Iron pigment deposits, small vessel vasculitis, and erythrophagocytosis in the muscle of human immunodeficiency virus-infected patients

Iron Pathways and Iron Chelation Approaches in Viral, Microbial, and Fungal Infections

Iron is an essential element required to support the health of organisms. This element is critical for regulating the activities of cellular enzymes including those involved in cellular metabolism and DNA replication. Mechanisms that underlie the tight control of iron levels are crucial in mediating the interaction between microorganisms and their host and hence, the spread of infection. Microorganisms including viruses, bacteria, and fungi have differing iron acquisition/utilization mechanisms to support their ability to acquire/use iron (e.g., from free iron and heme). These pathways of iron uptake are associated with promoting their growth and virulence and consequently, their pathogenicity. Thus, controlling microorganismal survival by limiting iron availability may prove feasible through the use of agents targeting their iron uptake pathways and/or use of iron chelators as a means to hinder development of infections. This review will serve to assimilate findings regarding iron and the pathogenicity of specific microorganisms, and furthermore, find whether treating infections mediated by such organisms via iron chelation approaches may have potential clinical benefit.

Anemia, Iron Status, and HIV: A Systematic Review of the Evidence

People living with HIV (PLWHIV) are at high risk of anemia due to inadequate iron intake, HIV and opportunistic infections, and inflammation, and as a side effect of antiretroviral therapy. Though iron supplementation can reduce iron deficiency anemia (IDA) in the general population, its role in anemia and in the health of PLWHIV is unclear due to concerns that iron supplementation may increase HIV replication and risk of opportunistic infections. We systematically reviewed the evidence on indicators of iron status, iron intake, and clinical outcomes among adults and children with HIV. The evidence suggests that anemia is associated with an increased risk of all-cause mortality and incident tuberculosis among HIV-infected individuals, regardless of anemia type, and the magnitude of the risk is greater with more severe anemia. High serum ferritin is associated with adverse clinical outcomes, although it is unclear if this is due to high iron or inflammation from disease progression. One large observational study found an increased risk of all-cause mortality among HIV-infected adults if they received iron supplementation. Published randomized controlled trials of iron supplementation among PLWHIV tend to have small sample sizes and have been inconclusive in terms of effectiveness and safety. Large randomized trials exploring approaches to safely and effectively provide iron supplementation to PLWHIV are warranted.

Minocycline-associated rimmed vacuolar myopathy in a patient with rheumatoid arthritis

BACKGROUND

The autophagic vacuolar myopathies (AVM) are a group of inherited myopathies defined by the presence of autophagic vacuoles in pathological muscle specimens. AVM can be categorized into three groups: acid maltase deficiency, myopathies characterized by autophagic vacuoles with unique sarcolemmal features, and rimmed vacuolar myopathies (RVM). While the pathogeneses of these conditions are still being elucidated, some drugs (e.g., chloroquine, its analog, hydroxychloroquine, and colchicine) can also cause AVM. Minocycline is a disease-modifying anti-rheumatic drug that may be used in the treatment of rheumatoid arthritis (RA). Here, we describe the first case of minocycline-associated AVM with rimmed vacuole formation.

CASE PRESENTATION

A 75-year-old woman suffering from RA has been continuously treated with minocycline (200 mg/day) for the past 7 years. During this time, she developed a myopathy that predominantly affected her lower limbs. Histological studies of biopsied muscle revealed scattered atrophic myofibers with rimmed vacuoles that contained pigment granules. Histochemical staining revealed that the pigment comprised both iron and melanin, which is consistent with type II minocycline-induced cutaneous pigmentation. Under electron microscopy, autophagic vacuoles were consistently observed in association with numerous collections of pigment granules.

CONCLUSIONS

This is the first report of minocycline-induced pigmentation in skeletal muscle. The strong association between autophagic vacuoles and the accumulation of minocycline-induced pigments suggest that long-term minocycline treatment induced pigment accumulation, leading to elevation of autophagic activity and RVM. It might also be possible that minocycline directly activated autophagy, as the observed pigments are known to form complexes containing minocycline and/or its metabolites. As long-term minocycline treatment is expected to be used more widely in the future, we must draw attention to this adverse effect.

