NOCTURNIN Gene Diurnal Variation in Healthy Volunteers and Expression Levels in Shift Workers.

OBJECTIVE: The NOCTURNIN gene links nutrient absorption and metabolism to the circadian clock. Shift workers are at a heightened risk of overweight and of developing obesity and metabolic syndrome. This study investigates the diurnal variation of NOCTURNIN in healthy volunteers and its expression levels in rotational shift and daytime workers. METHODS: NOCTURNIN expression levels were evaluated in peripheral blood lymphocytes from 15 healthy volunteers at 4-hour intervals for 24 h. Metabolic parameters and NOCTURNIN expression were measured in workers engaged in shift and daytime work. RESULTS: In the group of volunteers NOCTURNIN expression showed diurnal variation, with a peak at 8:00 AM. NOCTURNIN expression was higher in shift workers than in daytime workers. Multivariate analysis confirmed the role of shift work as an independent factor affecting NOCTURNIN expression. Notably, its level correlated directly with body mass index and inversely with total energy expenditure. CONCLUSIONS: Measuring NOCTURNIN expression levels in human peripheral blood lymphocytes can improve investigations on the relationship between changes in circadian rhythm and metabolic disorders. Shift workers show higher NOCTURNIN levels than daytime workers.

Working against the biological clock: a review for the Occupational Physician.

The master clock of the biological rhythm, located in the suprachiasmatic nucleus of the anterior hypothalamus, synchronizes the molecular biological clock found in every cell of most peripheral tissues. The human circadian rhythm is largely based on the light-dark cycle. In night shift workers, alteration of the cycle and inversion of the sleep-wake rhythm can result in disruption of the biological clock and induce adverse health effects. This paper offers an overview of the main physiological mechanisms that regulate the circadian rhythm and of the health risks that are associated with its perturbation in shift and night workers. The Occupational Physician should screen shift and night workers for clinical symptoms related to the perturbation of the biological clock and consider preventive strategies to reduce the associated health risks.

Peripheral Skin Temperature and Circadian Biological Clock in Shift Nurses after a Day off.

The circadian biological clock is essentially based on the light/dark cycle. Some people working with shift schedules cannot adjust their sleep/wake cycle to the light/dark cycle, and this may result in alterations of the circadian biological clock. This study explored the circadian biological clock of shift and daytime nurses using non-invasive methods. Peripheral skin temperature, cortisol and melatonin levels in saliva, and Per2 expression in pubic hair follicle cells were investigated for 24 h after a day off. Significant differences were observed in peripheral skin temperature and cortisol levels between shift and daytime nurses. No differences in melatonin levels were obtained. Per2 maximum values were significantly different between the two groups. Shift nurses exhibited lower circadian variations compared to daytime nurses, and this may indicate an adjustment of the circadian biological clock to continuous shift schedules. Non-invasive procedures, such as peripheral skin temperature measurement, determination of cortisol and melatonin in saliva, and analysis of clock genes in hair follicle cells, may be effective approaches to extensively study the circadian clock in shift workers.

Circadian Modulation of 8-Oxoguanine DNA Damage Repair.

The DNA base excision repair pathway is the main system involved in the removal of oxidative damage to DNA such as 8-Oxoguanine (8-oxoG) primarily via the 8-Oxoguanine DNA glycosylase (OGG1). Our goal was to investigate whether the repair of 8-oxoG DNA damage follow a circadian rhythm. In a group of 15 healthy volunteers, we found a daily variation of Ogg1 expression and activity with higher levels in the morning compared to the evening hours. Consistent with this, we also found lower levels of 8-oxoG in morning hours compared to those in the evening hours. Lymphocytes exposed to oxidative damage to DNA at 8:00 AM display lower accumulation of 8-oxoG than lymphocytes exposed at 8:00 PM. Furthermore, altered levels of Ogg1 expression were also observed in a group of shift workers experiencing a deregulation of circadian clock genes compared to a control group. Moreover, BMAL1 knockdown fibroblasts with a deregulated molecular clock showed an abolishment of circadian variation of Ogg1 expression and an increase of OGG1 activity. Our results suggest that the circadian modulation of 8-oxoG DNA damage repair, according to a variation of Ogg1 expression, could render humans less susceptible to accumulate 8-oxoG DNA damage in the morning hours.

