Chewing augments stress-induced increase of pERK-immunoreactive cells in the rat cingulate cortex

Acute stress transiently activates macrophages and chemokines in cervical lymph nodes

Acute restraint stress (RS) is routinely used to study the effects of psychological and/or physiological stress. We evaluated the impact of RS on cervical lymph nodes in rats at molecular and cellular levels. Male Sprague-Dawley rats were subjected to stress by immobilization for 30, 60, and 120 min (RS30, RS60, and RS120, respectively) and compared with rats of a no-stress control (C) group. The expression of genes encoding chemokines CXCL1/CXCL2 (Cxcl1 and Cxcl2) and their receptor CXCR2 (Cxcr2) was analyzed using reverse transcription-quantitative PCR (RT-qPCR) and microarray analyses. Immunohistochemistry and in situ hybridization were performed to determine the expression of these proteins and the macrophage biomarker CD68. Microarray analysis revealed that the expression of 514 and 496 genes was upregulated and downregulated, respectively, in the RS30 group. Compared with the C group, the RS30 group exhibited a 23.0-, 13.0-, and 1.6-fold increase in Cxcl1, Cxcl2, and Cxcr2 expression. Gene Ontology analysis revealed the involvement of these three upregulated genes in the cytokine network, inflammation, and leukocyte chemotaxis and migration. RT-qPCR analysis indicated that the mRNA levels of Cxcl1 and Cxcl2 were significantly increased in the RS30 group but were reverted to normal levels in the RS60 and RS120 groups. Cxcr2 mRNA level was significantly increased in the RS30 and RS120 groups compared with that in the C group. RS-induced CXCL1-immunopositive cells corresponded to B/plasma cells, whereas CXCL2-immunopositive cells corresponded to endothelial cells of the high endothelial venules. Stress-induced CXCR2-immunopositive cells corresponded to macrophages. Psychological and/or physiological stress induces an acute stress response and formation of an immunoreactive microenvironment in cervical lymph nodes, with the CXCL1/CXCL2-CXCR2 axis being pivotal in the acute stress response.

Expression of salivary immunoglobulins and their association with analgesic neuropeptide opiorphin in anorexia nervosa during adolescence

BACKGROUND

Patients who suffer from anorexia nervosa (AN) are characterized by exceedingly lower body weight, micro- and macro-nutrient deficiencies, and hyposalivation as compared to healthy subjects. In addition, AN may predispose to difficulties in oral health maintenance. However, little is known about the relationship between stress-dependent salivary neuro/immunopeptidergic biomarkers such as opiorphin and immunoglobulins (Ig) and AN.The aim of this case-control study was to evaluate salivary opiorphin and immunoglobulins in female children and adolescents diagnosed with AN compared to healthy controls.

METHODS

Adolescent patients with clinically-confirmed severe restrictive subtype AN (Body Mass Index BMI < 15 kg/m², mean age 15.0 ± 1.8, n = 83) were examined in the first week of hospital admission and compared to healthy matched controls (n = 79). Measurements of salivary opiorphin, IgA, IgG, IgM (ELISA technique), and oral hygiene levels (Plaque Control Record index-PCR) were performed.

RESULTS

In the AN group, a significantly higher concentration of opiorphin was evidenced (3.1 ± 4.1 ng/ml) compared to the control group (1.1 ± 1.2 ng/ml), (p < 0.001), contrary to IgM, which was significantly lower (311.0 ± 185.3 ng/ml) than in the control group (421.2 ± 168.1 ng/ml), (p < 0.001). There were no significant differences in the levels of IgA and IgG, despite a higher concentration of IgA in the AN group vs. controls (p = 0.14). Spearman analysis revealed a correlation between opiorphin and age (p < 0.05), but also with all immunoglobulins IgA, IgG, IgM (p = 0.006, p < 0.001, p < 0.001). Similarly a correlation was found between PCR index and immunoglobulins IgG, IgM (respectively p = 0.028, p < 0.001), and between body mass, BMI, IBW% and IgA, IgM (all p < 0.05).

CONCLUSIONS

In the acute phase of AN, salivary changes in opiorphin and immunoglobulins related to dental plaque suggest an essential role in oral health balance. Changes related to AN may affect the anti-inflammatory and analgesic components of saliva and suggest their use as neurobiological markers in severe malnutrition.