaged 59% for PAPP-A, 66% for STC2, 58% for IGF-I, and 52% for IGF-II. Discussion: This twin study confirms our hypothesis that the heritability of PAPP-A serum concentrations is substantial, and the same is true for STC2. As regards the age relationship, PAPP-A increases with age, whereas STC2 remains unchanged, thereby supporting the idea that the ability of STC2 to inhibit PAPP-A enzymatic activity decreases with increasing age.

Estimated exposure to perfluoroalkyl substances during infancy and serum-adipokine concentrations in later childhood.

BACKGROUND: Perfluoroalkyl substances (PFASs) are transferred through human milk and may cause elevated exposure during infancy. Given the lack of early postnatal blood samples, PFAS concentrations can be estimated to serve as predictors of subsequent metabolic toxicity. METHODS: A total of 298 children from a prospective birth cohort were followed up through to age 9 years. Serum-PFAS was measured at birth and 18 months of age, while exposures during infancy were estimated by structural equations. Adiponectin, resistin, leptin, and the leptin receptor were measured in serum at age 9. Adjusted regression coefficients for estimated serum-PFAS concentrations were calculated, with additional consideration of the duration of breastfeeding and potential effect modification by sex. RESULTS: A doubling in estimated serum-PFAS concentrations, particularly at ages 6 and 12 months, was associated with a loss of about 10-15% in age 9 resistin concentrations, while other associations were much weaker. Sex dependence of the associations was not observed, and neither did the duration of breastfeeding affect outcomes at age 9. CONCLUSION: Lowered serum-resistin concentrations at age 9 years were most strongly associated with early postnatal PFAS exposures. These findings suggest that infancy may represent a vulnerable time window for some aspects of metabolic programming that may be affected by PFAS exposure. IMPACT: Serum-PFAS concentrations during infancy can be estimated in the absence of blood samples. Adipokine concentrations were measured at age 9 years as metabolic biomarkers. Resistin was significantly lower in children with elevated PFAS exposures in infancy. The findings suggest that early postnatal PFAS exposures may affect subsequent metabolic health. Assessment of infancy vulnerability to PFAS can be explored using estimated serum-PFAS concentrations.

Comparison of plasma total carbon dioxide and standard hydrogen carbonate in a hospital laboratory setting.

BACKGROUND: Studies comparing venous total carbon dioxide (tCO2) and standard hydrogen carbonate (HCO3-(P,st)) has shown diverse results, and it is debatable whether these two parameters can be used interchangeably for workup of acid-base disorders in a hospital setting. METHOD: All patients with an HCO3-(P,st) requisition from any department at Odense University Hospital between 11th May 2021 and 1st June 2021 had tCO2 and HCO3-(P,st) analysed simultaneously. TCO2 was measured on Cobas® 8000, c702 module, while HCO3-(P,st) was calculated based on measurements on ABL835 Flex. RESULTS: From 1210 patients, mean (standard deviation (SD)) was 22.9 (3.7) mmol/L for tCO2 and 22.5 (2.9) mmol/L for HCO3-(P,st). TCO2 range was 10.1-42.3 mmol/L and 11.7-41.4 mmol/L for HCO3-(P,st). Linear regression showed that tCO2 (mmol/L) = -2.90 + 1.15 × HCO3-(P,st) (mmol/L) with R2 = 0.81. Bias (mean (SD) difference) between tCO2 and HCO3-(P,st)) was 0.4 (1.7) mmol/L with a -5.0-9.6 mmol/L range. Limits of agreement was -2.90-3.70 mmol/L. Comparison of classification within, above or below reference interval for tCO2 and HCO3-(P,st) showed that 984 samples (81%) retained their classification. Only one sample (0.1%) would be severely misclassified (outside the respective reference intervals) if HCO3-(P,st) was considered the gold standard. Of the samples investigated, 46.1% had a mean difference between tCO2 and HCO3-(P,st) of 0-1 mmol/L and 30.3% had 1.1-2.0 mmol/L. CONCLUSIONS: Our results indicate that venous tCO2 and venous HCO3-(P,st) can be used interchangeably in a hospital setting for workup of acid-base disorders.

Transient receptor potential (TRP) channels mRNA transcripts in the lumbar intervertebral discs: biomarkers for inflammation, pain, disability, and clinical outcome.

