Combination antiretroviral therapy -associated lipodystrophy : insights into pathogenesis and treatment

Introduction: Combination antiretroviral therapy (cART) has decreased morbidity and mortality of individuals infected with human immunodeficiency virus type 1 (HIV-1). Its use, however, is associated with adverse effects which increase the patients risk of conditions such as diabetes and coronary heart disease. Perhaps the most stigmatizing side effect is lipodystrophy, i.e., the loss of subcutaneous adipose tissue (SAT) in the face, limbs and trunk while fat accumulates intra-abdominally and dorsocervically. The pathogenesis of cART-associated lipodystrophy is obscure. Nucleoside reverse transcriptase inhibitors (NRTI) have been implicated to cause lipoatrophy via mitochondrial toxicity. There is no known effective treatment for cART-associated lipodystrophy during unchanged antiretroviral regimen in humans, but in vitro data have shown uridine to abrogate NRTI-induced toxicity in adipocytes. Aims: To investigate whether i) cART or lipodystrophy associated with its use affect arterial stiffness; ii) lipoatrophic SAT is inflamed compared to non-lipoatrophic SAT; iii) abdominal SAT from patients with compared to those without cART-associated lipoatrophy differs with respect to mitochondrial DNA (mtDNA) content, adipose tissue inflammation and gene expression, and if NRTIs stavudine and zidovudine are associated with different degree of changes; iv) lipoatrophic abdominal SAT differs from preserved dorsocervical SAT with respect to mtDNA content, adipose tissue inflammation and gene expression in patients with cART-associated lipodystrophy and v) whether uridine can revert lipoatrophy and the associated metabolic disturbances in patients on stavudine or zidovudine based cART. Subjects and methods: 64 cART-treated patients with (n=45) and without lipodystrophy/-atrophy (n=19) were compared cross-sectionally. A marker of arterial stiffness, heart rate corrected augmentation index (AgIHR), was measured by pulse wave analysis. Body composition was measured by magnetic resonance imaging and dual-energy X-ray absorptiometry, and liver fat content by proton magnetic resonance spectroscopy. Gene expression and mtDNA content in SAT were assessed by real-time polymerase chain reaction and microarray. Adipose tissue composition and inflammation were assessed by histology and immunohistochemistry. Dorsocervical and abdominal SAT were studied. The efficacy and safety of uridine for the treatment of cART-associated lipoatrophy were evaluated in a randomized, double-blind, placebo-controlled 3-month trial in 20 lipoatrophic cART-treated patients. Results: Duration of antiretroviral treatment and cumulative exposure to NRTIs and protease inhibitors, but not the presence of cART-associated lipodystrophy, predicted AgIHR independent of age and blood pressure. Gene expression of inflammatory markers was increased in SAT of lipodystrophic as compared to non-lipodystrophic patients. Expression of genes involved in adipogenesis, triglyceride synthesis and glucose disposal was lower and of those involved in mitochondrial biogenesis, apoptosis and oxidative stress higher in SAT of patients with than without cART-associated lipoatrophy. Most changes were more pronounced in stavudine-treated than in zidovudine-treated individuals. Lipoatrophic SAT had lower mtDNA than SAT of non-lipoatrophic patients. Expression of inflammatory genes was lower in dorsocervical than in abdominal SAT. Neither depot had characteristics of brown adipose tissue. Despite being spared from lipoatrophy, dorsocervical SAT of lipodystrophic patients had lower mtDNA than the phenotypically similar corresponding depot of non-lipodystrophic patients. The greatest difference in gene expression between dorsocervical and abdominal SAT, irrespective of lipodystrophy status, was in expression of homeobox genes that regulate transcription and regionalization of organs during embryonal development. Uridine increased limb fat and its proportion of total fat, but had no effect on liver fat content and markers of insulin resistance. Conclusions: Long-term cART is associated with increased arterial stiffness and, thus, with higher cardiovascular risk. Lipoatrophic abdominal SAT is characterized by inflammation, apoptosis and mtDNA depletion. As mtDNA is depleted even in non-lipoatrophic dorsocervical SAT, lipoatrophy is unlikely to be caused directly by mtDNA depletion. Preserved dorsocervical SAT of patients with cART-associated