Hypersensitivity reactions to metal implants: laboratory options

Background

All implant compounds undergo an electrochemical process when in contact with biological fluids, as well as mechanical corrosion due to abrasive wear, with production of metal debris that may inhibit repair processes. None of the commonly-used methods can diagnose implant allergies when used singly, therefore a panel of tests should be performed on allergic patients as pre-operative screening, or when a postoperative metal sensitisation is suspected.

Methods

We analysed patients with painful prostheses and subjects prone to allergies using the Patch Test in comparison with the Lymphocyte Transformation Test. Cytokine production was evaluated to identify prognostic markers for early diagnosis of aseptic loosening. Metal debris endocytosis and cytoskeletal rearrangement was visualised by confocal microscopy.

Results

Our results demonstrate that the Lymphocyte Transformation Test can identify patients who have a predisposition to develop allergic reactions and can confirm the diagnosis of hypersensitivity in patients with painful prostheses.

The prevalence of a Th2-cytokine pattern may be used to identify predisposition to the development of allergic diseases, while the selective presence of osteoclastogenic cytokines may be used as predictor of a negative outcome in patients with painful prosthesis.

The hypothesis of the prognostic value of these cytokines as early markers of aseptic loosening is attractive, but its confirmation would require extensive testing.

Conclusions

The Lymphocyte Transformation Test is the most suitable method for testing systemic allergies. We suggest that the combined use of the Patch Test and the Lymphocyte Transformation Test, associated with cytokine detection in selected patients, could provide a useful tool for preventive evaluation of immune reactivity in patients undergoing primary joint replacement surgery, and for clinical monitoring of the possible onset of a metal sensitization in patients with implanted devices.

Cystic bone angiomatosis: a case report treated with aminobisphosphonates and review of the literature

Cystic angiomatosis (CA) is a rare disease characterized by multifocal hemangiomatous and/or lymphangiomatous lesions of the skeleton with possible visceral organ involvement. The exact pathogenetic mechanism of the disease is still unknown. We describe a patient affected by CA of bone treated with surgical procedures and subsequently with intravenous aminobisphosphonates for 7 years. During the follow-up progression of lesions, the painful symptoms, markers of bone turnover, computed tomographic examination, and bone mineral density were evaluated. Aminobisphosphonate therapy showed an immediate effectiveness in reducing bone pain, with a significant decrease in circulating bone alkaline phosphatase and stable radiological findings during clinical follow-up. In addition, at baseline, high levels of bone biomarkers and cytokines (osteoprotegerin, osteopontin, and interleukin-6) capable of controlling bone metabolism and angiomatosis were identified. Aminobisphosphonate treatment produced a decrease of all these increased markers. Local cell therapy with bone marrow osteoblast precursors did not produce any measurable clinical improvement. Aminobisphosphonate therapy represents an elective treatment for bone angiomatosis syndromes, but further studies are necessary to understand the molecular basis of these disorders and of their pharmacological treatment.

Painful prosthesis: approaching the patient with persistent pain following total hip and knee arthroplasty

BACKGROUND

Symptomatic severe osteoarthritis and hip osteoporotic fractures are the main conditions requiring total hip arthroplasty (THA), whereas total knee arthroplasty (TKA) is mainly performed for pain, disability or deformity due to osteoarthritis. After surgery, some patients suffer from "painful prosthesis", which currently represents a clinical problem.

METHODS

A systematic review of scientific literature has been performed. A panel of experts has examined the issue of persistent pain following total hip or knee arthroplasty, in order to characterize etiopathological mechanisms and define how to cope with this condition.

RESULTS

Four major categories (non infective, septic, other and idiopathic causes) have been identified as possible origin of persistent pain after total joint arthroplasty (TJA). Time to surgery, pain level and function impairment before surgical intervention, mechanical stress following prosthesis implant, osseointegration deficiency, and post-traumatic or allergic inflammatory response are all factors playing an important role in causing persistent pain after joint arthroplasty. Diagnosis of persistent pain should be made in case of post-operative pain (self-reported as VAS ≥3) persisting for at least 4 months after surgery, or new onset of pain (VAS ≥3) after the first 4 months, lasting ≥2 months. Acute pain reported as VAS score ≥7 in patients who underwent TJA should be always immediately investigated.

