Asymmetric dimethylarginine (ADMA), symmetric dimethylarginine (SDMA) and L-arginine in patients with arteriogenic and non-arteriogenic erectile dysfunction.

The plasma concentration of asymmetrical dimethylarginine (ADMA), an inhibitor of nitric oxide synthase, has been linked to endothelial dysfunction. We investigated the relation between ADMA, symmetric dimethylarginine (SDMA) and L-arginine concentrations and erectile dysfunction. We compared plasma levels of ADMA, SDMA and L-arginine in 61 men in good health with erectile dysfunction of arteriogenic and non-arteriogenic origin. Diagnosis of erectile dysfunction was based on the International Index of Erectile Function Score and its aetiology was classified with penile echo-colour-Doppler in basal condition and after intracavernous injection of prostaglandin E1. The ADMA and SDMA concentrations were significantly higher in men with arteriogenic erectile dysfunction compared with those with erectile dysfunction of non-arteriogenic origin (p < 0.05) and the concentrations in both subgroups were significantly higher than in controls (p < 0.001). There was a negative correlation between ADMA and International Index of Erectile Function Score only in arteriogenic erectile dysfunction subgroup. L-arginine did not differ significantly neither between the two erectile dysfunction subgroups (p > 0.05) nor between each of the two erectile dysfunction subgroups and controls (p > 0.05). The L-arginine/ADMA and the L-arginine/SDMA ratios in arteriogenic erectile dysfunction subgroups were significantly lower than both in controls (p < 0.05) and in non-arteriogenic erectile dysfunction patients (p < 0.05); the two ratios in non-arteriogenic erectile dysfunction patients did not differ from those in the controls (p > 0.05). We conclude that ADMA and SDMA concentrations are significantly higher and L-arginine/ADMA ratio lower in patients who have arteriogenic erectile dysfunction compared with both patients with non-arteriogenic erectile dysfunction and controls. The negative correlation between ADMA and severity of erectile dysfunction is present only in patients with arteriogenic erectile dysfunction. This study supports the importance to always distinguish arteriogenic from non-arteriogenic erectile dysfunction patients to study the complicate erectogenic mechanisms that lead to erectile dysfunction and also to provide potential therapeutic agents for patients with arteriogenic erectile dysfunction.

Iron status evaluation as a marker of postoperative joint infection: a pilot study.

We evaluated the effect of different inflammatory conditions on iron status and, as a consequence, the possible use of iron markers as indicators of infection in the diagnosis of postoperative prosthetic orthopaedic joint infections. The study population was consisted of 26 patients undergoing revision of total hip or total knee joint arthroplasty and subdivided into three groups according to the cause of prosthesis implant failure: 10 as having had previous infection (Group A), 10 patients were categorized as having infection (Group B); and the remaining 6 (Group C) as not having infection. These patients were assayed for mean corpuscular haemoglobin concentration (MCHC) and serum values of iron (Fe), ferritin (Fer), transferrin (Tf), soluble transferrin receptor (sTfR), and transferrin saturation (sat Tf). Septic patients display statistically significant lower serum iron concentration, higher sTfR and ferritin levels, lower, but not statistically significant, MCHC compared to non septic ones. Little differences were observed for Tf, sat Tf, tibc, TfR index, among the three groups of patients. Our study suggests that iron status parameters, in particular serum iron, ferritin, sTfR and TfR index, could be useful tools for the early detection and the diagnosis of orthopaedic prosthetic joint infections.

Platelet rich plasma therapy: inflammatory molecules involved in tissue healing.

Inflammation represents a fundamental aspect of the healing process. Besides their primary role in hemostasis, platelets play an active role in the immunological and inflammatory aspect of tissue healing. Indeed , they can be directly involved in the inflammatory response by the production and release of several inflammatory mediators, including a variety of cytokines, such as TGF-beta, IL-1 beta, CD40L, and chemokines, such as CXCL7, CXCL4, CXCL4L1, CCl5, CXCL1, CXCL8, CXCL5, CXCL12, CCL2, CCL3. Platelet are not only a source of several chemokine involved in the inflammatory response and tissue healing, but they also express chemokine receptors, in particular CCR1 CCR3 CCR4 and CXCR4, thus being able to being able to regulate the inflammatory response associated to the healing process. However, this local inflammation must be taken under control, and platelets can prevent the excess of leukocytes recruitment by anti-inflammatory cytokines, such as TGF-beta. For this biological properties of platelets, platelet rich plasma therapy (PRP) is considered an innovative and promising approach that has been extended to many field of medicine, ranging from non-union defects, bone fractures, spinal fusion, bone implant and osteointegration, joint arthroplasty, to the treatment of several traumatic or degenerative pathologies of tendons, cartilage and ligaments.