lipodystrophy is less inflamed than their lipoatrophic abdominal SAT, and does not resemble brown adipose tissue. The greatest difference in gene expression between dorsocervical and abdominal SAT is in expression of transcriptional regulators, homeobox genes, which might explain the differential susceptibility of these adipose tissue depots to cART-induced toxicity. Uridine is able to increase peripheral SAT in lipoatrophic patients during unchanged cART.Johdanto: Ihmisen immuunikatoviruksen (HIV) hoitoon käytetyt lääkeyhdistelmät ovat vähentäneet HIV-positiivisten henkilöiden sairastuvuutta ja kuolleisuutta. Yhdistelmähoitoon liittyy kuitenkin vakavia sivuvaikutuksia, jotka lisäävät potilaiden riskiä sairastua mm. diabetekseen ja sepelvaltimotautiin. Yksi leimaavimpia sivuvaikutuksia on lipodystrofia eli ihonalaisen rasvakudoksen häviäminen (lipoatrofia) kasvoista, raajoista ja vatsalta samalla kun rasvaa kertyy ylen määrin vatsaonteloon ja niskaan. Ilmiön syyt ovat epäselvät. Useiden HIV:ta vastaan suunnattujen lääkeaineiden on epäilty aiheuttavan lipodystrofiaa mm. tuhoamalla mitokondrioita, solujen energiatehtaita . Lipodystrofiaan ei ole tehokasta hoitoa, ellei HIV-lääkitystä muuteta, mutta esim. uridiini on ollut lupaava apu solumallitutkimusten valossa. Tavoitteet: Tutkia liittyykö yhdistelmähoitoon tai sen käyttöön liittyvään lipodystrofiaan verisuonien jäykistymistä, onko lipoatrofinen rasvakudos tulehtunutta verrattuna ei-lipoatrofiseen rasvakudokseen, eroaako lipoatrofinen ei-lipoatrofisesta rasvakudoksesta mm. mitokondriomäärän ja aineenvaihduntaan vaikuttavien geenien ilmentymisen suhteen sekä poikkeaako lipodystrofiassa paremmin säilyvä niskan rasva häviävästä vatsan ihonalaisrasvasta ja onko se mahdollisesti ruskeata rasvaa. Lisäksi tutkimme, voiko ravintolisänä käytetty uridiini parantaa lipoatrofiaa ja siihen liittyviä aineenvaihduntahäiriöitä, kuten rasvamaksaa ja heikentynyttä insuliiniherkkyyttä. Menetelmät: Tutkimuksiin osallistui 64 HIV-positiivista yhdistelmähoidettua potilasta, joista 45:lla oli ja 19:lla ei ollut kehittynyt lääkitykseen liittyviä rasvakudoksen muutoksia. Verisuonijäykkyys tutkittiin pulssiaaltoanalyysilla, kehon koostumus mitattiin kaksienergisella röntgenabsorptiometria- sekä magneettikuvaantamisella ja maksan rasvapitoisuus protonispektroskopialla. Rasvakudosnäytteet otettiin potilaiden vatsan ja niskan ihoalaisrasvasta ja niistä mitattiin eri geenien ilmentymistä sekä mitokondrioiden ja tulehdussolujen määrää mm. DNA:n monistustekniikalla ja kudosleikevärjäyksin. Uridiinin tehoa lipoatrofian hoidossa arvioitiin 3kk satunnaistetussa lumelääkekontrolloidussa tutkimuksessa, johon osallistui 20 HIV-positiivista yhdistelmähoidettua lipoatrofista henkilöä. Tulokset: HIV-lääkityksen kesto, mutta ei lipodystrofia, altistaa verisuonien jäykistymiselle iästä ja verenpainetasosta riippumatta. Lipoatrofisessa rasvakudoksessa tulehdukseen liittyvien geenien ilmentyminen ja tulehdussolujen määrä ovat lisääntyneet, kun taas mitokondriomäärä sekä rasvasolujen muodostumiseen ja toimintaan liittyvien geenien ilmentyminen vähentyneet verrattuna ei-lipoatrofiseen rasvakudokseen. Lipodystrofiassa säilyvä/lisääntyvä niskan rasva on vähemmän tulehtunutta kuin herkemmin häviävä vatsan ihonalaisrasva eikä se ole ruskeata rasvaa. Lipodystrofisten henkilöiden niskan rasvassa on vähemmän mitokondrioita kuin ei-lipodystrofisten henkilöiden niskan rasvassa, vaikka kudokset ovat ulkoisesti samannäköisiä. Niskan ja vatsan alueen ihonalaisrasva eroaa eniten ns. homeobox-geenien ilmentymisessä eli sellaisten geenien, jotka määrittelevät kudosten sijainnin ja ominaisuudet sikiökehityksen varhaisvaiheessa. Uridiini lisää ihonalaisrasvan määrää lipoatrofisilla potilailla, mutta ei vaikuta maksan rasvapitoisuuteen tai insuliiniherkkyyteen. Johtopäätökset: HIV:n hoitoon käytettyjen lääkkeiden pitkäaikaiskäyttö lisää verisuonien jäykkyyttä ja siten potilaiden riskiä sairastua sydän- ja verisuonitauteihin. Lipoatrofinen rasva on tulehtunut ja sen mitokondriovarannot vähentyneet. Koska mitokondrioiden vähyys on todettavissa niskarasvassa myös sellaisilla lipodystrofisilla henkilöillä, joilla se on säilynyt atrofialta, mitokondriokatoa ei voida pitää lipoatrofiaa suoraan aiheuttavana tekijänä. Niskan ja vatsan ihonalaisrasvan merkittävin ero on elinkehitystä ohjaavissa geeneissä, mikä voi selittää kudosten erilaisen alttiuden lääkkeiden sivuvaikutuksille. Uridiini on tehokas hoito HIV-potilaiden lipodystrofiaan muuttumattoman yhdistelmähoidon aikana

