Phenotypic changes in T cell populations during the reactivation of tuberculosis in mice

The phenotypic changes of T lymphocytes during the reactivation of latent Mycobacterium tuberculosis infection by activation of the hypothalamic–pituitary–adrenal (HPA) axis was monitored using flow cytometric analysis. Subsets of CD4⁺ and CD8⁺ lymphocyte populations from the lung, spleen and draining lymph nodes of infected mice were identified based on their differential expression of the cell surface antigens CD44 and CD45RB. Latent infection was characterized by an accumulation of both naive, activated and memory CD4 and CD8 T lymphocytes in the lung and mediastinal lymph nodes. No changes were observed in the spleen of mice with latent infection when compared with uninfected mice. Immediately following the activation of the HPA axis, a reduction in all CD4⁺ and CD8⁺ T cells in the lung and mediastinal lymph nodes was observed. This correlated with the reactivation of mycobacterial growth. The decrease was transient for memory and naive CD4 and CD8 T lymphocyte populations in the lung. However, the number of naive CD4 and CD8 T lymphocyte populations in the mediastinal lymph node following reactivation was less than that found in mice with latent infection. These data provide the first characterization of T lymphocyte populations which may be functionally involved in the immunological response to HPA axis-induced reactivation of M. tuberculosis infection.     

Sleep characteristics as predictor variables of stress systems markers in insomnia disorder

This study investigates the extent to which sleep characteristics serve as predictor variables for inflammatory, hypothalamic–pituitary–adrenal and autonomic systems markers. Twenty‐nine participants with a diagnosis of insomnia disorder based on the Diagnostic Statistical Manual of Mental Disorders, Fifth Edition (age 25.3 ± 1.6 years, insomnia duration 6.6 ± 0.8 years) and 19 healthy control sleepers (age 25.4 ± 1.4 years) underwent a 2‐week at‐home evaluation keeping a sleep diary and wearing an actigraph, followed by a visit to the Research Center to measure blood pressure, and collect blood and urine samples. The actigraphy‐ and diary‐based variables of sleep duration, sleep‐onset latency, wake after sleep onset and sleep fragmentation/number of night‐time awakenings were averaged and entered as dependent variables in regression analyses. Composite scores were calculated for the autonomic (blood pressure, norepinephrine), inflammatory (monocyte counts, interleukin‐6, C‐reactive protein) and hypothalamic–pituitary–adrenal systems (cortisol), and used as predictor variables in regression models. Compared with controls, individuals with insomnia had a shorter sleep duration (P < 0.05), and a higher hypothalamic–pituitary–adrenal and inflammatory composite score (P < 0.05). The higher inflammatory score was mainly due to higher circulating monocytes (P < 0.05), rather than differences in interleukin‐6 or C‐reactive protein. In persistent insomnia disorder, cortisol is upregulated and associated with actigraphy‐ and diary‐based wake after sleep onset, suggesting that wake after sleep onset may serve as a marker to identify individuals at increased risks for disorders associated with a hyperactive hypothalamic–pituitary–adrenal system. The absence of autonomic and pro‐inflammatory changes (interleukin‐6, C‐reactive protein), despite a substantial decrease in actigraphic sleep duration, may relate to a higher resilience to the adverse biological consequences of insomnia in this young age group.     

