Glucagon-like peptide-1 and interleukin-6 interaction in response to physical exercise: An in-silico model in the framework of immunometabolism

BACKGROUND AND OBJECTIVE

Glucagon-like peptide 1 (GLP-1) is classically identified as an incretin hormone, secreted in response to nutrient ingestion and able to enhance glucose-stimulated insulin secretion. However, other stimuli, such as physical exercise, may enhance GLP-1 plasma levels, and this exercise-induced GLP-1 secretion is mediated by interleukin-6 (IL-6), a cytokine secreted by contracting skeletal muscle. The aim of the study is to propose a mathematical model of IL-6-induced GLP-1 secretion and kinetics in response to physical exercise of moderate intensity.

METHODS

The model includes the GLP-1 subsystem (with two pools: gut and plasma) and the IL-6 subsystem (again with two pools: skeletal muscle and plasma); it provides a parameter of possible clinical relevance representing the sensitivity of GLP-1 to IL-6 (k0). The model was validated on mean IL-6 and GLP-1 data derived from the scientific literature and on a total of 100 virtual subjects.

RESULTS

Model validation provided mean residuals between 0.0051 and 0.5493 pg⋅mL-1 for IL-6 (in view of concentration values ranging from 0.8405 to 3.9718 pg⋅mL-1) and between 0.0133 and 4.1540 pmol⋅L-1 for GLP-1 (in view of concentration values ranging from 0.9387 to 17.9714 pmol⋅L-1); a positive significant linear correlation (r = 0.85, p<0.001) was found between k0 and the ratio between areas under GLP-1 and IL-6 curve, over the virtual subjects.

CONCLUSIONS

The model accurately captures IL-6-induced GLP-1 kinetics in response to physical exercise.

Combining the Physical-Chemical Approach with Standard Base Excess to Understand the Compensation of Respiratory Acid-Base Derangements: An Individual Participant Meta-analysis Approach to Data from Multiple Canine and Human Experiments

BACKGROUND

Several studies explored the interdependence between Paco2 and bicarbonate during respiratory acid-base derangements. The authors aimed to reframe the bicarbonate adaptation to respiratory disorders according to the physical-chemical approach, hypothesizing that (1) bicarbonate concentration during respiratory derangements is associated with strong ion difference; and (2) during acute respiratory disorders, strong ion difference changes are not associated with standard base excess.

METHODS

This is an individual participant data meta-analysis from multiple canine and human experiments published up to April 29, 2021. Studies testing the effect of acute or chronic respiratory derangements and reporting the variations of Paco2, bicarbonate, and electrolytes were analyzed. Strong ion difference and standard base excess were calculated.

RESULTS

Eleven studies were included. Paco2 ranged between 21 and 142 mmHg, while bicarbonate and strong ion difference ranged between 12.3 and 43.8 mM, and 32.6 and 60.0 mEq/l, respectively. Bicarbonate changes were linearly associated with the strong ion difference variation in acute and chronic respiratory derangement (β-coefficient, 1.2; 95% CI, 1.2 to 1.3; P < 0.001). In the acute setting, sodium variations justified approximately 80% of strong ion difference change, while a similar percentage of chloride variation was responsible for chronic adaptations. In the acute setting, strong ion difference variation was not associated with standard base excess changes (β-coefficient, -0.02; 95% CI, -0.11 to 0.07; P = 0.719), while a positive linear association was present in chronic studies (β-coefficient, 1.04; 95% CI, 0.84 to 1.24; P < 0.001).

CONCLUSIONS

The bicarbonate adaptation that follows primary respiratory alterations is associated with variations of strong ion difference. In the acute phase, the variation in strong ion difference is mainly due to sodium variations and is not paralleled by modifications of standard base excess. In the chronic setting, strong ion difference changes are due to chloride variations and are mirrored by standard base excess.