Correlation of adipocytokine levels in different types of lipodistrophy in HIV/AIDS patients

Primenom kombinovane antiretrovirusne terapije (combination antiretroviral therapy, cART) došlo je do značajnog smanjenja morbiditeta i mortaliteta kod osoba inficiranih virusom humane imunodeficijencije (Human Immunodeficiency Virus, HIV) i sindromom stečene imunodeficijencije (Acquired immune deficiency syndrome, AIDS). Sa produženjem životnog veka pacijenata sa HIV-om od značaja je postalo praćenje neželjenih efekata cART-a među kojima se posebno izdvajaju poremećaj metabolizma lipida, dislipidemija, kao i periferna lipoatrofija i visceralna lipohipertrofija, zajednički označene kao lipodistrofija, i insulinska rezistencija. Sindrom lipodistrofije obuhvata tri klinička stanja koja se karakterišu poremećenom distribucijom telesnih masti, a to su lipoatrofija (gubitak potkožnog masnog tkiva), lipohipertrofija (povećanje visceralnog masnog tkiva) i mešoviti tip koji predstavlja kombinaciju dva navedena stanja. Skorašnja istraživanja su pokazala kompleksnu ulogu masnog tkiva, koje predstavlja metabolički aktivan endokrini organ i koje oslobađa u cirkulaciju biološki aktivne peptide, odnosno adipocitokine. Ćelije masnog tkiva aktivno proizvode brojne predstavnike familije citokina, kao što su adiponektin, leptin, rezistin, faktor tumorske nekroze alfa (TNF–α), inhibitor aktivatora plazminogena (PAI-1) i razne druge interleukine (IL). Adipocitokini imaju različite uloge u imunom odgovoru (interleukini), inflamaciji (IL-1β, IL-6, IL-8, IL-10, monocitni hemotaksni protein-1 (MCP- 1)), metabolizmu glukoze (leptin, adiponektin, rezistin), osetljivosti na insulin (leptin, adiponektin), ćelijskoj adheziji (PAI-1), rastu i funkciji vaskularnih ćelija (faktor rasta vaskularnog endotela, VEGF), razvoju ateroskleroze, adipogeneze i drugih bioloških procesa. U ovom radu je ispitivana povezanost nivoa adipocitokina i različitih podtipova lipodistrofije kod bolesnika sa HIV infekcijom. Ciljevi: (I) Utvrditi učestalost lipodistrofije kao i podtipova lipodistrofije (lipoatrofija, lipohipertrofija, mešoviti tip lipodistrofije) kod bolesnika sa HIV/AIDS-om; (II) Ispititati povezanost dužine trajanja cART-a i broja cART kombinacija sa pojavom lipodistrofije (odnosno odgovarajućeg podtipa lipodistrofije); (III) Ispititati povezanost nivoa adipocitokina (adiponektin, rezistin, leptin, interleukini (IL-2, IL-4, IL-6, IL-8, IL-10; IL-1 α, IL-1β), TNF- α, PAI-1, MCP-1, VEGF, EGF, IFN-γ, cistatin C) kod bolesnika sa HIV/AIDS-om sa i bez 2 lipodistrofije; (IV) Ispititati povezanost nivoa adipocitokina (adiponektin, rezistin, leptin, interleukini (IL-2, IL-4, IL-6, IL-8, IL-10; IL-1 α, IL-1β), TNF-α, PAI-1, MCP-1, VEGF, EGF, IFN-γ, cistatin C)) kod bolesnika sa HIV/AIDS-om sa različitim podtipovima lipodistrofije...The introduction of combination antiretroviral therapy (cART) has led to a significant decrease in morbidity and mortality in people infected with Human Immunodeficiency Virus (HIV) and Acquired Immune