"Neuropeptides in the brain defense against distant organ damage"

Ramelteon and suvorexant for postoperative delirium in elderly patients with esophageal cancer

BACKGROUND

There is no clear evidence on the prevention of postoperative delirium with pharmacotherapy in elderly patients with esophageal cancer. This retrospective study aimed to evaluate the efficacy of ramelteon and suvorexant in preventing postoperative delirium in this patient group.

METHODS

Data on 251 patients who received radical esophagectomy for thoracic esophageal cancer were collected from January 2010 to September 2021. In total, 74 patients did not receive preventive intervention, and 177 received ramelteon and suvorexant. After propensity score matching, the rate of postoperative delirium was compared between the two groups.

RESULTS

Seventy-two well-balanced patients in each group demonstrated similar clinical and pathological characteristics. The mean ages of the intervention and control groups were 70.8 and 70.3 years, respectively. All the patients underwent McKeown esophagectomy, and in the volume of intraoperative blood loss or operative time did not significantly differ between the two groups. The incidence rates of postoperative hyperactive delirium were 7% (5/72) in the intervention group and 32% (23/72) in the control group (p < 0.001). No severe adverse event potentially attributable to the intervention drug was observed. The multivariate analysis showed that the use of ramelteon and suvorexant was the only independent protective factor against postoperative delirium (hazard ratio 0.157, 95% CI 0.055-0.448, p < 0.001).

CONCLUSIONS

Ramelteon and suvorexant may play an important role in reducing postoperative delirium in elderly patients with esophageal cancer.

Orexin receptor antagonists versus antipsychotics for the management of delirium in intensive care unit patients with cardiovascular disease: A retrospective observational study

OBJECTIVE

Although antipsychotics are often used in the pharmacological treatment of delirium, recent reports suggest the efficacy of orexin receptor antagonists. This study investigated whether orexin receptor antagonists could be a possible treatment option for delirium.

METHOD

A nonblinded nonrandomized routine clinical treatment was performed. Patients treated in intensive care units (ICU) for cardiovascular disease and receiving psychiatric intervention were studied retrospectively. The scores from the Intensive Care Delirium Screening Checklist (ICDSC) were compared between patients treated with orexin receptor antagonists and those treated with antipsychotics.

RESULTS

The mean (standard deviation) ICDSC scores were 4.5 (1.8) at day -1 and 2.6 (2.6) at day 7 for orexin receptor antagonist group (n = 25) and 4.6 (2.4) at day -1 and 4.1 (2.2) at day 7 for antipsychotic group (n = 28). The orexin receptor antagonist group showed significantly lower ICDSC scores than the antipsychotic group (p = 0.021).

CONCLUSION

While precise efficacy cannot be determined from our retrospective, observational, and uncontrolled pilot study, this analysis encourages a future double-blind randomized placebo-controlled trial of orexin-antagonists for delirium treatment.

Potentials of Neuropeptides as Therapeutic Agents for Neurological Diseases

Despite recent leaps in modern medicine, progress in the treatment of neurological diseases remains slow. The near impermeable blood-brain barrier (BBB) that prevents the entry of therapeutics into the brain, and the complexity of neurological processes, limits the specificity of potential therapeutics. Moreover, a lack of etiological understanding and the irreversible nature of neurological conditions have resulted in low tolerability and high failure rates towards existing small molecule-based treatments. Neuropeptides, which are small proteinaceous molecules produced by the body, either in the nervous system or the peripheral organs, modulate neurological function. Although peptide-based therapeutics originated from the treatment of metabolic diseases in the 1920s, the adoption and development of peptide drugs for neurological conditions are relatively recent. In this review, we examine the natural roles of neuropeptides in the modulation of neurological function and the development of neurological disorders. Furthermore, we highlight the potential of these proteinaceous molecules in filling gaps in current therapeutics.

Comparative insights into the integration mechanism of neuropeptides to starvation and temperature stress

Stress is known as the process of biological responses evoked by internal or external stimuli. The ability to sense, integrate and respond to stress signals is a requisite for life. Temperature and photoperiod are very important environmental factors for animals. In addition, stress signals can also be inputted from peripheral tissue, such as starvation and inflammation. Through afferent pathways, stress signals input to the central nervous system (CNS), where various signals will integrate, and the integrated information will transmit to the peripheral effectors. As the regulators of neural activity, neuropeptides play important roles in these processes. The present review summarizes recent findings about the integration mechanism of stress signals in the CNS, emphasizing on the role of neuropeptides.

