Interindividual differences in the circadian hematologic time structure of cancer patients

A Tangled Threesome: Circadian Rhythm, Body Temperature Variations, and the Immune System

Simple Summary

In mammals, including humans, the body temperature displays a circadian rhythm and is maintained within a narrow range to facilitate the optimal functioning of physiological processes. Body temperature increases during the daytime and decreases during the nighttime thus influencing the expression of the molecular clock and the clock-control genes such as immune genes. An increase in body temperature (daytime, or fever) also prepares the organism to fight aggression by promoting the activation, function, and delivery of immune cells. Many factors may affect body temperature level and rhythm, including environment, age, hormones, or treatment. The disruption of the body temperature is associated with many kinds of diseases and their severity, thus supporting the assumed association between body temperature rhythm and immune functions. Recent studies using complex analysis suggest that circadian rhythm may change in all aspects (level, period, amplitude) and may be predictive of good or poor outcomes. The monitoring of body temperature is an easy tool to predict outcomes and maybe guide future studies in chronotherapy.

Abstract

The circadian rhythm of the body temperature (CRBT) is a marker of the central biological clock that results from multiple complex biological processes. In mammals, including humans, the body temperature displays a strict circadian rhythm and has to be maintained within a narrow range to allow optimal physiological functions. There is nowadays growing evidence on the role of the temperature circadian rhythm on the expression of the molecular clock. The CRBT likely participates in the phase coordination of circadian timekeepers in peripheral tissues, thus guaranteeing the proper functioning of the immune system. The disruption of the CRBT, such as fever, has been repeatedly described in diseases and likely reflects a physiological process to activate the molecular clock and trigger the immune response. On the other hand, temperature circadian disruption has also been described as associated with disease severity and thus may mirror or contribute to immune dysfunction. The present review aims to characterize the potential implication of the temperature circadian rhythm on the immune response, from molecular pathways to diseases. The origin of CRBT and physiological changes in body temperature will be mentioned. We further review the immune biological effects of temperature rhythmicity in hosts, vectors, and pathogens. Finally, we discuss the relationship between circadian disruption of the body temperature and diseases and highlight the emerging evidence that CRBT monitoring would be an easy tool to predict outcomes and guide future studies in chronotherapy.

Variability in body temperature in healthy adults and in patients receiving chemotherapy: prospective observational cohort study

Between-individual variability of body temperature has been little investigated, but is of clinical importance: for example, in detection of neutropenic sepsis during chemotherapy. We studied within-person and between-person variability in temperature in healthy adults and those receiving chemotherapy using a prospective observational design involving 29 healthy participants and 23 patients undergoing chemotherapy. Primary outcome was oral temperature. We calculated each patient's mean temperature, standard deviation within each patient (within-person variability), and between patients (between-person variability). Secondary analysis explored temperature changes in the three days before admission for neutropenic sepsis. 1,755 temperature readings were returned by healthy participants and 1,765 by chemotherapy patients. Mean participant temperature was 36.16 C (95% CI 36.07-36.26) in healthy participants and 36.32 C (95% CI 36.18-36.46) in chemotherapy patients. Healthy participant within-person variability was 0.40 C (95% CI 0.36-0.44) and between-person variability was 0.26 C (95% CI 0.16-0.35). Chemotherapy patient within-person variability was 0.39 C (95% CI 0.34-0.44) and between-person variability was 0.34 C (95% CI 0.26-0.48). Thus, use of a population mean rather than personalised baselines is probably sufficient for most clinical purposes as between-person variability is not large compared to within-person variability. Standardised guidance and provision of thermometers to patients might help to improve recording and guide management.

Mammary tumors compromise time-of-day differences in hypothalamic gene expression and circadian behavior and physiology in mice

