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Objectives To apply therapeutic drug monitoring and dose-individualization of intravenous Busulfan to paediatric patients and evaluate the impact of syringe-pump induced Busulfan infusion lag-time after in vitro estimation. Methods 76 children and adolescents were administered 2 h intravenous Busulfan infusion every 6 h (16 doses). Busulfan plasma levels, withdrawn by an optimized sampling scheme and measured by a validated HPLC–PDA method, were used to estimate basic PK parameters, AUC, Cmax, kel, t1/2, applying Non-Compartmental Analysis. In vivo infusion lag-time was simulated in vitro and used to evaluate its impact on AUC estimation. Key findings Mean (%CV) Busulfan AUC, Cmax, clearance and t1/2 for pediatric population were found 962.3 μm × min (33.1), 0.95 mg/L (41.4), 0.27 L/h/kg (33.3), 2.2 h (27.8), respectively. TDM applied to 76 children revealed 6 (7.9%) being above and 25 (32.9%) below therapeutic-range (AUC: 900–1350 μm × min). After dose correction, all patients were measured below toxic levels (AUC < 1500 μm × min), no patient below 900 μm × min. Incorporation of infusion lag-time revealed lower AUCs with 17.1% more patients and 23.1% more younger patients, with body weight Conclusions TDM, applied successfully to 76 children, confirmed the need for Busulfan dose-individualization in paediatric patients. Infusion lag-time was proved clinically significant for younger, low body-weight patients and those close to the lower therapeutic-range limit.

In this study, we aimed to illustrate the trajectory of humoral and cellular immunity nine months after primary vaccination with the BNT162b2 mRNA vaccine among 189 healthcare workers (HCWs). Additionally, we endeavored to identify correlations between immunity parameters and a number of common variables and comorbidities. A total of 189 healthcare workers (HCWs), vaccinated against COVID-19, were finally included in the study. All of the subjects had received two doses of the BNT162b2 vaccine; had undergone antibody tests one, four and nine months post-vaccination; and had completed a medical questionnaire. Further samples taken at nine months were tested for cellular immunity. No participants had evidence of COVID-19 infection pre- or post-vaccination. An anti-S1 receptor binding domain (RBD) antibody assay was used to assess humoral response, and cellular immunity was estimated with an INF-γ release assay (IGRA). Statistical analysis was performed using STATA. We report a statistically significant antibody drop over time. Being above the age of 40 or a smoker reduces the rise of antibodies by 37% and 28%, respectively. More than half of the participants did not demonstrate T-cell activation at nine months. Female gender and antibody levels at four months predispose detection of cellular immunity at nine months post-immunization. This study furthers the qualitative, quantitative, and temporal understanding of the immune response to the BNT162b2 mRNA vaccine and the effect of correlated factors.

INTRODUCTION: HCV infection in patients under hemodialysis for end stage chronic kidney disease (ESCKD) may exist despite the absence of anti-HCV antibodies. Molecular methods are widely accepted as “gold standard” techniques for the detection of viral RNA. However, the molecular methods are more expensive in comparison to conventional methods and their replacement is not cost-effective. The aim of this study was to estimate the prevalence of HCV RNA positivity in anti-HCV negative hemodialysis patients and evaluate new diagnostic methods for the detection and the monitoring of hepatitis C in ESCKD patients. METHODS: The study was performed in four hospitals of Thrace region of Greece and 233 patients with no history of hepatitis C were enrolled. Measurement of anti-HCV antibodies and HCV core antigen was performed by microparticle chemiluminescence immunoassay. Molecular detection of viral RNA was performed by the real-time RT PCR. RESULTS: The mean age of the patients was 64.9 ± 23.3 years. HCV-Ag was positive in 2/233 patients (0.86%). Nevertheless, viral RNA was negative in those patients. CONCLUSIONS: The results of the present study showed that the incidence of HCV-RNA in patients with negative anti-HCV Abs, in hemodialysis patients in Thrace region of Greece was negligible (0/233).