Deficiency Syndrome (AIDS). With the prolongation of the life span of patients with HIV, it became increasingly important to monitor adverse effects associated with cART, such as lipid metabolism disorders, dyslipidemia, and peripheral lipoatrophy and visceral lipohypertrophy, commonly referred to as lipodystrophy, and insulin resistance. Lipodystrophy syndrome (LD) groups together three clinical conditions characterized by fat redistribution: lipoatrophy (LA, loss of subcutaneous adipose tissue), lipohipertrophy (LH, increase in visceral adipose tissue), and a mixed lipodystrophy type (MFR, mixed fat redistibution) that represents a combination of the two states mentioned above. A number of evidence have demonstrated a much more complex function of adipose tissue, which is now considered not only an energy storage organ but also a metabolically active endocrine organ that releases bioactive peptides (e.g., adipokines) into the blood stream. Fat cells actively secrete many members of the cytokine family, such as adiponectin, leptin, resistin, tumor necrosis factor alpha (TNF-α), plasminogen activator inhibitor (PAI-1) and various interleukins (IL). Adipokines have been proposed to play specific roles in immune response (interleukins), inflammation (IL-1β, IL-6, IL-8, IL-10, monocyte chemoattractant protein-1 (MCP-1)), glucose metabolism (leptin, adiponectin), insulin sensitivity (leptin, adiponectin), cell adhesion (PAI-1), vascular growth and function (vascular endothelial growth factor, VEGF), development of atherosclerosis, adipogenesis and other biological processes. In our research, we investigated the association between levels of adipocytokines and different lipodystrophy subtypes in HIV/AIDS patients. Aims: (I) to assess the prevalence of lipodystrophy and its subtypes (lipoatrophy, lipohypertrophy, mixed fat redistribution) in HIV/AIDS patients; (II) to examine the relationship between the duration of cART and the number of cART combinations with the prevalence of lipodystrophy (as well as with different lipodystrophy subtypes); (III) to determine the correlation between adipocytokine levels (adiponectin, resistin, leptin, interleukins (IL-2, IL-4, IL-6, IL-8, IL-10, IL-1 α, IL-1β), PAI-1, MCP-1, VEGF, EGF, IFN6 γ, cystatin C) in HIV/AIDS patients with or without lipodystrophy; (IV) to determine the correlation between adipocytokine levels (adiponectin, resistin, leptin, interleukins (IL-2, IL- 4, IL-6, IL-8, IL-10, IL-1 α, IL-1β), PAI-1, MCP-1, VEGF, EGF, IFN-γ, cystatin C) in HIV/AIDS patients with different subtypes of lipodystrophy..

Current Perspectives in HIV Infection

This book gives a comprehensive overview of HIV and AIDS including NeuroAIDS, as well as general concepts of pathology, immunity and immunopathology, diagnosis, treatment, epidemiology and etiology to current clinical recommendations in management of HIV/AIDS including NeuroAIDS, highlighting the ongoing issues, recent advances and future directions in diagnostic approaches and therapeutic strategies

