Phosphorylcholine-Targeting Immunization Reduces Atherosclerosis

OBJECTIVES

The present study evaluated the effect of phosphorylcholine (PC) immunization on the extent of experimental atherosclerosis.

BACKGROUND

Immunization against oxidized lipoprotein (oxLDL) or Streptococcus pneumoconiae reduces atherosclerosis. Phosphorylcholine is the main epitope recognized by both antipneumococcus and anti-oxLDL antibodies. Therefore we reasoned that PC-specific antibodies might play an important role in atherogenesis.

METHODS

Apolipoprotein E knockout mice were immunized with PC every second week over 4 months. At the end of the study, serum antibodies directed to either PC or oxLDL were measured. Splenic and peritoneal B cells were analyzed by flow cytometry. Aortic root atherosclerotic lesions were quantified by morphometry and phenotyped by immunohistochemistry. Immune and control sera were also tested for their effect on foam cell formation in macrophage culture in the presence of oxLDL.

RESULTS

The PC-immunized mice showed 3-fold increase in titers of anti-PC and -oxLDL antibodies compared with control mice (p < 0.01). The PC-immunized mice also showed a significant increase in the number of splenic mature B cells. The extent of atherosclerotic aorta root lesions was reduced by >40% in the PC-immunized mice (p < 0.01). Immunohistochemistry showed reduced expression of major histocompatibility complex class II antigens (p < 0.05) and the presence of B-cell clusters in plaques of PC-immunized mice. Finally, PC-immune serum was able to reduce macrophage-derived foam cell formation in the presence of oxLDL in vitro.

CONCLUSIONS

Phosphorylcholine immunization drives a specific humoral immune response that reduces foam cell formation in vitro and is atheroprotective in vivo.

Atheroprotective effect of CD31 receptor globulin through enrichment of circulating regulatory T-cells

OBJECTIVES

This study was designed to evaluate whether replacing CD31 (PECAM-1) signaling can restore the regulation of lymphocyte activation and improve experimental atherosclerosis.

BACKGROUND

Atherosclerosis, the principal cause of myocardial infarction and stroke, is due to the development of a pathogenic immune response within the vascular wall and is aggravated by the reduction of regulatory T-cells. CD31, a transmembrane adhesion molecule with inhibitory signaling functions, is physiologically expressed on blood and vascular resting cells but is lost in pathologic conditions associated with atherosclerosis.

METHODS

Replacement therapy with a CD31 receptor globulin (Rg) was delivered by in vivo gene transfer in 6-week-old apolipoprotein E knockout mice (n = 14 per group) every 5 weeks for 6 months. Control groups were treated with a truncated CD31Rg or with vehicle alone. At the end of the study, plaque size and morphology and blood T-cell compartment were analyzed in all mice.

RESULTS

Atherosclerotic lesions of CD31Rg-treated mice were smaller (p < 0.01) and showed less neovascularization and intraplaque hemorrhage (p < 0.05) compared with control subjects. Furthermore, circulating regulatory T-cells were increased in vivo (p < 0.01) and showed normal suppressive function on proliferation of conventional T-cells in vitro. Indeed, CD31Rg treatment led to blunted blood T-cell activation (p < 0.05) and reduced T-cell infiltration within plaques (p < 0.01).

CONCLUSIONS

Our data suggest that CD31 plays a key role in the regulation of the immune response linked to atherosclerosis. CD31-targeting therapeutic approaches may therefore be envisaged for preventing and treating atherosclerotic diseases.

Depression and Quality of Life in Living Related Renal Transplantation

BACKGROUND

More than other operations on the body, organ transplantation has a psychological resonance relating to the self and body image representation, both in donors and in recipients. In the medical literature there are many psychopathological patterns related to ESRD and to the changes in psychologic assessment and lifestyle after transplantation. Similar changes have been found in living donors.

METHODS

Forty-eight donor-recipient couples were evaluated before and 4 months after transplantation, using clinical interview, according to the DSM IV TR criteria; The structured Interview for renal transplantation, both for recipients and for donors; psychodiagnostic tests: mini-mental state; Hamilton Rating Scale for Depression; Hamilton Anxiety Scale; Self-Rating Anxiety Scale; Short-Form 36 Health Survey Questionnaire.

RESULTS

Comparisons by paired Students t tests showed a significant Hamilton depression variation among recipients, with improvement in the gained score and reduction of depressive symptom (Hamilton score >7) frequency from 45.8% to 32%, and a decreased proportion of patients with a score >18 from 16.4% to 0%. There was no significant Hamilton Depression variation among donors, but there was somehow a reduction in depressive symptom frequency (Hamilton score >7) from 37.5% to 33.3% and a decrease among >18 scores from 12.6% to 0% patients.

CONCLUSIONS

Living donor kidney transplantation did not adversely affect the lives of donors and significantly improved many aspects of the lives of recipients. However, physical and psychological aspects may be impaired by living donation. Careful donor selection, with appropriate pretransplantation psychiatric consulting, allows those with a normal life quality to donate without consequence to their physical or psychological status.

