Immunology of Aging: the Birth of Inflammaging.

The inflammaging concept was introduced in 2000 by Prof. Franceschi. This was an evolutionary or rather a revolutionary conceptualization of the immune changes in response to a lifelong stress. This conceptualization permitted to consider the lifelong proinflammatory process as an adaptation which could eventually lead to either beneficial or detrimental consequences. This dichotomy is influenced by both the genetics and the environment. Depending on which way prevails in an individual, the outcome may be healthy longevity or pathological aging burdened with aging-related diseases. The concept of inflammaging has also revealed the complex, systemic nature of aging. Thus, this conceptualization opens the way to consider age-related processes in their complexity, meaning that not only the process but also all counter-processes should be considered. It has also opened the way to add new concepts to the original one, leading to better understanding of the nature of inflammaging and of aging itself. Finally, it showed the way towards potential multimodal interventions involving a holistic approach to optimize the aging process towards a healthy longevity.

Immunosenescence is both functional/adaptive and dysfunctional/maladaptive.

Alterations in the immune system with aging are considered to underlie many age-related diseases. However, many elderly individuals remain healthy until even a very advanced age. There is also an increase in numbers of centenarians and their apparent fitness. We should therefore change our unilaterally detrimental consideration of age-related immune changes. Recent data taking into consideration the immunobiography concept may allow for meaningful distinctions among various aging trajectories. This implies that the aging immune system has a homeodynamic characteristic balanced between adaptive and maladaptive aspects. The survival and health of an individual depends from the equilibrium of this balance. In this article, we highlight which parts of the aging of the immune system may be considered adaptive in contrast to those that may be maladaptive.

Induction of immunological tolerance by oral, but not intravenous and intraportal, administration of ovalbumin and the difference between young and old mice.

BACKGROUND: Induction of immunological tolerance is dependent on the route of antigenic administration, the dose of an antigen and the age of animals. OBJECTIVES: We investigated the effect of age on the tolerance induction in mice by administration of antigen through different routes and at different doses. DESIGN: Young and old BDF1 mice were orally, intraportally or intravenously administrated with a low or a high dose of ovalbumin (OVA). Then, delayed-type hypersensitivity (DTH) responses and serum anti-OVA antibody levels were assessed after systemic immunization of OVA with alum after appropriate intervals. RESULTS: In the young mice, oral administration of OVA suppressed DTH response and anti-OVA IgG1, IgG2b, IgM and IgE level in a dose-dependent manner. In the old mice, however, the suppression of IgG1 and IgE levels was induced by oral administration of a low dose of OVA, but no suppression by a high dose. On the other hand, intraportal or intravenous injection of OVA did not suppress DTH response and enhanced anti-OVA antibody levels in a dose-dependent manner in both young and old mice. Production of anti-OVA IgG2a antibody after systemic injection of OVA was detected in the mice, which had been treated with intraportal or intravenous injection of OVA, but not detected in the mice, which had been treated with oral administration of OVA. On the contrary, suppression of anti-OVA IgE antibody was observed only in the mice, which had been treated with oral administration of OVA. CONCLUSION: The oral administration of OVA, neither intravenous nor intraportal, induced immunological tolerance to OVA. An adequate dose of OVA for the tolerance induction and the suppression of antibody production are different between young and old mice. The suppression of IgE antibody was observed only by oral administration of OVA, much obviously in young mice than in the old. The results also indicated that the antigen processing in the liver did not play a major role in the induction of oral tolerance to OVA.

Age-related decline of brain monoamines in mice is reversed to young level by Japanese herbal medicine.

Young (3-month-old) and aged mice (18-month-old) were fed a diet containing Japanese herbal medicine (TJ-41 or TJ-48) for 5 months, and the effect of the herbal medicines were examined in terms of levels of monoamines and their metabolites in the brain of young and aged mice. In the aged mice, the levels of norepinepherine, serotonin and their metabolites in the brain were decreased in the cortex, hippocampus and hypothalamus. Feeding of diet containing TJ-48, but not TJ-41, enhanced the levels of some monoamines and their metabolites in the brains of aged mice, comparable to those of young mice. The results indicated that the improvement of levels of monoamines by Japanese herbal medicine was observed only in the aged mice, not in the young mice. The data have suggested the importance of the aged animals to see the effect of medicine on the functions of organs or systems.