Stress axis plasticity during vestibular compensation in the adult cat

The postural, ocular motor, perceptive and neurovegetative syndromes resulting from unilateral vestibular neurectomy (UVN) symptoms could generate a stress and thereby activate the hypothalamo-pituitary–adrenal (HPA) axis. This study was aimed at determining whether UVN causes changes in the activity of the HPA axis, and if so, evaluating the time course of changes associated with UVN syndrome. At the cellular level, corticotropin-releasing factor (CRF) and arginine vasopressin (AVP) immunoreactivity (Ir) were analyzed and quantified in the paraventricular nucleus (PVN) and the vestibular nuclei (VN) complex of cats killed early (1 and 7 days) or late (30 and 90 days) after UVN. Dopamine-β-hydroxylase (DβH), the enzyme synthesizing noradrenaline was examined in the locus coeruleus (LC) in these same cats. At the behavioral level, the time course of recovery of the postural and locomotor functions was quantified at the same postoperative delays in another group of UVN cats. Results showed a significant bilateral increase in the number of both AVP-Ir and CRF-Ir neurons in the PVN and an increase of DβH-Ir neurons in the LC at 1, 7 and 30 days after UVN. This increased number of neurons was no longer observed at 90 days. Conversely, a significant bilateral decrease of CRF-Ir neurons was observed in the VN at these same postlesion times, with a similar return to control values at 90 days. Our behavioral observations showed strong posturo-locomotor functional deficits early after UVN (1 and 7 days), which had recovered partially at 30 days and completely by 90 days postlesion. We demonstrate a long-lasting activation of the HPA axis, which likely reflects a chronic stress, experienced by the animals, which corresponds to the time course of full vestibular compensation, and which is no longer present when the animals are completely free of posturo-locomotor symptoms at 90 days.     

Effects of excessive glucocorticoid receptor stimulation during early gestation on psychomotor and social behavior in the rat

Severe psychological stress in the first trimester of pregnancy increases the risk of schizophrenia in the offspring. To begin to investigate the role of glucocorticoid receptors in this association, we determined the effects of the glucocorticoid dexamethasone (2 mg/kg), administered to pregnant rats on gestation days 6–8, on maternal behaviors and schizophrenia‐relevant behaviors in the offspring. Dams receiving dexamethasone exhibited increased milk ejection bouts during nursing. Offspring of dexamethasone‐treated dams (DEX) showed decreased juvenile social play and a blunted acoustic startle reflex in adolescence and adulthood, effects that were predicted by frequency of milk ejections in the dams. DEX offspring also showed increased prepulse inhibition of startle and reduced amphetamine‐induced motor activity, effects not correlated with maternal behavior. It is postulated that over‐stimulation of receptors targeted by glucocorticoids in the placenta or other maternal tissues during early gestation can lead to psychomotor and social behavioral deficits in the offspring. Moreover, some of these deficits may be mediated by alterations in postnatal maternal behavior and physiology produced by early gestational exposure to excess glucocorticoids. © 2010 Wiley Periodicals, Inc. Dev Psychobiol 52:121–132, 2010     

Postnatal foraging demands alter adrenocortical activity and psychosocial development

Mother squirrel monkeys stop carrying infants at earlier ages in high-demand (HD) conditions where food is difficult to find relative to low-demand (LD) conditions. To characterize these transitions in psychosocial development, from 10- to 21-weeks postpartum we collected measures of behavior, adrenocortical activity, and social transactions coded for initiator (mother or infant), goal (make-contact or break-contact), and outcome (success or failure). Make-contact attempts were most often initiated by HD infants, but mothers often opposed these attempts and less than 50% were successful. Break-contact attempts were most often initiated by LD infants, but mothers often opposed these attempts and fewer LD than HD infant break-contact attempts were successful. Plasma levels of cortisol were significantly higher in HD than LD mothers, but differences in adrenocortical activity were less consistent in their infants. HD and LD infants also spent similar amounts of time nursing on their mothers and feeding on solid foods. By rescheduling some transitions in development (carry→self-transport), and not others (nursing→self-feeding), mothers may have partially protected infants from the immediate impact of an otherwise stressful foraging task. © 1998 John Wiley & Sons, Inc. Dev Psychobiol 32: 285–291, 1998     

Sexually dimorphic effects of postnatal treatment on the development of activity‐based anorexia in adolescent and adult rats

