Showing papers by "Andrea Cossarizza published in 2014"

Circulating mitochondrial DNA increases with age and is a familiar trait: Implications for “inflamm-aging”

Abstract: Mitochondrial components, including mitochondrial DNA (mtDNA), when released extracellularly, can act as "damage-associated molecular pattern" (DAMP) agents and cause inflammation. As many elderly people are characterized by a low-grade, chronic inflammatory status defined "inflamm-aging," we evaluated if circulating mtDNA can contribute to this phenomenon. Eight hundred and thirty-one Caucasian subjects were enrolled in the study, including 429 siblings aged 90-104 (90+ siblings). mtDNA plasma levels increased gradually after the fifth decade of life. In 90+ subjects, mtDNA values of two members of the same sibling relationship were directly correlated, suggesting a role for familiar/genetic background in controlling the levels of circulating mtDNA. The subjects with the highest mtDNA plasma levels had the highest amounts of TNF-α, IL-6, RANTES, and IL-1ra; the subjects with the lowest mtDNA levels had the lowest levels of the same cytokines. In vitro stimulation of monocytes with mtDNA concentrations similar to the highest levels observed in vivo resulted in an increased production of TNF-α, suggesting that mtDNA can modulate the production of proinflammatory cytokines. Our findings therefore show that circulating mtDNA increases with age, and can significantly contribute to the maintenance of the low-grade, chronic inflammation observed in elderly people.

Mitochondria hyperfusion and elevated autophagic activity are key mechanisms for cellular bioenergetic preservation in centenarians

Abstract: Mitochondria have been considered for long time as important determinants of cell aging because of their role in the production of reactive oxygen species. In this study we investigated the impact of mitochondrial metabolism and biology as determinants of successful aging in primary cultures of fibroblasts isolated from the skin of long living individuals (LLI) (about 100 years old) compared with those from young (about 27 years old) and old (about 75 years old) subjects. We observed that fibroblasts from LLI displayed significantly lower complex I-driven ATP synthesis and higher production of H2O2 in comparison with old subjects. Despite these changes, bioenergetics of these cells appeared to operate normally. This lack of functional consequences was likely due to a compensatory phenomenon at the level of mitochondria, which displayed a maintained supercomplexes organization and an increased mass. This appears to be due to a decreased mitophagy, induced by hyperfused, elongated mitochondria. The overall data indicate that longevity is characterized by a preserved bioenergetic function likely attained by a successful mitochondria remodeling that can compensate for functional defects through an increase in mass, i.e. a sort of mitochondrial "hypertrophy".

Silencing of mitochondrial Lon protease deeply impairs mitochondrial proteome and function in colon cancer cells

Abstract: Lon is a nuclear-encoded, mitochondrial protease that assists protein folding, degrades oxidized/damaged proteins, and participates in maintaining mtDNA levels. Here we show that Lon is up-regulated in several human cancers and that its silencing in RKO colon cancer cells causes profound alterations of mitochondrial proteome and function, and cell death. We silenced Lon in RKO cells by constitutive or inducible expression of Lon shRNA. Lon-silenced cells displayed altered levels of 39 mitochondrial proteins (26% related to stress response, 14.8% to ribosome assembly, 12.7% to oxidative phosphorylation, 8.5% to Krebs cycle, 6.3% to β-oxidation, and 14.7% to crista integrity, ketone body catabolism, and mtDNA maintenance), low levels of mtDNA transcripts, and reduced levels of oxidative phosphorylation complexes (with >90% reduction of complex I). Oxygen consumption rate decreased 7.5-fold in basal conditions, and ATP synthesis dropped from 0.25 ± 0.04 to 0.03 ± 0.001 nmol/mg proteins, in the presence of 2-...

Life expectancy in the immune recovery era: the evolving scenario of the HIV epidemic in northern Italy.