Circadian rhythms influence various aspects of biology, including hormonal, immunological, and behavioral processes. These 24-hour oscillations are necessary to optimize cellular functions and to synchronize these processes with the environment. Breast cancer patients and survivors frequently report disruptions in circadian oscillations that adversely affect quality-of-life, including fragmented sleep-wake cycles and flattened cortisol rhythms, which are associated with negative behavioral comorbidities (e.g., fatigue). However, the potential causal role of tumor biology in circadian dysregulation has not been investigated. Here, we examined the extent to which sham surgery, non-metastatic mammary tumors, or mammary tumor removal in mice disrupts circadian rhythms in brain clock gene expression, locomotor behavior (free-running and entrained), and physiological rhythms that have been associated with cancer behavioral comorbidities. Tumors and tumor resection altered time-of-day differences in hypothalamic expression of eight circadian-regulated genes. The onset of activity in entrained running behavior was advanced in tumor-bearing mice, and the amplitude of free-running rhythms was increased in tumor-resected mice. Tumors flattened rhythms in circulating corticosterone and Ly6c^Hi monocytes which were largely restored by surgical tumor resection. This work implies that tumors alone may directly impact central and/or peripheral circadian rhythmicity in breast cancer patients, and that these effects may persist in cancer survivors, potentially contributing to behavioral comorbidities.

Prospective influences of circadian clocks in adipose tissue and metabolism

Circadian rhythms make a critical contribution to endocrine functions that involve adipose tissue. These contributions are made at the systemic, organ and stem cell levels. The transcription factors and enzymes responsible for the maintenance of circadian rhythms in adipose depots and other peripheral tissues that are metabolically active have now been identified. Furthermore, the circadian regulation of glucose and lipid metabolism is well-established. Animal and human models provide strong evidence that disturbances in circadian pathways are associated with an increased risk of type 2 diabetes mellitus, obesity and their comorbidities. Thus, circadian mechanisms represent a novel putative target for therapy in patients with metabolic diseases.

Marker rhythms of circadian system function: a study of patients with metastatic colorectal cancer and good performance status

Cancer patients may exhibit normal or altered circadian rhythms in tumor and healthy tissues. Four rhythms known to reflect circadian clock function were studied in 18 patients with metastatic colorectal cancer and good performance status. Rest-activity was monitored by wrist actigraphy for 72 h before treatment, and its circadian rhythm was estimated by an autocorrelation coefficient at 24h and a dichotomy index that compared the activity level when in and out of bed. Blood samples (9-11 time points, 3-6 h apart) were drawn on day 1 and day 4 of the first course of chronochemotherapy (5-fluorouracil: 800 mg/m2/day; folinic acid: 300 mg/m2/day; oxaliplatin: 25 mg/m2/day). Group 24h rhythms were validated statistically for plasma concentrations of melatonin, 6-alpha-sulfatoxymelatonin, and cortisol and for lymphocyte counts. Significant individual 24h rhythms were displayed in melatonin by 15 patients, cortisol by seven patients, lymphocytes by five patients, and prominent circadian rhythms in activity were displayed by 10 patients; only one patient exhibited significant rhythms in all the variables. The results suggest the rhythms of melatonin, cortisol, lymphocytes, and rest/activity reflect different components of the circadian system, which may be altered differently during cancer processes. Such 24h rhythm alterations appeared to be independent of conventional clinical factors.

Circadian rhythm of objectively recorded hot flashes in postmenopausal breast cancer survivors

OBJECTIVE

Similar to the circadian rhythm of core body temperature, hot flashes have been found to exhibit a circadian rhythm in healthy, naturally postmenopausal women, with a peak in frequency at 18:25 h. However, to date, no studies have evaluated whether this same pattern is found among breast cancer survivors reporting hot flashes.

DESIGN

Daily hot flash frequencies were measured among 21 postmenopausal breast cancer survivors using validated 24-h sternal skin conductance monitoring.

RESULTS

Hot flashes were noted in all women, ranging in frequency from 1 to 30 per 24-h period. A majority of the sample (86%) experienced > or = 1 nighttime hot flash, with 48% exhibiting > or = 3 but < or = 7 nighttime hot flashes. For the total sample, a modest circadian rhythm was noted with a peak in hot flash frequency occurring at 16:10 h. However, significant variability was observed across individual women, and, as a whole, breast cancer survivors demonstrated distorted to obliterated rhythms.

CONCLUSIONS

Data suggest that hot flashes in postmenopausal breast cancer survivors do not follow the same circadian pattern as previously seen in healthy, naturally postmenopausal women. Findings have implications for (1) understanding the potential for sleep disturbances and fatigue in breast cancer survivors experiencing hot flashes, and (2) future research examining circadian rhythms of core body temperature and hot flashes in breast cancer survivors.