Hyperactivity of the hypothalamic–pituitary–adrenal (HPA) axis is a marked feature of anorexia nervosa. Using a modified version of the activity‐based animal model of anorexia nervosa, we examine whether factors known to affect HPA axis activity influence the development of activity‐based anorexia (ABA). Male and female rats were subjected to maternal separation or handling procedures during the first two postnatal weeks and tested in a mild version of the ABA paradigm, comprised of 2‐hr daily running wheel access followed by 1‐hr food access, either in adolescence or adulthood. Compared to handled females, maternally separated females demonstrated greater increases in wheel running and a more pronounced running‐induced suppression of food intake during adolescence, but not in adulthood. In contrast, it was only in adulthood that wheel running produced more prolonged anorexic effects in maternally separated than in handled males. These findings highlight the interplay between early postnatal treatment, sex of the animal, and developmental age on running, food intake, and rate of body weight loss in a mild version of the ABA paradigm. © 2009 Wiley Periodicals, Inc. Dev Psychobiol 51: 679–695, 2009.     

Hormonal responses in athletes: the use of a two bout exercise protocol to detect subtle differences in (over)training status

In overtrained athletes, several signs and symptoms have been associated with the imbalance between training and recovery. However, reliable diagnostic markers for distinguishing between well-trained, overreached (OR) and overtrained (OT) athletes are lacking. A hallmark feature of overtraining syndrome (OTS) is the inability to sustain intense exercise and recover for the next training or competition session. We therefore devised a test protocol utilizing two bouts of maximal work. With this test protocol we tried to establish a difference in hormonal responses between the training status of T and OR athletes. Seven well-trained cyclists participated in this study and were tested before and after a training camp. We also present the data of one OT motocross athlete who was clinically diagnosed as overtrained. All athletes performed two maximal exercise tests separated by 4 h. Blood was analyzed for cortisol, adrenocorticotrophic hormone (ACTH), growth hormone and prolactin (PRL). Performance decreased by 6% between the first and the second exercise test in the OR group and by 11% in the OT subject. Moreover, during the second exercise test there were more marked differences between the T and OR athletes; in particular, the OT subject did not show an increase in some of the hormonal responses. PRL increased only by 14% in the OT subjects second test and there was a 7% decrease in ACTH. The two exercise approach enables us to detect subtle performance decrements that will not be identified by one exercise trigger. The hormonal responses to the second exercise test were different between the T and OR athletes (the increase in the T group was higher than in the OR that was higher than in the OT). The results of the case presentation of an overtrained athlete provide evidence of an altered and dysfunctional hypothalamic–pituitary axis response to two bouts of maximal exercise. These findings can be used to develop markers for diagnosis of OTS and to begin to address the pathologic mechanism operative in the syndrome, as well as providing an outcome measure to evaluate possible therapeutic regimes.     

Wilson cell origin for kupffer's vesicle in the zebrafish

Background: Bilaterally symmetric animals have evolved highly reproducible asymmetries between left and right. In teleosts, Kupffer's vesicle, the structure necessary for the determination of left–right asymmetry, is derived from a group of cells in the gastrula termed the dorsal forerunners. Results: Wilson cells are a ring of marginal enveloping layer cells that are cytoplasmically connected to the yolk cell and thus the last blastomeres to inherit yolk cell cytoplasm. Afterward, they collapse into the yolk to form the yolk syncytial layer. Without exception, forerunner cells are the progeny of dorsal Wilson cells. At the beginning of gastrulation, these Wilson cell progeny ingress beneath the enveloping layer, transform into Kupffer's vesicle, and eventually become tail notochord and muscle. Before ingressing, the forerunner precursor cells express endodermal promoting genes and require high‐levels of Nodal signaling. Conclusions: Despite a derived function of the enveloping layer as an epithelium covering the entire embryo, its dorsal margin retains many behaviors of what might be expected of the dorsal superficial layers of the ancestral fish embryo, including an early program of endodermal development, cell ingression, and an eventual contribution of cells to caudal notochord and muscle, as well as the control of laterality. Developmental Dynamics 247:1057‐1069, 2018. © 2018 Wiley Periodicals, Inc.     