Topological determinants and consequences of adventitial responses to arterial wall injury

Arteries are composed of 3 concentric tissue layers which exhibit different structures and properties. Because arterial injury is generally initiated at the interface with circulating blood, most studies performed to unravel the mechanisms involved in injury-induced arterial responses have focused on the innermost layer (intima) rather than on the outermost adventitial layer. In the present review, we focus on the involvement of the adventitia in response to various types of arterial injury leading to vascular remodeling. Physiologically, soluble vascular mediators are centrifugally conveyed by mass transport toward the adventitia. Moreover, in pathological conditions, neomediators and antigens can be generated within the arterial wall, whose outward conveyance triggers different patterns of local adventitial response. Adventitial angiogenesis, immunoinflammation, and fibrosis sequentially interact and their net balance defines the participation of the adventitial response in arterial pathology. In the present review we discuss 4 pathological entities in which the adventitial response to arterial wall injury participates in arterial wall remodeling. Hence, the adventitial adaptive immune response predominates in chronic rejection. Inflammatory phagocytic cell recruitment and initiation of a shift from innate to adaptive immunity characterize the adventitial response to products of proteolysis in abdominal aortic aneurysm. Adventitial sprouting of neovessels, leading to intraplaque hemorrhages, predominates in atherothrombosis. Adventitial fibrosis characterizes the response to mechanical stress and is responsible for the constrictive remodeling of arterial segments and initiating interstitial fibrosis in perivascular tissues. These adventitial events, therefore, have an impact not only on the vessel wall biology but also on the surrounding tissue.

Cartography of gene expression in CD8 single cells: novel CCR7− subsets suggest differentiation independent of CD45RA expression

Understanding the distribution, function, and lineage relationship of CD8+ T-cell subpopulations is of fundamental value for the monitoring of the immune system in several experimental and clinical situations. However, the available data concerning the description of effector and memory CD8+ subsets in humans remain rather fragmentary because different studies favored the usage of distinct and restricted sets of cell surface markers and functional parameters. We associated multiple markers to subdivide CD8+ T cells into 14 different cell types, several of which were not described previously, and evaluated the coexpression of 18 genes simultaneously in individual cells from each subset. Our results show that each subset has a defined pattern of gene expression. Moreover, effector gene expression of CCR7− cells correlated only with CD27 expression levels and CD27/CD28 coexpression but not with CD45RA/R0 phenotypes. Our findings thus describe new CD8+ cell subsets, allow the identification of relatively homogeneous CD8+ subpopulations, provide a predictable and precise correlation between particular cell surface markers and CD8+ T-cell functional properties, and identify effector cells present in both CCR7−CD45RA+ and CCR7−CD45R0+ compartments. The results also indicate that activated cells might modulate the expression of CD45RA/R0 asynchronously rather than CCR7−CD45RA+ cells always issuing from CD45RA− precursors.

Lymphoid neogenesis in chronic rejection: the murderer is in the house

Although chronic rejection is currently the main cause of long-term allograft failure, its pathogenesis remains elusive, hereby preventing the development of effective therapy. Recent advances in the comprehension of the pathophysiology of chronic inflammatory diseases could shed new light on the pathogenesis of chronic rejection. Lymphoid neogenesis is a mechanism responsible for the progressive organization of chronic inflammatory infiltrates into functional ectopic germinal centers, and has been evidenced recently in various pathological situations sharing a common feature: the failure of the immune response to eradicate the targeted antigen(s). Chronic rejection is such a situation as it results from a sustained alloimmune response against the donor's antigens that are constantly replenished by the grafted tissue. Accordingly, functional ectopic germinal centers develop within chronically rejected organs. This implies that, during chronic rejection, graft is at the same time the target and the site of elicitation of the alloimmune response.

Is defective lymphatic drainage a trigger for lymphoid neogenesis?

The progressive organization of cellular infiltrates into functional ectopic germinal centers (i.e. lymphoid neogenesis) has been recently evidenced in various chronic inflammatory diseases. Failure of the immune system to eradicate the targeted antigen(s) is a shared feature of all of the pathological situations associated with lymphoid neogenesis. Although necessary, inability of the immune system to eradicate the antigen(s) seems insufficient to trigger lymphoid neogenesis by itself. We propose that both defective lymphatic drainage of the inflamed tissue and enduring local antigenic stimulation are the crucial triggers of the cascade of events leading to lymphoid neogenesis. In turn, ectopic germinal centers prevent the restoration of lymph outflow by diverting inflammation-dependent lymphangiogenesis. Antigens and immune effectors are rerouted towards the neoformed ectopic lymphoid structures. A self-perpetuating feedback loop, which further sustains the development of the local immune response, is now imposed.

Direct and indirect effects of alloantibodies link neointimal and medial remodeling in graft arteriosclerosis

OBJECTIVE

Chronic vascular rejection, the main cause of allograft failure, is characterized by the destruction of smooth muscle cells (SMCs) in the media concomitantly with the proliferation of SMCs in the adjacent neointima. We hypothesized that alloantibodies might be responsible for these 2 opposite but coordinated events.

METHODS AND RESULTS

We used the rat aortic interposition model of chronic vascular rejection. During the rejection process, a neointima composed of proliferating SMCs from the recipient developed, whereas the SMCs in the media, all of donor origin, underwent apoptosis. Alloantibody deposition was detected only in the media. Using in vitro cultures experiments, we observed that alloantibody binding to donor SMCs exerts (1) a rapid upregulation of the transcription of growth factors genes, followed by (2) the induction of apoptosis after 24 hours. The transient production of growth factors by donor SMCs in response to the binding of alloantibodies induced the proliferation of recipient SMCs in culture supernatant transfer experiments. Additional data suggest that among the repertoire of alloantibodies, those directed against major histocompatibility complex I might carry the remodeling effect.