CONCLUSIONS

The cause of pain needs always to be indentified and removed whenever possible. Implant revision is indicated only when septic or aseptic loosening is diagnosed. Current evidence has shown that peri-and/or post-operative administration of bisphosphonates may have a role in pain management and periprosthetic bone loss prevention.

Biologic and clinical significance of cytokine production in B-cell malignancies

Cytokines are a group of polypeptide hormones endowed with pleiotropic biological properties. Normal B lymphocytes produce a number of these factors that subserve important regulatory functions in the combined processes of proliferation and differentiation. Also neoplastic B cells can release cytokines and, simultaneously, respond to the same factors in an autocrine circuit that supports their malignant growth. In addition, tumor cells can make use of the factors released by normal cells, either spontaneously or under the influence of inductive signals from the neoplastic cells. Inappropriate or excessive release of cytokines may have an important role in the pathophysiology of some clinical features. Thus, neutralization of cytokine biologic activity in vivo could be a therapeutic strategy for treatment of human B-cell neoplasias.

In vitro differentiation of human mesenchymal stem cells on Ti6Al4V surfaces

Long-term stability of arthroplasty prosthesis depends on the integration between the bone tissue and the implanted biomaterials, which requires the contribution of osteoblastic precursors and their continuous differentiation into the osteoblastic phenotype. Classically, these interactions are tested in vitro using mesenchymal stem cells (MSCs) isolated and ex vivo expanded from bone marrow aspirates. Human adipose tissue-derived stromal cells (AMSCs) may be a more convenient source of MSCs, according to their abundance and accessibility, but no data are available on their in vitro interactions with hard biomaterials. The aim of this work is to compare the osteogenic potential of human AMSCs and bone marrow-derived MSCs (BMMSCs) and to evaluate their response to Ti6Al4V alloy in terms of adhesion, proliferation and differentiation features, using the human osteosarcoma cell line SaOS-2 for comparison. The overall results showed that AMSCs have the same ability to produce bone matrix as BMMSCs and that Ti6Al4V surfaces exhibit an osteoinductive action on AMSCs, promoting their differentiation into functional osteoblasts and increasing bone formation. In conclusion, adipose tissue is a promising autologous source of osteoblastic cells with important clinical implications for bone tissue engineering.

Genetics and pharmacogenetics of estrogen response

Estrogens are a steroid hormone group distributed widely in animals and human beings. Estrogens diffuse across cell phospholipidic membranes and interact with estrogen receptors. Their highest concentration is found in target tissues with reproductive function (breast, ovary, vagina and uterus). High estrogen levels are usually associated with tumor onset and progression, while loss of estrogen or its receptor(s) contributes to development and/or progression of various diseases (osteoporosis, neurodegenerative disease and cardiovascular disease). Despite the numerous efforts to highlight estrogen's mechanism of action, recent discoveries showed an unexpected degree of complexity of estrogenic response.

Phytoestrogens: food or drug?

Within the past several years, the relation between diet and health has been accepted by the mainstream nutrition community and in this connection interest in the physiological role of bioactive compounds present in plants has dramatically increased over the last decade.The phytoestrogens are bioactive molecules present as nutritional constituents of widely consumed vegetables. Their name derives from the fact that they are able to bind to estrogen receptors and to induce an estrogenic/antiestrogenic response in target tissues. Natural estrogens are involved in a multiplicity of programmed events in target tissues as uterus, breast, pituitary gland and hormone responsive tumors. Phytoestrogens are present in many human foodstuffs including fruits (plum, pear, apple grape berries, …), vegetables (beans, sprouts, cabbage, spinach, soybeans, grains, hops, garlic, onion,…), wine, tea, and they have been identified in a number of botanical dietary supplements. They include a wide variety of structurally different compounds such as isoflavones, mainly found in soy, lignans found in grains, stilbenes found in the skin of grapes. Other less investigated compounds include flavones, flavans, isoflavanes and coumestans. The estrogenic or antiestrogenic activity of any chemicals depends on the ability of the compound to interact with the ERs (ERα , ERβ ).This article reported the knowledge about the activity of phytoestrogens from a pharmacological point of view for their estrogenicity or antiestrogenicity.

