Taltirelin alleviates fatigue-like behavior in mouse models of cancer-related fatigue

Connecting the dots: the role of fatigue in female infertility

Fatigue, an increasingly acknowledged symptom in various chronic diseases, has garnered heightened attention, during the medical era of bio-psycho-social model. Its persistence not only significantly compromises an individual's quality of life but also correlates with chronic organ damage. Surprisingly, the intricate relationship between fatigue and female reproductive health, specifically infertility, remains largely unexplored. Our exploration into the existing body of evidence establishes a compelling link between fatigue with uterine and ovarian diseases, as well as conditions associated with infertility, such as rheumatism. This observation suggests a potentially pivotal role of fatigue in influencing overall female fertility. Furthermore, we propose a hypothetical mechanism elucidating the impact of fatigue on infertility from multiple perspectives, postulating that neuroendocrine, neurotransmitter, inflammatory immune, and mitochondrial dysfunction resulting from fatigue and its co-factors may further contribute to endocrine disorders, menstrual irregularities, and sexual dysfunction, ultimately leading to infertility. In addition to providing this comprehensive theoretical framework, we summarize anti-fatigue strategies and accentuate current knowledge gaps. By doing so, our aim is to offer novel insights, stimulate further research, and advance our understanding of the crucial interplay between fatigue and female reproductive health.

Biomarkers of fatigue in oncology: A systematic review

Cancer-related fatigue (CRF) is a distressing side effect of cancer and treatment, affecting both patients during active treatment and survivors, negatively impacting quality of life. While its exact cause remains uncertain, various mechanisms such as immune dysfunction, HPA-axis dysfunction, and treatment toxicity are proposed. Inflammatory biomarkers of CRF have been explored in previous research, but non-inflammatory markers have not been comprehensively studied. This systematic review analysed 33 studies to identify non-inflammatory peripheral blood biomarkers associated with CRF. Promising markers included Hb, blood coagulation factors, BDNF, tryptophan, GAA, mtDNA, platinum, CA125, and cystatin-C. Inconsistent findings were observed for other markers like VEGF, leptin, and stress hormones. Most studies focused on adults. Research in pediatrics is limited. This review showed partial evidence for the inflammaging hypothesis (neurotoxicity due to neuro-inflammation) laying at the basis of CRF. Further research, especially in pediatrics, is needed to confirm this hypothesis and guide future biomarker studies.

A Panax quinquefolius-Based Preparation Prevents the Impact of 5-FU on Activity/Exploration Behaviors and Not on Cognitive Functions Mitigating Gut Microbiota and Inflammation in Mice

Simple Summary

Chemotherapy-related cognitive impairment (CRCI) and fatigue worsen the quality of life (QoL) of cancer patients. Multicenter studies have shown that Panax quinquefolius and vitamin C, respectively, were effective in reducing the symptoms of fatigue in treated cancer patients. We developed a behavioral C57Bl/6j mouse model to study the impact of 5-Fluorouracil (5-FU) chemotherapy on activity/fatigue, emotional reactivity and cognitive functions. We used this model to evaluate the potentially beneficial role of a Panax quinquefolius-based solution containing vitamin C (Qiseng^®) or vitamin C alone in these chemotherapy side effects. We established that Qiseng^® prevents the reduction in activity/exploration and symptoms of fatigue induced by 5-FU and dampens chemotherapy-induced intestinal dysbiosis and systemic inflammation. We further showed that Qiseng^® decreases macrophage infiltration in the intestinal compartment, thus preventing, at least in part, the systemic elevation of IL-6 and MCP-1 and further reducing the neuroinflammation likely responsible for the fatigue induced by chemotherapy, a major advance toward improving the QoL of patients.