Transient receptor potential (TRP) channels are widely expressed cation channels that play an essential role in mediating Ca2+ homeostasis and are considered potential regulators of inflammatory pain. This study investigates the expression of the TRP channel subtypes TRPV1, TRPV4, TRPC6, TRPM2, TRPM8 in lumbar intervertebral disc (IVD) biopsies from patients with chronic low back pain (LBP). We determined the expression of these TRP channel subtypes in the annulus fibrosus (AF) and the nucleus pulposus (NP) from 46 patients with LBP undergoing 1-2 level lumbar fusion surgery for degenerative disc disease. The mRNA transcripts were analyzed using quantitative real-time polymerase chain reaction (RT-qPCR), and the expression levels were compared against visual analog scale (VAS) and oswestry disability index (ODI) scores (0-100) for pain and disability. A significant positive correlation was demonstrated between VAS score and the mRNA expression of TRPV1, TRPC6, TRPM2, TRPM8 in the AF. We also found a significant positive correlation between ODI scores and expression of TRPV1 and TRPM8. Further, there is a significant positive correlation between TNF-α and TRPV1, TRPM2 and TRPM8 expression in the AF, and IL-6 to TRPV1 in the NP. Interestingly, when investigating treatment response via a 12-month postoperative follow-up ODI, we found a significant correlation between only TRPV1 expression at baseline and the follow-up ODI scores, which indicates this marker could predict the effectiveness of surgery. These results strongly suggest an association between pain, inflammatory mediators, and TRP channel expression in lumbar disc biopsies of patients with chronic LBP.

The expression of metalloproteinases in the lumbar disc correlates strongly with Pfirrmann MRI grades in lumbar spinal fusion patients.

Introduction: Increased catabolism of the extracellular matrix is observed under degenerative disc disease (DDD). The cleavage of extracellular matrix proteins in the nucleus pulposus (NP) by either matrix metalloproteinases (MMPs) or a disintegrin and metalloproteinases with thrombospondin motifs (ADAMTSs) is believed to be involved in the degeneration, but the mechanisms are not known. Research question: Here, we examine the correlation between expression of several MMPs and ADAMTSs subtypes in lumbar discs from 34 patients with low back pain (LBP) undergoing 1-2 level lumbar fusion surgery (L4/L5 and/or L5/S1) for DDD with or without spondylolisthesis. Materials and Methods: The mRNA levels of MMPs (subtypes 1, 2, 3, 10, and 13) and ADAMTSs (subtypes 1, 4, and 5) were analyzed using quantitative real-time polymerase chain reaction (RT-qPCR) and correlated to the Pfirrmann magnetic resonance imaging classification system (grade I-V) of lumbar DDD. Results: We find a highly significant positive correlation between Pfirrmann grades and the gene expression of MMP1 (r=0.67, p=0.0001), MMP3 (r=0.61, p=0.0002), MMP10 (r=0.6701, p=0.0001), MMP13 (r=0.48, p=0.004), ADAMTS1 (r=0.67, p=0.0001), and ADAMTS5 (r=0.53, p=0.0017). The similar regulation of these transcript suggests their involvement in disc degeneration. Interestingly, a post hoc analysis (uncorrected p-values) also demonstrated a positive correlation between expression of TNF-α, IL-6 and both ADAMTSs/MMPs and the Pfirrmann grades. Discussion and Conclusion: These findings show that disc degradation in DDD is strongly associated with the expression of some metalloproteinases.

Evaluation of the α-synuclein PET radiotracer (d3)-[11C]MODAG-001 in pigs.

BACKGROUND: A positron emission tomography (PET) radiotracer to neuroimage α-synuclein aggregates would be a crucial addition for early diagnosis and treatment development in disorders such as Parkinson's disease, where elevated aggregate levels are a histopathological hallmark. The radiotracer (d3)-[11C]MODAG-001 has recently shown promise for visualization of α-synuclein pre-formed fibrils (α-PFF) in rodents. We here test the radiotracer in a pig model where proteins are intracerebrally injected immediately before scanning. Four pigs were injected in one hemisphere with 150 µg α-PFF, and in the other hemisphere, either 75 µg α-PFF or human brain homogenate from either dementia with Lewy bodies (DLB) or Alzheimer's disease (AD) was injected. All pigs underwent one or two (d3)-[11C]MODAG-001 PET scans, quantified with the non-invasive Logan graphical analysis using the occipital cortex as a reference region. RESULTS: The α-PFF and AD homogenate injected brain regions had high uptake of (d3)-[11C]MODAG-001 compared to the occipital cortex or cerebellum. BPND values in 150 µg α-PFF injected regions was 0.78, and in the AD homogenate injected regions was 0.73. By contrast, the DLB homogenate injected region did not differ in uptake and clearance compared to the reference regions. The time-activity curves and BPND values in the 150 µg and 75 µg injected regions of α-PFFs show a dose-dependent effect, and the PET signal could be blocked by pretreatment with unlabeled MODAG-001. CONCLUSION: We find that both α-PFF and AD brain homogenates give rise to increased binding of (d3)-[11C]MODAG-001 when injected into the pig brain. Despite its limited specificity for cerebral α-synuclein pathology, (d3)-[11C]MODAG-001 shows promise as a lead tracer for future radiotracer development.