Circulating cytokines present in the serum of peripheral arterial disease patients induce endothelial dysfunction.

Peripheral arterial disease (PAD) is a chronic condition caused by atherosclerosis and is a severe complication of type 2 diabetes (T2D). We hypothesised that chronic condition of arterial disease engenders inflammation and endothelial damage in response to circulating cytokines released in the blood stream of PAD patients. We explored the levels of circulating cytokines in PAD patients with and without diabetes by multiplex cytokine array compared with non-PAD controls. Serum from PAD patients with or without diabetes showed high levels of VEGF, IFN-gamma, TNF-alpha, MCP-1, and EGF. VEGF levels correlated with TNF-alpha and IFN-gamma, significantly. Endothelial cells (ECs) were exposed to the different altered cytokines to evaluate changes in cell growth, migration and tubule-like formation, displaying impairment on proliferation, migration and tubule formation. Our findings demonstrate that a set of cytokines is significantly increased in the serum of PAD patients. These cytokines act to induce endothelial dysfunction synergistically. VEGF strongly correlated with TNF-alpha and IFN-gamma, opening new therapeutic perspectives.

Osteoprotegerin, RANK and RANKL are not modified by acute exercise in elite rugby players.

AIM: The OPG-RANK-RANKL system is a new family of bone metabolism biomarkers belonging to the immune system. In this study, were evaluated these biomarkers in professional rugby players after a single-bout of training session. METHODS: The study has been performed on 30 professional male rugby players during a training camp of the Italian National Team, in July, before the start of the competitive season. Blood drawings were performed before and after training in the same day. Levels of soluble OPG, RANKL RANK in serum specimens were measured by commercially available according to the manufacturers' protocols. RESULTS: All the bone markers examined displayed no significative changes after training session. CONCLUSION: Short exercise is insufficient for modifying serum concentrations of these osteoimmunologic markers, as previously indicated for commonly used bone metabolism markers. Future studies will be conducted over an entire competition season in order to define a common profile of bone markers in rugby players.

Circulating cytokines and growth factors in professional soccer players: correlation with in vitro-induced motor neuron death.

BACKGROUND: professional soccer players are susceptible to amyotrophic lateral sclerosis. Strenuous physical activity has been associated with persistent inflammatory conditions and elevation of systemic cytokine levels, which could contribute to the vulnerability of these athletes. To investigate changes induced by playing soccer in the systemic profiles of growth factors and of the principal cytokines involved in the inflammatory response, we compared the serum concentrations of these factors in Italian professional soccer players and sedentary subjects. We also investigated the effects of the sera on primary cultured motor neurons in relation to their cytokine and growth factor content. METHODS: serum concentrations of cytokines and growth factors were measured by a biochip array analyzer. Neurotoxicity of sera was assessed by immunocytochemical assays in primary motor neuron cultures from mouse embryos. RESULTS: circulating levels of interleukin-8, tumor necrosis factor-alpha and interleukin-4 were lower in soccer players than controls. However, the viability of primary cultured mouse motor neurons treated with sera from the two groups did not differ significantly. Vascular endothelial growth factor (VEGF) independently emerged as a systemic protective factor for motor neurons. CONCLUSIONS: we found significant alterations in circulating pro-inflammatory cytokines in Italian professional soccer players, showing an unbalanced inflammatory condition in these subjects. VEGF was a protective serum factor affecting motor neuron survival.

Procalcitonin, C-reactive protein, interleukin-6, and soluble intercellular adhesion molecule-1 as markers of postoperative orthopaedic joint prosthesis infections.