Circadian gene expression and extremely low-frequency magnetic fields: an in vitro study.

It is well known that circadian clocks are mainly regulated by light targeting signaling pathways in the hypothalamic suprachiasmatic nucleus. However, an entrainment mediated by non-photic sensory stimuli was also suggested for peripheral clocks. Exposure to extremely low frequency (ELF) electromagnetic fields might affect circadian rhythmicity. The goal of this research was to investigate effects of ELF magnetic fields (ELF-MF) on circadian clock genes in a human fibroblast cell line. We found that an ELF-MF (0.1 mT, 50 Hz) exposure was capable of entraining expression of clock genes BMAL1, PER2, PER3, CRY1, and CRY2. Moreover, ELF-MF treatment induced an alteration in circadian clock gene expression previously entrained by serum shock stimulation. These results support the hypothesis that ELF-MF may be able to drive circadian physiologic processes by modulating peripheral clock gene expression.

Low perceived social support is associated with CD8+CD57+ lymphocyte expansion and increased TNF-α levels.

Social support has been supposed to have a positive impact on the function of the immune system. However, the relationship between perceived social support and immune function has not yet been fully investigated. In this cross-sectional study, we investigated the link between perceived social support and lymphocyte subpopulations and cytokines. 232 healthy subjects provided a blood sample and completed the Multidimensional Scale of Perceived Social Support (MSPSS) questionnaire. Lymphocyte immunophenotypes and cytokines were determined. Significantly increased CD8+CD57+ lymphocytes and TNF-α levels were found in group with low perceived social support. Multivariate linear regression corrected for possible confounders confirmed a significant role of perceived social support in predicting the number of CD8+CD57+ lymphocyte and TNF-α levels. This study supports the association between perceived social support and immune function. In particular, poor social support may be related to a state of chronic inflammation sustained by CD8+CD57+ lymphocyte expansion and increased TNF-α levels.

Rotating-shift nurses after a day off: peripheral clock gene expression, urinary melatonin, and serum 17-ß-estradiol levels.

OBJECTIVE: Impairment of clock gene expression and changes in melatonin and 17-ß-estradiol levels may constitute biological alterations underlying the increased risk of breast cancer among shift workers. The aim of this study was to compare levels of selected core clock gene expression, 6-sulfatoxymelatonin (aMT6s), and 17-ß-estradiol between rotational shift work (SW) and daytime (DT) workers after a day off. METHODS: The cross-sectional study comprised 60 nurses with ≥2 years of SW and 56 permanent DT nurses. Transcript levels of circadian genes BMAL1, CLOCK, NPAS2, CRY1, CRY2, PER1, PER2, PER3, and REVERBα were determined by quantitative real-time polymerase chain reaction (PCR) in lymphocytes. All participants were tested in the early follicular phase of the menstrual cycle. Samples were collected at the beginning of the morning-shift after a regular night's sleep on a day off. Chronotype and sociodemographic characteristics were also evaluated. RESULTS: We found a significantly higher expression of BMAL1, CLOCK, NPAS2, PER1, PER2, and REVERBα and a lower expression of PER3, CRY1 and CRY2 among SW compared to DT nurses. SW participants did not demonstrate a significant difference in aMT6s levels, but they did show significantly higher 17-ß-estradiol levels compared to DT nurses. Multiple linear regression analysis confirmed the role of SW on expression of BMAL1 (ß 0.21, P=0.040), CLOCK (ß 0.35, P=0.008), NPAS2 (ß 0.30, P=0.012), PER1 (ß 0.33, P=0.008), PER2 (ß 0.19, P=0.047), PER3 (ß -0.27, P=0.012), CRY1 (ß -0.33, P=0.002), CRY2 (ß -0.31, P=0.005), REVERBα (ß 0.19, P=0.045), and on 17-ß-estradiol levels (ß 0.32, P=0.003). The analysis also confirmed the role of chronotype as an independent factor for PER1 (ß 0.48, P=0.001) and PER2 (ß -0.22, P=0.022) expression, and 17-ß-estradiol levels (ß 0.26, P=0.011). CONCLUSIONS: Rotating SW nurses show alterations in peripheral clock gene expression and 17-ß-estradiol levels at the beginning of the morning shift after a day off.