Investigating hypozincemia and validity of plasma zinc measurements in infected patients.

Hypozincemia is a well-known phenomenon in patients with infection caused by the activation of the acute phase response (APR). Zn status is still based upon plasma Zn levels in venous blood samples. Recent trials have questioned the validity of this measurement in infected patients. The aim of this study was to assess plasma levels of Zn, albumin and Zinc-binding capacity in patients during and following infection. Furthermore, to assess if an assay for albumin-corrected Zn could potentially replace or add knowledge to existing tools for assessment of Zinc-status. A prospective clinical observational trial was conducted. Associations between P-Zn, -Albumin, -Albumin-corrected Zn and Zn binding capacity were analyzed. Analyzes were based upon two venous blood samples drawn during and following infection, respectively. Twenty-three patients admitted to a medical ward showing paraclinical signs of infection were included in the study. Significantly lower levels of Zn and albumin were found during infection compared with the levels post-infection. These findings corresponded to the changes found in Zn binding capacity. About 52% of patients were deemed Zn deficient by plasma Zn levels during infection but after applying the correction for P-Albumin, all patients were found to be within normal ranges of Zn levels. Furthermore, we found no statistically significant difference between albumin-corrected Zn during infection and P-Zn post-infection. The new assay was found to accurately estimate the 'true' Zn levels in infected patients. Based on our findings, we propose albumin-corrected P-Zn as a promising new tool, which may result in more precise diagnostics and treatment.

Albumin-corrected Zn and available free Zn-binding capacity as indicators of Zn status - potential for clinical implementation.

We have established and describe two measurement procedures to diagnose possible zinc (Zn) deficiency; albumin-corrected Zn concentration and available free Zn-binding capacity. Reference intervals for both biomarkers were established in healthy adults from the Danish population. The clinical usefulness of the measurement procedures was investigated in patients with cirrhosis and in patients given parenteral nutrition due to short bowel syndrome. The results of both methods indicate that there is a risk of overdiagnosing Zn deficiency based on low plasma Zn concentrations. Needless Zn supplementation may thus be avoided by using the albumin-corrected Zn concentration or available free Zn-binding capacity.

An fMRI-compatible system for targeted electrical stimulation.

BACKGROUND: Neuromodulation is a rapidly expanding therapeutic option considered within neuropsychiatry, pain and rehabilitation therapy. Combining electrostimulation with feedback from fMRI can provide information about the mechanisms underlying the therapeutic effects, but so far, such studies have been hampered by the lack of technology to conduct safe and accurate experiments. Here we present a system for fMRI compatible electrical stimulation, and the first proof-of-concept neuroimaging data with deep brain stimulation (DBS) in pigs obtained with the device. NEW METHOD: The system consists of two modules, placed in the control and scanner room, connected by optical fiber. The system also connects to the MRI scanner to timely initiate the stimulation sequence at start of scan. We evaluated the system in four pigs with DBS in the subthalamic nucleus (STN) while we acquired BOLD responses in the STN and neocortex. RESULTS: We found that the system delivered robust electrical stimuli to the implanted electrode in sync with the preprogrammed fMRI sequence. All pigs displayed a DBS-STN induced neocortical BOLD response, but none in the STN. COMPARISONS WITH EXISTING METHOD: The system solves three major problems related to electric stimuli and fMRI examinations, namely preventing distortion of the fMRI signal, enabling communication that synchronize the experimental conditions, and surmounting the safety hazards caused by interference with the MRI scanner. CONCLUSIONS: The fMRI compatible electrical stimulator circumvents previous problems related to electroceuticals and fMRI. The system allows flexible modifications for fMRI designs and stimulation parameters, and can be customized to electroceutical applications beyond DBS.

Elucidating Pathway and Anesthetic Mechanism of Action of Clove Oil Nanoformulations in Fish.