Hot flashes and their management in breast cancer

OBJECTIVES

To review literature relevant to defining and managing hot flashes in women with breast cancer.

DATA SOURCES

Published literature on hot flashes in women with breast cancer and in healthy women.

CONCLUSIONS

The etiology of hot flashes is influenced by several breast cancer treatment-related factors. Hot flashes are a prevalent, severe problem that can negatively impact quality of life. Certain women are at higher risk for hot flashes following breast cancer treatment. Little research supports the safety or effectiveness of treatments in women with breast cancer.

IMPLICATIONS FOR NURSING PRACTICE

Implications include the need to improve patient education, perform comprehensive symptom assessments, and counsel women about various treatment alternatives.

Circadian variation of cell proliferation and cell cycle protein expression in man: clinical implications

Most physiological, biochemical and behavioural processes have been shown to vary in a regular and predictable periodic manner with respect to time. This review focuses on the circadian rhythm in cell proliferation in bone marrow and gut and how this is associated with a circadian expression of cell cycle proteins in human oral mucosa. The control of circadian rhythms by the suprachiasmatic nuclei and the evolving understanding of the genetic and molecular biology of the circadian clock is outlined. Finally, the potential clinical impact of chronobiology in cancer medicine is discussed.

Pharmacokinetically guided melatonin scheduling in rats with circadian system suppression

To obtain a pharmacologic effect of melatonin in rats kept under prolonged continuous light exposure, conditions known to produce functional suppression of the circadian system, mimicking of the physiologic 24-h pattern of melatonin secretion, a hormonal signal of darkness exposure may be needed. The delivery scheme for melatonin was established in rats in the present studies. First, the plasma pharmacokinetics of [3H]melatonin were determined in rats kept under continuous light and in rats synchronized by exposure to alternating 12 h light and 12 h darkness (LD 12:12) in the early light span. The pharmacokinetics of total radioactivity were similar in both groups. Further quantitation of melatonin by thin-layer chromatography revealed differences dependent on light conditions. The mean plasma clearance and steady-state distribution volume were approximately twice as low with continuous light as with LD 12:12. Plasma protein binding of melatonin was approximately 33%, irrespective of group or sampling time. These pharmacokinetic parameters were used to devise a 24-h periodic delivery schedule consisting of a 6-h constant infusion of exogenous melatonin, followed by an 18-h melatonin-free interval. In a second study, the melatonin 24-h pattern was estimated from the measurement of 2-h fractions of urinary 6-sulfatoxymelatonin excretion for 4 days. 6 unrestrained rats kept under continuous light received melatonin for 2 days from 22:00 to 04:00 h through an indwelling jugular catheter, connected to a reservoir from a programmable pump. Only the administration of low doses (0.01 mg/kg/day) resulted in both a circadian pattern for 6-sulfatoxymelatonin excretion and normal physiological values during the infusion-free intervals. The resynchronizing efficacy of this schedule should be tested in rats with functional suppression of the circadian system.

Rhythm alteration in patients with metastatic breast cancer and poor prognostic factors

Circulating blood cell counts, serum cortisol, proteins, alkaline phosphatase, carcinoembryonic antigen and CA15.3 displayed significant circadian rhythms in a group of 13 women with metastatic breast cancer. Statistical significance (P < 0.05) was assessed with both analysis of variance and cosinor analysis. All patients had been previously treated with chemo-and/or radiotherapy and/or antiestrogens. All patients had been treatment-free for 1 month prior to the study. Each patient had blood drawn every 4 h for 48 h. Circadian rhythms were examined as a function of performance status, graded according to the World Health Organization, liver involvement and number of metastatic sites. Group circadian rhythms in serum cortisol or proteins were abolished in patients with liver metastases, and were altered in cases of poor performance status. Circulating leukocytes, neutrophils or platelets did not exhibit synchronized circadian rhythmicity in patients with poor performance status or liver metastases. The number of metastatic organs had a minor influence on circadian rhythmicity. These results suggest that rhythm alteration may be associated with both poor performance status and liver metastases in patients with advanced breast cancer. Such alteration of the normal circadian time structure may favor and/or result from cancer spread.