Clodronate acts on human osteoclastic cell proliferation, differentiation and function in a bioreversible manner

Background. Clodronate is used in high bone resorption diseases. Its action was defined as "cytotoxic" based on the induced cellular ATP loss, without any experimental verification of reversibility. In the present report the reversibility of clodronate action was tested on cultured human osteoclastic cell cultures. As "in vitro" bioeffects of clodronate are reversible, this compound should not be defined as "cytotoxic".Introduction. Bisphosphonates are pyrophosphate analogs able to inhibit osteoclast-mediated bone resorption widely used in the treatment of diseases with high bone turnover. Several evidences have shown that bisphosphonates can be divided into two groups with distinct molecular mechanisms of action depending on the nature of the R(2)side chain. The nitrogen-containing bisphosphonates act on osteoclasts by preventing protein prenylation, while non-nitrogen-containing bisphosphonates, like clodronate, are metabolized intracellularly to a β-γ-methylene analog of ATP that induces inhibition of the ADP/ATP translocase.Materials and Methods. In order to evaluate clodronate effects on osteoclastic cells and the bioreversibility of its action, we have used a human preosteoclastic (FLG 29.1) cell line and primary cultures of human osteoclast-like (HOC) cells. Functional and differentiative modifications were evaluated with immunocytochemical tartrate-resistant acid phosphatase activity (TRAcP) assay and with rapid quantitative detection of the complex "matrix metalloproteinase 9/tissue inhibitor of metalloproteinase" (MMP9/TIMP1) by RT-PCR analysis based on "TaqMan" technology. The apoptosis phenomenon were detected by DNA ladder analysis and quantified by counting apoptotic cells with Transmission Electron Microscopy (TEM) analysis. Adenosine-5'-[ β - γ -dichloromethylene] triphosphate (AppCCl(2)p) was detected and identified in cell extract by HPLC-ESI-MS-MS Mass Spectrometry. Intracellular ATP modulation in the presence of clodronate was evaluated by luciferin-luciferase assay. The Mann-Whitney "U" test was conducted for statistical analysis.Results. We found that clodronate inhibited both proliferation and differentiative features of cells of the osteoclastic lineage. Furthermore, treatment of both cell types with clodronate caused apoptosis, generation of measurable levels of AppCCl(2)p, and reduction of intracellular ATP levels. Addition of ATP to the culture medium caused an inhibition of the biological actions of clodronate on the human osteoclastic cell lineage.Conclusions. These data indicate that intracellular accumulation of the metabolite AppCCl(2)p is the likely route by which clodronate inhibits osteoclastic function and this effect is reversed by ATP.

Methodological models for in vitro amplification and maintenance of human articular chondrocytes from elderly patients

Articular cartilage defects, an exceedingly common problem closely correlated with advancing age, is characterized by lack of spontaneous resolution because of the limited regenerative capacity of adult articular chondrocytes. Medical and surgical therapies yield unsatisfactory short-lasting results. Recently, cultured autologous chondrocytes have been proposed as a source to promote repair of deep cartilage defects. Despite encouraging preliminary results, this approach is not yet routinely applicable in clinical practice, but for young patients. One critical points is the isolation and ex vivo expansion of large enough number of differentiated articular chondrocytes. In general, human articular chondrocytes grown in monolayer cultures tend to undergo dedifferentiation. This reversible process produces morphological changes by which cells acquire fibroblast-like features, loosing typical functional characteristics, such as the ability to synthesize type II collagen. The aim of this study was to isolate human articular chondrocytes from elderly patients and to carefully characterize their morphological, proliferative, and differentiative features. Cells were morphologically analyzed by optic and transmission electron microscopy (TEM). Production of periodic acid-schiff (PAS)-positive cellular products and of type II collagen mRNA was monitored at different cellular passages. Typical chondrocytic characteristics were also studied in a suspension culture system with cells encapsulated in alginate-polylysine-alginate (APA) membranes. Results showed that human articular chondrocytes can be expanded in monolayers for several passages, and then microencapsulated, retaining their morphological and functional characteristics. The results obtained could contribute to optimize expansion and redifferentiation sequences for applying cartilage tissue engineering in the elderly patients.

