Cytokine-Mediated or Direct Effects of Thymulin on the Nervous System as Assessed by Pain-Related Behavior

Abstract

Thymulin is a thymic hormone with known immunomodulatory activities. Recent evidence has indicated a signaling role for this peptide in the interaction between the immune, endocrine and the nervous system. In this report, we review recent experimental findings on the analgesic actions of thymulin (high doses) in rats with endotoxin-induced localized inflammation and the hyperalgesic actions (low doses) of this peptide in intact animals. These actions involve both proinflammatory cytokines and PGE₂. The possibility of a dual role played by thymulin as a hormone that might also involve a direct effect on the nervous system is discussed.

Plasma thymulin and nerve growth factor levels in patients with primary open angle glaucoma and elevated intraocular pressure

“…Recently published animal experiments [4] support the immunomodulatory and anti-inflammatory properties of this hormone. Also of interest is that thymulin, depending on its dose, can play a dual role as a hormone [3]. The fact that the plasma level of thymulin was significantly elevated in a group of POAG patients supports an immune and/or inflammatory component in the pathogenesis of this disease, and may have implications for future therapeutic modalities.…”

Plasticity of neuroendocrine and immune systems in early development

“…Additionally, thymulin and its analogues modulate the sensory functions of the peripheral nervous system. At high concentrations, they cause an analgesic effect, whereas at low concen trations they induce hyperalgesia mediated by proin flammatory cytokines, nerve growth factor, and pros taglandin E2 (Safieh Garabedian et al, 1999).…”

Thymulin: An Emerging Anti-Inflammatory Molecule

“…Thymic peptides, a heterogeneous family of polypeptidic hormones synthesized within the thymus, not only exert important regulatory effects, within both the immune and neuroendocrine systems, but are also themselves subject to control by hormones derived from the hypothalamic-pituitaryadrenal axis (HPA) and other endocrine glands [14,57,64,72,74]. Thymulin, a nonapeptide member of this family originally known as serum thymic factor (FTS) [11,50], is a critical modulator of immunity and a mediator of neuro-endocrine interactions [24,64], in addition to regulating immune-related diseases and inflammation [25].…”

“…Thymulin, a nonapeptide member of this family originally known as serum thymic factor (FTS) [11,50], is a critical modulator of immunity and a mediator of neuro-endocrine interactions [24,64], in addition to regulating immune-related diseases and inflammation [25].…”

“…This effect is often associated with the exhibition of anti-inflammatory properties [64]. For example, in a model of peripheral localized inflammation, induced by intraplantar endotoxin (lipopolysaccharide; LPS), thymulin reduced inflammatory pain, as measured with mechanical and thermal hyperalgesia [59,64]. A recently synthesized peptide analogue of thymulin (PAT) was also reported to have antihyperalgesic and anti-inflammatory effects [69].…”