Abstract

Chemotherapy-related cognitive impairment (CRCI) and fatigue constitute common complaints among cancer patient survivors. Panax quinquefolius has been shown to be effective against fatigue in treated cancer patients. We developed a behavioral C57Bl/6j mouse model to study the role of a Panax quinquefolius-based solution containing vitamin C (Qiseng^®) or vitamin C alone in activity/fatigue, emotional reactivity and cognitive functions impacted by 5-Fluorouracil (5-FU) chemotherapy. 5-FU significantly reduces the locomotor/exploration activity potentially associated with fatigue, evokes spatial cognitive impairments and leads to a decreased neurogenesis within the hippocampus (Hp). Qiseng^® fully prevents the impact of chemotherapy on activity/fatigue and on neurogenesis, specifically in the ventral Hp. We observed that the chemotherapy treatment induces intestinal damage and inflammation associated with increased levels of Lactobacilli in mouse gut microbiota and increased expression of plasma pro-inflammatory cytokines, notably IL-6 and MCP-1. We demonstrated that Qiseng^® prevents the 5-FU-induced increase in Lactobacilli levels and further compensates the 5-FU-induced cytokine release. Concomitantly, in the brains of 5-FU-treated mice, Qiseng^® partially attenuates the IL-6 receptor gp130 expression associated with a decreased proliferation of neural stem cells in the Hp. In conclusion, Qiseng^® prevents the symptoms of fatigue, reduced chemotherapy-induced neuroinflammation and altered neurogenesis, while regulating the mouse gut microbiota composition, thus protecting against intestinal and systemic inflammation.

A novel PHD2 inhibitor acteoside from Cistanche tubulosa induces skeletal muscle mitophagy to improve cancer-related fatigue

OBJECTIVE

To study whether ACT exerts anti-fatigue activity against CRF by inducing skeletal muscle mitophagy via suppressing PHD2 to upregulate the HIF-1α/BNIP3 signaling pathway.

METHODS

In this study, the molecular docking virtual screening technique was used to screen active components in Cistanche tubulosa that act as potential PHD2 inhibitors; the preliminary verification was carried out by Surface plasmon resonance (SPR) technology. BALB/c mice were treated with Paclitaxel (PTX, 10 mg/kg) and ACT (50, 100 mg/kg) alone or in combination for 20 days. Fatigue-related behaviors, energy metabolism and skeletal muscle mitochondria were assessed. Murine C2C12 myoblast was cultured and differentiated; then, a C26 tumor cell-conditioned medium was added to induce cachexia. Intracellular reactive oxygen species (ROS), mitochondrial membrane potential, mitochondrial microstructure and function, autophagy, PHD2/HIF-1 and PINK1/Parkin signal pathway proteins were analyzed. Then, interfering RNA technology was used to silence PHD2 and observe the efficacy of ACT.

RESULTS

We demonstrated that ACT exerted good binding activity with PHD2; ACT administration ameliorated PTX-induced muscle fatigue-like behavior via improving muscle quality and mitochondria function, increasing mitophagy, upregulating COXIV, CytoC, PINK1, Parkin, HIF-1α and BNIP3 expression and inhibiting p62, LC3B, PHD2 and Beclin-1 expression. The protective effect of ACT disappeared after transfection with the PHD2 gene knockdown plasmid Egln-1-RNAi.

CONCLUSIONS

These results suggest that ACT can improve CRF by promoting mitophagy via suppression of PHD2 to remove dysfunctional mitochondria, demonstrating that ACT has huge prospects for clinical application in CRF treatment.

Sex differences in the behavioral and immune responses of mice to tumor growth and cancer therapy