Melatonin is a safe and effective treatment for chronic pulmonary and extrapulmonary sarcoidosis

Chronic sarcoidosis (CS) is often unresponsive to usual treatments. Melatonin, an immunoregulatory drug, was employed in CS patients in whom usual treatments were ineffective or induced severe side effects. Melatonin was given for 2 yr (20 mg/day in the first year, 10 mg/day in the second year) to 18 CS patients. Pulmonary function tests, chest X rays, pulmonary computed tomography, Ga(67) scintigraphy and angiotensin-converting enzyme (ACE) were assayed at baseline and in the follow-up. Normalization of ACE, improvement of pulmonary parameters and resolution of skin involvement were found in the patients given melatonin. After 24 months of melatonin therapy, hylar adenopathy completely resolved in eight patients and parenchymal lesions were markedly improved in all patients; in the five patients with reduced diffusion capacity of the lung for carbon monoxide, the values normalized after 6 months of therapy and remained stable until month 24. After 24 months, Ga(67) pulmonary and extra-pulmonary uptake was totally normalized in seven patients and, at month 12 months, ACE was normalized in six patients in which the values were high at the baseline. Skin lesions, present in three patients, completely disappeared at month 24 months. No side effects were experienced and no disease relapse was observed during melatonin treatment. Melatonin may be an effective and safe therapy for CS when other treatments fail or cause side effects.

Type 2 helper T-cell predominance and high CD30 expression in systemic sclerosis

The pattern of cytokine production of skin-infiltrating T cells from patients with progressive systemic sclerosis was investigated. Most CD4+ T-cell clones generated from skin biopsy specimens showed a type 2 helper (Th2) cytokine profile (production of interleukin-4, but no interferon (IFN)-gamma). High interleukin-4 but little or no IFN-gamma mRNA expression was found by in situ hybridization in skin perivascular mononuclear cell infiltrates. The immunohistochemical analysis revealed CD30 expression by high numbers of CD4+ T cells in the same specimens. Finally, the great majority of patients with diffuse disease had elevated levels of soluble CD30 in their sera. These data suggest the existence in patients with progressive systemic sclerosis of a predominant activation of Th2-like T cells, which may account for the major alterations (endothelial cell injury, fibrosis, and autoantibody production) occurring in this disease.

Effect of melatonin on normal and sclerodermic skin fibroblast proliferation

OBJECTIVE

We studied the effect of melatonin (MLT) (N-acetyl 5-methoxytryptamine) on the growth rate of normal skin fibroblasts and of fibroblasts from involved and apparently uninvolved skin of patients affected by systemic sclerosis (SSc).

METHODS

The growth rate was evaluated on the basis of growth curves and a 3H-thymidine incorporation assay.

RESULTS

Our results demonstrate that a dose of 200 micrograms/ml of MLT inhibits (> 80%) both control and SSc fibroblasts. Inhibition was dose-dependent and was greater than 70% for MLT concentrations of 100 micrograms/ml, 200 micrograms/ml and 400 micrograms/ml. 3H-thymidine incorporation was correlated with the effect on the growth curves (81% at 200 micrograms/ml of MLT). In contrast, at a low dosage of 6 micrograms/ml, MLT exerted a stimulatory effect on cell proliferation in all the cell lines analyzed. Cell viability was not affected by MLT at any of the concentrations tested. A recovery study indicated that replacement of MLT-containing medium with MLT-free medium resulted in a re-establishment of cell growth.

CONCLUSIONS

These results suggest that MLT, at higher dosages, is a potent inhibitor of the proliferation of fibroblasts derived from the skin of healthy and SSc patients.

c-myb proto-oncogene is expressed by quiescent scleroderma fibroblasts and, unlike B-myb gene, does not correlate with proliferation