Infants are subjected to hematopoietic stem cell transplantation (HSCT) due to malignant and non-malignant diseases. However, specific data concerning the outcome and transplantation-related complications in infants, as a separate age group, are limited. Our aim was to evaluate the impact of infancy on the outcome, toxicity, and complications after HSCT.We retrospectively analyzed data of 55 infants that underwent HSCT in our unit from May 1997 until February 2020, emphasizing on the probability of overall survival (OS) and the cumulative incidence (CI) of transplantation-related mortality (TRM) and complications.We report a probability of OS of 61%, a CI of TRM at day 100 and 365 post transplantation of 22% and 30%, respectively, and additionally a CI of graft failure, acute graft-versus-host disease (GvHD), and infectious complications, 18%, 44%, and 39%, respectively. No statistically significant association was detected between the above mentioned parameters and diagnosis, the use of myeloablative or non-myeloablative/reduced toxicity conditioning regimens or the type of donor.We conclude that HSCT in infancy is associated with significant mortality and morbidity. This is possibly attributed to endogenous, age-related factors. More specifically, infants may be at a higher risk of toxicities due to the immaturity of developing vital organs and the deficiency of the newly adopted immune system that predisposes them to infectious complications. The development of GvHD further augments the danger of infections, in a potential vice-versa relationship. Moreover, there are few data on pharmacokinetics of chemotherapy agents, making safe and efficacious drug administration hard.

We develop a population pharmacokinetic model to describe Busulfan pharmacokinetics in paediatric patients and investigate by simulations the impact of various sampling schedules on the calculation of AUC. Seventy-six children had 2 h infusions every 6 h. A two-compartment linear model was found to adequately describe the data. A lag-time was introduced to account for the delay of the administration of the drug through the infusion pump. The mean values of clearance, central volume of distribution, intercompartmental clearance, and peripheral volume of distribution were 10.7 L/h, 39.5 L, 4.68 L/h and 17.5 L, respectively, normalized for a Body Weight (BW) of 70 kg. BW was found to explain a portion of variability with an allometric relationship and fixed exponents of 0.75 on clearance parameters and 1 on volumes. Interindividual variability for clearance and volume of distribution was found to be 28% and 41%, respectively, and interoccasion variability for clearance was found to be 11%. Three sampling schedules were assessed by simulations for bias and imprecision to calculate AUC by a non-compartmental and a model-based method. The latter was found to be superior in all cases, while the non-compartmental was unbiased only in sampling up to 12 h corresponding to a once-daily dosing regimen. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.

We develop a population pharmacokinetic model to describe Busulfan pharmacokinetics in paediatric patients and investigate by simulations the impact of various sampling schedules on the calculation of AUC. Seventy-six children had 2 h infusions every 6 h. A two-compartment linear model was found to adequately describe the data. A lag-time was introduced to account for the delay of the administration of the drug through the infusion pump. The mean values of clearance, central volume of distribution, intercompartmental clearance, and peripheral volume of distribution were 10.7 L/h, 39.5 L, 4.68 L/h and 17.5 L, respectively, normalized for a Body Weight (BW) of 70 kg. BW was found to explain a portion of variability with an allometric relationship and fixed exponents of 0.75 on clearance parameters and 1 on volumes. Interindividual variability for clearance and volume of distribution was found to be 28% and 41%, respectively, and interoccasion variability for clearance was found to be 11%. Three sampling schedules were assessed by simulations for bias and imprecision to calculate AUC by a non-compartmental and a model-based method. The latter was found to be superior in all cases, while the non-compartmental was unbiased only in sampling up to 12 h corresponding to a once-daily dosing regimen.

The aim of this study was to estimate the immunogenic effect of mRNA vaccine against SARS-CoV-2. This study included 510 participants who received mRNA vaccine. The measurement of anti-COVID-19 antibodies was performed using the Abbott SARS-CoV-2 IgG quantitative assay (Abbott). Overall, mean titer of anti-Spike antibodies was 19,319.2 ± 1787.5 AU/mL. Vaccination induced a robust immunogenic response in those previously infected with SARS-CoV-2 compared with non-infected subjects. Additionally, individuals that were asymptomatic after vaccination produced lower levels of antibodies compared to feverish individuals. In conclusion, remarkably high levels of anti-Spike COVID-19 antibodies were observed after vaccination.