CONCLUSIONS

Our data suggest that during chronic vascular rejection, alloantibody binding to donor medial SMCs is a crucial event that links neointimal and medial remodeling.

[Immunological aspects of atherosclerosis]

The pathogenesis of atherosclerosis remains incompletely understood. Accumulation of oxidized lipoproteins (oxLDL) within the vascular wall drives a related immune response very early during the disease course. Such an immune response is self-amplified and eventually escapes from physiologic control mechanisms. Certain lymphocytes may become pathogenic. B cells play a protective role by producing antibodies able to neutralize oxLDL. Elucidation of the immune control mechanisms in atherosclerosis will open the way to new therapeutic perspectives.

Mice chronically fed a westernized experimental diet as a model of obesity, metabolic syndrome and osteoporosis

BACKGROUND

Most studies in animals use diets with several features (for example low-fat, rich in micronutriments), likely to be strongly protective against chronic diseases.

AIM OF THE STUDY

The present study, performed in wild type outbred mice, was designed to evaluate the validity of a model of 'westernized' (W) diet reproducing, as closely as possible, the overall composition of an average human regime in western countries

RESULTS

In contrast to the standard (S) diet, the W diet triggered a marked increase in adiposity with some characteristics of metabolic syndrome (hypercholesterolemia, hyperinsulinemia...). There was an heterogeneity in the propensity to become obese upon exposure to the W diet in female mice. Overweight mice also presented some disturbances of renal function, such as hyperalbuminuria and hypocitraturia. Mice adapted to the W diet showed a reduction of bone mineral density, especially the non-obese ones.

CONCLUSION

These data suggest that a model of westernized diet could be appropriate for exploring the effects of mutations, drugs, or specific nutritional factors in animals and could be more relevant for human situations.

Possible increasing risk of multiple sclerosis in Catania, Sicily

OBJECTIVE

To update prevalence and incidence rates of multiple sclerosis (MS) in Catania, Italy during 1990 to 1999 and evaluate their temporal profiles to assess a possible increase in the MS risk in our study population.

METHODS

We studied the frequency of MS in Catania, Italy (population of 313,110 as reported in the 2001 census). The primary sources for the case ascertainment were the neurologic and motor-rehabilitation departments, the MS centers, the Italian MS Association, private neurologists, and family doctors. We considered as prevalent and incident cases all patients who satisfied Poser's criteria for clinically definite MS (CDMS), laboratory-supported definite MS (LSDMS), clinically probable MS (CPMS), and laboratory-supported probable MS (LSPMS).

RESULTS

We found 288 subjects with MS who had onset of disease before December 31, 1999 (prevalence day) in a population of 313,110 inhabitants. The prevalence rate was 92.0/100,000 (95% CI 81.8 to 103.2) and was higher in women (102.4/100,000) than in men (80.4/100,000). The age-specific prevalence showed a peak in the group aged 35 to 44 years (208.2/100,000). From 1990 to 1999, 155 patients with MS had the clinical onset of the disease. The mean annual incidence was 4.7/100,000 (95% CI 4.0 to 5.5). Age-specific incidence showed a peak in the group aged 25 to 34 years (11.7/100,000). Mean annual incidence for 5-year intervals increased from 3.9/100,000 during 1990 to 1994 to 5.5/100,000 during 1995 to 1999.

CONCLUSIONS

Prevalence and incidence rates of multiple sclerosis have further increased during the last decade.

Intravenous immunoglobulin in autoimmune disorders: An insight into the immunoregulatory mechanisms

Intravenous immunoglobulin (IGIV) has increasingly been used for the treatment of autoimmune and systemic inflammatory diseases in addition to supportive therapy of immunodeficient patients. IGIV is beneficial in several diseases, including acute and chronic/relapsing diseases, autoimmune diseases and inflammatory disorders. Therapeutic efficacy of IGIV has also been established in a number of dermatologic diseases. Although a considerable progress has been made in understanding the mechanisms by which IGIV exerts immunomodulatory functions in autoimmune diseases, they remain not fully elucidated. The mode of action of IGIV is complex, involving modulation of expression and function of Fc receptors, interference with activation of complement and the cytokine network, modulation of idiotype network, regulation of cell growth, alteration of cellular adhesion process, and effects on the activation differentiation and effector functions of T and B cells and of antigen-presenting cells. The therapeutic effects of IGIV most likely reflect the functions of natural antibodies in maintaining immune homeostasis in healthy people. The ability of IGIV to interact through V regions with complementary V regions of antibodies and antigen receptors as well as with relevant soluble and surface molecules provides the basis for inducing the selection of immune repertoires. Since IGIV is frequently used to treat autoimmune and inflammatory diseases for which evidence of its efficacy is insufficiently documented, controlled trials, particularly of some neurologic and dermatologic diseases, are imperative.