EDITOR’S PERSPECTIVE

Survey on centres and procedures for the diagnosis and treatment of adult ADHD in public services in Italy

Attention deficit/hyperactivity disorder (ADHD) often persists into adulthood. Although its persistence and relative high prevalence, ADHD in adults is often underdiagnosed and undertreated in Italy, leading to poor clinical and functional outcomes, and higher costs of illness. The aims of the study were to identify the Italian mental health services for ADHD in adults, describe the diagnostic and treatment procedures they follow, and compare this offer with the recommendations of the German and English guidelines. The centres, that adopt a clinical and assessment protocol for adult ADHD diagnosis (carried out by specifically trained personnel) and prescribe pharmacological treatment for adult ADHD, were selected from the list of accredited services provided by the Appendix B.2 of the ISTISAN 16/37 Reports of the ISS. An ad-hoc survey including open-ended and close-ended questions was sent to each selected centre in February 2020. The overall picture resulting from the data analysis was compared with the recommendations of the German and English guidelines. The present survey shows that only a few centres are specialised in the diagnosis and treatment of ADHD in adults in Italy. Furthermore, there are no national guidelines for adult ADHD in Italy. The collected data also suggest that there is no a unified practice shared by the Centres both for the patient's transition from child and adolescent to adult mental health services and for the diagnostic-therapeutic process. It is therefore crucial to create specific protocols and develop national guidelines to better identify and diagnose ADHD in adults and provide targeted and more efficient multimodal treatments.

Predictors of stigma in a sample of mental health professionals: Network and moderator analysis on gender, years of experience, personality traits, and levels of burnout

Background.

Stigma is one of the most important barriers to help-seeking and to personal recovery for people suffering from mental disorders. Stigmatizing attitudes are present among mental health professionals with negative effects on the quality of health care.

Methods.

Network and moderator analysis were used to identify what path determines stigma, considering demographic and professional variables, personality traits, and burnout dimensions in a sample of mental health professionals (n = 318) from six Community Mental Health Services. The survey included the Attribution Questionnaire-9, the Maslach Burnout Inventory, and the Ten-Item Personality Inventory.

Results.

The personality trait of openness to new experiences resulted to determine lower levels of stigma. Burnout (personal accomplishment) interacted with emotional stability in predicting stigma, and specifically, for subjects with lower emotional stability lower levels of personal accomplishment were associated with higher levels of stigma.

Conclusions.

Some personality traits may be accompanied by better empathic and communication skills, and may have a protective role against stigma. Moreover, burnout can increase stigma, in particular in subjects with specific personality traits. Assessing personality and burnout levels could help in identifying mental health professionals at higher risk of developing stigma. Future studies should determine whether targeted interventions in mental health professionals at risk of developing stigma may be effective in stigma prevention.

Exploring the relationships among personality traits, burnout dimensions and stigma in a sample of mental health professionals

A sample of mental health professionals (n = 215) from six Community Mental Health Services was examined using a short version of the Attribution Questionnaire-27, the Maslach Burnout Inventory and the Ten Items Personality Inventory to detect possible associations among stigma, burnout dimensions and personality traits. The role of demographic and professional variables was also explored. Perception of workplace safety resulted to significantly affect attitudes toward patients. The concern about being assaulted and a low level of Personal Accomplishment were both related to avoidant attitudes, while the presence of procedures for managing the violent patient was associated with a higher level of Personal Accomplishment. Conversely, Emotional Stability and Openness to new experiences were inversely correlated with burnout dimensions and avoidant attitudes, respectively. Overall, our study supports the view of a significant association among some dimensions of stigma, burnout and personality factors. In particular, avoidant attitudes toward patients may be influenced by Personal Accomplishment and Openness to new experiences.

Gadobenate dimeglumine and cerebral glucose metabolism: Continuous monitoring of striatal lactate levels in freely moving rats

Purpose: Brain contrast-enhanced MR imaging reflects the leakage of contrast material into the brain tissue due to blood-brain barrier (BBB) disruption. The contact between brain tissue and contrast material requires a high level of neurotolerability of the contrast agent (CA). In the present study, we investigated the neurotolerability of the paramagnetic CA gadobenate dimeglumine, locally applied into the corpus striatum of freely moving rats, by evaluating its potential effects on cerebral glucose metabolism based on lactate levels.

Material and Methods: Lactate levels were monitored using a microdialysis technique coupled with an enzyme reaction. A microdialysis probe for extracellular fluid sampling, together with a stainless steel cannula for CA administration, were inserted into the right corpus striatum of rats. Lactate levels were monitored for 2 h after gadobenate dimeglumine administration at 120 nmol/rat, at fixed volume of 1.2  μl. The same volume of artificial cerebrospinal fluid (aCSF) was administered to control rats.