Complications musculaires de l’infection par le virus de l’immunodéficience humaine (VIH) à l’ère des trithérapies

Introduction of highly active antiretroviral therapy (HAART) has dramatically modified the natural history of HIV disease, but lengthening the survival of HIV-infected individuals has been associated with an increasing prevalence of iatrogenic conditions. Muscular complications of HIV infection are classified as follows: (1) HIV-associated myopathies and related conditions including polymyositis, inclusion-body myositis, nemaline myopathy, diffuse infiltrative lymphocytosis syndrome (DILS), HIV-wasting syndrome, vasculitis, myasthenic syndromes, and chronic fatigue; (2) iatrogenic conditions including mitochondrial myopathies, HIV-associated lipodystrophy syndrome, and immune restoration syndrome; (3) opportunistic infections and tumor infiltrations of skeletal muscle; and (4) rhabdomyolysis. These features are described in the present review.

Skeletal muscle involvement in human immunodeficiency virus (HIV)-infected patients in the era of highly active antiretroviral therapy (HAART)

Skeletal muscle involvement can occur at all stages of human immunodeficiency virus (HIV) infection, and may represent the first manifestation of the disease. Myopathies in HIV-infected patients are classified as follows: (1) HIV-associated myopathies and related conditions, including HIV polymyositis, inclusion-body myositis, nemaline myopathy, diffuse infiltrative lymphocytosis syndrome (DILS), HIV-wasting syndrome, vasculitic processes, myasthenic syndromes, and chronic fatigue; (2) muscle complications of antiretroviral therapy, including zidovudine and toxic mitochondrial myopathies related to other nucleoside-analogue reverse-transcriptase inhibitors (NRTIs), HIV-associated lipodystrophy syndrome, and immune restoration syndrome related to highly active antiretroviral therapy (HAART); (3) opportunistic infections and tumor infiltrations of skeletal muscle; and (4) rhabdomyolysis. Introduction of HAART has dramatically modified the natural history of HIV disease by controlling viral replication, but, in turn, lengthening of the survival of HIV-infected individuals has been associated with an increasing prevalence of iatrogenic conditions.

Non-systemic vasculitic neuropathy

PURPOSE OF REVIEW

This article reviews the literature on non-systemic vasculitic neuropathy, with emphasis on recent advances, summarizing the clinical presentation, diagnosis, pathology, treatment, and outcome of this condition, and speculating on its nosological status vis-à-vis the systemic vasculitides.

RECENT FINDINGS

A new cohort of non-systemic vasculitic neuropathy patients was recently reported. Analysis of the clinical characteristics of this cohort demonstrated a higher incidence of painful, asymmetric, overlapping deficits than in previous studies. Extended follow-up revealed a high relapse rate, low risk of systemic spread, high incidence of chronic pain, relatively good neurological outcome, and low mortality rate. Analysis of therapeutic responses showed better outcomes with combination therapy than corticosteroid monotherapy. Another recent report proposed a role for magnetic resonance angiography in the diagnosis and follow-up of non-systemic vasculitic neuropathy. Recent pathological studies implicated proinflammatory cytokines and matrix metalloproteinase-9 in the mediation of vascular and axonal damage in non-systemic vasculitic neuropathy.

SUMMARY

Non-systemic vasculitic neuropathy is one of many localized vasculitides, with involvement restricted to nerves and (possibly) muscles. Inclusion and exclusion criteria differ between reported cohorts. All require a nerve biopsy diagnostic of or suspicious for vasculitis and no extra-neuromuscular involvement. Patients typically present subacutely with a painful, multifocal/asymmetric, distal-predominant neuropathy. In the absence of clinical or laboratory evidence of systemic vasculitis or a condition predisposing to such, prognosis with treatment is good. Pathological data are supportive of a primary T-cell-mediated immunopathogenesis. Some patients classified as having non-systemic vasculitic neuropathy have a systemic vasculitis presenting with neuropathy; in others, the disease is organ-specific.