In vitro studies on drug- induced metabolic alterations

Over the last few decades some mechanisms of diseases, especially those which are associated with recently described dysregulation of the adipose tissue due to certain medications/drugs, have been discovered, shedding light on the pathophysiology of obesity-associated metabolic alterations. Investigation of the functions of distinct cytokines, overall redox status, transcriptional regulation and protein expression of crucial adipogeneic markers may provide new comprehension of the pathophysiology of obesity, diabetes and cardiovascular diseases, as well as specific targets for future therapeutic approaches. This study was particularly designed with the knowledge that certain medications and drugs such as paracetamol, caffeine, rilpivirine, estradiol and β-naphthoflavone (BNF) may contribute significantly to the process of adipogenesis, broadly termed drug-induced metabolic alterations. Furthermore, the present study investigated the combined effects of some of these drugs for comparison. The results from the treatment of adipose cells with caffeine, paracetamol and β-naphthoflavone either alone or in combination have shown anti-adipogenic effects of caffeine, paracetamol and β-naphthoflavone through inhibition of adipogenesis and enhancement of the lipolytic process. A combination of β-naphthoflavone with caffeine and paracetamol was further shown to attenuate triglyceride accumulation. This study also investigated the inflammatory status of 3T3-L1 human pre-adipocytes when treated with different concentrations of either rilpivirine or estradiol alone and in combination with β-naphthoflavone (BNF). The results show that either rilpivirine or estradiol individually or during their combination can evoke significant increases in glycerol release and a concomitant significant decrease of adiponectin from adipocytes in a dose dependent manner. The effects of combined treatments were much larger than individual concentration for each drug. Both drugs had little or no effect on leptin levels, except for a small decrease with 10 µM rilpivirine alone or when combined with estradiol. In addition, both drugs evoked small increases in the release of resistin and interleukin-8 with significant values at higher doses compared to untreated adipocytes.When adipocytes were pretreated with BNF, either rilpivirine or, estradiol or when combined evoked a much larger release in glycerol and a much larger decrease in adiponectin compared to the absence of BNF. The study further investigated the lipodystrophic effects of rilpivirine on adipose cells and its nutritional management using quercetin. The results have shown that rilpivirine exerts lipoatrophic effects on adipose cells by impairing triglyceride accumulation, increasing inflammation, repressing anti-oxidant enzymes and inhibiting the expression of genes controlling adipogenesis (PPARg, C/EBPα, SREBP-1c, fatty acid synthase and aP2). A combination of rilpivirine and quercetin shows that quercetin was able to decrease inflammation and restore the levels of anti-oxidant enzymes but failed to overcome the lipoatrophic effects of rilpivirine. The present study also elucidated the role of 17β-estradiol on human subcutaneous cells in vitro either individually or in combination with quercetin. The results revealed that both estradiol and quercetin can promote leanness in part by reducing adipocyte size through reduced uptake of fatty acids and reduced lipogenesis. Experimental data show a decrease in the expression of adipogenesis target genes suggesting anti-adipogenic as well as anti-lipogenic action of estradiol and quercetin in adipose cells. In conclusion, the results from this study revealed complex interactions between metabolic and inflammatory pathways during the process of adipogenesis. However, the data further suggests that HIV and obese patients who are under increased risk should seek advice from their physicians to offer differentiated and optimized therapeutic approaches

Molecular and Cellular Mechanisms of Preeclampsia

This Special Issue on the “Molecular and Cellular Mechanisms of Preeclampsia” belongs to the section “Molecular Pathology, Diagnostics, and Therapeutics” of the International Journal of Molecular Sciences. It was a very successful Special Issue as it contains 20 published papers, including one editorial, nine original research papers, and ten reviews on the topic. The original publications cover a wide spectrum of topics, including alterations and involvement of specific factors during preeclampsia, new non-invasive technologies to identify changes, new treatment options, animal models, gender aspects, and effects of the pregnancy pathology later in life. The review publications again cover a wide spectrum of topics, including factors and pathways involved in preeclampsia, effects on the maternal vascular and immune systems, effects on the placenta and the trophoblast, epigenetic changes, new preventive strategies, and new views on the current hypotheses on preeclampsia. Taken together, this Special Issue gives a fantastic overview on a broad spectrum of topics, all of which are important to identify the real etiology of preeclampsia and to finally develop real treatment options

Adipose tissue immunomodulation: A novel therapeutic approach in cardiovascular and metabolic diseases