There is a universally recognized need to identify new, reliable markers of inflammation that can aid in the rapid diagnosis of orthopaedic joint prosthesis infections (OJP-Is). Since prompt diagnosis is key to timely intervention in the course of infection, different molecules have been studied. In this study, we examined three groups of patients: those with prosthesis infection, those without infection, and a third group with previous infection in whom the infection had been cleared. Four presumed markers of infection were tested: procalcitonin (PCT); C-reactive protein (CRP); interleukin-6 (IL-6); and soluble intercellular adhesion molecule-1 (sICAM-1). The results showed that PCT cannot be considered as a good marker of periprosthetic infection as no statistically significant difference in serum PCT levels emerged between patients with infection and controls or patients without infection. In contrast, both sICAM-1 and CRP may be considered as good markers of infection, as measurement of their levels allowed us to distinguish between patients with and without infection, and between patients with infection and those with previous infection, since marker levels quickly returned to baseline values after clearance of the infection. IL-6 was found to be a good marker for inflammation, as it distinguished between patients with infection and the other groups. In the patients with previous infection, the IL-6 values remained high versus the controls but lower and with a statistically significant difference versus the patients with infection. Further studies are needed to determine the cut-off value of IL-6 between patients with infection and those with previous infection.

High articular levels of the angiogenetic factors VEGF and VEGF-receptor 2 as tissue healing biomarkers after single bundle anterior cruciate ligament reconstruction.

Various factors may account for the positive association between meniscal repair and anterior cruciate ligament reconstruction, one being the modulation of healing response of meniscal fibrochondrocytes by growth factors released with intra-articular bleeding and fibrin clot formation. Analysis of vascular endothelial growth factor (VEGF) and its receptors, VEGFR1 and VEGFR2, may be useful in the clinical assessment of bone and soft-tissue remodeling. We measured systemic and local levels of VEGF (VEGF165), VEGFR1 and VEGFR2 after either arthroscopic partial meniscectomy (APM) or single-bundle anterior cruciate ligament reconstruction (ACLR) in order to determine the local effect of bone tunnelling and notchplasty on the release of these growth factors. The study population included 40 patients: 20 consecutive patients had undergone ACLR with hamstring grafts and 20 had undergone APM. Thirty minutes after the end of the operation, knee joint fluid samples were collected via the drainage tube and at the same time venous blood samples were drawn. In both sets of samples, VEGF, VEGFR1 and VEGFR2 concentrations were determined by enzyme-linked immunosorbent assay (ELISA). No significant differences in VEGF, VEGFR1 or VEGFR2 concentrations in the venous blood were observed between the two treatment groups. In contrast, VEGF and VEGFR2 levels were significantly higher in the knee joint fluid of the ACLR group; furthermore, VEGF and VEGFR1 were significantly higher in the knee joint fluid than in the venous blood, whereas VEGFR2 was lower in the knee joint fluid than in the venous blood. Local release of VEGF and its angiogenetic receptor VEGFR2, but not the negative regulator VEGFR1, was significantly higher after ACLR than after APM, indicating a better vasculogenic potential for enhanced bone-graft and meniscus healing. These results could suggest that VEGF and VEGFRs could be considered as good biomarkers of tissue healing after knee joint surgery.

Plasma adiponectin and leptin concentrations in professional rugby players.

Adipose tissue synthesizes and secretes a number of cytokine hormones, defined adipokines, which have emerged as critical regulators of several metabolic functions, including energy homeostasis, insulin action and lipid metabolism. The present study is aimed at assessing the relationship between plasma concentrations of leptin and adiponectin and body composition in a cohort of 38 male professional rugby players (age: 22-35 years). Anthropometric evaluation included body mass index (BMI, range: 23.4-35.1 kg/m2) and whole body bioelectric impedance to determine absolute fat-free mass (FFM), absolute fat mass (FAT), relative percentage of fat mass (FAT percent) and fat-free mass (FFM percent). FAT percent ranged from 15 to 34 percent, corresponding to a FAT of 11.5-38.7 kg, whereas FFM range was 62.1-83.5 kg. Plasma leptin range was 1.2-4.3 ng/mL and adiponectin range was 2.0-16.6 microg/mL. Plasma leptin and adiponectin concentrations and their ratio did not correlate with BMI, nor with FAT, FAT percent, FFM and FFM percent, even after correction for BMI. The findings of this study suggest that in professional rugby players some additional factors, like neuroendocrine adaptations, other than adipose mass play a relevant role in the determination of adipokine levels, which in this group appear to be rather independent of body composition.

Growth factors in the management of sport-induced tendinopathies: results after 24 months from treatment. A pilot study.

