Vegan Diet and Bone Health—Results from the Cross-Sectional RBVD Study

Scientific evidence suggests that a vegan diet might be associated with impaired bone health. Therefore, a cross-sectional study (n = 36 vegans, n = 36 omnivores) was used to investigate the associations of veganism with calcaneal quantitative ultrasound (QUS) measurements, along with the investigation of differences in the concentrations of nutrition- and bone-related biomarkers between vegans and omnivores. This study revealed lower levels in the QUS parameters in vegans compared to omnivores, e.g., broadband ultrasound attenuation (vegans: 111.8 ± 10.7 dB/MHz, omnivores: 118.0 ± 10.8 dB/MHz, p = 0.02). Vegans had lower levels of vitamin A, B2, lysine, zinc, selenoprotein P, n-3 fatty acids, urinary iodine, and calcium levels, while the concentrations of vitamin K1, folate, and glutamine were higher in vegans compared to omnivores. Applying a reduced rank regression, 12 out of the 28 biomarkers were identified to contribute most to bone health, i.e., lysine, urinary iodine, thyroid-stimulating hormone, selenoprotein P, vitamin A, leucine, α-klotho, n-3 fatty acids, urinary calcium/magnesium, vitamin B6, and FGF23. All QUS parameters increased across the tertiles of the pattern score. The study provides evidence of lower bone health in vegans compared to omnivores, additionally revealing a combination of nutrition-related biomarkers, which may contribute to bone health. Further studies are needed to confirm these findings.     

Markers of Intestinal Permeability Are Rapidly Improved by Alcohol Withdrawal in Patients with Alcohol-Related Liver Disease

Changes in intestinal microbiome and barrier function are critical in the development of alcohol-related liver disease (ALD). Here, we determined the effects of a one-week alcohol withdrawal on parameters of intestinal barrier function in heavy drinkers with ALD in comparison to healthy non-drinkers (controls). In serum samples of 17 controls (m = 10/f = 7) and 37 age-matched ALD patients (m = 26/f = 11) undergoing a one-week alcohol withdrawal, markers of liver health and intestinal barrier function were assessed. Liver damage, e.g., fibrosis and hepatic steatosis, were assessed using FibroScan. Before alcohol withdrawal, markers of liver damage, lipopolysaccharide binding protein (LBP) and overall TLR4/TLR2 ligands in serum were significantly higher in ALD patients than in controls, whereas intestinal fatty acid binding protein (I-FABP) and zonulin protein concentrations in serum were lower. All parameters, with the exception of LBP, were significantly improved after alcohol withdrawal; however, not to the level of controls. Our data suggest that one-week of abstinence improves markers of intestinal barrier function and liver health in ALD patients.     

The Hunger Games: Homeostatic State-Dependent Fluctuations in Disinhibition Measured with a Novel Gamified Test Battery

Food homeostatic states (hunger and satiety) influence the cognitive systems regulating impulsive responses, but the direction and specific mechanisms involved in this effect remain elusive. We examined how fasting, and satiety, affect cognitive mechanisms underpinning disinhibition using a novel framework and a gamified test-battery. Thirty-four participants completed the test-battery measuring three cognitive facets of disinhibition: attentional control, information gathering and monitoring of feedback, across two experimental sessions: one after overnight fasting and another after a standardised meal. Homeostatic state was assessed using subjective self-reports and biological markers (i.e., blood-derived liver-expressed antimicrobial protein 2 (LEAP-2), insulin and leptin). We found that participants who experienced greater subjective hunger during the satiety session were more impulsive in the information gathering task; results were not confounded by changes in mood or anxiety. Homeostatic state did not significantly influence disinhibition mechanisms linked to attentional control or feedback monitoring. However, we found a significant interaction between homeostatic state and LEAP-2 on attentional control, with higher LEAP-2 associated with faster reaction times in the fasted condition only. Our findings indicate lingering hunger after eating increases impulsive behaviour via reduced information gathering. These findings identify a novel mechanism that may underpin the tendency to overeat and/or engage in broader impulsive behaviours.     