Styrene altered clock gene expression in serum-shocked cultured human fibroblasts.

The circadian clock can regulate the metabolic process of xenobiotics, but little is known as to circadian rhythms can be perturbed by xenobiotics. Styrene is a organic chemical widely used in occupational settings. The effects of styrene on the circadian genes of HuDE cells were evaluated after serum-shocking synchronization. A subtoxic dose of 100 µM of styrene altered the expression of clock genes BMAL1, PER2, PER3, CRY1, CRY2, and REV-ERB-α.

Attachment style and immunity: a 1-year longitudinal study.

Previous cross-sectional studies suggested an association between attachment-related avoidance and altered immune function. We aimed at testing this hypothesis with longitudinal data. A random sample of 65 female nurses provided a blood sample and completed measures of perceived stress, social support, alexithymia, and attachment style. Immune assays included lymphocyte proliferative response (LPR) to Phytohemagglutinin and NK cell cytotoxicity (NKCC). State measures (perceived stress and support) and immune measures were collected again after 4, 8, and 12 months. Linear mixed effects models were used to examine the relationship between attachment and immunity. While low to moderate levels of attachment-related avoidance were not associated with NKCC, there was a significant negative association (beta -.35; p=.005) between high levels of avoidance and NKCC. No association was observed between NKCC and attachment-related anxiety, and between LPR and both attachment dimensions. While our findings should be interpreted with caution due to study limitations such as the relatively small sample size and the inclusion of only female participants, they corroborate the notion that attachment is linked to physiology and health.

Influence of shift-work on selected immune variables in nurses.

Shift-work, particularly night-work, interferes with the physiological circadian rhythm and has the potential to induce psycho-physiological disturbances. A nurse population was investigated to establish whether shift-work can induce changes in a number of immune variables. Lymphocyte immunophenotype and proliferative response, NK cytotoxicity, cytokines and cortisol were determined in 68 shift-working and 28 daytime nurses at baseline and at 12 months. None of the variables studied differed significantly between shift and daytime workers, either at baseline or at 12 months, except IL-1ß and TNF-α, which were significantly higher among daytime nurses at baseline, but not at follow-up. No effect of shift-work on immune variable and cortisol levels was seen at 12 months after adjustment for baseline values and job seniority. The specific work schedule as well as job type likely influenced our results, suggesting that rotational shift-work does not necessarily affect the immune system adversely. The immune changes reported by other studies in shift-workers should not be generalized.

Relationship of job satisfaction, psychological distress and stress-related biological parameters among healthy nurses: a longitudinal study.

OBJECTIVE: To examine the relationship between job satisfaction, psychological distress, psychosocial processes and stress-related biological factors, and to evaluate whether over time changes of work satisfaction could affect the immunological-inflammatory status of workers. METHODS: One hundred and one nurses were enrolled at the Clinic of Occupational Medicine, Polytechnic University of Marche, Ancona, Italy. Perceived job satisfaction, psychological distress, and social support were assessed every 4 mo over a 1-yr period using 4 self-reported questionnaires. T lymphocytes CD3, CD4(+), CD8(+), CD8(+)-CD57(+), B lymphocyte CD19(+), NK cells CD56(+), and NK cell activity were determined. RESULTS: Job satisfaction was associated with reduced psychological distress and was characterized by low cell numbers of CD8(+) suppressor T cells, CD8(+)-CD57(+) activated T cells, CD56(+) NK cells and low IL-6 levels. Over time changes in psychological parameters were related to changes in the immunological-inflammatory variables. Subjects who increased their job satisfaction showed a reduced psychological stress associated with reduced number of CD8(+)-CD57(+) activated T cells and inflammatory cytokines. CONCLUSIONS: Job (dis)satisfaction is related with psychological mechanisms in stress affecting cellular immune function.