Systemic sclerosis (scleroderma) is characterized by excessive deposition of extracellular matrix constituents. Although it has been proposed that tissue fibrosis is due to increased fibroblast synthesis of various collagen polypeptides, there is some experimental evidence that patients with systemic sclerosis have a defect in the control of fibroblast growth. The myb family of genes includes, among others, the c-myb proto-oncogene and the structurally related gene, B-myb, which are both implicated in the regulation of differentiation and/or proliferation of hematopoietic and nonhematopoietic cells. To elucidate the molecular basis responsible for scleroderma fibroblast proliferation, we therefore elected to investigate the expression of c-myb and B-myb genes in scleroderma and control cells. Using the reverse transcriptase polymerase chain reaction technique, we detected c-myb transcripts in scleroderma skin fibroblasts rendered quiescent by serum deprivation. Under the same experimental conditions, c-myb message was not found in normal skin fibroblasts, but, after serum stimulation, c-myb RNA was clearly evident from 3 to 72 h in both normal and pathologic cells. Treatment of these cells with c-myb antisense oligonucleotides caused downregulation of c-myb expression, and the inhibition of scleroderma fibroblast proliferation was 42%, whereas in normal fibroblasts the inhibition was weaker (22%). In contrast to c-myb, in normal and scleroderma fibroblasts the level of expression of B-myb correlated with cell proliferation assessed by cell count, and densitometric analysis showed that B-myb message was 1.5-5 times higher in most of pathologic cells studied. The antisense B-myb oligonucleotides had a weaker antiproliferative effect compared with antisense c-myb, inhibiting scleroderma and normal fibroblasts by 23% and 13%, respectively. These data suggest that the B-myb and c-myb genes may play a role in scleroderma fibroblast proliferation and function.

CD40 expression and function in murine B cell ontogeny

The CD40 antigen, a member of the nerve growth factor/tumor necrosis factor receptor family, is expressed on all mature B lymphocytes and plays a crucial role in B cell activation, T cell-dependent antigen-driven isotype switching and germinal center formation. We have analyzed CD40 expression and function during mouse B cell development by examining B cell precursors in normal mice and in transgenic animals in which B cell development is frozen at discrete stages. These models included RAG-2-/- mice, and transgenic littermates that express a mu heavy chain and/or the bcl-2 proto-oncogene transgene. CD40 was undetectable at the pro-B cell stage, but was expressed, although at low levels, on pre-B cells. However, pre-B cells failed to respond to CD40 triggering either by expression of CD23 or by proliferation in the presence of IL-4. Overexpression of bcl-2 increased the density of CD40 expression on pre-B cells: these cells respond to CD40 ligation by expressing CD23 and by proliferating in the presence of IL-4.

[Patterns of ventricular late potentials in systemic sclerosis: a noninvasive method in the study of cardiac involvement]

The aim of our study was to ascertain the prevalence of ventricular late potentials (VLP) in systemic sclerosis (SSc) and their correlation with the immunologic patterns and cutaneous and pulmonary involvement of the disease. Ventricular late potentials, which are low-amplitude high-frequency signals present in the terminal portion of the QRS complex, express the delayed and fragmented depolarization of ventricular myocardial fibers. Observed in myocardial interstitial fibrosis, they are characteristic of the myocardial alterations occurring in SSc. Twenty-six patients with SSc (1 man, 25 women) with a confirmed lack of cardiac involvement (negative history and normal clinical, electrocardiographic, and echocardiographic findings) underwent signal averaged high resolution electrocardiography. Pulmonary involvement was evaluated by pulmonary function tests and high resolution computed tomography. The degree of cutaneous involvement was assessed by skin score. In the patients with SSc, VLP presence with time-domain analysis was 30.8% when a 25-250 Hz pass-band filter was used and 26.9% when a 40-250 Hz pass-band filter was used whereas with frequency domain analysis it was 23.1%. Ventricular late potentials were confirmed in 7.7% of the control subjects, no matter what filter or technique was used. No significant correlations among VLP, pulmonary involvement, skin score and specific antibody patterns were found. Although this technique requires further consolidation, it seems to have the potential for use as an early index of myocardial fibrosis.

Potential role of interleukin-1 as the trigger for diffuse intravascular coagulation in acute nonlymphoblastic leukemia