There is significant variability in the expression of cancer-related fatigue. Understanding the factors that account for this variation provide insight into the underlying mechanisms. One important, but often overlooked, variable is biological sex. While a few clinical studies have indicated that female patients report higher levels of fatigue, these studies are subject to potential socio-culture reporting biases. Only a limited number of preclinical studies have considered sex differences in animal model of fatigue and few have simultaneously considered both disease- and treatment-related factors. The present series of studies was initiated to address the current knowledge gap on the importance of sex differences in cancer-related fatigue. We selected a murine model of human papilloma virus-positive head and neck cancer based on heterotypic injection of the mEERL95 cell line that grows in both male and female mice and responds to a regimen of cisplatin plus irradiation. We also tested the impact of immunotherapy treatment targeting PD1. Voluntary wheel running was used to evaluate fatigue-like behavior. Male mice grew larger tumors than did female mice and showed more severe fatigue-like behavior. We confirmed that the tumor increased the expression of inflammatory cytokines in the liver, but no sex differences were observed. As a trend toward elevated Cd3 mRNA was observed in female mice, we tested the importance of T cells using female Rag2-/- mice. The Rag2-/- female mice had accelerated tumor growth and more severe fatigue-like behavior. In response to cisplatin alone non-tumor-bearing female mice showed a slower recovery of wheel running activity compared to males. However, in response to chemoradiation and anti-PD1 neutralizing antibody, tumor-bearing female mice showed a better tumor response to therapy than male mice, but no significant sex differences were observed for wheel running. These findings point to different mechanisms underlying tumor- and treatment-induced behavioral fatigue and indicate that the sex factor can intervene to modulate the expression of fatigue-like behavior in particular circumstances.

Ganoderic acid alleviates chemotherapy-induced fatigue in mice bearing colon tumor

Chemotherapy-related fatigue (CRF) is increasingly being recognized as one of the severe symptoms in patients undergoing chemotherapy, which not only largely reduces the quality of life in patients, but also diminishes their physical and social function. At present, there is no effective drug for preventing and treating CRF. Ganoderic acid (GA), isolated from traditional Chinese medicine Ganoderma lucidum, has shown a variety of pharmacological activities such as anti-tumor, anti-inflammation, immunoregulation, etc. In this study, we investigated whether GA possessed anti-fatigue activity against CRF. CT26 tumor-bearing mice were treated with 5-fluorouracil (5-FU, 30 mg/kg) and GA (50 mg/kg) alone or in combination for 18 days. Peripheral and central fatigue-related behaviors, energy metabolism and inflammatory factors were assessed. We demonstrated that co-administration of GA ameliorated 5-FU-induced peripheral muscle fatigue-like behavior via improving muscle quality and mitochondria function, increasing glycogen content and ATP production, reducing lactic acid content and LDH activity, and inhibiting p-AMPK, IL-6 and TNF-α expression in skeletal muscle. Co-administration of GA also retarded the 5-FU-induced central fatigue-like behavior accompanied by down-regulating the expression of IL-6, iNOS and COX2 in the hippocampus through inhibiting TLR4/Myd88/NF-κB pathway. These results suggest that GA could attenuate 5-FU-induced peripheral and central fatigue in tumor-bearing mice, which provides evidence for GA as a potential drug for treatment of CRF in clinic.

Voluntary wheel running ameliorates select paclitaxel chemotherapy-induced sickness behaviors and associated melanocortin signaling

While chemotherapy remains a common cancer treatment, it is associated with debilitating side effects (e.g., anorexia, weight loss, and fatigue) that adversely affect patient quality of life and increase mortality. However, the mechanisms underlying taxane chemotherapy-induced side effects, and effective treatments to ameliorate them, are not well-established. Here, we tested the longitudinal relationship between a clinically-relevant paclitaxel regimen, inflammation, and sickness behaviors (loss of body mass, anorexia, fever, and fatigue) in adult, female mice. Furthermore, we sought to identify the extent to which voluntary exercise (wheel running) attenuates paclitaxel-induced sickness behaviors and underlying central pathways. Body mass and food intake decreased following six doses of chemotherapy treatment relative to vehicle controls, lasting less than 5 days after the last dose. Paclitaxel treatment also transiently decreased locomotion (open field test), voluntary wheel running, home-cage locomotion, and core body temperature without affecting motor coordination (rotarod task). Circulating interleukin (IL)-6 and hypothalamic Il1b gene expression remained elevated in chemotherapy-treated mice at least 3 days after the last dose. Exercise intervention did not ameliorate fatigue or inflammation, but hastened recovery from paclitaxel-induced weight loss. Body mass recovery was associated with the wheel running-induced recovery of body composition, paclitaxel-induced alterations to hypothalamic melanocortin signaling, and associated peripheral circulating hormones (ghrelin and leptin). The present findings demonstrate the benefits of exercise on faster recovery from paclitaxel-induced body mass loss and deficits in melanocortin signaling and suggests the development of therapies targeting the melanocortin pathway to reduce paclitaxel-induced weight loss.

