Inflammatory diseases of the aorta include routine atherosclerosis, aortitis, periaortitis, and atherosclerosis with excessive inflammatory responses, such as inflammatory atherosclerotic aneurysms. The nomenclature and histologic features of these disorders are reviewed and discussed. In addition, diagnostic criteria are provided to distinguish between these disorders in surgical pathology specimens. An initial classification scheme is provided for aortitis and periaortitis based on the pattern of the inflammatory infiltrate: granulomatous/giant cell pattern, lymphoplasmacytic pattern, mixed inflammatory pattern, and the suppurative pattern. These inflammatory patterns are discussed in relation to specific systemic diseases including giant cell arteritis, Takayasu arteritis, granulomatosis with polyangiitis (Wegener's), rheumatoid arthritis, sarcoidosis, ankylosing spondylitis, Cogan syndrome, Behçet's disease, relapsing polychondritis, syphilitic aortitis, and bacterial and fungal infections.

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The development of the thymus and the hypothalamic-pituitary-gonadal axis are linked by bidirectional hormonally mediated relationships. In the present study, the direct involvement of the neuropeptide LHRH in the maturation of the thymus and development of the cell-mediated and humoral immune responses were assessed after treatment of neonatal (from post-natal day 1-day 5) female rats with a potent LHRH-antagonist (LHRH-anta, p-Glu-D-Phe 2.6,Pro3-LHRH, 50 micrograms/rat), and the effects compared to those resulting from neonatal castration. Whereas in control animals the maturation of mitogenic potential in thymocyte cultures showed a progressive and age-dependent increase, reaching a maximal activity at 30 days of age and then decreasing after puberty onset, in LHRH-anta-treated rats, the thymocyte's proliferative response was completely blocked at 7 days of age and remained very low at each time interval studied, until 3 months of age. A similar effect of the LHRH-anta treatment on splenocyte cultures was measured. Moreover, a reduced percentage of the T-helper lymphocyte subpopulation followed LHRH-anta administration. By contrast, in neonatally castrated rats, blastogenic activity was significantly higher, compared to control cultures, at each stage studied. Treatment with LHRH-anta produced a significant decrease in thymus wt, an alteration of the maturational pattern characterized by a cellular monomorphism, reduced thymocyte volume, reduction of the cortical area, and depauperation of the epithelial microenvironment. Moreover, a morphometric analysis revealed a selective decrease in the large lymphoid cell population of the subcapsular cortex at 7 and 15 days. On the other hand, neonatal castration produced an opposite effect, leading to a marked hypertrophy of the cortical area, and counteracted the post-puberal thymus atrophy. When LHRH-anta-treated adult (3-month-old) rats were challenged with an antigenic stimulus (multiple sc injections of complete Freund adjuvant and BSA) and antibody (anti-BSA antibodies of the immunoglobulin G class) production measured in the serum after 15 days, a marked and significant decrease in immunoglobulin G levels was observed, compared to the values measured in untreated control. The described immune deficiencies in LHRH-anta-treated rats were associated with a clear inhibition of sexual maturation. This study clearly indicates that the blockade of central and peripheral LHRH receptors during a critical period for maturation of both hypothalamus-hypophyseal-gonadal axis and brain-thymus-lymphoid axis dramatically impairs immune system development, suggesting a potential role of the neuropeptide LHRH in the bidirectional programming of both neuroendocrine and immune functions.