Adipose tissue is a critical regulator of systemic metabolism and bodily homeostasis as it secretes a myriad of adipokines, including inflammatory and anti-inflammatory cytokines. As the main storage pool of lipids, subcutaneous and visceral adipose tissues undergo marked hypertrophy and hyperplasia in response to nutritional excess leading to hypoxia, adipokine dysregulation, and subsequent low-grade inflammation that is characterized by increased infiltration and activation of innate and adaptive immune cells. The specific localization, physiology, susceptibility to inflammation and the heterogeneity of the inflammatory cell population of each adipose depot are unique and thus dictate the possible complications of adipose tissue chronic inflammation. Several lines of evidence link visceral and particularly perivascular, pericardial, and perirenal adipose tissue inflammation to the development of metabolic syndrome, insulin resistance, type 2 diabetes and cardiovascular diseases. In addition to the implication of the immune system in the regulation of adipose tissue function, adipose tissue immune components are pivotal in detrimental or otherwise favorable adipose tissue remodeling and thermogenesis. Adipose tissue resident and infiltrating immune cells undergo metabolic and morphological adaptation based on the systemic energy status and thus a better comprehension of the metabolic regulation of immune cells in adipose tissues is pivotal to address complications of chronic adipose tissue inflammation. In this review, we discuss the role of adipose innate and adaptive immune cells across various physiological and pathophysiological states that pertain to the development or progression of cardiovascular diseases associated with metabolic disorders. Understanding such mechanisms allows for the exploitation of the adipose tissue-immune system crosstalk, exploring how the adipose immune system might be targeted as a strategy to treat cardiovascular derangements associated with metabolic dysfunctions.This work was supported by AUB-Faculty of Medicine Medical Practice Plan Grant No. 320148 and an AUB President Collaborative Research Stimulus Grant to AE-Y

Mechanisms involved in the accumulation of mitochrondrial DNA defects following anti-HIV therapy

PhD ThesisHIV-infected patients present with a range of pathologies that have been associated with mitochondrial toxicity, and more specifically, induced through exposure to the main class of antiretrovirals used in anti-HIV therapy (HAART), nucleoside analogue reverse transcriptase inhibitors, or NRTIs. It has recently been found that such patients have an excess of mitochondrial DNA mutations when exposed to NRTIs; however, the underlying pathophysiological process of this remains undetermined. To elaborate upon this further, a range of molecular approaches were developed to study the behaviour of mitochondrial DNA mutations, both large scale deletions and single point mutations, in both tissue samples and in vitro. High throughput, ultra-deep DNA sequencing technology was also utilised to characterise mitochondrial DNA mutation burden in detail. Here I present data from physiological samples of HIV-infected individuals receiving NRTIs indicating an increased level of point mutation heteroplasmy and the level of the common mitochondrial deletion, compared to HIV-infected individuals who are NRTI treatment naïve. The mechanisms of this mutation level increase are elucidated through in vitro studies indicating that deletions accumulate through a size dependent mechanism during exposure and a point mutation level increase is mediated through a bottleneck mechanism. The possibility of NRTI de novo mutagenesis is refuted through the use of next generation sequencing technologies; the data also further supports a bottleneck mechanism of increased point mutation level. I also refute the idea that compounds associated with mitochondrial biogenesis can reduce mitochondrial depletion during NRTI exposure and that there appears to be no genetic predisposition to pathologies in sub-Saharan African individuals. I therefore conclude that there is an accelerated clonal expansion of pre-existing mitochondrial DNA mutations through NRTI exposure, which is mediated by a size dependent replication bias for deletions, and a molecular bottleneck effect which accelerates drift for point mutations. These data suggest an acceleration of normal cellular ageing through mitochondrial mechanisms in HIV-infected individuals

Trending Topics in Multiple Sclerosis

Multiple sclerosis (MS) is a chronic inflammatory disease characterized by progressive demyelination and neurodegeneration of the central nervous system (CNS), constituting the most common demyelinating disease of the CNS in humans. Although intensive research over many decades has unveiled many pathophysiological mechanisms in the development of MS, the cause is still unknown. Nevertheless, it does seem clear that genetic susceptibility and environmental factors play crucial roles. Trending Topics in Multiple Sclerosis is a book that provides an insight into some of the main problems currently debated in this area of research, focusing on topics that deal with genetic and environmental risk factors, pathophysiological mechanisms, neurocognitive findings, and neuroprotective strategies