Correction to: How to support dental students in reading radiographs: effects of a gaze‑based compare‑and‑contrast intervention

Advances in Health Sciences Education -     

TrkC Is Essential for Nephron Function and Trans-Activates Igf1R Signaling

BackgroundInjury to kidney podocytes often results in chronic glomerular disease and consecutive nephron malfunction. For most glomerular diseases, targeted therapies are lacking. Thus, it is important to identify novel signaling pathways contributing to glomerular disease. Neurotrophic tyrosine kinase receptor 3 (TrkC) is expressed in podocytes and the protein transmits signals to the podocyte actin cytoskeleton.MethodsNephron-specific TrkC knockout (TrkC-KO) and nephron-specific TrkC-overexpressing (TrkC-OE) mice were generated to dissect the role of TrkC in nephron development and maintenance.ResultsBoth TrkC-KO and TrkC-OE mice exhibited enlarged glomeruli, mesangial proliferation, basement membrane thickening, albuminuria, podocyte loss, and aspects of FSGS during aging. Igf1 receptor (Igf1R)–associated gene expression was dysregulated in TrkC-KO mouse glomeruli. Phosphoproteins associated with insulin, erb-b2 receptor tyrosine kinase (Erbb), and Toll-like receptor signaling were enriched in lysates of podocytes treated with the TrkC ligand neurotrophin-3 (Nt-3). Activation of TrkC by Nt-3 resulted in phosphorylation of the Igf1R on activating tyrosine residues in podocytes. Igf1R phosphorylation was increased in TrkC-OE mouse kidneys while it was decreased in TrkC-KO kidneys. Furthermore, TrkC expression was elevated in glomerular tissue of patients with diabetic kidney disease compared with control glomerular tissue.ConclusionsOur results show that TrkC is essential for maintaining glomerular integrity. Furthermore, TrkC modulates Igf-related signaling in podocytes.     

Outcomes of patients older than 55 years undergoing abdominoplasty after bariatric surgery

BackgroundBariatric surgery has become widely performed for treating patients with morbid obesity, and the age limits are being pushed further and further as the procedure proves safe. After massive weight loss, many of those patients seek body-contouring surgery for excess skin and fat.ObjectivesTo analyze the feasibility and the safety of abdominoplasty in patients older than 55 years old after bariatric surgery.SettingUniversity hospital medical center.MethodsWe performed a retrospective review of prospectively collected data from patients aged older than 55 years who had undergone abdominoplasty following massive weight loss due to a bariatric surgery at a single institution from 2004 to 2017. The data analyzed included age, gender, preoperative body mass index, associated interventions, co-morbidities, and postoperative complications.ResultsWe retrieved records for 104 patients; 85.6% percent of them were female, and the mean age was 60.1 ± 3.9 years old. Of the 104 patients, 21 (20.2%) underwent a sleeve gastrectomy and 77 (74%) underwent a Roux-en-Y gastric bypass. The mean interval between the bariatric surgery and the abdominoplasty was 33.6 ± 26.9 months. The mean preoperative weight and body mass index were 76.1 ± 14.5 kg and 28.9 ± 4.5 kg/m², respectively. A total complication rate of 20% was observed. The only factor significantly associated with postoperative morbidity was the associated procedure (P = .03), when we performed another procedure at the same time as the abdominoplasty. Complications included postoperative bleeding in 5 patients (4.8%), seromas in 5 patients (4.8%), surgical site infections in 12 patients (11.5%), and wound dehiscence or ischemia in 2 patients (1.9%). No mortality occurred.ConclusionAbdominoplasty can be safely performed in carefully selected patients older than 55 years old after weight loss surgery, and does not present increased morbidity or mortality. We recommend that surgeons avoid adding concomitant procedures when possible, to decrease the risk of complications. It is also important to look at the patient’s previous maximum BMI levels, as a higher maximum BMI can predict higher postoperative risks and longer hospital stays.     

Distribution of neuropeptide Y in the prosencephalon of man and Cotton-head Tamarin (Saguinus oedipus): colocalization with somatostatin in neurons of striatum and amygdala

Summary The presence, chromatographic properties and localization of neuropeptide Y was demonstrated in postmortem human brain areas of neurologically and neuropsychiatrically normative controls using immunocytochemistry and high performance liquid chromatography combined with radioimmunoassay. NPY-immunoreactivity was found in many regions of the prosencephalon. Numerous perikarya and fibers were present in the neocortex, basal ganglia and limbic-hypothalamic areas. A moderate number of neurons and fibers was observed in the basal forebrain, including the septal complex. A comparative immunohistochemical investigation in perfusion-fixed brains of the old-world ape Saguinus oedipus revealed an almost identical distribution of NPY-immunoreactivity with only minor differences. Colocalization experiments on 1–2 m thin consecutive paraffin sections revealed a large number of NPY neurons throughout the human neostriatum and amygdaloid complex that were also positive for somatostatin. Our findings indicate that detection of neuropeptides in fresh or fixed post-mortem human tissue by different immunochemical methods may actually reflect the in vivo conditions. In addition, the wide distribution of NPY throughout the human brain and its colocalization with other neurotransmitters suggests a physiological role as neuroactive substance, i.e. neuromodulator in the primate central nervous system.     