Associations of menstrual pain with intakes of soy, fat and dietary fiber in Japanese women.

OBJECTIVE: Intakes of soy, fat, and dietary fiber may be associated with the symptoms of dysmenorrhea through their biological effects on estrogens or prostaglandin production. The present study was to examine the relationships between intakes of soy, fat, and dietary fiber and the severity of menstrual pain. DESIGN: Cross-sectional study. SETTING: Three colleges and two nursing schools. SUBJECTS: A total of 276 Japanese women aged 19-24 y. METHODS: Intakes of nutrients and foods including soy products, isoflavones, fats and dietary fiber were estimated by a validated semiquantitative food frequency questionnaire. Severity of menstrual pain was assessed by the multidimensional scoring system reported by Andersch and Milson. RESULTS: Intake of dietary fiber was significantly inversely correlated with the menstrual pain scale (r=-0.12, P=0.04) after controlling for age, smoking status, age at menarche and total energy intake. Neither soy nor fat intake was significantly correlated with menstrual pain after controlling for the covariates. CONCLUSIONS: The cross-sectional difference in dietary fiber intake across the level of menstrual pain was small in magnitude but warrants further studies.

Expression of IAP family proteins in colon cancers from patients with different age groups.

Members of the inhibitor of apoptosis protein (IAP) family including survivin, are expressed in many tumors. However, age-related changes in their expression in cancer have not been clarified. Thus, we investigated the expression of mRNA-coding for IAP family proteins in colon cancer samples from young (<70 years of age) and elderly (>70 years) patients by real-time quantitative RT-PCR. Samples were collected from cases with well-differentiated adenocarcinoma or moderately differentiated adenocarcinoma and their adjacent normal epithelial tissue. Well-differentiated adenocarcinoma tended to express higher levels of survivin than normal mucosa, and expression in moderately differentiated adenocarcinoma was significantly greater than in normal mucosa in samples from both groups of patients ( p<0.05, respectively). When samples were compared between the different age groups, the normal mucosa exhibited similar levels of survivin expression. However, samples from older patients showed a significantly higher level of expression than those from younger patients in well and moderately differentiated adenocarcinomas ( p<0.05, respectively). In contrast, the levels of expression of cIAP1, cIAP2, and NAIP in the cancerous tissues were lower than those found in normal mucosa regardless of age. As for age-related changes, the expression of cIAP2 in normal mucosa and moderately differentiated adenocarcinoma was stronger in the elderly group than the young group ( p<0.05, respectively), and NAIP expression in well-differentiated adenocarcinoma was higher in the young group than the elderly group ( p<0.05). XIAP expression was similar in normal and cancerous tissues in both the young and elderly groups. These results suggest that the expression of IAP family proteins, especially survivin, is associated with the age-related biological characteristics of colon cancer.

Essential microenvironment for thymopoiesis is preserved in human adult and aged thymus.

Normal human thymuses at various ages were immunohistologically examined in order to determine whether adult or aged thymus maintained the microenvironment for the T cell development and thymopoiesis was really ongoing. To analyze the thymic microenvironment, two monoclonal antibodies (MoAb) were employed. One is MoAb to IL-1 receptor (IL-1R) recognizing medullary and subcapsular cortical epithelial cells of normal infant human thymus. The other is UH-1 MoAb recognizing thymic epithelial cells within the cortex, which are negative with IL-1R-MoAb. Thymus of subjects over 20 years of age was split into many fragments and dispersed in the fatty tissue. However, the microenvironment of each fragment was composed of both IL-1R positive and UH-1 positive epithelial cells, and the UH-1 positive portion was populated with lymphocytes showing a follicle-like appearance. Lymphocytes in these follicle-like portions were mostly CD4+CD8+ double positive cells and contained many proliferating cells as well as apoptotic cells. Thus these follicle-like portions in adult and aged thymus were considered to be functioning as cortex as in infant thymus. Proliferative activity of thymocytes in the thymic cortex and the follicle-like portions definitely declined with advance of age, while incidence of apoptotic thymocytes increased with aging.