Abnormalities of coagulation are common in patients with acute nonlymphoblastic leukemia, although the mechanisms involved are unclear, except in a few cases. To investigate the pathogenesis of this coagulopathy, suspensions of purified leukemic cells were prepared and tested for procoagulant activity. Neither the leukemic cells nor their supernatants directly accelerated the clotting of plasma. Since the leukemic cells did not possess direct procoagulant activity, their ability or inability to elaborate a mediator of cellular coagulant properties, interleukin-1, was studied. Leukemic cells from patients with coagulopathy elaborated interleukin-1, and addition of phytohemagglutinin increased interleukin-1 release. In contrast, no interleukin-1 was released, before or after stimulation with phytohemagglutinin, from leukemic cells from patients without coagulopathy. Leukemic cells from another group of patients with abnormalities of coagulation released interleukin-1 only after phytohemagglutinin treatment. In terms of the coagulation mechanism, interleukin-1 containing supernatants from leukemic cell cultures induced the procoagulant receptor tissue factor, a co-factor in the initiation of coagulation, on the endothelial cell surface. There was coordinate suppression of the anticoagulant endothelial cell receptor thrombomodulin, a co-factor for the antithrombotic protein C pathway. Antibody to interleukin-1 prevented these changes in cellular coagulant properties. Taken together, these changes result in a shift in the balance of endothelial cell coagulant properties to an activated state in which mechanisms promoting procoagulant reactions on the vessel surface predominate. Synthesis and release of the mediator interleukin-1 by leukemic cells thus defines a new mechanism through which malignant cells can potentially activate the coagulation mechanism.

Characterization of cells from invaded lymph nodes in patients with solid tumors. Lymphokine requirement for tumor-specific lymphoproliferative response

The specific immune response against the malignant cells was investigated in patients with urinary bladder or larynx cancer. Lymphocytes from lymph nodes that drain the tumor site were tested for their proliferative and cytotoxic capacities against autologous malignant cells isolated from the primary tumor. In no occasion was a proliferative or a cytotoxic response observed. However, when the lymph node cell suspensions were depleted of cells expressing both OKM1 and Leu-7 markers by rosetting with the appropriate mAbs, a proliferative response could be observed. The lymphocytes responded to autologous tumor cells only if IL-2 was added to the cultures. IL-2 alone induced some cell proliferation, which was not, however, comparable to that observed in response to both IL-2 and tumor cells. A panel of allogeneic tumor cells consistently failed to stimulate OKM1-, Leu-7- cells in vitro. Response to autologous tumor cells was not caused by HLA-encoded molecules, as occurs in the autologous mixed lymphocyte reaction, since OKM1-, Leu-7- cells failed to be stimulated by autologous non-T cells. A proliferative response was observed only with cells from lymph nodes that had been classified as invaded by malignant cells according to histopathologic criteria. Cells from noninvaded lymph nodes consistently failed to respond. Cells stimulated with autologous tumor cells could be expanded in short-term lines by continuous addition of IL-2 and malignant cells. One of these lines, which comprised mainly T8+ cells, was stimulated to proliferate only by autologous tumor cells, and its proliferative response was inhibitable by anti-class I and not by anti-class II mAbs. This line showed lytic capacities against autologous malignant targets, while it was inefficient against all of the other allogeneic cells tested. In another set of experiments, the mechanisms whereby exogenous IL-2 had to be added to the cultures to sustain a proliferative response against neoplastic cells were investigated. When cocultured with autologous malignant cells, OKM1-, Leu-7- lymphocytes expressed IL-2 receptors, as could be assessed by anti-Tac fluorescent staining. Under these culture conditions, these cells did not produce IL-2, and no proliferation was observed. Addition of purified IL-1 to the cultures induced IL-2 production and cell proliferation. It is concluded that metastatic lymph nodes contain a T cell population that can be detected in a proliferative assay when both suppressor cells are removed and the appropriate molecular signals are supplied.

Presence of activated T-cells with a T8+ M1+ Leu 7+ surface phenotype in invaded lymph nodes from patients with solid tumors

The lymphocyte surface phenotype of lymph nodes from patients with larynx or urinary bladder carcinoma was investigated by using a panel of monoclonal antibodies. The phenotype pattern of lymphocytes from lymph nodes invaded by malignant cells (as assessed by histopathology) was different from that of the cells from noninvaded or normal control nodes. Although the proportion of natural killer cells or macrophages was similar in the 3 groups of lymph nodes, invaded lymph nodes contained a higher proportion of T-cells and a lower B-cell percentage. Furthermore, cells from invaded nodes comprised 15-20% of T3+ T8+ cells that coexpressed the M1 marker and, to some extent, also the Leu 7 marker. A large proportion of cells with multiple markers were activated, as shown by the expression of Tac and HLA-DR antigens. In 2 patients activated T8+ cells expressing also M1 and Leu 7 markers infiltrated the tumor site. The presence of these activated cells both in involved nodes and tumor mass may indicate that they originate in response to cancer.