AIM: The efficacy of PRP in the treatment of tendinopathies has been already studied both in in vitro and in clinical studies. This paper describes the local and the systemic effects of US-guided autologous PRP (Platelet Rich Plasma) injections in chronic tendinopathies in sportspersons. METHODS: Fifteen patients (13 male, 2 female) between 17 and 68 years old, affected by chronic tendinopathies at different sites were treated with an echographically guided injection of autologous PRP within the pathological area of the tendons. VISA score and MRI data were collected pre interventions and after 90 days and 24 months from treatment. Changes in different inteleukins (ILs), tumour necrosis factor α (TNF α), interferon γ, vascular endothelial growth factor (VEGF), endothelial growth factor (EGF), chemokine (C-C motif) ligand 2 (CCL2), were analysed at four time points in the peripheral blood of five patients. RESULTS: After 90 days the VISA score significantly improved from 36±12 (range 21-64) to 74±17 (range 40-92). Reduction of irregularities was found in 80% of the tendons. After 24 months patients reported an average VISA score of 73±16 (range 42-100). No changes in IL, TNF α and interferon γ were observed. VEGF, EGF and CCL2 decreased progressively from 30m to 3 h after the treatment and returned to near the baselines after 24 h. CONCLUSION: PRP injection allow an improvement of the clinical symptomatology, which is well maintained at least for two years from treatment. The PRP-based local therapy could influence systems homeostasis and antidoping evaluations, but, in our opinion, it doesn't represent a doping substance in itself.

Protein biochip array of adhesion molecule expression in peripheral blood of patients with nasal polyposis.

Nasal polyposis is a chronic non-infectious inflammatory disease of the nasal and paranasal cavity mucosa of unknown multifactorial origin in which inflammatory cells, and in particular eosinophils, seem to play a pivotal role. Eosinophil migration from the bloodstream to nasal polyps is considered to be specific and is a complex process involving several different molecules such as ICAM-1, VCAM-1, and L-, P- and E-selectins. The aim of this study was to investigate, using a protein biochip array technology, the concentrations of these molecules in the peripheral blood of a group of patients affected by nasal polyposis. Patients exhibited a significantly higher expression of VCAM-1, E-selectin, and L-selectin compared to healthy controls, and Spearman's rank correlation test limited to the molecules with significant betweengroup differences demonstrated a significant correlation between VCAM-1 and E-selectin, VCAM-1 and L-selectin, and Eselectin and L-selectin. The results of this investigation are in line with those coming from various imunohistochemical analyses, and seem to confirm the role of inflammation in the pathogenesis of nasal polyposis. These molecules may also represent novel therapeutic targets in the treatment of nasal polyps, and may allow the selection of pharmacological prophylactics that would allow effective inhibition of the inflammation induced by a given allergen.

Chemokines and bone remodeling.

Bone remodeling is characterized by spatial and temporal coupling of bone resorption and formation and is necessary for skeletal growth and normal bone structure maintenance. Imbalance of this process is related to metabolic bone disorders such as osteoporosis or rheumatoid arthritis. For this reason, bone remodeling is under the control of several local and systemic factors, including molecules of the immune system. The importance of the interplay of both the skeletal and immune systems is reflected by the emerging interdisciplinary research field, called osteoimmunology, focused on common aspects of osteology and immunology. This review focuses on the role of inflammatory mediators, such as cytokines in bone remodeling and, in particular, a subfamily of chemotactic cytokines or chemokines which are involved not only in several aspects of physiological bone remodeling but also in pathological bone disorders, such as rheumatoid arthritis or osteoporosis. Understanding the role of inflammation and chemokines will provide new insights for the treatment of diseases affecting both skeletal and immune systems, by the development of new therapeutic strategies targeting common inflammatory mediators.

Soluble adhesion molecules levels in patients with Cushing's syndrome before and after cure.