[Shift work and cardiometabolic risk]. / Lavoro a turni e rischio cardiometabolico.

Shift work is frequently associated with coronary heart disease. Medical research indicate metabolic disturbance among shift workers, which is characterized by associated modifications in the concentration of serum glucose and serum lipids, hypertension and obesity, especially addominal weight. Atrasversal study has been carried out: 193 (126 females and 67 males) healthcare shift workers were compared with 221 (160 females and 61 males) day workers. Medical history, health examination including anthropometric and arterial blood pressure measurements were assessed. All participants were submitted a standardized questionnaire on health-related behaviours and biochemical determinations (fasting plasma glucose, HDL-cholesterol, triglycerides). Job seniority of shift work resulted at 13.5 +/- 8.2 among shift workers and 19.0 +/- 11.3 among day workers. Assessment of the metabolic syndrome relevance was defined according to the criterions proposed by the International Diabetes Federation. The 20% shift workers (33% males and 13% females) was affected by metabolic syndrome against 12% non shift workers (20% males and 9% females). The most frequently altered parameter, apart from metabolic syndrome, was high abdominal obesity, which occurred in 64% of the sample (70% shift workers vs 58% day workers). The results of multiple logistic regression attested the presence of a higher relative risk among shift workers regarding both the prevalence of a metabolic syndrome (OR 2,1 - 95% Cl 1.15-3.86) and the excess in abdominal obesity (OR 1.8 - 95% Cl 1.16-3.25). After adjusting confusing factors such as smoke, age, alchool, consumption, physical activity, scholastic degree, a OR 2.9 - 95%Cl 1,53-5.53 and a OR 1.9 - 95%.Cl 1.32-3.86 were confirmed.

[Prevalence of metabolic syndrome among forestry department agents in the Marche Region (italy)]. / La sindrome metabolica nella Regione Marche: studio di prevalenza tra gli agenti del corpo forestale dello stato.

AIM: to investigate the prevalence of metabolic syndrome and associations among cardiovascular risk factors in an Italian cohort of forestry agents, born and living in the Marche Region, everybody in good health. The results of this research can be used for subsequent comparison with other working population. DESIGN: the sample arises from a beginning selection of the participants to the public competition for forestry agents, in order to assess their qualifying attitudes to hold that position. Health examination was conducted during the annual health check-up of forestry agents evaluating the maintenance of the beginning psycho-physical attitudes. During periodic medical controls, the metabolic and physical parameters related to cardiovascular risk factors have been analyzed. SETTING AND PARTICIPANTS: a total of 207 forestry agents (87% males and 13% females) have been submitted to health examination, including anthropometric and arterial blood pressure measurements and biochemical determinations, in order to evaluate the parameters competing to formulate a diagnosis of metabolic syndrome, using the criteria proposed by the International Diabetes Federation (IDF). MAIN OUTCOMES MEASURES: metabolic syndrome was defined by the clustering of three or more of the following abnormalities: waist circumference larger than 94 cm in men and 80 cm in women; serum triglycerides level of at least 150 mg/dL; highdensity lipoprotein cholesterol less than 40 mg/dL in men and 50 mg/dL in women; blood pressure higher than 130/85 mmHg; or fast plasma glucose higher than 100 mg/dL. Waist circumference has been measured following the indications of the European Health Risk Monitoring. RESULTS: compared to the general population of the Region, the agents of the CFS exhibit considerably lower values of cholesterol, triglycerides and fast plasma glucose. They show a lower presence in diseases such as diabetes and arterial hypertension. Cigarette smokers are very few. The prevalence of the metabolic syndrome is lower than general population: 6%, 11.5% and 22.5, in groups aged 21-35, 36-42 and 43-60, respectively. CONCLUSIONS: CFS agents have of a lower cardiometabolic risk compared to general population; therefore they represent a <> for future comparison with other working populations.