Chronic restraint stress has no more stimulatory effects on colonic motility in rats

Previous studies have shown that acute stress stimulates colonic motor function via a central corticotropin releasing factor (CRF) in rodents. However, little is known whether colonic motility is altered following chronic stress. We studied the changes of colonic motor function in response to chronic stress or daily administration of CRF in rats. Rats were subjected to restraint stress for 90 min for 5 consecutive days (chronic stress). Another group of rats received intracisternal (IC)-injection of CRF (1 μg) for 5 consecutive days. At the 1st day of restraint stress, calculated motility index was significantly increased by over 200% of basal in the proximal and distal colon. Similar results were obtained in response to the 2nd and 3rd day of restraint stress. In contrast, at the 5th day, restraint stress caused no more significant increase of colonic motility. Similarly, accelerated colonic transit induced by acute stress was no more observed following chronic stress. Increased, colonic motility and accelerated colonic transit induced by CRF were not attenuated at the 5th day. It is suggested that adaptation mechanism is developed following chronic stress. The decrease in colonic motor function in chronic stress is not due to reduced sensitivity to central CRF.     

Depressive symptoms in patients with chronic hepatitis C are correlated with elevated plasma levels of interleukin-1beta and tumor necrosis factor-alpha

Studies suggest that cytokines have a role in the biology of depression. In this study, we evaluated depression and cytokine levels in patients with and without chronic hepatitis C (HCV) to better assess how chronic infection alters cytokines levels and may contribute to depressive symptomotology. Twenty-three adults with (n=16) and without (n=7) HCV were recruited through the Portland VA Medical Center. Research participants were excluded for current substance abuse, psychotic disorder, liver cirrhosis, or interferon (IFN) therapy. Participants completed the Beck Depression Inventory-II (BDI-II) and a blood draw to evaluate plasma cytokine levels [i.e., interleukin (IL)-1beta, IL-10 and tumor necrosis factor (TNF)-alpha]. t-Tests were performed to compare cytokine levels in patients with or without HCV. HCV patients showed higher TNF-alpha values compared to patients without HCV (group means=7.94 vs. 3.41pg/mL, respectively, p=0.047). There were no significant differences between the groups for the other cytokines assessed. In patients with HCV, TNF-alpha and IL-1beta levels (but not IL-10) were correlated with BDI-II scores [r=0.594, p=0.020 and r=0.489, p=0.055 (trend), respectively]. Taken together, these results show an association between severity of depressive symptoms and expression of pro-inflammatory cytokines in patients with HCV. Future studies should investigate how inflammatory mediators play a role in the expression of specific depressive symptoms in patients with chronic infection. Patients with HCV represent an interesting model to examine this relationship.     

Taurine prevents enhancement of acetylcholinesterase activity induced by acute ethanol exposure and decreases the level of markers of oxidative stress in zebrafish brain

Ethanol (EtOH) is a drug widely consumed throughout the world that promotes several neurochemical disorders. Its deleterious effects are generally associated with modifications in oxidative stress parameters, signaling transduction pathways, and neurotransmitter systems, leading to distinct behavioral changes. Taurine (2-aminoethanesulfonic acid) is a β-amino acid not incorporated into proteins found in mM range in the central nervous system (CNS). The actions of taurine as an inhibitory neurotransmitter, neuromodulator, and antioxidant make it attractive for studying a potential protective role against EtOH-mediated neurotoxicity. In this study, we investigated whether acute taurine cotreatment or pretreatment (1 h) prevent EtOH-induced changes in acetylcholinesterase (AChE) activity and in oxidative stress parameters in zebrafish brain. The results showed that EtOH exposure (1% in volume) during 1 h increased AChE activity, whereas the cotreatment with 400 mg·L(-1) taurine prevented this enhancement. A similar protective effect of 150 and 400 mg·L(-1) taurine was also observed when the animals were pretreated with this amino acid. Taurine treatments also prevented the alterations promoted in superoxide dismutase and catalase activities by EtOH, suggesting a modulatory role in enzymatic antioxidant defenses. The pretreatment with 150 and 400 mg·L(-1) taurine significantly increased the sulfydryl levels as compared to control and EtOH groups. Moreover, 150 and 400 mg·L(-1) taurine significantly decreased thiobarbituric acid reactive species (TBARS) levels, but the cotreatment with EtOH plus 400 mg·L(-1) taurine did not prevent the EtOH-induced lipoperoxidation. In contrast, the pretreatment with 150 and 400 mg·L(-1) taurine prevented the TBARS increase besides decreased the basal levels of lipid peroxides. Altogether, our data showed for the first time that EtOH induced oxidative stress in adult zebrafish brain and reinforce the idea that this vertebrate is an attractive alternative model to evaluate the beneficial effect of taurine against acute EtOH exposure.     

