Monica De Mattei

BK and JC Human Polyomaviruses and Simian Virus 40: Natural History of Infection in Humans, Experimental Oncogenicity, and Association with Human Tumors

Publisher Summary Several viruses are ubiquitous in the human population and produce a persistent or latent infection in humans. Some of them—such as human polyomaviruses BK (BKV) and JC (JCV)—are oncogenic in experimental systems and are associated with human tumors. This chapter considers the general properties of the human polyomaviruses BK and JC, the characteristics of the latent infection and of the ubiquitous state of these viruses in humans, their transforming capacity in vitro , their oncogenicity in experimental animals, and their possible etiologic role in human tumors are also evaluated. It is noted that the classic Kochs postulates cannot be applied to latent viruses. New rules are considered for these viruses to establish their oncogenic role. It is reported that BKV fulfills these criteria, suggesting that BKV may cooperate, under peculiar conditions, as a cofactor in the development or progression of human tumors. BKV oncogenicity is revealed by cooperating events, such as oncogene activation, loss of tumor suppressor genes, or rearrangements of the viral genome, inducing proliferation of clonal neoplastic cells in a population of latently BKV-infected cells.

Effects of electromagnetic fields on proteoglycan metabolism of bovine articular cartilage explants.

Electromagnetic field (EMF) exposure has been proposed for the treatment of osteoarthritis. In this study, we investigated the effects of EMF (75 Hz, 2,3 mT) on proteoglycan (PG) metabolism of bovine articular cartilage explants cultured in vitro, both under basal conditions and in the presence of interleukin-1 g (IL-1 g ) in the culture medium. Proteoglycan synthesis and the residual PG tissue content resulted significantly higher in EMF-exposed explants than in controls, whereas no effect was observed on PG release and nitric oxide (NO) production. IL-1 g induced both a reduction in PG synthesis and an increase in PG release, related to a strong stimulation of NO production, which resulted in a net loss of tissue PG content. In IL-1 g -treated explants, EMF increased PG synthesis, whereas in spite of a slight stimulation of NO production EMF did not modify PG release. This resulted in the residual PG tissue content being maintained at the control level. In both experimental conditions, the effects of EMF were associated with an increase in lactate production. The results of our study show that EMFs are able to promote anabolic activities and PG synthesis in bovine articular cartilage explants. This effect also is maintained in the presence of IL-1 g , thus counteracting the catabolic activity of the cytokine. Altogether, these data suggest that EMF exposure exerts a chondroprotective effect on articular cartilage in vitro.

Effects of Pulsed Electromagnetic Fields on Human Articular Chondrocyte Proliferation

Low-energy, low-frequency pulsed electromagnetic fields (PEMFs) can induce cell proliferation in several cell culture models. In this work we analysed the proliferative response of human articular chondrocytes, cultured in medium containing 10% FBS, following prolonged exposure to PEMFs (75 Hz, 2.3 mT), currently used in the treatment of some orthopaedic pathologies. In particular, we investigated the dependence of the proliferative effects on the cell density, the availability of growth factors and the exposure lengths. We observed that PEMFs can induce cell proliferation of low density chondrocyte cultures for a long time (6 days), when fresh serum is added again in the culture medium. In the same conditions, in high density cultures, the PEMF-induced increase in cell proliferation was observed only in the first three days of exposure. The data presented in this study show that the availability of growth factors and the environmental constrictions strongly condition the cellular proliferative response to PEMFs.