OBJECTIVE: Patients with Cushing's syndrome (CS) show a high prevalence of cardiovascular risk factors and atherosclerosis, persisting even after cure. Soluble intercellular adhesion molecule-1 (sICAM-1) and vascular cell adhesion molecule-1 (sVCAM-1) are surrogate markers of endothelial function involved in the initiation of atherosclerosis. This study aimed to evaluate sICAM-1 and sVCAM-1 levels in patients with CS before and after successful cure. SUBJECTS AND METHODS: sICAM-1 and sVCAM-1 levels were evaluated in 28 patients with active CS and in 12 patients with Cushing's disease (CD), 6-12 months after disease remission. Body mass index (BMI), blood pressure, glucose, serum lipids, ACTH, cortisol and urinary free cortisol (UFC) were measured in basal conditions in all patients. RESULTS: At baseline, sICAM-1 levels positively correlated with BMI (r=0.443, p<0.01), while no correlations between sICAM/sVCAM levels and ACTH, cortisol or UFC were found. Plasma ACTH, serum cortisol, and UFC levels significantly decreased in 12 cured patients, but ICAM-1 and VCAM-1 levels were unchanged (12.7+/-1.8 vs 10.1+/-0.9 ng/ml and 33.5+/-4.4 vs 35.8+/-4.0 ng/ml, respectively). Obesity, hypertension, and impaired glucose metabolism persisted 1 yr after the biochemical cure of hypercortisolism. A significant reduction in ICAM-1 levels was observed in 4 out of 12 cured patients as well as a remission from diabetes, hypertension or obesity. CONCLUSIONS: ICAM/VCAM-1 levels show a great variability in patients with active CS, not correlated with cortisol levels, and are slightly modified in some cured patients with CD. The persistence of obesity, hypertension, and impaired glucose metabolism may be responsible for the maintenance of a subclinical endothelial dysfunction, making these subjects still at high cardiovascular risk and needing a long-term follow-up.

Oxidated low-density lipoproteins (oxLDL) and peroxides in plasma of Down syndrome patients.

A low prevalence of coronary artery disease is usually observed in adult Down syndrome (DS) subjects, and these patients rarely die because of atherosclerotic complications. High levels of oxLDL were found in plasma from children and adults with DS. Plasma oxLDL were still increased in elderly with DS, however, difference with controls was not statistically significant. Concentrations of plasma peroxides were significantly higher in children and adults with DS than controls. No differences between elderly DS subjects and controls were present. We speculated that increased levels of protective antiathero-sclerosis factors might be produced in young and adult DS subjects and these may explain low incidence of cardiovascular diseases in the syndrome. Up-regulation of vascular andothelial growth factor (VEGF)-mediated signals and increased nerve growth factor (NGF) expression might be two of these important protective factors.

Erythrocyte glycohydrolases in subjects with trisomy 21: could Down's syndrome be a model of accelerated ageing?

We studied some erythrocyte glycohydrolases, erythrocyte membrane fluidity, plasma hydroperoxides and total antioxidant defences in 23 Down syndrome (DS) individuals in comparison with healthy age-matched and elderly controls. With regard to erythrocyte plasma membrane fluidity, plasma hydroperoxides and total plasma oxidative defences, DS subjects resembled the age-matched controls more than the elderly ones. Membrane glycohydrolases in DS, however, presented a pattern partly similar to age-matched controls and partly to elderly controls. Concerning cytosol glycohydrolases, DS subjects had lower levels of hexosaminidase and N-acetyl-beta-D-glucosaminidase, the latter specific for the hydrolysis of GlcNAc residues O-linked to proteins. In general, erythrocyte membrane and cytosol glycohydrolases decreased during erythrocyte ageing in DS subjects and in all controls. The increased levels of the same enzymes in DS plasma might be attributed to an alteration of their release-uptake mechanisms between the two different compartments, on account of the higher plasma hydroperoxide levels. These findings indicate that erythrocyte ageing in DS differs partially from that of age-matched and elderly controls. In any case, the accelerated ageing seen in DS is no fully comparable to physiological ageing.

Altered vessel signalling molecules in subjects with Downs syndrome.

Downs syndrome (DS) is the most frequent human chromosomal abnormality and is associated with mental retardation. Some evidence indicates that certain inflammatory molecules may be increased in DS. Proinflammatory and vasoactive molecules in the blood of non demented subjects with DS were measured in the present investigation. Plasma levels of interleukin-6 (IL-6), vascular endothelial growth factor (VEGF), monocyte chemoattractant protein-1 (MCP-1) and C reactive protein (CRP) were measured in child (2-14 years), adult (20-50 yrs) and elderly (> 60 yrs) DS subjects. Increased plasma levels of IL-6 and MCP-1 were present in DS. Plasma levels of VEGF were increased only in DS adults. Positive linear correlation between IL-6 and MCP-1 levels was present. However, no subclinical inflammation was apparent in DS, since neopterin and CRP levels were within the normal range. An altered regulation of these molecules might interfere with some processes involved in cognitive performances of DS subjects.

Altered cytokine and acute phase response protein levels in the blood of children with Downs syndrome: relationship with dementia of Alzheimer's type.