Results: Gadobenate dimeglumine did not induce any significant changes in the lactate striatal levels over the 30-min period after administration. Small, but significant, reductions in lactate concentration were found from the 45-min control point after gadobenate dimeglumine administration. Lactate response showed the same pattern in rats given aCSF.

Conclusion: Gadobenate dimeglumine, intracerebrally administered, did not affect cerebral glucose metabolism in rats as it showed the same behaviour as aCSF on cerebral glucose utilization. The gradual attenuation in the endogenous lactate release observed 45 min after test compound administration is possibly due to a slight reduction in the probe recovery. The present findings confirm the neurotolerability of gadobenate dimeglumine previously shown in behavioural and electrophysiological studies.

Atlantic salmon (Salmo salar L.) parr fed genetically modified soybeans and maize: Histological, digestive, metabolic, and immunological investigations

Physiological and health related responses to dietary inclusion of genetically modified (GM) full-fat soybean meal (Roundup Ready; GM-soy) and maize (MON810 Bt-maize; GM-maize), as well as non-parental, untransformed lines (nGM-soy and nGM-maize D2), were evaluated in farmed Atlantic salmon (Salmo salar L.) parr during the first 8 months of feeding. Significant effects of dietary GM presence were only found in intestinal Na+-dependent d-glucose uptake and SGLT1 protein level in the region pyloric caeca in which the highest values were found in the GM-soy, intermediate in the nGM-soy, and lowest in the standard FM fed groups. Data from this study confirm that GM soybeans (RRS) and maize (MON810) at inclusion levels of about 6% appear to be as safe as commercially available nGM soy and maize in diets for Atlantic salmon parr. Results from studies with higher inclusion levels and with non-modified, isogenic or near-isogenic parental lines as control groups are pending.

[Heterogeneity of the Departments of Mental Health in the Veneto Region ten years after the National Plan 1994-96 for Mental Health. Which implication for clinical practice? Findings from the PICOS Project]

AIMS

This study aims to present data on structural and human resources of public mental health services located in the Veneto Region, Italy, and to discuss them in the light of implementation of the first National Target Plan for Mental Health ("Progetto Obiettivo 1994-1996") ten years after its launch.

METHODS

The study was conducted in the context of the PICOS (Psychosis Incident Cohort Outcome Study) Project, a large first-presentation multisite study on patients with psychotic disorders attending community mental heath services in the Veneto Region. Human and structural resources were surveyed in 26 study sites using a structured interview administered by the PICOS local referents.

RESULTS

CMHCs and Day Centres were homogeneously distributed across the Region and their overall rates per resident population met the national standards; a wide variability in the distribution of Day Hospitals was found, with the overall rate per resident population very far from meeting the national standard; the overall rate for Residential Facilities beds was higher than the recommended national standard, showing however an high variability across sites. The overall rate of mental health professionals per resident population was only slightly below the national standard: this was mainly achieved thanks to non-profit organizations which supplement the public system with unspecialised professionals; however, a wide variability in the local rates per resident population was found, with the 50% of the sites showing rates far lower the national standard. Specific lack of trained professionals involved in the provision of psychosocial interventions was found in most sites.

CONCLUSIONS

A marked variability in human and structural resources across community mental health services in the Veneto Region was found. Possible reasons for this heterogeneity were analysed and implications for mental health care provision were further discussed.

Characterisation of intestinal peptide transporter of the Antarctic haemoglobinless teleost Chionodraco hamatus