In vivo distribution of receptor for ecotropic murine leukemia virus and binding of envelope protein of Friend Murine leukemia virus.

Ecotropic infection by Murine leukemia virus (MuLV) infection is initiated by the interaction between the receptor-binding domain of the viral surface glycoprotein (SU) and the cell-surface receptor, mCAT-1. To study the in vivo localization of viral binding site in mice, green fluorescence protein (GFP)-tagged Friend SU (F-SU/GFP) was incubated with tissue sections. Lymphohematopoietic organs and a part of the glandular tissues of C3H as well as C57BL/6 mice revealed positive signals for F-SU/GFP binding on the cell surface. In contrast, C4W mice, which is a partial congenic mouse strain carrying the Fv-4 (r) gene on a BALB/c genetic background, exhibited negative signals in most of the organs except for a very weak binding in the pancreas. The expression of mCAT-1 mRNA determined by reverse transcriptase (RT)-polymerase chain reaction (PCR) revealed a similar distribution in C3H, C57BL/6 and C4W mice. Most of the organs including lymphohematopoietic organs and glandular organs revealed significant expression of mRNA for mCAT-1 gene, while the liver, heart and muscle did not. The results from binding assay were consistent with the fact that Friend MuLV-induced pathogenesis was usually associated with lymphohematopoietic systems, although mRNA expression for mCAT-1 was rather ubiquitous. The discrepancy between F-SU/GFP binding and mRNA expression for mCAT-1 in lymphohematopoietic organs of C4W mice would support the receptor interference effect by the Fv-4 (r) gene causing the resistance of C4W mouse to Friend MuLV infection.

Animal models and possible human application of immunological restoration in the elderly.

Autopsy reports by pathologists in geriatric hospitals reveal that the leading direct cause of death in the elderly over 65 years of age are infectious diseases such as pneumonia and urinary tract infection, neither cancer nor vascular diseases in the brain and heart. This indicates that severe impairment of immune functions is developing in the elderly people. The impairment of immune functions does not occur abruptly in the elderly people. The immune function starts to decline as early as at the 2nd decades, showing approximately 50 and 90% decline at the 5th and 8th decades, respectively. Thus, immunological restoration is acutely needed for the improvement of their general health condition of the elderly. This report communicates several methods of immunological restoration using animal models and suggests possibilities of human application. Methods presented are: (1) a low dose of cyclophosphamide; (2) vitamin E; (3) Japanese herbal medicines; (4) caloric restriction and exercise; (5) vaccine; (6) oral administration of antigens; (7) grafting of cells and tissues, including a future program. Discussion will be made on the possibilities of these methods for human application.

Anti-Ki antibodies recognize an epitope homologous with SV40 nuclear localization signal: clinical significance and reactivities in various immunoassays.

Abstract We studied the characteristics of anti-Ki antibodies that react with a synthetic peptide (KILT) which has homology with SV40 large T antigen nuclear localization signal (SV40 T NLS). Immunoreactivity of antibodies to KILT was tested by enzyme-linked immunosorbent assay (ELISA), and this reactivity was compared with results obtained by immunoblotting using purified Ki and ELISA using purified or recombinant Ki antigen. The clinical significance of anti-KILT antibodies in lupus patients was also studied. Twenty percent of anti-Ki sera reacted with KILT, and all sera that reacted with KILT recognized both purified and recombinant Ki antigen in all our assay systems. A significant correlation was observed between reactivities in ELISA using KILT and with these using purified and recombinant Ki. Some sera with low titers by double immunodiffusion (DID) reacted with KILT, whereas high-titer anti-Ki sera showed a tendency to react with Ki antigen in different assays. The prevalence of discoid rash and sicca complex was higher in the anti-KILT-positive group. The amino acid sequence homologous to SV40 T NLS is an immunologically active epitope on the Ki antigen; reactivity to this epitope is associated with characteristic clinical features allied with anti-Ki antibodies in lupus patients.

Cyclosporin A therapy for interstitial pneumonitis associated with rheumatic disease.