The forgotten effects of thyrotropin-releasing hormone: Metabolic functions and medical applications

Thyrotropin-releasing hormone (TRH) causes a variety of thyroidal and non-thyroidal effects, the best known being the feedback regulation of thyroid hormone levels. This was employed in the TRH stimulation test, which is currently little used. The role of TRH as a cancer biomarker is minor, but exaggerated responses to TSH and prolactin levels in breast cancer led to the hypothesis of a potential role for TRH in the pathogenesis of this disease. TRH is a rapidly degraded peptide with multiple targets, limiting its suitability as a biomarker and drug candidate. Although some studies reported efficacy in neural diseases (depression, spinal cord injury, amyotrophic lateral sclerosis, etc.), therapeutic use of TRH is presently restricted to spinocerebellar degenerative disease. Regulation of TRH production in the hypothalamus, patterns of expression of TRH and its receptor in the body, its role in energy metabolism and in prolactin secretion are addressed in this review.

Evaluation of the effects of chemotherapy-induced fatigue and pharmacological interventions in multiple mouse behavioral assays

Fatigue is a common symptom in many diseases and disorders and can reduce quality of life, yet lacks an adequate pharmacological intervention. To identify and develop such interventions, and to better understand fatigue, additional preclinical research is necessary. However, despite numerous mouse behavioral assays reportedly detecting fatigue-like behavior, the assumption that fatigue-like behavior is detected in many assays has not been validated through a cross-assay study. Thus, we modeled fatigue in mice by administering 5-fluorouracil, a chemotherapy drug known to cause fatigue in humans and fatigue-like behavior in mice, then evaluated its effects via voluntary wheel running activity (VWRA), locomotor activity in the open field test (OFT), immobility in the forced swim test (FST), and distance run in the treadmill fatigue test (TFT) and treadmill exercise capacity test. Additionally, taltirelin or methylphenidate was administered to alleviate fatigue-like behavior. As a result of 5-fluorouracil treatment, VWRA and the TFT were markedly reduced, indicating fatigue. The OFT, FST, and treadmill exercise capacity test, however, failed to detect fatigue-like behavior. Interestingly, both taltirelin and methylphenidate alleviated fatigue-like behavior in TFT. These data suggest that, of the current assays, only the TFT and VWRA should be expected to detect fatigue-like behavior. Moreover, this study provides additional evidence that taltirelin may provide a novel treatment for chemotherapy-induced fatigue and warrants further evaluation as an anti-fatigue therapeutic.

Comparing passive measures of fatigue-like behavior in mice

Fatigue is a very common and costly symptom associated with various diseases and disorders. Nonetheless, understanding the pathobiology and developing of therapies for fatigue have been difficult, partly because of a lack of consensus on the measures to phenotype this behavior, both in clinical settings and in animal studies. Here, we describe a fatigue-like behavior induced in mice by abdominal irradiation and compare three different methods of measuring changes in physical activity over time: running wheels, video home cage monitoring, and telemetry. These methods collect data passively and continuously, requiring no disruption of animals’ normal home cage behavior. In our experiments, all three methods reported a fatigue-like behavior, exhibited by a reduction in physical activity following abdominal irradiation. Video tracking showed the largest fatigue effect size (Cohen’s D = 1.78) over four days of monitoring, and was the only method showing a significant decrease in activity during the light period. Telemetry and running wheels showed a similar effect size (D = 1.68 and 1.65, respectively), but running wheels showed different circadian patterns of physical activity. In addition, we conducted rotarod and inverted grid suspension tests, which suggested that fatigue-like behavior was not the result of gross motor abnormalities.