Gene polymorphisms in folate metabolizing enzymes in adult acute lymphoblastic leukemia: effects on methotrexate-related toxicity and survival

Individual variations in response and/or toxicity to anti-cancer agents is common. The antifolate agent methotrexate is frequently used in maintenace therapy of acute lymphoblastic leukemia. The findings of this study suggest that genotyping of folate polymorphisms might be useful in adult acute lymphoblastic leukemia to optimize methotrexate therapy, reducing the associated toxicity with possible effects on survival. Background The antifolate agent methotrexate is an important component of maintenance therapy in acute lymphoblastic leukemia, although methotrexate-related toxicity is often a reason for interruption of chemotherapy. Prediction of toxicity is difficult because of inter-individual variability susceptibility to antileukemic agents. Methotrexate interferes with folate metabolism leading to depletion of reduced folates. Design and Methods The aim of this study was to investigate the influence of polymorphisms for folate metabolizing enzymes with respect to toxicity and survival in adult patients with acute lymphoblastic leukemia treated with methotrexate maintenance therapy. To this purpose, we evaluated possible associations between genotype and hematologic and non-hematologic toxicity and effects on survival at 2 years of follow-up in patients with acute lymphoblastic leukemia. Results Polymorphisms in the genes encoding for methylenetetrahydrofolate reductase (MTHFR 677C>T) and in dihydrofolate reductase (DHFR 19 bp deletion) significantly increased the risk of hepatotoxicity in single (odds ratio 5.23, 95% confidence interval 1.13–21.95 and odds ratio 4.57, 95% confidence interval 1.01–20.77, respectively) and in combined analysis (odds ratio 6.82, 95% confidence interval 1.38–33.59). MTHFR 677C>T also increased the risk of leukopenia and gastrointestinal toxicity, whilst thymidylate synthase 28 bp repeat polymorphism increased the risk of anemia (odds ratio 8.48, 95% confidence interval 2.00–36.09). Finally, patients with MTHFR 677TT had a decreased overall survival rate (hazard ratio 2.37, 95% confidence interval 1.46–8.45). Conclusions Genotyping of folate polymorphisms might be useful in adult acute lymphoblastic leukemia to optimize methotrexate therapy, reducing the associated toxicity with possible effects on survival.

Chondroprotective effects of pulsed electromagnetic fields on human cartilage explants

This study investigated the effects of pulsed electromagnetic fields (PEMFs) on proteoglycan (PG) metabolism of human articular cartilage explants from patients with osteoarthritis (OA). Human cartilage explants, recovered from lateral and medial femoral condyles, were classified according to the International Cartilage Repair Society (ICRS) and graded based on Outerbridge scores. Explants cultured in the absence and presence of IL-1β were treated with PEMF (1.5  mT, 75  Hz) or IGF-I alone or in combination for 1 and 7 days. PG synthesis and release were determined. Results showed that explants derived from lateral and medial condyles scored OA grades I and III, respectively. In OA grade I explants, after 7 days exposure, PEMF and IGF-I significantly increased (35) S-sulfate incorporation 49% and 53%, respectively, compared to control, and counteracted the inhibitory effect of IL 1β (0.01 ng/ml). The combined exposure to PEMF and IGF-I was additive in all conditions. Similar results were obtained in OA grade III cartilage explants. In conclusion, PEMF and IGF-I augment cartilage explant anabolic activities, increase PG synthesis, and counteract the catabolic activity of IL-1β in OA grades I and III. We hypothesize that both IGF-I and PEMF have chondroprotective effects on human articular cartilage, particularly in early stages of OA.

Pulsed electromagnetic fields stimulate osteogenic differentiation in human bone marrow and adipose tissue derived mesenchymal stem cells

Pulsed electromagnetic fields (PEMFs) play a regulatory role on osteoblast activity and are clinically beneficial during fracture healing. Human mesenchymal stem cells (MSCs) derived from different sources have been extensively used in bone tissue engineering. Compared with MSCs isolated from bone marrow (BMSCs), those derived from adipose tissue (ASCs) are easier to obtain and available in larger amounts, although they show a less osteogenic differentiation potential than BMSCs. The hypothesis tested in this study was to evaluate whether PEMFs favor osteogenic differentiation both in BMSCs and in ASCs and to compare the role of PEMFs alone and in combination with the biochemical osteogenic stimulus bone morphogenetic protein (BMP)-2. Early and later osteogenic markers, such as alkaline phosphatase (ALP) activity, osteocalcin levels, and matrix mineralization, were analyzed at different times during osteogenic differentiation. Results showed that PEMFs induced osteogenic differentiation by increasing ALP activity, osteocalcin, and matrix mineralization in both BMSCs and ASCs, suggesting that PEMF activity is maintained during the whole differentiation period. The addition of BMP-2 in PEMF exposed cultures further increased all the osteogenic markers in BMSCs, while in ASCs, the stimulatory role of PEMFs was independent of BMP-2. Our results indicate that PEMFs may stimulate an early osteogenic induction in both BMSCs and ASCs and they suggest PEMFs as a bioactive factor to enhance the osteogenesis of ASCs, which are an attractive cell source for clinical applications. In conclusion, PEMFs may be considered a possible tool to improve autologous cell-based regeneration of bone defects in orthopedics.