“Green odor” inhalation by rats down-regulates stress-induced increases in Fos expression in stress-related forebrain regions

In the present study, on rats, a quantitative analysis of Fos protein immunohistochemistry was performed as a way of investigating the effects of inhalation of green odor (a mixture of equal amounts of trans-2-hexenal and cis-3-hexenol) on the neuronal activations in stress-related forebrain regions induced by acute and repeated stress. Rats were exposed to restraint stress for 90 min each day for 1, 2, 4, 7, or 11 consecutive days. The hypothalamic paraventricular nucleus (PVN), amygdala, hippocampus and paraventricular thalamic nucleus (PVT) were examined. Both acute and repeated restraint stress increased Fos-positive cells in the entire hypothalamic PVN, in the central and medial amygdala, and in PVT, although these responses declined upon repeated exposure to such stress. The stress-induced Fos responses were much weaker in rats that inhaled green odor during each day's restraint. No increases in Fos-positive cells were observed in the hippocampus in acutely stressed rats. The Fos-immunoreactive response to acute stress shown by the piriform cortex did not differ significantly between the vehicle + stress and green + stress groups. Green odor had inhibitory effects on the stress-induced corticosterone response, body-weight loss, and adrenal hypertrophy. These results suggest that in rats, green odor inhalation may, in an as yet unknown way, act on the brain to suppress activity in the neuronal networks involved in stress-related responses (such as activation of the hypothalamo–pituitary–adrenocortical axis and activation of the sympathetic nervous system, as well as stress-induced fear responses).     

Expression of strawberry notch family genes during zebrafish embryogenesis

Our previous study suggested a possible role for Sbno1, a mouse homologue of strawberry notch gene during brain development. In this report, we cloned the zebrafish homologues of sbno, and examined their expression pattern during embryogenesis by whole‐mount in situ hybridization. Zebrafish have three sbno genes: one Sbno1 homologue and two Sbno2 homologues, sbno2a and sbno2b. We observed that the expression of sbno1 and sbno2a was initially ubiquitous and gradually became predominant in the central nervous system as development progressed. The expression of sbno2b was observed in non‐neural tissues in contrast to the other two genes. sbno1 and sbno2a exhibited higher expression in distinct regions within the nervous system of pharyngula‐stage embryos, suggesting possible differing roles for sbno1 and sbno2a during later stages of embryogenesis. Together, the observed gene expression patterns suggest an important role of sbno‐family genes during development of the vertebrate central nervous system. Developmental Dynamics 239:1789–1796, 2010. © 2010 Wiley‐Liss, Inc.     