Introduction: The aim of this study was to assess the clinical performance of different automated immunoassays available in Europe to detect anti-SARS-CoV-2 antibodies; an ELISA assay and a CLIA. The second goal was to estimate the seroprevalence of SARS-CoV-2 antibodies among healthcare workers in Evros area during the first pandemic wave of COVID-19. Methods: The study included serum samples from 101 patients with confirmed COVID-19 by RT-PCR and 208 negative patients. Furthermore, it included 1036 healthcare workers (HWs) of the Evros Region, Northern Greece. The measurement of anti-SARS-CoV-2 antibodies was performed using the Abbott SARS-CoV-2 IgG and anti-SARS-CoV-2 ELISA IgG assay (Epitope Diagnostics, USA). Results: Of 101 confirmed COVID-19 patients, 82 were hospitalized and 19 were outpatients. Hospitalized patients had higher IgG levels in comparison to outpatients (6.46±2.2 vs. 3.52±1.52, p

Objectives: To apply therapeutic drug monitoring and dose-individualization of intravenous Busulfan to paediatric patients and evaluate the impact of syringe-pump induced Busulfan infusion lag-time after in vitro estimation. Methods: 76 children and adolescents were administered 2 h intravenous Busulfan infusion every 6 h (16 doses). Busulfan plasma levels, withdrawn by an optimized sampling scheme and measured by a validated HPLC-PDA method, were used to estimate basic PK parameters, AUC, Cmax, kel, t1/2, applying Non-Compartmental Analysis. In vivo infusion lag-time was simulated in vitro and used to evaluate its impact on AUC estimation. Key findings: Mean (%CV) Busulfan AUC, Cmax, clearance and t1/2 for pediatric population were found 962.3 μm × min (33.1), 0.95 mg/L (41.4), 0.27 L/h/kg (33.3), 2.2 h (27.8), respectively. TDM applied to 76 children revealed 6 (7.9%) being above and 25 (32.9%) below therapeutic-range (AUC: 900-1350 μm × min). After dose correction, all patients were measured below toxic levels (AUC < 1500 μm × min), no patient below 900 μm × min. Incorporation of infusion lag-time revealed lower AUCs with 17.1% more patients and 23.1% more younger patients, with body weight

Alzheimer's disease (AD) has been associated with up-regulation of pro-inflammatory cytokines (e.g., specific gene variants for TNF-alpha; IL-6; IFN-gamma) and low plasma levels of cyanocobalamin (vitamin B12). Our goal was to relate B12 levels to AD symptoms and to expression of pro-inflammatory cytokines. Clinical manifestations were investigated for a case series of fifty-five outpatients using the MMSE, Neuropsychiatric Inventory (NPI) and Cornell Scale for Depression in Dementia (CDDS). Plasma B12 levels were measured by radioligand binding assay. Basal and PMA-stimulated levels of IFN-gamma, TNF-alpha, and IL-6 were measured by ELISPOT (PBMC culture supernatant). 47 patients were genotyped for APOE. Ten patients (18%) had their B12 levels below < 250 pg/ml. They did not statistically differ from those 45 who had normal levels in most demographic and clinical features; their MMSE scores were lower (14.7 vs 19.6 p=0.03) but not after adjustment for disease duration. A greater basal production of IL-6 was reported in patients who had low B12 levels compared to normal B12 subjects (1333 pg/ml vs 976 p< 0.01); this association was confirmed after controlling for age of onset and APOE genotype. In conclusion, low B12 level is associated with greater production of IL-6 in peripheral blood mononuclear cells. Further research is warranted to elucidate whether this neuroinflammatory effect of cobalamin is implicated in the pathophysiology of AD.