[Assessment of plasma homocysteine levels in shift healthcare workers]. / Valutazione dell'omocisteina nei lavoratori turnisti.

BACKGROUND: Previous studies have indicated an association between shift work and cardiovascular disease. Increased plasma homocysteine levels has been proposed as a cardiovascular risk factor independent of other conventional risk factors. AIMS: Our aim is to verify the usefulness of plasma homocysteine as a screening test to prevent cardiovascular diseases in shift workers. METHODS: Thirty rotating shift nurses and 28 daytime nurses have been submitted during 18 months to regular taking of arterial pressure and body weight. Venous blood was drawn to measure glycaemia, triglycerides, plasma cortisol level, HDL cholesterol, blood cell count, alanine-aminotransferase, aspartate-aminotransferasi, gamma-GT, and plasma homocysteine. RESULTS: No increase in average plasma homocysteine in rotating shift nurses, nor a higher frequency in hyperomocisteinemia than in daytime workers was found. A significant difference was observed in body weight and systolic blood pressure (p<0.05), which resulted higher in rotating shift workers than in daytime workers. A significant increase was observed in alanine-aminotransferase (ALT) among shift workers (p<0.05). CONCLUSION: Plasma homocysteine measurement should not be employed as a screening test for the prevention of cardiovascular disease in rotating shift workers.

Assessment of cardiovascular risk in shift healthcare workers.

BACKGROUND: Shift work has been associated with an increased risk of cardiovascular disease (CVD); in particular, night work affects the circadian rhythm. DESIGN AND METHODS: The study examines the effectiveness of three screening methods and plasma hyperhomocysteinemia, an independent risk factor, in assessing the risk of CVD in 147 healthcare providers doing daytime or rotational shift work. The methods applied were: (i) the method proposed by the European Cardiovascular Indicators Surveillance Set (EUROCISS); (ii) the metabolic syndrome (MS) criteria of the Third Report of the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (ATPIII) and (iii) the MS criteria of the International Diabetes Federation (IDF). RESULTS: EUROCISS was unable to distinguish between the CVD risk of daytime and rotational shift workers. Both the ATPIII and the IDF detected MS, which is strongly associated with CVD, but only the IDF evidenced a significantly greater prevalence of MS (P<0.05) among shift workers. Hyperhomocysteinemia was unable to discriminate the CVD risk between daytime and shift workers, as it was influenced by multiple confounding factors. CONCLUSIONS: The increased risk of CVD associated with shift work is related to the greater incidence of MS among these workers. In our study a high prevalence of MS was detected only with the IDF. The method is useful for CVD prevention and the promotion of health during any medical examination of shift workers.

Attachment security and immunity in healthy women.

BACKGROUND: Attachment security is associated with health and possibly autonomic and endocrine reactivity to stress, however the relationship between attachment style and immune function has not yet been investigated. METHODS: A random sample of 61 female nurses provided a blood sample and completed the Perceived Stress Scale, the Multidimensional Scale of Perceived Social Support, the 20-item Toronto Alexithymia Scale, and the Experiences in Close Relationships questionnaire. Immune measures included immunophenotypic analysis, lymphocyte proliferative response to Phytohemagglutinin, and NK cell cytotoxicity (NKCC). Statistical analysis focused on the relationship between attachment-related anxiety or avoidance and immune measures. Multiple regression was used to control for perceived stress and support, alexithymia, health-related behaviors possibly influencing immunity, and use of anti-inflammatory drugs, tobacco or alcohol. RESULTS: Attachment-related anxiety was not associated with any immune parameter. Attachment-related avoidance was associated with lower NKCC. This association was independent from the number of circulating NK cells, which suggests a change in cell functionality. Perceived stress was also associated with lower NKCC. CONCLUSIONS: This study suggests a link between attachment security and immunity. While our findings should be interpreted with great caution and need replication, they are consistent with previous work suggesting that insecure attachment may be a risk factor for health and may relate to biological processes relevant to health.