Fibronectin mediates correct positioning of the interrenal organ in zebrafish

Background: Fibronectin (Fn) forms a centripetal gradient during the fetal adrenal gland organogenesis, and modulates hormone responsiveness of adrenocortical cells in the primary culture. However, how Fn is involved in organ formation of the adrenal gland remains unclear. Results: In this study, we found that Fn accumulates around migrating ff1b‐expressing interrenal cells, which were marked by the ff1b promoter‐driven transgenic fluorescence, during the course of interrenal organ assembly. The interrenal cells displaying the migratory phenotype were absent in the fn1 mutant, while specification and kidney association of the interrenal tissue remained normal. The Fn deposition in the interrenal microenvironment was severely reduced in the vessel‐deficient ets1b morphant, implying its origin of synthesis from the peri‐interrenal vasculature. In the fn1 mutant, early‐migrating chromaffin cells were capable of interacting with steroidogenic interrenal cells, yet continuous migration and midline convergence of chromaffin cells were disrupted. Migration defects of both interrenal and chromaffin lineages, in the absence of Fn, thus led to incomplete interrenal organ assembly in aberrant positions. Conclusions: Our results indicate that Fn is essential for patterning interrenal organ formation, by modulating the migratory behavior of both steroidogenic interrenal and chromaffin cells. Developmental Dynamics 242:432–443, 2013. © 2013 Wiley Periodicals, Inc.     

Dysregulation of the stress response in asthmatic children

The stress system co-ordinates the adaptive responses of the organism to stressors of any kind. Inappropriate responsiveness may account for increased susceptibility to a variety of disorders, including asthma. Accumulated evidence from animal models suggests that exogenously applied stress enhances airway reactivity and increases allergen-induced airway inflammation. This is in agreement with the clinical observation that stressful life events increase the risk of a new asthma attack. Activation of the hypothalamic–pituitary–adrenal (HPA) axis by specific cytokines increases the release of cortisol, which in turn feeds back and suppresses the immune reaction. Data from animal models suggest that inability to increase glucocorticoid production in response to stress is associated with increased airway inflammation with mechanical dysfunction of the lungs. Recently, a growing body of evidence shows that asthmatic subjects who are not treated with inhaled corticosteroids (ICS) are likely to have an attenuated activity and/or responsiveness of their HPA axis. In line with this concept, most asthmatic children demonstrate improved HPA axis responsiveness on conventional doses of ICS, as their airway inflammation subsides. Few patients may experience further deterioration of adrenal function, a phenomenon which may be genetically determined.     

Bone growth in zebrafish fins occurs via multiple pulses of cell proliferation.

Fin length in the zebrafish is achieved by the distal addition of bony segments of the correct length. Genetic and molecular data provided evidence that segment growth uses a single pulse of growth, followed by a period of stasis. Examination of cell proliferation during segment growth was predicted to expose a graphical model consistent with a single burst of cell division (e.g., constant, parabolic, or exponential decay) during the lengthening of the distal-most segment. Cell proliferation was detected either by labeling animals with bromodeoxyuridine (during S-phase) or monitoring histone3-phosphate (mitosis). Results from both methods revealed that the number of proliferating cells fluctuates in apparent pulses as a segment grows (i.e., during the growth phase). Thus, rather than segment size being the result of a single burst of proliferation, it appears that segment growth is the result of several pulses of cell division that occur approximately every 60 microns (average segment length approximately 250 microns). These results indicate that segment lengthening requires multiple pulses of cell proliferation.     

Maternal stress and behavior modulate relationships between neonatal stress, attention, and basal cortisol at 8 months in preterm infants

There is evidence that the developmental trajectory of cortisol secretion in preterm infants is altered, with elevated basal cortisol levels observed postnatally through at least 18 months corrected age (CA). This alteration is possibly due to neonatal pain-related stress. High cortisol levels might contribute to greater risk of impaired neurodevelopment. Since maternal factors are important for the regulation of infant stress responses, we investigated relationships between infant (neonatal pain-related stress, attention, cortisol) and maternal (stress, interactive behaviors) factors at age 8 months CA. We found that interactive maternal behaviors buffered the relationship between high neonatal pain-related stress exposure and poorer focused attention in mothers who self-reported low concurrent stress. Furthermore, in preterm infants exposed to high concurrent maternal stress and overwhelming interactive maternal behaviors, higher basal cortisol levels were associated with poor focused attention. Overall, these findings suggest that maternal factors can influence the cognitive resilience at 8 months of preterm infants exposed to early life stress.