Effects of repeated administrations of facteur thymique sérique (FTS) on biochemical changes related to aging in senescence-accelerated mouse (SAM)

The Relationship between Annual Airborne Pollen Levels and Occurrence of All Cancers, and Lung, Stomach, Colorectal, Pancreatic and Breast Cancers: A Retrospective Study from the National Registry Database of Cancer Incidence in Japan, 1975-2015

Suppression of risk factors including smoking, overdrinking and infections by human papilloma and hepatitis B and C viruses has been recommended for cancer prevention; however, identification of other environmental risk factors has not been enough. Besides the 2003 report that Kawasaki disease may be triggered by pollen exposure, 40 Japanese specific intractable diseases have recently been reported as "pollen diseases," also potentially triggered by pollen exposure．Various human organs are affected by pollen exposure, leading to systemic vasculitis; autoimmune connective tissue diseases, inflammatory bowel diseases and intractable neuromuscular and bone diseases, suggesting the common effects of pollen exposure on fundamental functions of vital metabolism. In this context, cancer and malignant tumors may be another group of intractable diseases triggered by epigenetic pollen exposure. Thus, this study compared the number of newly registered patients with 24 types of cancer and airborne pollen levels measured from 1975 to 2015. We searched for statistical correlations with Bonferroni correction between the annual number of newly registered patients for all cancers or for each of lung, stomach, colorectal, pancreatic and breast cancers in the patient-registry year "x", and annual airborne pollen levels measured in the same year as "x", or 1-7 years prior to the year "x". The number of newly registered patients for lung, and pancreatic cancers in the patient-registry year "x" was highly correlated with airborne pollen levels measured 2 years prior to "x". That for breast cancer was correlated with pollen levels measured 2 and 5 years prior to "x". To our knowledge, this is the first rapid communication of the association between pollen levels and cancer incidence.

Protective Effect of Serum Thymic Factor, FTS, on Cephaloridine-Induced Nephrotoxicity in Rats

Serum thymic factor (FTS), a thymic peptide hormone, has been reported to increase superoxide disumutase (SOD) levels in senescence-accelerated mice. In the present study, we examined the effect of FTS on cephaloridine (CER)-induced nephrotoxicity in vivo and in vitro. We previously reported that CER led to extracellular signal-regulated protein kinase (ERK) activation in the rat kidney. So, we also investigated whether FTS has an effect on ERK activation induced by CER. Treatment of male Sprague-Dawley rats with intravenous CER (1.2 g/kg) for 24 h markedly increased BUN and plasma creatinine levels and urinary excretion of glucose and protein, decreased creatinine clearance and also led to marked pathological changes in the proximal tubules, as revealed by electron micrographs. An increase in phosphorylated ERK (pERK) was detected in the nuclear fraction prepared from the rat kidney cortex 24 h after CER injection. Pretreatment of rats with FTS (50 microg/kg, i.v.) attenuated the CER-induced renal dysfunction and pathological damage. FTS also suppressed CER-induced ERK activation in the kidney. In vitro treatment of the established cell line, LLC-PK1 cells, with FTS significantly ameliorated CER-induced cell injury, as measured by lactate dehydrogenase (LDH) leakage. Our results, taken together with our previous report that MEK inhibitors ameliorated CER-induced renal cell injury and ERK activation induced by CER, suggest that FTS participates in protection from CER-induced nephrotoxicity by suppressing ERK activation induced by CER.

Individuals exhibiting conspicuous nevi (lentigo simplex) are resistant to allergic rhinitis/conjunctivitis (pollinosis), but those who do not show increased susceptibility to pollinosis

We investigated 115 individuals in Tokyo from two groups of persons with conspicuous nevi on the head, neck, and arms, etc. (nevus-positive group) and persons who do not exhibit such nevi (nevi-negative group) interviewing them to determine whether they suffered from allergic rhinitis/conjunctivitis (pollinosis) and examining them for the presence and extent of nevi. There was a distinct correlation: only 5 persons among 85 individuals of the nevus-positive group suffered from pollinosis, and all 30 people in the nevus-negative group had pollinosis. Thus, individuals exhibiting conspicuous nevi are resistant to pollinosis, but those who do not show increased susceptibility to pollinosis.

[Immunological aging]

Immune responses decline with age, as assessed by the increasing role of infections in elderly subjects. This decline is, however, very progressive, and usually only clear-cut after 80 years of age. Major difficulties have been encountered to delineate the cellular basis of this immunodeficiency, which is subtle and inconsistent, at the origin of contradictory reports. This is, however, an important challenge in view of the possible therapeutic perspectives of immunotherapy of aged subjects.

FTS reduces bleomycin-induced cytokine and chemokine production and inhibits pulmonary fibrosis in mice

Bleomycin (BLM), an antitumour drug, is known to cause interstitial pneumonia followed by pulmonary fibrosis, and has often been used to produce an animal model of pulmonary fibrosis. In the present study, we examined the effect of a nonapeptide thymic hormone, facteur thymique serique (FTS), on the murine lung fibrosis induced by intratracheal instillation of BLM. Treatment with FTS ameliorated BLM-induced fibrotic changes in a dose-dependent manner, as indicated by the reduced accumulation of hydroxyproline (HP). In addition, FTS suppressed BLM-induced cellular inflammatory response in the lungs, as evidenced by inhibition of increased lung weight, reduced accumulation of inflammatory leucocytes, including lymphocytes and neutrophils, but not macrophages, and less pronounced histopathological changes. Finally, BLM challenge increased the local synthesis of proinflammatory cytokines, TNF-alpha and IL-1beta and chemokines, MCP-1, MIP-1alpha RANTES, MIP-2 and KC, while administration of FTS suppressed the production of these cytokines, except for MCP-1. These effects of FTS were observed only when mice received intratracheal instillation with BLM. Considered collectively, our results indicated that FTS treatment ameliorated the cellular inflammatory responses and fibrotic changes in the lungs caused by BLM and such inhibition was well correlated with reduced synthesis of several fibrosis-related cytokines, and suggested that FTS may be potentially useful for the treatment of pulmonary fibrosis.