We assessed a set of biological (HDL, LDL, SGOT, SGPT, GGT, HTc, Hb and T levels) and psychometric variables (investigated through HAM-D, HAM-A, GAS, Liebowitz Social Anxiety Scale, Mark & Mathews Scale, Leyton scale, and Pilowski scale) in a sample of 64 alcohol dependent patients, at baseline and after a detoxification treatment. Moreover, we recruited 47 non-consanguineous relatives who did not suffer alcohol related disorders and underwent the same tests. In both groups we genotyped 11 genetic variations (rs1800587; rs3087258; rs1799724; 5-HTTLPR; rs1386493; rs1386494; rs1487275; rs1843809; rs4570625; rs2129575; rs6313) located in genes whose impact on alcohol related behaviors and disorders has been hypothesized (IL1A, IL1B, TNF, 5-HTTLPR, TPH2 and HTR2A). We analyzed the epistasis of these genetic variations upon the biological and psychological dimensions in the cases and their relatives. Further on, we analyzed the effects of the combined genetic variations on the short - term detoxification treatment efficacy. Finally, being the only not yet investigated variation within this sample, we analyzed the impact of the rs6313 alone on baseline assessment and treatment efficacy. We detected the following results: the couple rs6313 + rs2129575 affected the Leyton -Trait at admission (p = 0.01) (obsessive-compulsive trait), whilst rs1800587 + 5-HTTLPR impacted the Pilowski test at admission (p = 0.01) (hypochondriac symptoms). These results did not survive Bonferroni correction (p < or = 0.004). This lack of association may depend on the incomplete gene coverage or on the small sample size which limited the power of the study. On the other hand, it may reflect a substantial absence of relevance of the genotype variants toward the alcohol related investigated dimensions. Nonetheless, the marginal significance we detected could witness an informative correlation worth investigating in larger samples.

Clinical outcome of alcoholism may be partly under genetic control. The serotonergic system is involved in alcohol intake, and it has been widely investigated in alcohol dependence. Recently, attention has been focused on the neuronal tryptophan hydroxylase 2 gene (TPH2). TPH2 variants have been consistently associated with anxiety-related traits; since anxiety is critical for alcohol dependence treatment, in the present paper we investigated 9 SNPs within the THP2 gene in anxiety symptoms during the detoxification procedure. The sample comprised 68 alcohol-dependent patients who where evaluated with the Hamilton Rating Scale for Anxiety, before and after the detoxification procedure. Other psychopathological indicators of outcome, such as depression and anxiety sub-features were also investigated. We did not observe a role for TPH2 variants in the efficacy of treatment in relieving anxiety and other psychopathological symptoms. However, a haplotype that included the promoter rs4570625 polymorphism (associated with anxiety-related traits in previous studies) showed an association with the severity of anxiety symptoms on admission. This preliminary finding, although obtained on a small sample, may provide further support for a role of the TPH2 gene in emotional behaviors. Furthermore, the present study suggests the possible functional significance of the promoter rs4570625 polymorphism. The present preliminary results are of interest in alcoholism, given that comorbidity with anxiety represents a critical problem in treatment settings and response to detoxification.

Background: According to the self-medication hypothesis, individuals with depression and anxiety disorders use alcohol to control their symptoms and subsequently become dependent. Conversely, alcohol dependence disorder (ADD) can cause or exacerbate psychiatric disorders. This study analyzed the characteristics of depression and social phobia secondary to ADD. (1) What is their functional impact? (2) Are they independent or associated conditions? (3) Do they completely remit in abstinent individuals? (4) Is the remission of one disorder associated with the remission of the other disorder? Methods: Sixty-four inpatients with ADD were evaluated with depression and anxiety disorder scales upon admission to hospital and after 5 weeks of detoxification. Results: Baseline comparisons differentiated patients with a Hamilton Rating Scale for Depression (HDRS) score >35 (n = 50; 78%) from those with an HDRS score ≤35 by higher levels of generalized anxiety and lower global functioning. Patients with generalized social phobia [Leibowitz Social Anxiety Scale (LSAS) score >60: n = 20; 31.2%] were not distinguishable from those with an LSAS score ≤60 by depressive and anxiety disorder symptoms. In postdetoxification assessment, patients who remitted from depression (HDRS score Conclusions: Depression and social phobia secondary to ADD are independent conditions that do not completely remit after cessation of drinking. Specific treatments are needed to reduce residual depressive and anxiety symptoms in abstinent alcoholics.