Abstract: Introduction: National cohort and intercohort studies have been set to describe the differences of life expectancy (LE) of HIV-infected individuals Objective: The aim of this study was to assess the impact of immune recovery (IR) on LE of patients with HIV undergoing combination antiretroviral therapy Methods: In this retrospective observational study, outcome measure was LE of patients with HIV compared with LE of northern Italian population Group categorizations were as follows: patients with no immune recovery (nIR), patients with IR, patients who are immune maintained, and pre-highly active antiretroviral therapy (HAART) and post-HAART Abridged life tables were constructed from age-specific mortality rates (per 1000 person years) to estimate LE from the age of 20–55 years Results: A total of 9671 patients, 71% men, were included After 2005, we assisted to a rapid increase in the overall rate of patients attaining IR in the community coupled with a progressive decrease of AIDS death, but not of non-AIDS deaths In a 40-year-old patient, LE was 3810 years [standard error (SE) = 260], 3008 years (SE = 098), and 229 (SE = 069) in the IR, post-HAART group and nIR, respectively, compared with 4138 years of the general Italian population An approximately 5-year gap in LE was observed in IR patients Discussion: We describe IR at a “community” level, related to calendar year and apparent 10 years after HAART introduction HAART community IR is significantly influencing LE and is associated with the changing clinical picture of HIV disease An increasing gradient of LE exists between nIR, post-HAART, and IR groups, with the latter, above the age of 40 years only, reaching LE of general population

Switching to darunavir/ritonavir monotherapy vs. triple-therapy on body fat redistribution and bone mass in HIV-infected adults: the Monarch randomized controlled trial

Abstract: Changes in body fat distribution and bone mass in HIV-infected patients may be associated with long-term use of nucleoside reverse transcriptase inhibitors (NRTIs). The Monarch trial recruited 30 patients receiving non-nucleoside reverse transcriptase inhibitor or protease inhibitor-based highly active antiretroviral therapy, with HIV RNA <40 copies/mL. Patients were randomized to either darunavir/ritonavir 800/100 mg once daily monotherapy or darunavir/ritonavir 800/100 mg once daily + two NRTIs. Bone mass, peripheral lipoatrophy and central fat accumulation were assessed using dual-energy X-ray absorptiometry scanning, supplemented by computed tomography scans. Median age was 43 years, 77% were men. Visceral adipose tissue remained stable from baseline to Week 48 in the whole group (p = 0.261) with no significant difference between arms (p = 0.56). There was a significant reduction in insulin resistance (HOMA-IR, p = 0.013) over 48 weeks in the whole group, but not of body mass index (p = 0.24). In the darunavir/ritonavir monotherapy arm, there was a small but significant increase in both lumbar and femur bone mineral density at 48 weeks and was observed after correction for baseline values. The absolute change in lumbar bone mineral density at 48 weeks was more pronounced in the darunavir/ritonavir arm compared with the darunavir/ritonavir + 2NRTIs arm. In this study, discontinuing nucleoside analogues and switching to darunavir/ritonavir monotherapy was associated with a small but statistically significant increase in bone mineral density, but stable levels of limb fat and visceral adipose tissue.

Successful treatment of HIV-1 infection increases the expression of a novel, short transcript for IL-18 receptor α chain.

Abstract: The importance of interleukin (IL)-18 in mediating immune activation during HIV infection has recently emerged. IL-18 activity is regulated by its receptor (IL-18R), formed by an α and a β chain, the IL-18-binding protein, and the newly identified shorter isoforms of both IL-18R chains. We evaluated gene expression of the IL-18/IL-18R system in peripheral blood mononuclear cells from HIV+ patients. Compared with healthy donors, IL-18 expression decreased in patients with primary infection. The IL-18Rα short transcript expression was strongly upregulated by successful highly active antiretroviral therapy. HIV progression and its treatment can influence the expression of different components of the complex IL-18/IL-18R system.

Cytometry for immunology: the marriage continues.