Intravenous immunoglobulin and dendritic cells

Intravenous immunoglobulin (IVIg) has increasingly been used for the treatment of autoimmune and systemic inflammatory diseases, and in supportive therapy of immunodeficient patients. Available clinical and experimental evidence suggests, however, that a wide spectrum of immune-mediated conditions could benefit from IVIg, including acute and chronic/relapsing diseases and autoimmune diseases mediated by pathogenic autoantibodies or by autoaggressive T-cells. Dendritic cells (DCs) are professional antigen-presenting cells and because of their capacity to stimulate naïve T-cells, they play a central role in the initiation of primary immune responses. Several immunomodulatory agents have been shown to inhibit DC activation. Recently, we examined the effects of IVIg on differentiation, maturation, and functions of DCs. We demonstrate that DCs are one of the targets for the immunomodulatory effects of IVIg.

Reduced Immunoregulatory CD31 + T Cells in Patients With Atherosclerotic Abdominal Aortic Aneurysm

Background— Cell-mediated immunity is considered to contribute to the pathogenesis of abdominal aortic aneurysms (AAA). In particular, infiltrating macrophages and CD8 + T lymphocytes participate in the destruction of the aortic wall extracellular matrix and smooth muscle cells. We surmise that these pathological events are controlled by circulating regulatory lymphocytes.

Methods and Results— Circulating CD4 + /CD31 + cells were reduced in AAA patients (n=80, 8.9±0.6%) as compared with controls (n=69, 13.7±0.8%; P <0.001) and inversely proportional to AAA size. Exclusion of the aneurysm by an endoprothesis did not affect CD31 + T cell values. Reduction of blood CD4 + /CD31 + cells was not attributable to their enrichment in AAA tissue. In contrast, CD8 + /CD31 + cells were slightly reduced in the blood while increased in the aneurysmal tissue (29.2±0.5 versus 20.2±4.7% in blood, n=6; P <0.05). Remarkably, high percentages of CD4 + /CD31 + cells were able to regulate proliferation and cytokine production of CD8 + lymphocytes, as well as CD8 + cell-mediated cytotoxicity of aortic smooth muscle cells ( P <0.01). Finally, CD4 + /CD31 + cells reduced the production and activity of metalloproteinase-9 by lipopolysaccharide-stimulated macrophages.

Conclusions— Circulating CD4 + /CD31 + T cells regulate macrophage and CD8 + T cell activation and effector function in the arterial wall. Their reduction might promote the development of AAA.

Atheroprotective effect of adjuvants in apolipoprotein E knockout mice

Strategies aimed at treating atherosclerosis by immunization protocols are emerging. Such protocols commonly use adjuvants as non-specific stimulators of immune responses. However, adjuvants are known to modify various disease processes. The aim of this study was to determine whether adjuvants alter the development of atherosclerosis. We performed immunization protocols in apolipoprotein E knockout mice (E degrees ) following chronic administration schedules commonly employed in experimental atherosclerosis. Our results point out a dramatic effect of several adjuvants on the development of atherosclerosis; three of the four adjuvants tested reduced lesion size. The Alum adjuvant, which is the adjuvant currently used in most vaccination protocols in humans, displayed a strong atheroprotective effect. Mechanisms accounting for atheroprotective effect of Freund's adjuvants included their capacity to increase both Th2 responses and anti-MDA-LDL IgM titers, and/or to impose atheroprotective lipoprotein profiles. The present study indicates that adjuvants have potent atheromodulating capabilities, and thus, implies that the choice of adjuvant is crucial in long-term immunization protocols in experimental atherosclerosis.

Interleukin-12 is associated with the in vivo anti-tumor effect of mistletoe extracts in B16 mouse melanoma

Viscum album (VA) preparations consist of aqueous extracts of different types of lectins of mistletoe. VA exert cytotoxic and immunomodulatory properties that may be relevant for the inhibition of tumor growth. We addressed the effects of VA preparation VA Qu FrF on growth of B16F1 melanoma implanted in mice and on proliferation and cytokine synthesis of splenocytes. In C57BL6 mice, inhibition of tumor growth by VA was associated with an enhancement of splenocyte proliferation and with an up-regulation of IL-12 secretion. In IL-12-deficient strain of mice the inhibition of melanoma growth by VA and the splenocyte proliferation were abrogated. Results from the present study strongly suggest a crucial role of IL-12 in the anti-tumor properties of VA extracts.

Immunoglobulin treatment reduces atherosclerosis in apolipoprotein E-/- low-density lipoprotein receptor-/- mice via the complement system

Atherosclerosis is associated with activation of the immune system. Intravenously applied normal polyclonal immunoglobulins (IVIg) have broad therapeutic applications in the treatment of autoimmune and systemic inflammatory diseases. Recently, IVIg have been shown to inhibit atherogenesis in experimental animal models. To investigate the role of the complement system in this process, we used third complement component-deficient (C3(-/-)) and control atherosclerosis-prone apolipoprotein E (ApoE) and low-density lipoprotein receptor (LDLR) double knock-out mice fed a normal diet. IVIg treatment reduced lesion fraction area in the aortic root of complement-sufficient mice whereas the lesion fraction area of C3(-/-) mice was not affected. Thus, complement activation plays a role in the anti-atherosclerotic effects of IVIg, possibly by C3-derived fragments generated through Fc-dependent complement activation.

HIV-HCV co-infection during pregnancy

AIM

Hepatitis C virus (HCV) infection is common in human immunodeficiency virus (HIV) infected individuals in the United States and in Western Europe. The aim of this study is to describe our experience in the management of HIV-HCV co-infected women during pregnancy and to report the rates of HIV and HCV vertical transmission in this particular population.