Abstract To determine the efficacy of cyclosporin A (CysA) for the treatment of steroid-resistant interstitial pneumonitis (IP), we enrolled 25 patients with various rheumatic diseases and steroid-resistant IP in a pilot study [4 patients with rheumatoid arthritis (RA), 2 with systemic lupus erythematosus (SLE), 11 with polymyositis/dermatomyositis (PM/DM), 4 with systemic sclerosis (SSc), 1 with mixed connective tissue disease (MCTD), 3 with Sjögren syndrome (SS)]. Twelve patients (48%) showed a persistent response to CysA therapy, and 7 of them had PM/DM, including so-called amyopathic DM. Patients with a persistent response had moderately elevated lactate dehydroxygenase (LDH) levels, whereas patients who died had much higher LDH levels and hypoxia. Even patients with low blood levels of CysA achieved a persistent response. In responding patients, the symptoms, chest X-ray findings, arterial oxygen tension, and LDH level all improved after less than 4 weeks. In conclusion, CysA seem to be useful for treating patients with steroid-resistant IP, whose duration is short and severity is mild.

Effect of maternal age on incidences of apoptotic and proliferative cells in trophoblasts of full-term human placenta.

Advanced maternal age is known to be a risk factor for various kinds of obstetric complications, including placental dysfunction. As a first step towards determining the maternal age-related changes in placental, as well as trophoblastic function, we examined the incidences of apoptotic and proliferative cells in trophoblasts of placentae from women of various ages using the TUNEL method and immunohistochemistry for Ki-67 antigen. Tissue sections were collected from the placentae of healthy mothers with normal delivery of healthy babies so that the placental cell kinetics maintaining normal pregnancy and delivery could be studied. The TUNEL-positive cells of the placenta were syncytiotrophoblasts with clustering of nuclei and the TUNEL-positive index of these cells varied from 0.28-1.2%. This index revealed a significant inverse correlation with maternal age. In contrast, the Ki-67-positive index of mononuclear trophoblasts of the placenta ranged between 1.2-2.8% and showed a positive correlation with maternal age. Many of the apoptotic cells of placental villi expressed the pro-apoptotic Bak protein, but were negative for expression of the anti-apoptotic Bcl-2 protein. These results suggest that trophoblasts have higher proliferative activity in older mothers, with a normal process of pregnancy and delivery. The Bcl-2 family proteins could be important for the regulation of trophoblastic apoptosis, although the cellular and molecular mechanisms mediating maternal age-related changes of the placenta remain to be determined.

Mouse homologue of coq7/clk-1, longevity gene in Caenorhabditis elegans, is essential for coenzyme Q synthesis, maintenance of mitochondrial integrity, and neurogenesis.

coq7/clk-1 was isolated from a long-lived mutant of Caenorhabditis elegans, which showed sluggish behavior and an extended life span. Mouse coq7 is homologous to Saccharomyces cerevisiae coq7/cat5 that is required for biosynthesis of coenzyme Q (CoQ), an essential cofactor in mitochondrial respiration. Here we generated COQ7-deficient mice to investigate the biological role of COQ7 in mammals. COQ7-deficient mouse embryos failed to survive beyond embryonic day 10.5, exhibiting small-sized body and delayed embryogenesis. Morphological studies showed that COQ7-deficient neuroepithelial cells failed to show the radial arrangement in the developing cerebral wall, aborting neurogenesis at E10.5. Electron microscopic analysis further showed the enlarged mitochondria with vesicular cristae and enlarged lysosomes filled with disrupted membranes, which is consistent with mitochondriopathy. Biochemical analysis demonstrated that COQ7-deficient embryos failed to synthesize CoQ(9), but instead yielded demethoxyubiquinone 9 (DMQ(9)). Cultured embryonic cells from COQ7-deficient mice were rescued by adding bovine fetal serum in vitro, but exhibited slowed cell proliferation, which resembled to the phenotype of clk-1 with delayed cell divisions. The result implied the essential role of coq7 in CoQ synthesis, maintenance of mitochondrial integrity, and neurogenesis in mice.

Age-related hypermethylation of the hMLH1 promoter in gastric cancers.