Cytokine and chemokine levels in the heart tissue of aged rats following severe acute pancreatitis

Severe acute pancreatitis (AP) is a disease associated with high mortality and characterized by overwhelming systemic inflammation. Older people have a prolonged hospital stay and worst prognosis, when affected by this disease. Our group hypothesized, thus, that the systemic inflammatory response in the elderly would promote more organ damage when compared to the young. We sought to investigate the effect of systemic inflammation on the gene expression of cytokines, chemokines, and growth factors in the hearts of older and younger rats in an animal model of AP. AP was induced in all rats by injection of 0.5 mL of 2.5% taurocholate. There were two healthy age-matched control groups. An array of 79 cytokines, chemokines, and growth factors was measured in samples of cardiac tissue taken from the AP rats after 10 h, and from control rats. Older healthy rats had significantly higher levels of interleukin-10 (IL-10) and CCL1 gene expression than younger ones ( P < 0.05), but all other measurements were similar among the study groups. This study indicates the systemic inflammation may show unique features for different organs in the body, but older animals with systemic inflammation are similar to the young regarding the cardiac inflammatory response.

Gut microbiota modulate host immune cells in cancer development and growth

Emerging evidence shows that microbe interactions with the host immune system impact diverse aspects of cancer development and treatment. As a result, exciting new opportunities exist for engineering diets and microbe cocktails to lower cancer risks with fewer adverse clinical effects than traditional strategies. Microbe-based therapies may ultimately be used to reinforce host immune balance and extinguish cancer for generations to come.

Approaches Mediating Oxytocin Regulation of the Immune System

The hypothalamic neuroendocrine system is mainly composed of the neural structures regulating hormone secretion from the pituitary gland and has been considered as the higher regulatory center of the immune system. Recently, the hypothalamo-neurohypophysial system (HNS) emerged as an important component of neuroendocrine–immune network, wherein the oxytocin (OT)-secreting system (OSS) plays an essential role. The OSS, consisting of OT neurons in the supraoptic nucleus, paraventricular nucleus, their several accessory nuclei and associated structures, can integrate neural, endocrine, metabolic, and immune information and plays a pivotal role in the development and functions of the immune system. The OSS can promote the development of thymus and bone marrow, perform immune surveillance, strengthen immune defense, and maintain immune homeostasis. Correspondingly, OT can inhibit inflammation, exert antibiotic-like effect, promote wound healing and regeneration, and suppress stress-associated immune disorders. In this process, the OSS can release OT to act on immune system directly by activating OT receptors or through modulating activities of other hypothalamic–pituitary–immune axes and autonomic nervous system indirectly. However, our understandings of the role of the OSS in neuroendocrine regulation of immune system are largely incomplete, particularly its relationship with other hypothalamic–pituitary–immune axes and the vasopressin-secreting system that coexists with the OSS in the HNS. In addition, it remains unclear about the relationship between the OSS and peripherally produced OT in immune regulation, particularly intrathymic OT that is known to elicit central immunological self-tolerance of T-cells to hypophysial hormones. In this work, we provide a brief review of current knowledge of the features of OSS regulation of the immune system and of potential approaches that mediate OSS coordination of the activities of entire neuroendocrine–immune network.

Microbes and Oxytocin: Benefits for Host Physiology and Behavior

It is now understood that gut bacteria exert effects beyond the local boundaries of the gastrointestinal tract to include distant tissues and overall health. Prototype probiotic bacterium Lactobacillus reuteri has been found to upregulate hormone oxytocin and systemic immune responses to achieve a wide array of health benefits involving wound healing, mental health, metabolism, and myoskeletal maintenance. Together these display that the gut microbiome and host animal interact via immune-endocrine-brain signaling networks. Such findings provide novel therapeutic strategies to stimulate powerful homeostatic pathways and genetic programs, stemming from the coevolution of mammals and their microbiome.