METHODS

This is a prospective study including all HIV-HCV coinfected women who delivered in the major public hospital of Genoa from April 1990 to December 2002. The method of delivery and breastfeeding habits were recorded. The babies were monitored at the paediatric referral centre.

RESULTS

Thirty-nine HIV-HCV co-infected pregnant women were included in the analysis, 2 of these women delivered twice during the study period. The mean age (+/-SD) of this population at delivery was 30.4+/-4.9 years. Thirty-four (87.2%) HIV-HCV co-infected women had a history of intravenous drug use. Seventeen (43.5%) women reported regular alcohol intake during pregnancy. Forty-one infants were born during the study period. There was no case of HIV-vertical transmission in our population. Thirty-six (87.8%) of 41 babies were born to women with positive HCV-RNA. Two babies (4.9%) were HCV-infected.

CONCLUSIONS

The improved prognosis for HIV-infected people has increased the desire of parenthood. There is no evidence to support advising against pregnancy in HIV-HCV co-infected women.

The proatherogenic role of T cells requires cell division and is dependent on the stage of the disease

OBJECTIVE

The mechanism by which T cells exert a proatherogenic potential is unclear. In order to determine whether this potential requires their replication, we crossed atherosclerosis-prone apolipoprotein E knockout mice (ApoE degrees) with transgenic mice in which exclusive and conditional ablation of dividing T cells relies on their specific expression of the herpes simplex type 1 thymidine kinase (TK) suicide gene.

METHODS AND RESULTS

We first showed that conalbumin-immunized ApoE degrees TK mice mounted a significant immune response to the antigen that was fully and specifically blocked by an in vivo ganciclovir (GCV) treatment. Next, ApoE degrees TK mice and ApoE degrees mice were treated or not with GCV either during the first 4 weeks (GCV 1 to 4w), the last 4 weeks (GCV 5 to 8w), or during 8 weeks (GCV 1 to 8w). Strikingly, ApoE degrees TK mice displayed a dramatic decrease in lesion development in the GCV 1 to 8w and GCV 5 to 8w groups, whereas the GCV had no effect when administered during the first 4 weeks. In protected mice, the inflammatory parameters in lesions, the percentage of CD69+ CD3+ splenocytes, and the circulating natural killer T cells were reduced.

CONCLUSIONS

The present study, therefore, shows that the proatherogenic potential of T cells is crucial in the progression of fatty streaks to mature plaques and requires cell division.

Lymphoid neogenesis in chronic rejection: evidence for a local humoral alloimmune response

Recent advances indicate that, in various chronic inflammatory disorders, the activation of the immune system is triggered locally rather than in lymphoid organs. In this study, we have evaluated whether the humoral alloimmune response involved in chronic rejection is elicited within the graft. We used the rat aortic interposition model and microdissected the adventitia of the graft. Over time, the T cell infiltrate shifted toward a B helper phenotype. B lymphocyte clusters were detected and were the site of intense proliferation and apoptosis. Simultaneously, adventitial vascular endothelium acquired a high endothelial venule phenotype. Similar features were evidenced in the interstitium of chronically allografts (hearts and kidneys). Strikingly, ganocultured graft interstitial tissue was found to be the site of production of antibodies directed against donor MHC-I molecules. These findings, therefore, document the appearance of germinal centers in chronically rejected tissues. This lymphoid neogenesis implies that the graft is not only the target of the alloimmune response but also a site where this response actually develops, so as to optimize the communication between the targeted tissue and the immune effectors.

Role of the Intrinsic Coagulation Pathway in Atherogenesis Assessed in Hemophilic Apolipoprotein E Knockout Mice

Objective— The contribution of thrombosis and coagulation in atherogenesis is largely unknown. We investigated the contribution of the coagulation intrinsic factor VIII (FVIII)–dependent pathway in atherogenesis.

Methods and Results— Apolipoprotein E and FVIII double–deficient mice (E°/FVIII°) were generated. Aortic root lesions were analyzed in 14-week-old and 22-week-old female mice maintained for 8 or 16 weeks, respectively, on a normal chow diet or a hypercholesterolemic diet.

Conclusion— Despite a higher plasma total cholesterol concentration compared with E° mice, E°/FVIII° mice developed dramatically less early-stage atherosclerotic lesions. Whereas early lesions in E° mice contained abundant fibrin(ogen) deposits on which few platelets adhered, lesions in E°/FVIII° were almost devoid of fibrin(ogen), and no platelets could be detected. The genotype effect on development and composition of lesions tended to decrease with time. This study demonstrates that the activation of the intrinsic pathway of coagulation is potently proatherogenic at the early stage of atherogenesis.

Reduced Immunoregulatory CD31+T Cells in the Blood of Atherosclerotic Mice With Plaque Thrombosis

OBJECTIVE

Lymphocyte activation is thought to play a major role in the pathogenesis of atherosclerotic complications such as plaque thrombosis. Circulating CD31+ T cells have been shown to regulate human T cell activation. Aim of this study was to evaluate whether the proportion of circulating immunoregulatory CD31+ T cells is correlated to the occurrence of plaque thrombosis in aged apolipoprotein (apo) E knockout (KO) mice.