To determine whether methylation of the hMLH1 promoter is related to increasing age and gastric carcinogenesis, we examined hMLH1 methylation and expression in 100 gastric cancers. hMLH1 methylation and aberrant protein expression were observed in 9 and 13 cancers, respectively. Normal and intestinal metaplastic tissues adjacent to cancers with hypermethylation did not exhibit any hMLH1 methylation, indicating that it may be specific to gastric cancers. The frequency of hMLH1 methylation significantly increased with age. These results suggest that hMLH1 methylation plays an important role in gastric carcinogenesis in old people.

A gene therapy model for retrovirus-induced disease with a viral env gene: expression-dependent resistance in immunosuppressed hosts.

At the initial stage of retroviral infection, virion envelope glycoprotein (env product) binds to cell surface receptors. Cells infected with retrovirus or into which the env gene was introduced, become resistant to superinfection by other retroviruses with the same receptor specificity, a phenomenon known as receptor interference. We have demonstrated previously that the introduction of an env gene from a truncated endogenous ecotropic murine leukemia virus (MuLV), the Fv-4 resistance (Fv-4r) gene, into the bone marrow hematopoietic cells of Fv-4 sensitive (Fv-4s) mice protected mice from ecotropic retrovirus-induced disease. Using the gene transfer system under the control of the retroviral vector and bone marrow transplantation (BMT), here we could show that the expression of an introduced Fv-4r gene in hematopoietic cells continued for more than 1 year after BMT. To determine the inhibitory mechanism of Fv-4r env gene expression against FLV-infection in this model system, peripheral blood mononuclear cells (PBMCs), or spleen cells from chimeras with various degrees of env-expression, were mixed with green fluorescence protein (GFP)-conjugated Friend MuLV envglycoprotein (GFP-Fr-ENV). The amount of GFP-Fr-ENV bound to these cells inversely correlated with the expression intensity of the transduced env gene indicating the receptor interference effect. Next, to see whether transduction of the Fv-4r gene would protect an immunosuppressed host from FLV-induced leukemogenesis, we generated immunocompromised chimeras by transplanting env-transduced bone marrow cells into a thymectomized host. These chimeras also resisted FLV-induced leukemogenesis, indicating that receptor interference-based gene therapy could become a therapeutic basis for immunodeficiency virus-induced diseases in vivo.

Immunohistological analysis of thymoma by molecules differentially expressed in the thymic cortex and medulla, and its application in the differential diagnosis of thymoma from esophageal and lung cancer.

The purpose of this study was to verify the WHO classification of thymic tumors using immunohistological methods, and to discover whether these methods can be applied to differentiate thymoma from squamous cell carcinoma (SCC) of the esophagus and the lung. Twenty-nine thymoma cases were classified according to WHO and were then immunohistologically examined for the positivity of these molecules. All thymoma cases investigated in this study were positive for IL-1R, and most of them were also positive for bek. In contrast, UH-1 was highly positive in B1 and B2 type thymomas, but negative or weakly positive in A, AB and B3 type thymomas. Twelve esophageal cancers and 21 lung cancers were also examined for the positivity of the same molecules. All esophageal cancers were negative for UH-1. Three of 12 cases were weakly positive for IL-1R, and four of these 12 cases were also weakly positive for bek. Twelve of 21 lung cancer cases were adenocarcinomas, all of them negative for IL-1R, bek and UH-1. Nine of 21 lung cancer cases were SCCs, all of them negative for UH-1. Eight of nine SCC cases were strongly positive for IL-1R, while seven of these were weakly positive for bek. We conclude that the WHO classification of thymic tumors is still valid as demonstrated by immunohistological analysis and that the positivity of UH-1, IL- 1R and bek might be helpful in differentiating thymoma from SCC of the esophagus and the lung.

Altered T cell signalling in ageing.

T cell responses are altered in the aged in a manner usually interpreted as detrimental to host defences against infectious agents and possibly also against cancer. T cell dysregulation may be caused by any or a combination of stem cell deficits, compromised T cell differentiation, inefficient antigen processing and presentation by antigen presenting cells, suboptimal processing of the antigenic signal by T cells or inability of the T cell to respond appropriately thereafter. This review will focus on altered T cell signalling in ageing, encompassing not only alterations in signal transduction by the antigen-specific T cell receptor, but changes in the balance of positive and negative T cell costimulation and the resultant modified cytokine environment, the response to which is itself altered in ageing.