Kawasaki-like syndromes and other vasculitic syndromes in HIV-infected patients

Excluding drug-related hypersensitivity reactions, vasculitic syndromes are not common in HIV-positive patients. Review of the existing literature suggests that HIV positive patients may be predisposed to polyarteritis nodosa, microscopic polyarteritis, Kawasaki-like syndromes, acute occlusion syndromes, primary angiitis of the central nervous system and erythema elevatum diutinum. With the exception of erythema elevatum diutinum, these vasculitic syndromes have significant morbidities and mortality if they are not treated. It is therefore important to make these diagnoses and to initiate appropriate therapy in a timely fashion. Because fevers, malaise, weakness, rashes, headaches and neurologic symptoms are common in HIV-positive patients, it is probable that some cases of vasculitis go undiagnosed. In this report, we review vasculitic syndromes seen in HIV-positive patients. We also re-examine a previously published case of a young HIV-positive male who died of an acute myocardial infarction without atherosclerotic disease. Immunohistopathology of the affected arteries suggests that he died of a Kawasaki-like syndrome.

Polyarteritis nodosa, microscopic polyangiitis, and Churg-Strauss syndrome: clinical aspects, neurologic manifestations, and treatment

Polyarteritis nodosa (PAN), microscopic polyangiitis (MPA), and Churg-Strauss syndrome (CSS) all have neurologic symptoms and share characteristics and outcomes. Clinical aspects, neurologic manifestations, and treatment of these three diseases are examined in this article.

Human immunodeficiency virus-associated vasculopathy in transgenic mice

There is substantial clinical evidence for the development of vascular disorders in human immunodeficiency virus (HIV)-infected individuals, particularly in the form of vasculitis. Transgenic mice carrying a replication-defective HIV-1 provirus with selective deletion of the gag, pol, and env genes developed extensive vasculopathy. Restricted expression of HIV nonstructural genes in smooth muscle cells was accompanied by the migration and proliferation of these cells in blood vessels of all sizes and at different body sites. The frequent infiltration observed in the hypertrophic vessel walls occurred predominantly in the adventitia and was composed of primarily T cells and occasionally plasma cells. The intimal thickening generated significant luminal narrowing in some vessels, and the restricted blood flow led to ischemia in the affected tissues. Interestingly, the endothelium did not appear to support HIV gene expression or be involved in the pathological process. This transgenic model provides an opportunity to dissect the mechanism underlying HIV-associated vasculopathy.

Peripheral neuropathy in human immunodeficiency virus-infected patients with the diffuse infiltrative lymphocytosis syndrome

A subset of human immunodeficiency virus (HIV)-infected patients develop persistent CD8 hyperlymphocytosis and a Sjogren's syndrome-like syndrome associated with multivisceral CD8 T-cell infiltration, known as the diffuse infiltrative lymphocytosis syndrome (DILS). Patients with DILS tend to have higher CD4 cell counts, fewer opportunistic infections, and longer survival times than other HIV-infected patients. Peripheral nerve involvement in DILS has been poorly documented. We studied 12 HIV-infected patients with CD8 hyperlymphocytosis, DILS, and clinical signs of peripheral neuropathy. Two of 4 patients who were HLA typed were HLA-DR5 and 1 was HLA-DR6. All patients had the sicca syndrome and multivisceral involvement. The neuropathy was acute or subacute, always painful, and symmetrical in 8 cases. Electrophysiology was consistent with axonal neuropathy in 10 of 12 patients. Nerve biopsy showed marked angiocentric CD8 infiltrates without mural necrosis (12 of 12), and abundant expression of HIV p24 protein in macrophages (12 of 12). The HIV genome was detected by polymerase chain reaction in nerve homogenates. Zidovudine therapy was associated with improvement in 6 of 6 patients and steroid therapy was beneficial in 4 of 5 patients. No T-cell lymphoma was observed during follow-up, but 2 patients developed a primary B-cell lymphoma. We conclude that DILS neuropathy represents HIV-associated neuropathy, characterized by marked CD8 infiltration and abundant HIV in nerve, that improves with zidovudine or steroid therapy, and probably reflects a systemic host-determined and antigen-driven response to HIV.