Abstract: THIS issue of Cytometry contains three reviews that further celebrate the longstanding, intense, and happy marriage between Cytometry and Immunology, as highlighted recently during the XV International Congress of Immunology, held in Milan, Italy, August 22–27, 2013. Scanning the scientific contributions of the Conference reveals that cytometric technology was used in the vast majority of abstracts and presentations. In other words, very few scientists did not switch on one or more lasers! It is obvious, that nowadays very few studies in the field of Immunology are possible without techniques based upon single cell analysis. In our previous editorial (1), we have underlined how the creation of monoclonal antibodies (mAbs) (2) and their conjugation with a variety of fluorochromes has been an unprecedented motivation and help (that we defined as the “official exchange of rings”) for the development of an instrument, i.e., the flow cytometer, that only a few years before had been built and commercialized for measuring cellular DNA by fluorescent intercalating dyes such as ethidium bromide. Fluorescent mAbs detecting the CD4 molecule became then crucial not only for the identification of the alterations occurring in patients infected by the human immunodeficiency virus (HIV), but also to follow the efficacy of antiretroviral therapy, as more than 3 decades of studies teach us (3). The clinical use of mAbs and flow cytometry had finally led to the development of cytometers that are much easier to use than the original instruments they derive from. They are user friendly and can have affordable prices, and they have become workhorses for the immunologist. Though still today, the preparation of cells and the evaluation of cytometric data remain challenges. But the field is moving and enchanting new developments become available in cytometry. This adds some spice and excitement to the relationship. In the aftermath of the XVth International Congress on Immunology, we thought it is worthwhile to give some feedback on exciting developments in immunology to the Cytometry community and dedicate some space to the discussion of cutting-edge immunology in the August issue of Cytometry, the pre-eminent journal in the field, and some more space in this issue. Here, immunologists with longstanding cytometric experience provide three reviews that address the impact of state-of-the-art cytometry on the understanding of how lymphocytes function and how they are instructed and imprinted for function. Understanding these mechanisms is key to understand the role of the immune system in protection, infection, chronic inflammatory diseases, and aging. Cosmi et al. discuss novel aspects related to CD41 T lymphocytes, which are crucial cells for the regulation of immune responses and the development of immunological memory. CD41 T cells are a very heterogeneous population, and cytometry has and still is playing a key role in deciphering this heterogeneity and understanding its impact on immune reactions, protective, and pathogenic ones. The importance of Th1 and Th2 lymphocytes are discussed, along with other populations that have been phenotypically thoroughly characterized, such as the Th17 subset, but also less well accepted subtypes, like Th22, Th9, and T follicular helper (Tfh) lymphocytes. In particular, this review discusses the

Cytometry for Immunology: The Marriage

Abstract: issue of Cytometry contains three reviews that furthercelebrate the longstanding, intense, and happy marriagebetween Cytometry and Immunology, as highlighted recentlyduring the XV International Congress of Immunology, held inMilan, Italy, August 22–27, 2013. Scanning the scientific con-tributions of the Conference reveals that cytometric technol-ogy was used in the vast majority of abstracts andpresentations. In other words, very few scientists did notswitch on one or more lasers! It is obvious, that nowadaysvery few studies in the field of Immunology are possible with-out techniques based upon single cell analysis.In our previous editorial (1), we have underlined howthe creation of monoclonal antibodies (mAbs) (2) and theirconjugation with a variety of fluorochromes has been anunprecedented motivation and help (that we defined as the“official exchange of rings”) for the development of an instru-ment, i.e., the flow cytometer, that only a few years before hadbeen built and commercialized for measuring cellular DNA byfluorescent intercalating dyes such as ethidium bromide. Fluo-rescent mAbs detecting the CD4 molecule became then crucialnot only for the identification of the alterations occurring inpatients infected by the human immunodeficiency virus(HIV), but also to follow the efficacy of antiretroviral therapy,as more than 3 decades of studies teach us (3). The clinicaluse of mAbs and flow cytometry had finally led to the devel-opment of cytometers that are much easier to use than theoriginal instruments they derive from. They are user friendlyand can have affordable prices, and they have become work-horses for the immunologist. Though still today, the prepara-tion of cells and the evaluation of cytometric data remainchallenges. But the field is moving and enchanting new devel-opments become available in cytometry. This adds some spiceand excitement to the relationship.In the aftermath of the XVth International Congress onImmunology, we thought it is worthwhile to give some feed-back on exciting developments in immunology to the Cytom-etry community and dedicate some space to the discussion ofcutting-edge immunology in the August issue of Cytometry,the pre-eminent journal in the field, and some more space inthis issue. Here, immunologists with longstanding cytometricexperience provide three reviews that address the impact ofstate-of-the-art cytometry on the understanding of how lym-phocytes function and how they are instructed and imprintedfor function. Understanding these mechanisms is key tounderstand the role of the immune system in protection,infection, chronic inflammatory diseases, and aging.Cosmi et al. discuss novel aspects related to CD41 Tlymphocytes, which are crucial cells for the regulation ofimmune responses and the development of immunologicalmemory. CD41 T cells are a very heterogeneous population,and cytometry has and still is playing a key role in decipheringthis heterogeneity and understanding its impact on immunereactions, protective, and pathogenic ones. The importance ofTh1 and Th2 lymphocytes are discussed, along with otherpopulations that have been phenotypically thoroughly charac-terized, such as the Th17 subset, but also less well acceptedsubtypes, like Th22, Th9, and T follicular helper (Tfh) lym-phocytes. In particular, this review discusses the