Factor XIII V34L polymorphism modulates the risk of chronic venous leg ulcer progression and extension

Low Factor XIII (FXIII) activity has been reported in the blood of patients with chronic venous leg ulcer (CVU). In vivo studies have described increased wound healing in CVU patients treated with FXIII concentrate, and in vitro studies have shown increased regenerative capacity in FXIII‐treated fibroblasts. In addition, a common G‐to‐T polymorphism in the FXIIIA‐subunit gene (V34L) significantly increases the activity and modifies the cross‐linking properties of the FXIII molecule and this variant has been investigated as a protective factor against thrombosis, a recognized risk factor for CVU establishment. Therefore, the role of FXIII levels, FXIII V34L, FVR506Q, and FIIG20210A, common gene polymorphisms in the pathogenesis of CVU was investigated. Ninety‐one patients with CVU and 195 healthy controls (91 of them sex‐ and age‐matched) were PCR‐genotyped for the FXIIIV34L, FVR506Q, and FIIG20210A substitutions and FXIIIA‐subunit levels were determined by immuno‐electrophoresis. The extent of the venous ulcer surface in patients was measured by computer software. The allele frequency and the genotype distribution of the FXIII polymorphism did not show significant differences between the whole group of cases and controls as well as prothrombin variants did. On the contrary, the FVR506Q variant (FV Leiden) allele was more frequent in patients, yielding a significant OR value of 5.93 (95 percent CI, 1.83–19.17; p= 0.003). Considering only CVU cases secondary to a post–thrombotic syndrome (n= 24), FV Leiden yielded a greater OR value of 16.08 (95 percent CI, 4.33‐59.6; p < 0.0001). When the CVU cases were stratified by the three possible FXIII genotypes, a significant trend toward a lower mean value of the ulcerated area was clearly evident as the number of the polymorphic alleles (L34) increased in the genotype of patients (VV = 11.9 cm2,± 23.6; VL = 6.1 cm2,± 6.9; LL = 4.1 cm2,± 2.8; p= 0.01). On the other hand, FXIIIA antigen levels were similar between CVU cases and matched controls, but 11 percent of cases had FXIII deficiency (FXIIIA ≤ 0.65 U/ml; p= 0.003) and they showed a greater mean extension of the lesion if compared with the remaining cases without FXIIIA deficiency (14.5 cm2, ± 20.2 vs. 9.0 cm2, ± 6.3; p= 0.08). We conclude that FXIII antigen levels and FXIII V34L polymorphism may play a crucial role in the complex cascade of CVU pathophysiology, being significantly related to the CVU progression and extension because of the direct effects they have on the FXIII molecular activity.

Harmful lifestyles on orthopedic implantation surgery: a descriptive review on alcohol and tobacco use

Alcohol abuse and smoking habits have adverse effects on bone health and are a risk factor for osteoporosis, fractures and impaired fracture repair. Osteointegration processes around implanted biomaterials involve a coordinated cascade of complex events that are very similar to those occurring during fracture repair and require a suitable microenvironment and the coordinated action of cells and signal molecules. Therefore, diseases and harmful lifestyles that impair the normal bone healing process can reduce the success of implant surgery and may negatively influence the osteointegration of prostheses and implant devices for fracture fixation such as screws, nails and plates. Understanding the effects of harmful lifestyles on bone implant osteointegration is important for successful implant therapy, orthopedic reconstructive surgery and tissue-engineered-based therapies. However, the mechanisms by which smoking and alcoholism affect bone metabolism, bone mass and the balance of bone resorption and formation, also in the presence of an orthopedic implant, are not completely understood and remain inadequately elucidated. This review aims to analyze in vitro and in vivo studies regarding orthopedic implant integration in the presence of tobacco smoking and alcohol consumption with a focus on pathophysiology and local or systemic mechanisms of action on bone.