Immunocytochemical localization of immunoglobulins in disc herniations

STUDY DESIGN

Disc herniation and control discs were studied for the presence of immunoglobulins immunocytochemically.

OBJECTIVES

To study a possible presence of immunoglobulin complexes in herniated disc tissue and to locate them at the tissue level by immunocytochemistry; to compare immunohistologic findings with those obtained in control disc tissue; and to compare the prevalences of immunoglobulin M and immunoglobulin G.

SUMMARY OF BACKGROUND DATA

In herniated disc tissue, high activity of inflammatory phospholipase A2 was previously demonstrated, and inflammatory cells were noted immunohistochemically. Immunoglobulins G and M were observed biochemically but have not been located at the tissue level.

METHODS

Fifty-two disc herniations and three macroscopically normal fresh cadaver discs were managed by an identical immunocytochemical protocol, using monoclonal antihuman antibodies to immunoglobulins M and G.

RESULTS

In 29 of 52 disc herniations (56%), immunoglobulin M deposits were observed, and in 18 of 52 disc herniations (35%) immunoglobulin G could be demonstrated. Almost all the disc herniations where immunoglobulin G was present also contained immunoglobulin M deposits (except for two). In the control discs studied, neither immunoglobulin could be observed immunohistochemically. The immunoglobulin deposits were noted in areas where blood vessels were also present. Morphologically, immunoglobulin immunoreactivity resembling immune complexes was observed.

CONCLUSIONS

The results lend support to previous suggestions of inflammation and immune reaction in disc herniations, including previous biochemical studies suggesting immunoglobulin deposition. The exact role of the demonstrated immunoglobulins in disc tissue pathophysiology will have to be clarified further.

Cytochrome c oxidase deficiency in zidovudine myopathy affects perifascicular muscle fibres and arterial smooth muscle cells

In order to assess the pathogenesis of myopathological alterations induced by zidovudine, we studied muscle samples from 21 patients infected by human immunodeficiency virus with zidovudine myopathy. Cytochrome c oxidase histoenzymatic reaction was evaluated in skeletal muscle fibres and arterial smooth muscle cells. Other investigations included immunocytochemistry for membrane attack complex and endomysial capillary counts. All patients had partial cytochrome c oxidase deficiency. A perifascicular distribution of cytochrome c oxidase-deficient fibres was found in 14 of 21 patients. Cytochrome c oxidase-deficient fibres were significantly more frequent in perifascicular areas than in the complete muscle sections (28% vs 12%, P < 0.001). Cytochrome c oxidase-deficient arteries were found in 11 patients, of whom 10 also had a perifascicular deficiency. Mononuclear microvascular inflammation was observed in four patients and membrane attack complex deposition in capillary walls in two patients. The capillary counts were not significantly different in the patients and in the controls. These results suggest that, in addition to a direct action of zidovudine on mitochondrial DNA, chronic muscle ischaemia related to zidovudine-induced vascular dysfunction might be implicated at the inception of muscle damage in zidovudine myopathy.

Iron: mammalian defense systems, mechanisms of disease, and chelation therapy approaches

During the past 6 decades, much attention has been devoted to understanding the uses, metabolism and hazards of iron in living systems. A great variety of heme and non-heme iron-containing enzymes have been characterized in nearly all forms of life. The existence of both ferrous and ferric ions in low- and high-spin configuration, as well as the ability of the metal to function over a wide range of redox potentials, contributes to its unique versatility. Not surprisingly, the singular attributes of iron that permit it to be so useful to life likewise render the metal dangerous to manipulate and to sequester. All vertebrate animals are prone to tissue damage from exposure to excess iron. In order to protect them from this threat, a complex system has evolved to contain and detoxify this metal. This is known as the iron withholding defense system, which mainly serves to scavenge toxic quantities of iron and also for depriving microbial and neoplastic invaders of iron essential for their growth. Since 1970, medical scientists have become increasingly aware of the problems involved in cellular iron homeostasis and of the disease states related to its malfunctioning. Scores of studies have reported that excessive iron in specific tissue sites is associated with development of infection, neoplasia, cardiomyopathy, arthropathy and a variety of endocrine and neurologic deficits. Accordingly, several research groups have attempted to develop chemical agents that might prevent and even eliminate deposits of excess iron. A few of these drugs now are in clinical use, e.g. deferiprone (L1). In the present review, we focus on recent developments in (i) selected aspects of the iron withholding defense system, and (ii) pharmacologic methods that can assist the iron-burdened patient.