Voriconazole levels were determined with high-performance liquid chromatography (HPLC) and a microbiological agar diffusion assay using a Candida parapsilosis isolate in 103 serum samples from an HPLC-tested external quality control program (n = 39), 21 patients receiving voriconazole monotherapy (n = 39), and 7 patients receiving combination therapy (n = 25). The results of the bioassay were correlated with the results obtained from the external quality control program samples and with the HPLC results in sera from patients on voriconazole monotherapy and on combination therapy with an echinocandin (Spearman's rank correlation coefficient [rs], > 0.93; mean ± standard error of the mean [SEM] % difference

Voriconazole levels were determined with high-performance liquid chromatography (HPLC) and a microbiological agar diffusion assay using a Candida parapsilosis isolate in 103 serum samples from an HPLC-tested external quality control program ( n = 39), 21 patients receiving voriconazole monotherapy ( n = 39), and 7 patients receiving combination therapy ( n = 25). The results of the bioassay were correlated with the results obtained from the external quality control program samples and with the HPLC results in sera from patients on voriconazole monotherapy and on combination therapy with an echinocandin (Spearman's rank correlation coefficient [ r s ], > 0.93; mean ± standard error of the mean [SEM] % difference

Among the several genes associated with late-onset Alzheimer’s disease (LOAD), recently, Sirtuin genes have roused a growing interest because of their involvement in metabolic homeostasis and in brain aging. Particularly SIRT2 gene has been associated with Alzheimer’s disease (AD) as well as with mood disorders. The aim of this study is to investigate the possible associations between Sirtuin 2 gene (SIRT2) rs10410544 polymorphism and AD as well as depression in AD. In addition, we performed some exploratory analyses to investigate possible associations between the rs10410544 genotype and clinical features. We investigated these associations in two independent samples: the first one was composed of 275 Greek inhabitants and 117 patients; the second sample counted 181 Italian people and 43 patients. All patients were affected by LOAD. We failed to find any association between rs10410544 genotype and AD in the two samples. On the other hand, we found an association between the single nucleotide polymorphism (SNP) and depressive symptomatology (in the total sample p = 0.002), which was modulated by the tumor necrosis factor (TNF) values. Particularly, TT genotype seems to be protective versus depression. Finally, in the exploratory analyses, we found that the TT genotype was associated with earlier AD onset and a longer duration of the illness. In conclusion, we confirmed the association between SIRT2 gene and mood disturbances, although in AD patients. Further, we provided evidence that the TT genotype may be protective versus depressive symptoms, allowing an easier and thus earlier diagnosis of AD. This awareness may lead to a more detailed approach to these patients concerning diagnosis and therapy.

Background: Anti-thymocyte globulin (ATG) has been used to prevent graft failure/rejection in the setting of allogeneic stem cell transplantation (allo-SCT) for hemoglobinopathies; however, epidemiology data for transplant-related infections in this population are scarce. Method: We retrospectively analyzed the epidemiology of bacterial, fungal, viral, and parasitic infections in a cohort of 105 children and adolescents with β-thalassemia (n = 100) or sickle cell disease (n = 5) who underwent allo-SCT using human leukocyte antigen (HLA)-identical sibling (n = 96) or HLA-compatible unrelated donors (n = 9) in a single institution. All patients received an ATG-based conditioning regimen. Results: The cumulative incidence of cytomegalovirus (CMV) viremia was 45.7% (95% confidence interval [CI] 33-55%), developing at a median of 48 (range 12-142) days without evidence of overt CMV disease. Herpes zoster developed in 8 patients at a median of 12 months post transplant, while 10 patients presented with late onset hemorrhagic cystitis at a median of 35 days post transplant. The cumulative incidence of bacteremia was 17.1% (95% CI 10.6-25%), occurring at a median of 74 (range 24-110) days. No patient developed probable or definite invasive fungal infection. Four deaths were recorded; 2 of them were attributed to infections (toxoplasmosis and Pneumocystis jirovecii pneumonia, respectively). Conclusion: The rate of infections after allo-SCT, using an ATG-containing preparative regimen, in our population of pediatric patients with hemoglobinopathies is comparable to that reported elsewhere with the use of non-ATG containing regimens. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Atherosclerotic coronary heart disease and other forms of cardiovascular disease (CVD) are the major cause of mortality in type II diabetes (T2DM) as well as a major contributor to morbidity and lifetime costs. The purpose of this article is the identification of the biochemical parameters in plasma, which may serve as predisposition factors to CVD in T2DM patients of different ages. The variability of hyperglycemia, dyslipidemia, and inflammation with age progression was also studied for comparison. Four different diabetic groups allocated on the basis of the subjects' age (Group A: 15-25 years old; Group B: 26-40 years old; Group C: 40-60 years old; Group D: 60-80 years old) and consisting of 10 patients each, in parallel with 10 healthy controls matched for age, sex, and ethnic origin were screened for glucose, insulin, lipid profile (total cholesterol, triglycerides, LDL, and HDL), and inflammatory mediators (CRP, IL-6, and TNF-alpha). Significant differences were observed among the expressions of biochemical markers among different age groups. Hyperglycemia showed no variability with age whereas dyslipidemia correlated positively with age progression, as well as obesity, low physical activity, and family history of heart disease or diabetes. Marked inflammation was prominent only in Groups C and D. This article indicates that different biochemical parameters may be used for the assessment of CVD risk in T2DM patients of variable age.