The presence of specific LHRH-binding sites within the rat thymus gland and the ability of LHRH and its agonistic and antagonistic analogs to directly modulate thymus function prompted us to study the possible changes in the number of thymic LHRH-binding sites during aging-induced physiological immunosenescence. Moreover, the effects of chronic treatment of aging rats with a potent LHRH agonist (LHRH-A) on thymic LHRH receptors, thymus weight and histology, as well as thymocyte proliferative capacity were assessed. For comparison, the effects of castration on the same parameters was also investigated. The process of aging is accompanied by a sharp reduction in LHRH-A-binding sites within the thymus gland of both female and male rats. Starting at 7 months of age, a 50% decrease in thymic LHRH-A binding was followed, at 11-13 months of age, by a nearly 65% inhibition of receptor numbers. In 16- to 19-month-old rats, LHRH-A binding was almost completely lost. Thymus weight was 30% reduced in 7-month-old animals, while a 50% reduction in thymic size was reached at 11 months of age in males and 13 months in female rats. A further decrease in thymic mass was observed at 16 and 19 months. Chronic (45-day) treatment of aging (15-16 months old) female and male rates with the potent LHRH-A, [D-Trp6,Des-Gly10]LHRH-N-ethylamide, reversed the age-related decreases in both thymus weight and thymic LHRH-binding sites. Similarly, surgical removal of testicular hormones by castration restored thymus weight and increased LHRH-A binding in the thymus of aged rats. While thymus histology in 3-month-old rats was characterized by a clear demarcation of cortical and medullary regions, only thymic remnants were present in 16- to 17-month-old animals. Castration of old rats resulted in a partial restoration of thymic structure, while chronic treatment of aging rats with the LHRH-A produced a homogeneous organization of both cortical and medullary compartments accompanied by a marked increase in the width of the cortical layer, densely packed with lymphocytes. While the process of aging was accompanied by an almost complete loss of the proliferative response of thymocytes to optimal concentrations of the mitogen Concanavalin-A, thymocyte cultures from old rats treated with LHRH-A or from castrated animals, displayed significantly greater proliferative responses. Furthermore, the combination of both manipulations resulted in a further significant increase in thymocyte proliferative capacity.(ABSTRACT TRUNCATED AT 400 WORDS)

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The present study was designed to explore the effects of LHRH and its agonists on immune system function. As a first step, to identify a putative site of action, the very potent and stable LHRH agonist (LHRH-A), [D-Ser(TBU6)] des-Gly10-LHRH ethylamide (buserelin), was used as an iodinated ligand to characterize LHRH receptors in a membrane preparation of rat thymus, a key organ of the immune system. The effects of LHRH and LHRH-A were then investigated on the proliferative capacity of rat thymocytes exposed in vitro to a mitogen and on ornithine decarboxylase specific activity. In addition, to determine whether LHRH-A treatment in vivo might directly influence thymic function, we treated hypophysectomized (hypox) rats with a moderately high dose of LHRH-A for a period of 2 weeks, and thymocyte mitogenic capacity, thymus weight, and the histological and functional appearance of the thymus were then assessed. Specific binding of LHRH-A to rat thymic membrane preparations is a saturable process, depending on both time and temperature of incubation, but differs markedly from binding to the rat pituitary or ovarian LHRH receptor in its low binding affinity. Binding is optimal in the absence of chelating agents (EDTA) or divalent metal ions, and increases linearly with increasing protein concentration. Binding is specific for LHRH, LHRH-A, and antagonists. Both the C-terminal amide and N-terminal regions of the LHRH molecule were required for binding, and amino acid substitutions at position 6 markedly enhanced and at position 8 markedly reduced binding potencies in rat thymic tissue. A number of peptides, proteins, and other agents had no effect on the specific binding of LHRH-A to thymic membrane preparations. The binding affinity (Ka) of the membrane receptor of the rat thymus for the LHRH superagonist buserelin was 8.4 x 10(8) M-1, while a higher binding affinity (Ka = 2.8 x 10(9) M-1) was calculated for the ovarian LHRH-binding site. Preincubation of rat thymocytes with LHRH-A for 20 h induced a significant dose-dependent increase in the proliferative response to the mitogen Concanavalin-A, monitored by [3H]thymidine incorporation. Using native LHRH, it was also possible to elicit stimulatory effects on the same parameter, although much higher concentrations were required than with LHRH-A. Furthermore, simultaneous addition of a LHRH antagonist, abolished the LHRH effect on thymocytes. Ornithine decarboxylase specific activity under lectin stimulation was also significantly increased by LHRH-A in cultures of rat thymocytes.(ABSTRACT TRUNCATED AT 400 WORDS)

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Three uterine leiomyomas with vascular invasion (LWVI), two of which were associated with pulmonary leiomyomatous nodules, and a case of intravenous leiomyomatosis (IVL) invading the vena cava and extending to the right atrium, are described. Despite their histological benignity, these lesions have a strong tendency to metastasize and are closely related to the so-called benign metastasizing leiomyoma (BML). From a clinical point of view, the pulmonary nodules of LWVI are stable or slowly-growing. The IVL was a "worm-like" tumour that presented as a cardiac mass. On the basis of their histological and immunohistological features, a unified histogenetic view of LWVI, IVL and BML of the uterus is proposed. LWVI and BML may be the same pathological entity and microscopic vascular invasion may represent the metastatic mechanism of BML. Alternatively, LWVI may be the initial stage of IVL. In rare instances, IVL may be associated with distant parenchymal (pulmonary) metastases. LWVI seems to be the precursor of both BML and IVL.