Age-related defects in lifespan and learning ability in SAMP8 mice

Pertinent animal models of age-related learning deficiencies are required to elucidate the mechanism of age-related learning deficiencies and to develop novel therapeutic drugs for age-related diseases such as learning defects. Among many strains of accelerated senescence prone, senescence-accelerated mouse (SAM), SAMP8 mice have age-related defects in learning and cognitive abilities. We review recent findings on alterations in SAMP8 brain in neurochemical parameters related to neurotransmission and synaptic plasticity compared to those in SAMR1 brain as the control. In addition, we report the preventive effects of drugs on learning deficiencies in SAMP8 and discuss the usefulness of SAMP8 as an animal model of age-related learning deficiencies.

Senescence-accelerated mouse (SAM): a biogerontological resource in aging research

The senescence-accelerated mouse (SAM), consisting of 14 senescence-prone inbred strains (SAMP) and 4 senescence-resistant inbred strains (SAMR) has been under development since 1970 through the selective inbreeding of AKR/J strain mice donated by the Jackson laboratory in 1968, based on the data of the grading score of senescence, life span, and pathologic phenotypes. The characteristic feature of aging common to all SAMP and SAMR mice is accelerated senescence and normal aging, respectively. Furthermore, SAMP and SAMR strains manifest various pathobiological phenotypes which include such neurobiological phenotypes as deficits in learning and memory, emotional disorders, abnormal circadian rhythms, brain atrophy, hearing impairment, etc., and are often characteristic enough to differentiate the strains. Various efforts are currently being made using the SAM model to clarify the underlying mechanisms in accelerated senescence as well as the etiopathogenic mechanisms in age-associated pathobiologies. Genetic background and significance of SAM development are discussed.

Senescence-accelerated mouse (SAM) as an animal model of senile dementia: pharmacological, neurochemical and molecular biological approach

To elucidate the fundamental mechanism of age-related deficiencies of learning and to develop effective drugs for intervention in age-related diseases such as learning dysfunctions, pertinent animal models that have characteristics closely similar to human dysfunctions should be established. SAM (senescence-accelerated mouse) has been established as a murine model of the SAM strains, groups of related inbred strains including nine strains of accelerated senescence-prone, short-lived mice (SAMP) and three strains of accelerated senescence-resistant, long-lived mice (SAMR). SAMP-strain mice show relatively strain-specific age-associated phenotypic pathologies such as shortened life span and early manifestation of senescence. Among the SAMP-strain mice, SAMP8 mice show an age-related deterioration in learning ability. Here, the neuropathological, neurochemical and pharmacological features of SAM are reported, especially for SAMP8. Moreover, the effects of several drugs on the biochemical and behavioral alterations in SAMP8 and the etiologic manifestation of accelerated senescence are also discussed.

Learning disorders in thymectomized mice: a new screening model for cognitive enhancer

Although the close relationship between the thymus and neuroendocrine system during the aging process has been well documented, influence of the thymus on the cognitive function of the central nervous system remains unknown. Male ddY mice were thymectomized 3-4 weeks after birth. Learning behavior, tested in a step-down test and in a spatial memory task, was significantly impaired in thymectomized mice at 10 months, but not before 5 months, after thymectomy. Reduced immune response was also not obvious before 10 months. These results suggested that thymectomy in young adult life in mice not only impaired the immune response, but also deteriorated the learning and memory ability, and that learning disorders in thymectomized mice could be utilized as a new screening model for cognitive enhancer.

Thymectomy-induced deterioration of learning and memory in mice

Male ddY mice were thymectomized 4 weeks after birth. Learning behaviors, tested in passive and active avoidance performances and in a spatial memory task, were significantly impaired in thymectomized mice at 10 months after thymectomy, in addition to the reduced immune response. Contents of hypothalamic norepinephrine and hypothalamic choline acetyltransferase activity were significantly increased in thymectomized mice. These results suggested that thymectomy at young adult life in mice not only impaired the immune response, but also deteriorated the learning and memory ability.

Prevention of diabetes by thymic hormone in alloxan-treated rats

We investigated the effects of facteur thymique sérique (FTS), a thymic peptide hormone, on alloxan- and streptozotocin-induced diabetes in rats. Pretreatment with intravenous injection of FTS significantly suppressed both alloxan- and streptozotocin-induced hyperglycemia. The effects of FTS were time dependent. FTS suppressed hyperglycemia in a dose range of 1-6600 micrograms/kg. Alloxan-induced hyperglycemia was completely prevented when FTS was injected in doses of 40-50 micrograms/kg 1 min before injection of alloxan. Histological examination of islet areas showed that alloxan-induced destruction of beta-cells was inhibited by FTS. FTS had no significant effects on lymphocyte subsets and immunity-related cells or on plasma superoxide dismutase activity and total glutathione level. The blood half-life time of exogenously injected FTS was short (2-3 min), indicating acute internalization of FTS into pancreatic beta-cells. Our results suggested that FTS acutely and directly blocks some initial effect of alloxan, preventing the destruction of beta-cells.