METHODS AND RESULTS

CD31+ T cell depletion of spleen T cells enhanced proliferation (P<0.05) and interferon-gamma production (P<0.01) while reducing interleukin (IL)-4 (P<0.001) and IL-10 (P=0.001) secretion in response to minimally modified low-density lipoprotein. CD31+ T cells were counted in 65 apoE KO mice (46-week-old) by flow cytometry. Organizing thrombi could be documented in 28 of 195 (14%) lesions and in at least one of the aorta root lesions in 23 of 65 mice (35%). CD31+ T cell count was significantly reduced in mice showing plaque thrombosis (72.3+/-1.5% versus 84.1+/-1.2%; P<0.0001), but such reduction did not follow induced plaque rupture or experimentally controlled thrombosis.

CONCLUSIONS

Reduced CD31+ T cells in circulating blood is a hallmark of atherosclerotic plaque thrombosis. Our data suggest that CD31+ T cells may play an important regulatory role in the development of plaque thrombosis.

Intravenous immunoglobulin in neurological disorders: a mechanistic perspective

Intravenous immunoglobulin (IVIg) has been used in the treatment of primary and secondary antibody deficiencies for over 25 years. It is a safe preparation with no long-term side effects. IVIg was first demonstrated to be effective in autoimmune disorders, two decades ago, in the treatment of acute immune thrombocytopenia. Since then, the therapeutic efficacy of IVIg has been established in Guillain Barré syndrome (GBS), chronic inflammatory demyelinating polyneuropathy (CIDP), myasthenia gravis (MG), dermatomyositis (DM), Kawasaki syndrome and the prevention of graft-versus-host disease in recipients of allogeneic bone marrow transplants and reported in a large number of other autoimmune and systemic inflammatory conditions.

CD1d-dependent activation of NKT cells aggravates atherosclerosis

Adaptive and innate immunity have been implicated in the pathogenesis of atherosclerosis. Given their abundance in the lesion, lipids might be targets of the atherosclerosis-associated immune response. Natural killer T (NKT) cells can recognize lipid antigens presented by CD1 molecules. We have explored the role of CD1d-restricted NKT cells in atherosclerosis by using apolipoprotein E–deficient (apoE^−/−) mice, a hypercholesterolemic mouse model that develops atherosclerosis. ApoE^−/− mice crossed with CD1d^−/− (CD1d^−/−apoE^−/−) mice exhibited a 25% decrease in lesion size compared with apoE^−/− mice. Administration of α-galactosylceramide, a synthetic glycolipid that activates NKT cells via CD1d, induced a 50% increase in lesion size in apoE^−/− mice, whereas it did not affect lesion size in apoE^−/−CD1d^−/− mice. Treatment was accompanied by an early burst of cytokines (IFNγ, MCP-1, TNFα, IL-2, IL-4, IL-5, and IL-6) followed by sustained increases in IFNγ and IL-4 transcripts in the spleen and aorta. Early activation of both T and B cells was followed by recruitment of T and NKT cells to the aorta and activation of inflammatory genes. These results show that activation of CD1d-restricted NKT cells exacerbates atherosclerosis.

Allergic and pseudoallergic reactions induced by glucocorticoids: a review

Glucocorticoids (GCs) represent the most effective treatment for autoimmune and allergic diseases, even if collateral effects are not rare, especially endocrine and immunosuppressive manifestations. Moreover, these drugs can develop adverse immunological reactions of I, III or IV type. Though immediate adverse reactions caused by systemic therapy with GCs are not very frequent, the possible beginning of anaphylactic and pseudo-anaphylactic manifestations in patients undergoing therapy with these drugs has to be considered. It has been observed that immediate adverse reactions usually are happened in asthmatic patients and in patients obliged to assume GCs again and again because of their pathology (e.g, kidney transplant). Other risk factors resulted to be female sex and hypersensibility to acetylsalicylic acid (ASA). Both in the cases of pseudo-allergic and allergic reactions, the pharmacological principle is hardly the responsible agent for the reaction; instead the excipients in drugs are often implicated (succinate salt, sulphites and carboxy-methyl-cellulose). It is possible that the IgE-response is highly specific for a fixed GC molecule as well depending on the way of administration and its salification. Moreover, it has been hypothesized that in patients with a first type allergic reaction to GCs there is a fourth type, sensitization to GCs, which is not usually diagnosed and even comes before IgE sensitization. Third type hypersensibility reactions may occur, too. Since GCs are large-scale drugs, also in emergency medicine and reanimation, allergic sensitization towards them, although infrequent, gives many interventionist problems. In the light of this feature, it seems of crucial importance to verify the tolerance toward other GC molecules. And in particular, it has been noted that patients presenting immediate reactions to hydrocortisone (HC) and methylprednisolone (MP) could tolerate prednisone and prednisolone per os and second-generation GCs, such as desamathazone and betamethazone. Nevertheless, second-generation GCs must not be considered safe; in fact, the beginning of allergic manifestations has been pointed out even towards them.

Prevalence of Parkinson's disease: a door-to-door survey in rural Bolivia

A door-to-door survey was carried out in rural areas of the Cordillera Province, Bolivia, to determine the prevalence of Parkinson's diseases (PD) in a sample of 9955 subjects. We found five cases of PD on prevalence day, November 1, 1994. The crude prevalence was 50.2/100,000 (95% CI 18.5-124.5) and 286/100,000 (95% CI 28-543) in subjects aged 40 years or more. Our prevalence is close to rates found in other in developing countries.