Factor XIII contrasts the effects of metalloproteinases in human dermal fibroblast cultured cells

Matrix metalloproteinases (MMPs) are overexpressed in venous leg ulcers, determining a breakdown of the main extracellular matrix (ECM) components owing mainly to collagenase activities, and so playing a crucial role in ulcer pathogenesis. The authors studied the effects of coagulation factor XIII (FXIII), which cross-links collagen and other ECM components, in human fibroblast cultured cells in the presence and in the absence of matrix metalloproteinases from Clostridium histolyticum collagenase. Clostridium collagenase at concentrations of 2.0, 1.0, and 0.5 mg/mL was added to normal human dermal fibroblasts cultured in the presence of 0.0, 1.0, and 5.0 U/mL of FXIII concentrate (Fibrogammin P, Aventis Behring). Cell counting and metabolically active fibroblast evaluation in the cultures were monitored for 72 hours, by means of trypan-blue dye and MTT test, respectively. The MTT test showed that at the highest collagenase concentration (2.0 mg/mL), the cell number decreased more than 95% in 72 hours of treatment and no significant differences were observed regardless of the FXIII concentrations utilized. At lower collagenase concentration (1.0 mg/mL), in absence or in presence of FXIII (1.0 U/mL), the cell number decreased by about 80% in 72 hours. In contrast, in the presence of higher FXIII levels (5.0 U/mL), cells suffered globally significantly less collagenase effects (p=0.011) and the gain was appreciable at each time tested. Finally, at 0.5 mg/mL of collagenase concentration, in the absence of FXIII, the cell number decreased by about 60% in 72 hours, whereas in presence of FXIII 1.0 U/mL and 5.0 U/mL, cells decreased significantly less, by about 35% and 20%, respectively (p<0.025 and p<0.01, respectively). These data were also confirmed by direct cell counting utilizing the trypan-blue test. Factor XIII contrasts effectively the detrimental action of Clostridium collagenases in human fibroblast cultured cells. These results support several in vivo reports about the effectiveness of its topical application in order to enhance the venous ulcer healing processes.

Time- and Dose-Dependent Effects of Chronic Wound Fluid on Human Adult Dermal Fibroblasts

BACKGROUND Wound healing is a biologic process that is altered in patients affected by chronic venous ulcers. The wound microenvironment is reflected in the chronic wound fluid (CWF), an exudate containing serum components and tissue-derived proteins. OBJECTIVES We investigated the effects of increasing doses of CWF collected from patients suffering from chronic venous ulcers on human adult dermal fibroblasts cultured in vitro and the relationship among CWF effects and treatment length. METHODS Fibroblasts were treated with 60, 240, and 720 μg/mL CWF for 3 and 7 days. We evaluated cell proliferation and viability by MTT and Trypan blue assay, cell morphology by light microscopy, F-actin microfilaments organization by tetramethylrhodamine B isothiocyanate-conjugated phalloidin, α-smooth muscle actin expression by immunofluorescence, and senescence-associated β-galactosidase activity. RESULTS CWF induced an increase in cell proliferation in the first 3 days of treatment. In contrast, at 7 days, a strong decrease in cell viability was observed. These changes were related to a cytoskeletal F-actin reorganization and not to fibroblast–myofibroblast differentiation nor to changes in cellular senescence. CONCLUSIONS This study shows a dose-dependent and biphasic effect of CWF on dermal fibroblasts, suggesting that a continuous exposure to chronic wounds microenvironment may induce late cellular dysfunctions possibly involved in the delayed wound healing.