H(+)/peptide cotransport was studied in brush-border membrane vesicles (BBMV) from the intestine of the haemoglobinless Antarctic teleost Chionodraco hamatus by monitoring peptide-dependent intravesicular acidification with the pH-sensitive dye Acridine Orange. Diethylpyrocarbonate-inhibited intravesicular acidification was specifically achieved in the presence of extravesicular glycyl-L-proline (Gly-L-Pro) as well as of glycyl-L-alanine (Gly-L-Ala) and D-phenylalanyl-L-alanine (D-Phe-L-Ala). H(+)/Gly-L-Pro cotransport displayed saturable kinetics, involving a single carrier system with an apparent substrate affinity (K(m,app)) of 0.806+/-0.161 mmol l(-1). Using degenerated primers from eel and human (PepT1) transporter sequence, a reverse transcription-polymerase chain reaction (RT-PCR) signal was detected in C. hamatus intestine. RT-PCR paralleled kinetic analysis, confirming the hypothesis of the existence of a PepT1-type transport system in the brush-border membranes of icefish intestine. Functional expression of H(+)/peptide cotransport was successfully performed in Xenopus laevis oocytes after injection of poly(A)(+) RNA (mRNA) isolated from icefish intestinal mucosa. Injection of mRNA stimulated D-Phe-L-Ala uptake in a dose-dependent manner and an excess of glycyl-L-glutamine inhibited this transport. H(+)/peptide cotransport in the Antarctic teleost BBMV exhibited a marked difference in temperature optimum with respect to the temperate teleost Anguilla anguilla, the maximal activity rate occurring at approximately 0 degrees C for the former and 25 degrees C for the latter. Temperature dependence of icefish and eel intestinal mRNA-stimulated uptake in the heterologous system (oocytes) was comparable.

Characterisation of the H(+)/peptide cotransporter of eel intestinal brush-border membranes

H(+)/peptide cotransport in brush-border membrane vesicles (BBMVs) from eel (Anguilla anguilla) intestine was studied by measuring d-[(3)H]-phenylalanyl-l-alanine uptake and by monitoring peptide-dependent intravesicular acidification using the pH-sensitive dye Acridine Orange. d-[(3)H]-phenylalanyl-l-alanine influx was greatly stimulated by an inside-negative membrane potential and enhanced by an inwardly directed H(+) gradient. In parallel, vesicular H(+) influx was significantly increased in the presence of extravesicular d-phenylalanyl-l-alanine or a series of glycyl and l-prolyl peptides. H(+)/peptide cotransport displayed saturable kinetics involving a single carrier system with apparent substrate affinities of 0.9-2.6 mmol l(−1) depending on the particular peptide. All substrates tested competed with this system. Pre-incubation of BBMVs with dipeptides prevented diethylpyrocarbonate inhibition of transport activity, suggesting that the substrates mask histidine residues involved in the catalytic function of the transporter. Using human PepT1-specific primers, a reverse transcription-polymerase chain reaction (RT-PCR) signal was detected in eel intestine. Our results suggest that, in eel intestine, a brush-border membrane ‘low-affinity’-type H(+)/peptide cotransport system is present that shares kinetic features with the mammalian intestinal PepT1-type transporters.

Gadobenate dimeglumine and cerebral glucose metabolism. Continuous monitoring of striatal lactate levels in freely moving rats

PURPOSE

Brain contrast-enhanced MR imaging reflects the leakage of contrast material into the brain tissue due to blood-brain barrier (BBB) disruption. The contact between brain tissue and contrast material requires a high level of neurotolerability of the contrast agent (CA). In the present study, we investigated the neurotolerability of the paramagnetic CA gadobenate dimeglumine, locally applied into the corpus striatum of freely moving rats, by evaluating its potential effects on cerebral glucose metabolism based on lactate levels.

MATERIAL AND METHODS

Lactate levels were monitored using a microdialysis technique coupled with an enzyme reaction. A microdialysis probe for extracellular fluid sampling, together with a stainless steel cannula for CA administration, were inserted into the right corpus striatum of rats. Lactate levels were monitored for 2 h after gadobenate dimeglumine administration at 120 nmol/rat, at fixed volume of 1.2 microl. The same volume of artificial cerebrospinal fluid (aCSF) was administered to control rats.

RESULTS

Gadobenate dimeglumine did not induce any significant changes in the lactate striatal levels over the 30-min period after administration. Small, but significant, reductions in lactate concentration were found from the 45-min control point after gadobenate dimeglumine administration. Lactate response showed the same pattern in rats given aCSF.

CONCLUSION

Gadobenate dimeglumine, intracerebrally administered, did not affect cerebral glucose metabolism in rats as it showed the same behaviour as aCSF on cerebral glucose utilization. The gradual attenuation in the endogenous lactate release observed 45 min after test compound administration is possibly due to a slight reduction in the probe recovery. The present findings confirm the neurotolerability of gadobenate dimeglumine previously shown in behavioural and electrophysiological studies.

