Showing papers by "Andrea Cossarizza published in 2002"

Early changes in intramitochondrial cardiolipin distribution during apoptosis.

Abstract: Cardiolipin (CL) is essential for the functionality of several mitochondrial proteins. Its distribution between the inner and outer leaflet of the mitochondrial internal membrane is crucial for ATP synthesis. We have investigated alterations in CL distribution during the early phases of apoptosis. Using two classical models (staurosporine-treated HL-60 cells and tumor necrosis factor alpha-treated U937 cells), we found that in apoptotic cells CL moves to the outer leaflet of mitochondrial inner membrane in a time-dependent manner. This occurs before the appearance of apoptosis markers such as plasma-membrane exposure of phosphatidylserine, changes in mitochondrial membrane potential, DNA fragmentation, but after the production of reactive oxygen species. The exposure of a phospholipid on the outer surface during apoptosis thus occurs not only at the plasma membrane level but also in mitochondria, reinforcing the hypothesis of mitoptosis as a crucial regulating system for programmed cell death, also occurring in cancer cells after treatment with antineoplastic agents.

Digging for innate immunity since Darwin and Metchnikoff.

Abstract: Immune systems are, increasingly, being studied from comparative perspectives. The analysis of the immunedefense systems of invertebrates, such as fruit flies and earthworms, is an important part of this effort. These systems are innate, natural non-specific, non-anticipatory and non-clonal. This is in contrast to the macrophage T and B systems that characterize vertebrate adaptive immunity whose properties can be categorized as adaptive, induced, specific, anticipatory, and clonal. In this review, we will focus on the earthworm system. Earthworms, like other complex invertebrates, possess several leukocyte types and synthesize and secrete a variety of immunoprotective molecules. The system as a whole effects phagocytosis, encapsulation, agglutination, opsonization, clotting and lysis of foreign components. At least two major leukocytes, small coelomocytes, and large coelomocytes mediate lytic reactions against several targets. Destruction of tumor cells in vitro shows that phagocytosis and natural killer cell responses are distinct properties of coelomocytes. A third type, the chlorogogen cell, synthesizes and sheds effector lytic molecules. Among the lytic molecules, three have been identified and sequenced (fetidins, CCF-1, lysenin) and another has been discovered (eiseniapore), while three other molecules, H1 H2 H3, share agglutinating and lysing functions. In contrast to these, Lumbricin I is the only known molecule of the earthworm system that is antimicrobial but non-lytic. Altogether the cellular and humoral components of the earthworm system function to distinguish between self and not self, dispose of internal (cancer?), damaged components and external antigens (microbes). The evolutionary context of the earthworm innate immune system is discussed at the end of this article. BioEssays 24:319–333, 2002. ©2002 Wiley Periodicals, Inc.

Mitochondrial functionality and mitochondrial DNA content in lymphocytes of vertically infected human immunodeficiency virus-positive children with highly active antiretroviral therapy-related lipodystrophy.

Abstract: Mitochondria functionality and apoptosis were studied in peripheral blood lymphocytes (PBL) of human immunodeficiency virus type 1‐ infected children, with or without lipodystrophy (LD), who were receiving highly active antiretroviral therapy (HAART) and in PBL of healthy control subjects (HCs). By flow cytometry, mitochondrial (mt) membrane potential, mt mass, intra-mt cardiolipin distribution, and early and late apoptosis in fresh PBL or in PBL cultured with different stimuli were assessed. mtDNA content was evaluated in fresh PBL by an original double-competitive quantitative polymerase chain reaction method, which enabled direct quantification of the number of mtDNA copies present in human lymphocytes. PBL from LDpositive and LD-negative children and from HCs were similar in mt functionality and in their tendency to undergo apoptosis. mtDNA content was also similar in PBL of LD-positive children and HCs, suggesting that normal mt functionality and normal tendency to undergo apoptosis are present in PBL of children with HAART-associated LD. Changes in body shape with a redistribution of body fat and glucose/lipid abnormalities have been described in human immunodeficiency virus (HIV) type 1‐infected patients receiving antiretroviral therapy [1]. The clinical presentation of the fat redistribution syndrome, named lipodystrophy (LD), is variable but is frequently characterized by peripheral fat wasting, with or without truncal obesity. Available data in HIV-infected adults suggest that protease inhibitors (PIs) and nucleoside reversetranscriptase inhibitors (NRTIs), both components of highly active antiretroviral therapy (HAART), may play a role in the development of the LD syndrome [2‐6].

Features of 'CD4-exploders', HIV-positive patients with an optimal immune reconstitution after potent antiretroviral therapy.