Natural autoantibodies as tools to predict the outcome of immune response?

Natural autoantibodies (NAbs), produced by B-1 B-cells, are directed against autoantigens and pathogens. NAbs can capture and present antigen to T helper cells thereby initiating adaptive immunities. It is proposed that screening for NAbs against pathogens will predict the strength of an antigen-induced immune response and could be used as a tool for vaccine development.

Pulmonary endothelium as a site of synthesis and storage of interleukin-6 in experimental congestive heart failure

BACKGROUND

Pulmonary endothelium is an early upstream hemodynamic target of left ventricular dysfunction. Interleukin 6 (IL-6) is a pro-inflammatory cytokine reported to increase in congestive heart failure (CHF) patients.

AIMS

We sought to determine the origin of IL-6, IL-6 receptor (IL-6R) and gp130 in experimental CHF.

METHODS

We used rats with coronary artery ligation as an experimental model of either compensated or decompensated heart failure. Lung and aorta samples were analysed by RT-PCR, ELISA and immunohistochemistry for IL-6 and its receptors.

RESULTS

IL-6 mRNA expression increased in the lung of rats with decompensated heart failure and was positively correlated with infarct severity whereas IL-6R mRNA decreased in the lung of myocardial infarction rats and gp130 mRNA remained unchanged. In contrast, there were no changes in IL-6 mRNA expression in the aorta and left ventricular myocardium. IL-6 peptide content as determined by ELISA and Western Blot in lung tissue was 2-fold higher in decompensated heart failure as compared to control rats. These data were confirmed by immunohistochemistry showing a preferential endothelial localization of IL-6 in the CHF lung. IL-6 peptide was also present in the pleural effusion of decompensated heart failure and was positively correlated with IL-6 mRNA expression in the lungs of decompensated HF rats. Pulmonary IL-6 overexpression was associated with nuclear translocation of NF-kappaB and cytosolic degradation of IkappaB.

CONCLUSION

Dysfunctional pulmonary endothelium is a source of synthesis and storage of IL-6 in an experimental model of CHF.

Autoreactive antibody repertoire is perturbed in atherosclerotic patients

In patients with clinical symptoms of coronary atherosclerosis, T cells are activated and directed to autologous proteins contained in the active plaques, suggesting that autoimmune responses may play a role in atherosclerosis progression. Organ-specific autoimmune diseases are sometimes accompanied by broad alterations of serum autoreactive antibody repertoires. We thus investigated antibody repertoires at a global level, using a technique of immunoblotting that allows for the quantitative screening of antibody reactivities in complex antibody mixtures toward a large panel of antigens derived from homologous tissue extracts, followed by multiparametric statistical analysis of the data. We analyzed the autoreactive IgG repertoire in 20 patients with documented coronary atherosclerosis and in 20 matched healthy controls. Total proteins from atherosclerotic carotid specimens and normal arterial tissues (target organs) and from kidney, liver, and stomach (non-target control organs) were used as panels of antigens. Patients had a significantly perturbed antibody repertoire and an enhanced autoreactivity of IgG to target and non-target organs, as compared with controls. Reactivity of purified IgG to plaque and normal artery proteins was greater in patients, but reactivity of IgG in the whole serum toward normal arterial tissue was lower than in controls; this suggests that, in patients, autoreactivity toward normal arteries is regulated by serum factors. Our data indicate that atherosclerotic patients develop a perturbed humoral immune response directed toward arterial proteins, which impacts on the overall autoreactive repertoire. These findings further substantiate that autoimmune processes take place in atherosclerosis and most likely influence disease progression.

Non-viral gene transfer of murine spleen cells achieved by in vivo electroporation

Gene electrotranfer is an attractive physical method to deliver genes to target tissues. The aim of this study was to evaluate in vivo gene electrotransfer into spleen, one of the most important lymphoid organ, in order to create a new tool to modulate the immuno-inflammatory system. C57Bl/6 mice were submitted either to intramuscular electrotransfer (IME) as a reference method or to intrasplenic (ISE) gene electrotransfer. In the naked injected plasmids, the CMV promoter controlled the expression of luciferase, secreted alkaline phosphatase, EGFP, or IFNgamma. The ISE optimal electrotransfer conditions were first determined and ISE was found to be an efficient gene transfer method, which can be used to express secreted or intracellular proteins transiently. Although transfected cells were still present in the spleen 30 days after ISE, transfected spleen cells could recirculate since they were detected in extrasplenic locations. Using a T-lymphocyte-specific promoter controlling the expression of EGFP, splenic T cells could be targeted. Finally, it appeared that ISE procedure does not impair by itself the immune response and does not result in a significant production of antibodies directed to the transgenic proteins in C57Bl/6 mice. This strategy constitutes a new method to manipulate the immune response that can be used in various experimental designs.

[Isolated peripheral arterial ischaemia and medullary neurostimulation: case report]

Isolated peripheral arterial ischaemia (IPAI) is an unusual pathology of dialysis and peritoneal patients which represents the first sign of a complication of uraemia known as calciphylaxis. Recent studies have revealed an increased incidence of this complication. Risk factors are known but there is no consensus on them: elevated CaxP product, female gender, elevated serum parathormone. We present here the case of a 65-year-old man with 21-year history of dialysis, distal isolated ulceration and without any signs of severe vasculopathy. Our clinical diagnosis was calciphylaxis. In this case, the role of early PTX is not clear and the use of steroids is recommended only in non-ulcerating cases. The therapy gives good results but not in all patients. Electrical stimulation of the posterior roots of the spinal cord is an alternative approach to this case. We hypothesised that the electrical action, through cutaneous vasodilatation of afferent dorsal fibres and release of calcitonin gene-releasing protein, determines the release of prostaglandin E sub 2 that may positively affect the proliferation and activity of epidermal fibroblasts.