Neurotolerability of gadobenate dimeglumine. Evaluation of brain dopamine concentration in freely moving rats by microdialysis

RATIONALE AND OBJECTIVES

Magnetic resonance imaging with contrast agents (CAs) is a procedure currently used for the diagnosis of neurologic pathologies. These pathologies are often characterized by blood-brain barrier disruptions, which determines a direct contact between CA and brain tissue. For this reason, an accurate assessment of neurotolerability is useful for the development of new CAs. The present study was designed to evaluate the neurotolerability of a new CA for MRI, gadobenate dimeglumine, employing a neurochemical method. The effect of gadobenate dimeglumine on the striatal levels of neurotransmitters was determined. In particular, the brain concentrations of dopamine and dopamine metabolites, 3,4-dihydroxyphenylacetic and homovanillic acid, were measured using microdialysis, after the direct application of gadobenate dimeglumine into the rat corpus striatum. Gadopentetate dimeglumine and gadoteridol were employed as reference compounds.

METHODS

A microdialysis probe for brain extracellular fluid sampling and a stainless-steel cannula for CA application were chronically inserted into the right corpus striatum of rats. All CAs were administered at a dose of 5.4 nmol/rat. Dopamine and metabolite concentrations were analyzed using high-performance liquid chromatography.

RESULTS

Gadobenate dimeglumine did not induce any significant changes in the extracellular levels of dopamine or dopamine metabolites up to 2 hours after administration. Gadoteridol produced similar results. Gadopentetate dimeglumine caused a moderate but not significant increase in dopamine levels throughout the duration of the experiments.

CONCLUSIONS

Gadobenate dimeglumine directly administered into the corpus striatum of freely moving rats did not affect the dopaminergic system. This result demonstrates the safety of gadobenate dimeglumine under the experimental conditions used, thus confirming previous behavioral and electrophysiologic findings.

H(+)-glycyl-L-proline cotransport in brush-border membrane vesicles of eel (Anguilla anguilla) intestine

A plasma membrane H(+)-glycyl-L-proline (Gly-L-Pro) cotransport mechanism has been identified in isolated eel intestinal brush-border membrane vesicles (BBMV) by both measuring radiolabeled Gly-L-Pro uptake and monitoring Gly-L-Pro-dependent H+ influx with the pH-sensitive dye acridine orange. The application of an inside negative membrane potential resulted in increasing Gly-L-Pro uptake, as well as the application of inwardly directed H+ gradient (although only when an inside negative membrane potential was present). Furthermore, vesicular H+ influx was found specifically associated with the presence of Gly-L-Pro in the extravesicular medium. The carrier-mediated nature of H(+)-Gly-L-Pro cotransport was assessed, and its concentration that yielded one-half maximal Gly-L-Pro influx was approximately 1.30 mM when measured by either radioactive or fluorescent tracers. Different dipeptides strongly inhibited Gly-L-Pro uptake by eel intestinal BBMV, as well as the cephalosporin antibiotic cephalexin, suggesting that dipeptide molecules and cephalosporin antibiotics may share a common transport system in eel intestinal BBMV.

Conditioned taste aversion in rats following intrathecal administration of contrast media

PURPOSE

The occurrence of side-effects such as visceral malaise after intrathecal administration of the non-ionic radiography contrast media iomeprol, iopamidol, and iotrolan was assessed in rats by the conditioned tasted aversion procedure.

METHODS

Reduced preference towards a saccharose solution compared with normal water following intraventricular administration of a contrast medium was used as a measure of the aversive response.

RESULTS

At a dose of 100 mg I/kg none of the tested contrast media induced aversion. At 200 and 300 mg I/kg, both iopamidol and iomeprol induced significant aversive responses with respect to control, although the response of the iomeprol group appeared milder than that of the iopamidol group at a dose of 200 mg I/kg. Iotrolan could be tested only at the lowest dose since the high doses caused excessive mortality.

CONCLUSION

Intrathecally administered iomeprol appeared to be well tolerated in rats at doses higher than those suggested for clinical use.

Free and bound testosterone in male heroin addicts

The plasma levels of the active (free) fraction of testosterone (Te) and of Te Binding Globulin (TeBG) in a group of 42 heroin addicts with similar sexual difficulties were investigated for almost 2 years. Plasma levels of free Te were significantly low and TeBG were significantly high not only in the addicts with low total Te concentrations, but also in the addicts with normal values of total Te.