Abstract: Objective: To identify crucial immunological characteristics of a group of patients, defined 'CD4-exploders', who were able to fully reconstitute their immune system after receiving highly active antiretroviral therapy (HAART). Patients: Among a population of 540 HIV-positive patients treated with HAART, six individuals were identified who experienced a nadir of less than 85 × 10 6 CD4+ cells/I, had major opportunistic infections (four out of six), started HAART in 1996 or 1997, and showed a rapid and relevant CD4+ lymphocyte increase (mainly due to virgin cells), in some cases regardless of virological control. Methods: Enzyme-linked immunosorbent assay for the determination of interleukin (IL)-7 plasma levels; flow cytometry to analyse surface antigens and CD127 (IL-7 receptor α-chain) expression; quantitative-competitive (QC) PCR for detecting cells containing T-cell receptor rearrangement excision circles (TREC); chest-computed tomography (CT) to analyse thymus volume and content. Results: In 'CD4-exploders', high levels of TREC+ lymphocytes were found among CD4+ T cells, which also contained a high percentage of naive cells. However, CT revealed a dramatic depletion of intrathymic lymphoid tissue. Plasma levels of IL-7 were significantly high. Most CD4+ and CD8+ T lymphocytes expressed CD127, whose level was similar to that of healthy donors. CD127 expression on CD8+ lymphocytes was markedly higher than in HIV-positive individuals treated with the same therapy or in patients with AIDS. Conclusion: In 'CD4-exploders', HAART-induced reconstitution of the T-cell compartment is independent from thymus volume, and is favoured by the upregulation of the IL-7/IL-7 receptor system.

Genetic polymorphisms of Fas (CD95) and FasL (CD178) in human longevity: studies on centenarians.

Abstract: Apoptosis plays a crucial role in immunosenescence, as also evidenced by the increased expression of Fas in lymphocytes from aged people. However, little is known about the genetic regulation of Fas and its ligand, FasL. We have studied their polymorphisms in 50 centenarians and 86 young donors living in Northern Italy. The first Fas polymorphism, at position -670, has in Caucasian a heterozigosity of 51%; the second, at -1377 position, has the wild type allele (G) with a very high frequency (83%) respect to the mutant allele. Genotype and allele distribution for both polymorphisms were similar in controls and centenarians. Similar results were found as far as two FasL polymorphisms (IVS2nt-124 and IVS3nt169) are concerned. On the whole, our data suggest that Fas and FasL polymorphisms, as well as their haplotypes, are unlikely to be associated with successful human longevity.

Mitochondria and HIV infection: the first decade.

Abstract: In the last few years, the interactions between mitochondria and infection with the human immunodeficiency virus (HIV) have received careful attention. Starting from the first studies regarding the presence of mitochondrial damage in cardiac tissue from patients who died of AIDS, researchers have investigated different aspects of the interactions between the virus and mitochondria, from acute primary infection to the final stages of the disease. Only recently a significant impulse to this type of research has come from the observation that the so called "highly active antiretroviral therapy" (HAART), a combination of potent antiretroviral drugs such as viral protease inhibitors or nucleoside-analogue reverse-transcriptase inhibitors, is capable of damaging these organelles and cause a clinical syndrome called lipodystrophy. There is still an open debate concerning the exact responsibility of HAART as well as on metabolic pathways and mechanisms that are involved in the onset of lipodystrophy. The hypothesis that drug-induced damage to mitochondrial (mt) DNA is able to alter mitochondria functionality to a similar extent as that occurring in genetic disease affecting mtDNA suggests that mitochondria plays a crucial role in the pathogenesis of this syndrome. In this paper, data concerning the interactions between mitochondria and HIV infection will be reviewed.

Kinetics of CD4 cells after discontinuation of antiretroviral therapy in patients with virological failure and a CD4 cell count greater than 500 cells/μl

Abstract: After a median of 37 months on antiretroviral therapy, 16 patients were asked to discontinue treatment instead of changing it. After a median observation time of 10.5 months, most patients experienced a rapid and progressive decrease in their CD4 cell count, even without a high viral load rebound. This decline was unrelated to the CD4 cell count and HIV-RNA values at interruption, but was more profound in patients in whom the M184V mutation had disappeared after lamivudine discontinuation.

An observational study on patients treated or not for acute HIV infection.

Abstract: Background. A vast majority of HIV-infected subjects who experience HIV acute seroconversion actually receive treatment. Open questions are how can we identify patients who will be slow progressors or long-term non progressors, and, as a consequence, do not require treatment.Methods. An observational retrospective study on patients who experienced acute HIV seroconversion from August 1995 to June 2001, who are still alive and followed as outpatients at the Clinic of Infectious Diseases of Modena, Italy.Results. Twelve patients were studied. Five patients (45.4%) were treated during acute seroconversion, while 7 were not treated. Two of these seven subjects received antiretroviral treatment 12 and 26 weeks after acute seroconversion. All the untreated patients were in good viro-immunological condition 6 months after seroconversion, and 2 of them also after 3 and 7 years. Patients who were treated showed a significant daily increase in CD4/CD8 T cell ratio with longer time spent on therapy (0.04% increase per day longer on antiretroviral therapy, p=0.02).Conclusions. This study suggests that treatment during primary HIV infection should not be considered in all patients. Randomized clinical trials enrolling patients with an asymptomatic primary HIV infection, with a high CD4 count and low HIV plasma viremia are needed to evaluate the indications for treatment in this subgroup of patients. On the other hand, this study confirms the good viro-immunological response obtained after treating patients during primary HIV infection.