Clove oil (CO), an essential oil of Syzygium aromaticum, has been reported as an anesthetic for many fish species. However, its insoluble properties require a suitable delivery system for its application. In the present study, nanoformulations of CO as a nanoemulsion (CO-NE), a self-microemulsifying drug-delivery system (CO-SMEDDS), and a self-nanoemulsifying drug-delivery system (CO-SNEDDS) were prepared for delivering CO. Zebrafish were used as a fish model to investigate oil pathways. The result shows fluorescence spots of fluorescence-labeled CO accumulate on the gills, skin, and brain. All CO nanoformulations significantly increased penetration flux compared to CO ethanolic solution. Investigation of the anesthetic mechanism of action using a rat brain γ-aminobutyric acid subtype A (GABAA) receptor-binding test demonstrates that CO and its major compound, eugenol, modulate [3H]muscimol binding. CO-NE exhibited a concentration-dependent binding activity with an EC50 value of 175 µg/mL, significantly higher than CO solution in dimethyl sulfoxide. In conclusion, CO enters the fish through the skin and gills. The anesthetic mechanism of action of CO is based on modulation of [3H] muscimol binding to GABAA receptors. Among three nanoformulations tested, CO-NE is the most effective at increasing permeability and enhancing the receptor-binding activity of the oil.

Hot and Cold Cognitive Disturbances in Parkinson Patients Treated with DBS-STN: A Combined PET and Neuropsychological Study.

Patients with Parkinson's disease (PD) often suffer from non-motor symptoms, which may be caused by serotonergic dysfunction. Deep Brain Stimulation (DBS) in the subthalamic nucleus (STN) may also influence non-motor symptoms. The aim of this study is to investigate how the cerebral 5-HT system associates to disturbances in cognition and mood in PD patients with DBS-STN turned on and off. We used psychological tests and questionnaires to evaluate cognitive function and the effects on mood from turning DBS-STN off. We applied a novel PET neuroimaging methodology to evaluate the integrity of the cerebral serotonin system. We measured 5-HT1BR binding in 13 DBS-STN-treated PD patients, at baseline and after turning DBS off. Thirteen age-matched volunteers served as controls. The measures for cognition and mood were correlated to the 5-HT1BR availability in temporal limbic cortex. 5-HT1BR binding was proportional to working memory performance and inverse proportional to affective bias for face recognition. When DBS is turned off, patients feel less vigorous; the higher the limbic and temporal 5-HT1BR binding, the more they are affected by DBS being turned off. Our study suggests that cerebral 5-HTR binding is associated with non-motor symptoms, and that preservation of serotonergic functions may be predictive of DBS-STN effects.

An in vivo Pig Model for Testing Novel Positron Emission Tomography Radioligands Targeting Cerebral Protein Aggregates.

Positron emission tomography (PET) has become an essential clinical tool for diagnosing neurodegenerative diseases with abnormal accumulation of proteins like amyloid-ß or tau. Despite many attempts, it has not been possible to develop an appropriate radioligand for imaging aggregated α-synuclein in the brain for diagnosing, e.g., Parkinson's Disease. Access to a large animal model with α-synuclein pathology would critically enable a more translationally appropriate evaluation of novel radioligands. We here establish a pig model with cerebral injections of α-synuclein preformed fibrils or brain homogenate from postmortem human brain tissue from individuals with Alzheimer's disease (AD) or dementia with Lewy body (DLB) into the pig's brain, using minimally invasive surgery and validated against saline injections. In the absence of a suitable α-synuclein radioligand, we validated the model with the unselective amyloid-ß tracer [11C]PIB, which has a high affinity for ß-sheet structures in aggregates. Gadolinium-enhanced MRI confirmed that the blood-brain barrier was intact. A few hours post-injection, pigs were PET scanned with [11C]PIB. Quantification was done with Logan invasive graphical analysis and simplified reference tissue model 2 using the occipital cortex as a reference region. After the scan, we retrieved the brains to confirm successful injection using autoradiography and immunohistochemistry. We found four times higher [11C]PIB uptake in AD-homogenate-injected regions and two times higher uptake in regions injected with α-synuclein-preformed-fibrils compared to saline. The [11C]PIB uptake was the same in non-injected (occipital cortex, cerebellum) and injected (DLB-homogenate, saline) regions. With its large brain and ability to undergo repeated PET scans as well as neurosurgical procedures, the pig provides a robust, cost-effective, and good translational model for assessment of novel radioligands including, but not limited to, proteinopathies.

Integrative analyses of probiotics, pathogenic infections and host immune response highlight the importance of gut microbiota in understanding disease recovery in rainbow trout (Oncorhynchus mykiss).