Cytokine expression in the muscle of HIV-infected patients: evidence for interleukin-1 alpha accumulation in mitochondria of AZT fibers

To evaluate the possible role of cytokines in human immunodeficiency virus (HIV)-associated muscular disorders, we performed immunocytochemistry for interleukin-1 alpha, -1 beta, and -6 and tumor necrosis factor-alpha on frozen muscle biopsy specimens from HIV-infected patients with various myopathies (HIV polymyositis in 5, HIV-wasting syndrome in 5, zidovudine myopathy in 10) and from seronegative individuals (normal muscle in 2, mitochondrial cytopathies in 10). The HIV-infected patients showed positive reactivities in vessels (interleukin-1) and in inflammatory cells (mainly interleukin-1 and tumor necrosis factor-alpha), including perivascular hemosiderin-laden macrophages in 5 patients. In zidovudine myopathy, a majority of AZT fibers (i.e., ragged-red fibers with marked myofibrillar changes) showed mild to marked expression of interleukin-1. Expression of interleukin-1 in the other mitochondrial myopathies was much weaker. Interleukin-1 beta messenger RNA was demonstrated in muscle fibers by in situ hybridization, implying that interleukin-1 was produced in muscle cells. Immunoelectron microscopy showed that interleukin-1 alpha was mainly bound to mitochondrial membranes in AZT fibers. Proinflammatory and destructive effects of the studied cytokines might be responsible for several myopathological changes observed in HIV-infected patients, including inflammation and hemosiderin deposits in muscle tissue, and prominent myofibrillar breakdown in AZT fibers.

Determination of the blood lactate:pyruvate ratio as a noninvasive test for the diagnosis of zidovudine myopathy

OBJECTIVE

To evaluate the use of the lactate: pyruvate ratio as a test for the detection of zidovudine myopathy.

METHODS

Twenty consecutive human immunodeficiency virus-infected patients with muscle involvement and 20 without muscle involvement were studied prospectively. Blood lactate and pyruvate levels and serum creatine kinase levels were tested, muscle involvement was assessed both clinically and electrophysiologically, and muscle biopsy was performed in patients with myopathy.

RESULTS

Nine patients had biopsy-proven zidovudine myopathy. All 9 had a high lactate:pyruvate ratio, with elevations on 2 of 2 determinations in 6 patients and on 1 of 2 in 3 patients. Two of 11 patients with other myopathies and 2 of 20 patients without myopathy had a high lactate:pyruvate ratio on 1 of 2 determinations.

CONCLUSION

The lactate:pyruvate ratio, when determined repeatedly, is a sensitive test for detecting mitochondrial muscular toxicity of zidovudine.

The spectrum of vasculitis in human immunodeficiency virus-infected patients. A clinicopathologic evaluation

OBJECTIVE

To delineate the different types of inflammatory vascular diseases (IVD) occurring in patients with human immunodeficiency virus (HIV) infection.

METHODS

Muscle, nerve, or skin biopsy specimens from 148 symptomatic HIV-infected individuals were reviewed, and subgroups of vasculitis were identified using the American College of Rheumatology (ACR) 1990 clinicopathologic criteria for the classification of vasculitis.

RESULTS

IVD was documented in 34 patients (23%) and included necrotizing arteritis (3 patients), non-necrotizing arteritis (1 patient), neutrophilic IVD (7 patients), mononuclear IVD (17 patients), and other small vessel inflammatory changes (6 patients). According to the ACR criteria, 11 patients could be classified as having a distinct category of vasculitis, including polyarteritis nodosa (4 patients), Henoch-Schönlein purpura (1 patient), and drug-induced hypersensitivity vasculitis (6 patients), and 23 were classified in the group "other vasculitis, type unspecified." One patient had hepatitis B virus surface antigenemia, 2 had cryoglobulinemia, and 2 were coinfected by human T lymphotropic virus type I. Cytomegalovirus inclusions and antigens were found in endothelial cells in 1 patient. HIV antigens and genome were detected in perivascular cells of 2 of the 3 patients with necrotizing arteritis; in 1, HIV-like particles were seen by electron microscopy. Immune deposits were found in small vessel walls in 5 skin biopsy samples showing small vessel vasculitis and in the muscle of the 3 patients with necrotizing arteritis.