Fluvastatin prevents renal dysfunction and vascular NO deficit in apolipoprotein E-deficient mice

OBJECTIVE

The objective of this study was to investigate the effects of fluvastatin on atherosclerosis, systemic and regional hemodynamics, and vascular reactivity in apolipoprotein E-deficient (ApoE(-/-)) mice.

METHODS AND RESULTS

Hemodynamics (fluospheres) and vasomotor responses of thoracic aorta and carotid artery were evaluated in male wild-type (WT) and untreated (ApoE(-/-) Control) or fluvastatin-treated (50 mg/kg per day for 20 weeks) ApoE(-/-) mice, all fed a Western-type diet. Plasma cholesterol and aortic root atherosclerotic lesions (ALs) were greater in ApoE(-/-) Control mice (19+/-1 mmol/L and 63,0176+/-38,785 micro m(2), respectively) than in WT mice (2+/-1 mmol/L and 1+/-1 micro m(2), respectively, P<0.01). Fluvastatin significantly decreased plasma cholesterol (-53%) but failed to limit ALs. Renal blood flow was significantly reduced in ApoE(-/-) Control versus WT (-25%, P<0.05) mice. This reduction was prevented by fluvastatin. Aortic and carotid endothelium-dependent relaxations to acetylcholine were not altered in ApoE(-/-) Control versus WT mice. In carotid arteries from WT mice, these responses were abolished after nitro-L-arginine (L-NA), whereas those from ApoE(-/-) Control were only partially inhibited after L-NA but fully abolished after L-NA+diclofenac. Thus, in carotid arteries from ApoE(-/-) mice, vasodilating prostanoids compensate the deficit in NO availability. Fluvastatin prevented this carotid NO deficit.

CONCLUSIONS

In ApoE(-/-) mice, chronic fluvastatin treatment preserved renal perfusion and vascular NO availability independently from atherosclerotic lesion prevention.

Interleukin-10 deficiency increases atherosclerosis, thrombosis, and low-density lipoproteins in apolipoprotein E knockout mice

Interleukin (IL)-10 is an anti-inflammatory cytokine that may play a protective role in atherosclerosis. The aim of this study was to assess the effect of IL-10 deficiency in the apolipoprotein E knockout mouse. Apolipoprotein E deficient (E-/-) and IL-10 deficient (-/-) mice were crossed to generate E-/- x IL-10-/- double knockout mice. By 16 wk, cholesterol and triglycerides were similar in double and single knockouts but the lack of IL-10 led to increased low-density lipoprotein cholesterol whereas very-low-density lipoprotein was reduced. In parallel, T-helper 1 responses and lesion size were dramatically increased in double knockout compared with E-/- controls. At 48 wk, matrix metalloproteinases and tissue factor activities were increased in lesions of double-knockout mice. Furthermore, markers of systemic coagulation were increased, and vascular thrombosis in response to i.v. thrombin occurred more frequently in E-/- x IL-10-/- than in E-/- mice. Our findings suggest that IL-10 deficiency plays a deleterious role in atherosclerosis. The early phase of lesion development was increased, and the proteolytic and procoagulant activity was elevated in advanced lesions. These data show that IL-10 may reduce atherogenesis and improve the stability of plaques.

Mesangial expansion associated with glomerular endothelial cell activation and macrophage recruitment is developing in hyperlipidaemic apoE null mice

BACKGROUND

Lipids are involved in the onset and/or the progression of renal diseases. ApoE null mice are hyperlipidaemic and thus represent an experimental model for the study of the effect of severe hypercholesterolaemia on renal lesion development.

METHODS

ApoE null mice were studied at 6 weeks of age fed a normal chow, after 20 weeks on a normal chow (mild hypercholesterolaemia), or a 0.15% cholesterol Western diet (WD; severe hypercholesterolaemia). Age- and diet-matched C57/B6 mice were used as controls. Glomerular structure was assessed by histology, electron microscopy and computerized morphometry. Glomerular macrophage recruitment and alpha-smooth-muscle actin, PCNA, VCAM-1 and MHC class II (I-A(b)) expressions were assessed by immunohistochemistry.

RESULTS

ApoE null mice fed the WD developed mesangial expansion characterized by an increase in mesangial area (P<0.05 vs C57BL/6 mice at 20 weeks). In apoE null mice, this was accompanied by a glomerular inflammatory process as demonstrated by (i) the presence of foam cells, (ii) macrophage recruitment, (iii) a higher expression of the I-A(b) activation marker and (iv) endothelial-cell activation (VCAM-1 expression in 100% of glomeruli and electron microscopy showing cytoplasmic foldings protruding in the capillary lumina). This might explain why we also observed blood monocytes adhering to glomerular endothelial cells.

CONCLUSIONS

In apoE null mice, severe hyperlipidaemia leads to glomerular injury characterized by glomerular endothelial cell activation and macrophage recruitment.