Mechanistic insight of interleukin-9 induced osteoclastogenesis

Interleukin (IL)-9 is an emerging player in the pathogenesis of various chronic inflammatory diseases including bone disorders like rheumatoid arthritis (RA) and psoriatic arthritis. Recently, IL-9 was shown to enhance the osteoclast formation and their function in RA. However, the mechanisms by which IL-9 influences osteoclastogenesis are not known. Therefore, in this study we aimed to unravel the direct and indirect ways by which IL-9 can influence osteoclast formation. We used mouse bone marrow precursor cells for checking the effect of IL-9 on osteoclast differentiation and its function. Next, IL-9 induced signalling pathway were checked in the process of osteoclastogenesis. T cells play an important role in enhancing osteoclastogenesis in inflammatory conditions. We used splenic T cells to understand the impact of IL-9 on the functions of T effector (Teff) and regulatory T (Treg) cells. Furthermore, the effect of IL-9 mediated modulation of the T cell response on osteoclasts was checked using a coculture model of T cells with osteoclast precursors. We showed that IL-9 enhanced osteoclast formation and its function. We found that IL-9 activates STAT3, P38 MAPK, ERK1/2, NFκB and we hypothesize that it mediates the effect on osteoclastogenesis by accelerating mitochondrial biogenesis. Additionally, IL-9 was observed to facilitate the functions of pro-osteoclastogenic IL-17 producing T cells, but inhibits the function of anti-osteoclastogenic Treg cells. Our observations suggest that IL-9 can influence osteoclastogenesis directly by modulating the signalling cascade in the precursor cells; indirectly by enhancing IL-17 producing T cells and by reducing the functions of Treg cells.     

Cationic amino acid fluxes beyond the proximal convoluted tubule of rat kidney

To investigate the fluxes of cationic amino acids beyond the proximal convolution, we micropunctured and microperfused superficial tubules of male Wistar rats in vivo et situ. In free-flow micropuncture experiments, the concentrations of endogenous L-arginine⁺, [Arg], and of intravenously infused L-homoarginine⁺, [HoArg], were determined by HPLC. Fluorescein isothiocyanatelabeled inulin was detected on-line in the same tubular fluid samples. To determine undirectional fluxes, radiolabeled Arg and inulin were (1) microperfused through short loops of Henle and (2) microinfused into different tubule segments to measure urinary recovery of the radiolabel. At a mean [Arg]_plasma of 116 mol/l, [Arg] was 9.3 mol/l in the late proximal tubule (LPT), and 35.6 mol/l in the early distal tubule (EDT) corresponding to fractional deliveries (FD) of 0.055 in LPT and 0.078 in EDT. Fractional urinary excretion (FE) of Arg was 0.00033 (P<0.05 vs FD_EDT). Infusion of HoArg (2.5 or 7.5 mol/min) led to respective mean [HoArg]_plasma values of 1.44 and 3.73 mmol/l, and resulted in respective FD_LPT values for HoArg of 0.23 and 0.53, respective FD_EDT values of 0.29 and 0.41, and finally, respective FE values for HoArg of 0.25 and 0.58. When short loops of Henle were microperfused with 1 or 50 mmol/l [¹⁴C]Arg (+[³H]inulin), fractional recovery (FR) of ¹⁴C (relative to inulin) in the EDT was 0.13 and 0.36, respectively. During microinfusion of radiolabeled Arg (1 or 50 mmol/l) and inulin into LPT, the urinary FR of the radiolabel was 0.14, or 0.59, respectively. If 0.007, 1 or 50 mmol/l radiolabeled Arg were microinfused into EDT, the respective urinary FR of the radioactivity was 1.02, 1.10, or 1.01. Microperfusion of microinfusion of 1 mmol/l [¹⁴C]Arg plus 50 mmol/l HoArg resulted in a FR_EDT of ¹⁴C of 0.43 (loop, perfusion) and an FE for ¹⁴C of 0.69. Five conclusions can be drawn. First, cationic amino acids can enter and leave the lumen of short loops of Henle through specific carrier(s) at high rates, although, secondly, net transport is small or absent. Thus, medullary tubule cells can be supplied with Arg from the lumen of short loops of Henle for urea and nitric oxide production. Thirdly, the distal convolution of superficial nephrons and the collecting duct are not permeable to Arg. Thus, fourthly, the difference between FD_EDT and urinary FE of Arg must be explained by an inter-nephron heterogeneity between deep and superficial nephrons. Finally, the process responsible for the different Arg handling in deep nephrons is not accessible to HoArg or, if so, it is saturated at millimolar concentrations.