Circadian rhythms and cancer chemotherapy

Experimental and clinical pertinent data regarding circadian rhythmicities are reviewed in (1) target tissues, i.e., healthy tissues (actively proliferating or not) and tumor tissues, (2) pharmacology of anticancer agents, (3) toxicity and tolerance of these agents and (4) antitumor activity of cancer chemotherapy. The basic concepts of chronotolerance and/or of chronoefficacy have brought new hopes for further amelioration in the management of cancer patients. Quite recent published Phase II and III clinical trials have demonstrated that new improvements on the therapeutic index have been achieved through ambulatory chronotherapy for various solid tumors.

Haematological profile in cancer patients: analysis of circadian pattern

This study was intended to evaluate whether unusual circadian patterns in blood cells exist in cancer patients. Ten patients (five men and five women) suffering from advanced malignancy were compared with a control group of apparently healthy volunteers, of comparable age and sex. After synchronization of daily activities, meals and rest of the two groups, blood samples were taken four times (at 8.00 a.m., 12.00 a.m., 4.00 p.m. and 8.00 p.m.) in a single day. The total red and white cell counts, haemoglobin, platelet count, and neutrophil, lymphocyte, eosinophil, monocyte and basophil differential white cell counts were analysed by both conventional (Student's t-test; multifactorial analysis of variance) and inferential statistics (single and mean cosinor). The average values for platelets (P = 0.04), white blood cells (P = 0.004) and lymphocytes (P << 0.001) showed significant changes with time, independently of disease state. Cosinor analysis indicated a circadian rhythmicity for haemoglobin (P = 0.02), eosinophils (P = 0.014), and lymphocytes (P = 0.001) in healthy subjects, and for eosinophils only (P = 0.024) in cancer patients.

Interindividual differences in chronopharmacologic effects of drugs: a background for individualization of chronotherapy

In order to optimize chronotherapeutic schedules (designs), we examined the interindividual differences in chronopharmacologic effects of drugs with consideration of the following three factors: (a) inherited factors of direct relevance to chronopharmacology (genetic variability, gender-related differences) as well as age-related differences; (b) interindividual difference in chronoeffectiveness related to disease (e.g., various types and stages of cancer, affective disorders, etc.) as well as to drug-dependent alteration (phase shifts, distortion) of biological rhythms; and (c) means to solve problems resulting from the need of individualization in chronotherapy. These involve the use of circadian marker rhythms (MR) whose characteristics (peak or trough time, amplitude, etc.) can be precisely quantified and thus are applicable as a reference system for physiologic, pathologic, pharmacologic, and therapeutic uses. The MR has to be specific and pertinent and must be easily monitored and documented. This approach can be further advanced by the use of a battery of MRs rather than a single MR. Other suggested means relate to the fact that chronobiotics (agents capable of influencing parameters of a set of biological rhythms) should be considered (e.g., corticoids and adrenocorticotropic hormone) and/or to the subject's synchronization should be enforced by "conventional" zeitgebers (e.g., bright light, physical activity).

Circadian variation in serum cortisol and circulating neutrophils are markers for circadian variation of bone marrow proliferation in cancer patients

Serum cortisol, circulating white blood cells and DNA cell cycle distribution in bone marrow cells were measured during daytime (11.00) and at midnight (24.00) over single 24-hour periods in 15 cancer patients. The neutrophils and fraction of bone marrow cells in S-phase showed the same circadian variation as cortisol with higher values in daytime as compared to midnight in 11 patients with a normal cortisol rhythm (p < 0.05). The lymphocytes, eosinophils and basophils all had significantly higher values at midnight as compared to daytime. There were significant correlations between cortisol and neutrophils, lymphocytes, eosinophils and basophils. The correlation between neutrophils and fractions of bone marrow cells in S-phase and S + G2/M-phase were highly significant (r = 0.74, p = 0.0001 and r = 0.72, p = 0.0001, respectively). In 8 of 13 patients (61.5%) without bone marrow infiltration both cortisol and neutrophils showed identical circadian variation as bone marrow cells in S-phase and S + G2/M-phase. Furthermore, for the total series a significant correlation between S-phase, cortisol and neutrophils was found by multiple regression analysis (p < 0.0001). These findings strengthen the possibility of using the circadian variation in cortisol and neutrophils as marker rhythms for circadian variation in bone marrow proliferation, thus allowing optimization of cytotoxic therapy and individualization of chronotherapy.