AIMS: Given the pivotal role played by the gut microbiota in regulating the host immune system, great interest has arisen in the possibility of controlling fish health by modulating the gut microbiota. Hence, there is a need to better understand of the host-microbiota interactions after disease responses to optimize the use of probiotics to strengthen disease resilience and recovery. METHODS AND RESULTS: We tested the effects of a probiotic feed additive in rainbow trout and challenged the fish with the causative agent for enteric red mouth disease, Yersinia ruckeri. We evaluated the survival, host immune gene expression and the gut microbiota composition. Results revealed that provision of probiotics and exposure to Y. ruckeri induced immune gene expression in the host, which were associated with changes in the gut microbiota. Subsequently, infection with Y. ruckeri had very little effect on microbiota composition when probiotics were applied, indicating that probiotics increased stabilisation of the microbiota. Our analysis revealed potential biomarkers for monitoring infection status and fish health. Finally, we used modelling approaches to decipher interactions between gut bacteria and the host immune gene responses, indicating removal of endogenous bacteria elicited by non-specific immune responses. CONCLUSIONS: We discuss the relevance of these results emphasizing the importance of host-microbiota interactions, including the protective potential of the gut microbiota in disease responses. SIGNIFICANCE AND IMPACT OF THE STUDY: Our results highlight the functional consequences of probiotic-induced changes in the gut microbiota post infection and the resulting host immune response.

Toxicity of the antiparasitic lipopeptide biosurfactant SPH6 to green algae, cyanobacteria, crustaceans and zebrafish.

A lipopeptide with biosurfactant properties produced by the bacterium Pseudomonas H6 (SPH6) has antiparasitic effects and may serve as an alternative to chemotherapeutants against aquatic pathogens in aquaculture. We have elucidated its ecotoxicological potential by short-term standardized tests, including a growth rate inhibition test with algae (Raphidocelis subcapitata), a lethality test on the cyanobacteria Phormidium autumnale, a lethality test using crustaceans (Daphnia magna), a fish embryo acute toxicity test and a fish acute toxicity test using zebrafish (Danio rerio). The decrease of the biosurfactant concentration in zebrafish test water during 24 h was measured. The toxicity for crustaceans was highest (LC50 = 20 mg/L), followed by the test with the zebrafish embryo (LC50 = 27 mg/L). The juvenile zebrafish fish (complete mortality occurred between 40 and 80 mg/L), the cyanobacteria (LC50 = 80 mg/L) and the green algae (EC50 = 170 mg/L) showed higher tolerance. The determination of SPH6 concentrations in fish tank (up to 50% elimination over 24 h) suggested that the compound may become adsorbed to tank walls, absorbed by fish or degraded. Further studies should determine its impact under different environmental settings (e.g. temperature) relevant for different branches of the aquaculture sector.

Early-life exposure to perfluoroalkyl substances in relation to serum adipokines in a longitudinal birth cohort.

BACKGROUND: Per- and polyfluoroalkyl substances (PFAS) exposure has been linked to metabolic health outcomes such as obesity, and changes in adipokine hormones may be one of the underlying biological mechanisms. We prospectively evaluated the associations between prenatal and early childhood exposures to PFASs and adipokines in children. MATERIAL AND METHODS: PFAS concentrations were measured in serum samples collected at birth, 18 months, and 5 and 9 years, and adiponectin, leptin, leptin receptor, and resistin were measured in serum samples collected at birth and 9 years. We used multivariable linear regression models to estimate the percent change in serum-adipokine concentrations for a doubling in serum-PFAS concentrations. The potential sex-specific effect of PFAS was assessed by including an interaction term between PFAS and sex in each model. Bayesian kernel machine regression (BKMR) was implemented to evaluate the overall effect of PFAS mixtures. RESULTS: Significant associations with leptin, leptin receptor, and resistin at age 9 years were observed for serum-PFAS concentrations at 18 months and 5 and 9 years, whereas associations for PFAS concentrations at birth were mostly null. However, we observed a positive association between serum-PFHxS at birth and leptin receptor at birth. We found limited evidence regarding modification effect of sex on serum-PFAS concentrations. BKMR findings were consistent and suggested some significant effects of the overall PFAS mixtures at 18 months and 5 and 9 years on adipokine concentrations at 9 years. CONCLUSIONS: Given the associations of PFAS exposure with both adipokine hormones and metabolic functions, future studies should include assessment of adipokine hormones when examining PFAS-associated metabolic alterations.