CONCLUSION

A wide range of inflammatory vascular diseases may occur in HIV-infected individuals. Vascular inflammation appears multifactorial and may result from HIV-induced immunologic abnormalities and exposure to a variety of xenoantigens, such as HIV itself, other infectious agents, and drugs.

Early central nervous system changes in human immunodeficiency virus (HIV)-infection

Early HIV infection of the CNS, as demonstrated by cerebrospinal fluid studies, seems relatively common. However most HIV carriers remain neurologically unimpaired during the incubation period. A few psychometric, radiological, and electrophysiological studies suggest that neurological abnormalities are present at early stages of HIV infection; the findings of these studies are controversial and until recently, they have not been supported by neuropathological data. Early brain changes, including leptomeningitis and vasculitis with myelin pallor and gliosis of the deep white matter are probably secondary to vascular inflammation and opening of the blood-brain barrier. Such conclusions are drawn from the examination of brains of asymptomatic HIV-positive individuals who died from unnatural causes, and of rare cases with acute fatal encephalopathy revealing HIV infection. In addition, early experimental simian immunodeficiency virus infection and feline immunodeficiency virus encephalopathy have demonstrated similar changes to those in man. Although small amounts of viral genome were detected by PCR in a few cases, the early changes in the human brain do not seem to result from a productive HIV infection of the CNS, as seen in HIV encephalitis. The occurrence of a usually asymptomatic and transient immunopathological reaction coinciding with early HIV infection of the nervous system appears to be more likely.

Tubular aggregates and partial cytochrome c oxidase deficiency in skeletal muscle of patients with AIDS treated with zidovudine

We report on two patients, who had myalgias while receiving long-term zidovudine treatment for an HIV infection, in whom muscle biopsy findings included a partial cytochrome c oxidase (CCO) deficiency, a feature of zidovudine myopathy, and tubular aggregates, a finding hitherto unreported in HIV-infected patients. The CCO deficit was observed in 28% and 24% of muscle fibers, respectively. Tubular aggregates were the prominent histopathological feature in patient 1, and were detected by systematic electron microscopy in patient 2. Inflammation and myonecrosis were not detected. In patient 1, the typical mitochondrial and myofibrillar changes of zidovudine myopathy were present and 12% of fibers showed tubular aggregates. The aggregates were not stained at CCO reaction, and 96% of myofibers enclosing tubular aggregates showed a decreased CCO activity. This suggested more than a chance association between mitochondrial dysfunction and the formation of tubular aggregates. We conclude that tubular aggregates are detected in some patients treated by zidovudine, and that the finding could be related to the long-term administration of the drug.

Partial cytochrome c oxidase deficiency and cytoplasmic bodies in patients with zidovudine myopathy

A histochemical study of cytochrome c oxidase (CCO) was performed in the muscles from eight patients with full-blown zidovudine myopathy. All patients had ragged-red fibres (total cumulative count: 160) and myofilamentous changes, that predominated in type 1 fibres and included diffuse or punch-out myofibrillar loss (75 affected fibres) and constant cytoplasmic body formation (106 affected fibres). Inflammatory infiltrates were present in four out of eight patients. A partial CCO deficiency (22-47% of fibres; both types 1 and 2 affected) was detected in all cases, and contrasted with the normal or increased succinate dehydrogenase activity observed in most fibres. Among CCO-deficient fibres, 71% were normal on trichrome, but all ragged-red fibres were CCO-negative. Myofilamentous changes were restricted to CCO-deficient fibres. The present study strongly supports the idea that mitochondrial toxicity is the specific mechanism of zidovudine myopathy.