Downs syndrome (DS) subjects are at high risk of developing Alzheimer's disease (AD). Patients with AD often show altered levels of some immune molecules in their peripheral blood which correlate with cognitive impairment. However, whether the altered peripheral immune phenotype is a late and secondary phenomenon associated with dementia or an early impairment linked to mechanisms controlling neurodegeneration of the central nervous system (CNS) is still an unanswered question. Here we studied immune molecules in the blood of non demented children with DS to investigate whether altered peripheral immune phenotype could be present in these subjects without dementia, many years before the presentation of clinical signs of cognitive deterioration. Plasma levels of interleukin-6 (IL-6) and soluble IL-6 receptor (sIL-6R) were significantly higher in DS than in control children. Plasma levels of soluble intercellular adhesion molecule-3 (sICAM-3), soluble vascular cell adhesion molecule-1 (sVCAM-1) and C reactive protein (CRP) were also increased in DS. The increase of IL-6 and CRP from DS children was similar to that found in elderly patients with clinical AD. Peripheral altered immune phenotype in healthy young subjects with DS might be an early sign of CNS alterations leading many years later to cognitive deterioration and dementia.

Activity in vitro of resveratrol on granulocyte and monocyte adhesion to endothelium.

BACKGROUND: Resveratrol is a phytoalexin present in red wine. It has been shown to protect LDL from peroxidative degradation. OBJECTIVE: In consideration of the low plasma concentration of orally adsorbed resveratrol (which is insufficient for antioxidant protection of LDL), we studied another effect of the compound. DESIGN: Because resveratrol is a tyrosine kinase inhibitor like other members of the tyrphostin family, we hypothesized that it has the ability to modify intracellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1) expression by stimulated endothelial cells. We studied the ability of resveratrol to inhibit such adhesion molecule expression and to block the adhesion of monocytes and granulocytes to endothelial cells. RESULTS: We showed that resveratrol, at concentrations as low as 1 micromol/L and 100 nmol/L, significantly inhibited ICAM-1 and VCAM-1 expression by tumor necrosis factor alpha (TNF-alpha)-stimulated human umbilical vein endothelial cells and lipopolysaccharide-stimulated human saphenous vein endothelial cells (HSVEC), respectively. In addition, we showed that resveratrol induced a significant inhibition in the adhesion of U937 monocytoid cells to lipopolysaccharide-stimulated HSVEC. Such inhibition was comparable with that obtained when anti-VCAM-1 monoclonal antibody was used instead of resveratrol. Resveratrol also significantly inhibited the adhesion of neutrophils to TNF-alpha-stimulated NIH/3T3 ICAM-1-transfected cells, whereas neutrophils activated by formyl-methionyl-leucyl-phenylalanine did not significantly modify adhesion to NIH/3T3 ICAM-1-transfected cells. CONCLUSIONS: Our results indicate activity of resveratrol on endothelial cells and a new interpretation of an effect independent of its antioxidant function.

Cobalamin (vitamin B(12)) positively regulates interleukin-6 levels in rat cerebrospinal fluid.

We have previously demonstrated that the repeated intracerebroventricular (i.c.v.) microinjection of interleukin-6 (IL-6) prevented the myelinolytic lesions of cobalamin-deficient (Cbl-D) central neuropathy [or subacute combined degeneration (SCD)] in totally gastrectomized (TGX) rats. We therefore hypothesized that cobalamin (Cbl) may actually regulate IL-6 levels in rat cerebrospinal fluid (CSF). We measured IL-6 levels in the CSF of rats made Cbl-D by means of total gastrectomy (TG) or chronic feeding with a Cbl-D diet and killed at different times from the beginning of the experiment, and found that IL-6 levels significantly and progressively decreased over time. Chronic 2-month Cbl administration started 1 week after surgery prevented the decrease in IL-6 levels and, when it was started 2 months after surgery, it significantly increased IL-6 levels, but not to presurgical values. We also investigated whether IL-6 decrease might be ultimately due to the Cbl-deficiency-linked decrease in epidermal growth factor (EGF) synthesis. Repeated i.c.v. administrations of EGF to TGX rats did not modify CSF IL-6 levels. These results, together with those of a previous study showing the preventive effect of IL-6 treatment on SCD lesions, demonstrate that: (i) Cbl selectively regulates CSF IL-6 levels; and (ii) decreased IL-6 availability plays a role in the pathogenesis of the experimental SCD, in which no evidence of inflammatory and/or immunological reaction has been observed.