The pathophysiology of Alzheimer's disease (AD) is influenced by sorting-protein related receptor (sorLa) that is less expressed in AD patients. The gene encoding sorLa (SORL1) has been investigated as a susceptibility factor for late-onset AD (LOAD) with conflicting results. Our objectives were to confirm the association between SORL1 SNPs and LOAD in two independent South-European centers and to perform a mega-analysis of published samples. We analyzed three SORL1 SNPs (intron 6: rs668387; rs689021; rs641120) from the Greece-Italy Genetic Association Study on lateonset AD (GIGAS_LOAD). Greek sample included 96 patients with LOAD (DSM-IV) and 120 unrelated controls. In Italy, a community-based sample is ongoing. 47 LOAD patients and 165 controls were recruited until study endpoint. These samples and previously published ones (Alzgene) were pooled as in a single study. A test for trend was used to analyze genotype association. In the GIGAS_LOAD sample no association was detected between SORL1 genotypes and LOAD. Conversely all SNPs were associated with LOAD in mega-analysis based on ordinal classification of genotypes (Armitage's test: p < 0.001). Although our analysis of pooled samples has positive results for the association between SORL1 and AD, there is substantial heterogeneity across studies. Thus further examination into SORL1 SNPs and the population is necessary to determine the role of SORL1 in LOAD.

It was suggested that the gene encoding for sorLa, (SORL1) may affect Alzheimer's disease (LOAD) through a female-specific mechanism. The aims of this study were to confirm the role of gender in modulating the association between SORL1 and LOAD and to ascertain the influence of SORL1 on cognitive impairment, neuropsychiatric symptoms (BPSD) and secretion of pro-inflammatory cytokines. Ninety six outpatients with LOAD and 120 unrelated controls were genotyped for APOE and three SNPs at the 5' end of SORL1(intron 6): SNP 8 (rs668387); SNP 9 (rs68902); SNP 10 (rs641120). Clinical evaluation was made with the MMSE, Neuropsychiatric Inventory (NPI) and Cornell Scale for Depression in Dementia (CDDS). ELISPOT assays were used to measure pro-inflammatory cytokine (TNF-alpha; IL-6; IL-1beta; IFN-gamma) production in peripheral blood mononuclear cell (PBMC) supernatant from AD patients. SORL1 SNPs were not associated with LOAD in overall sample. Instead the G-alleles at SNPs 9 (p=0.015) and 10 (p=0.015) and the CGG haplotype (p=0.02) were associated with LOAD in the women subgroup. The TAA haplotype was marginally protective in AD patients being associated with lower BPSD scores (p=0.01). The same haplotype was also associated with higher IL-1beta (p=0.01) production. These genetic effects were not modified by APOE4 allele and controlled for illness duration and treatment. In conclusion, SORL1 does not appear to be a major risk factor for LOAD. Its contribution could be underestimated in our small sample. Sex-specific factors could modulate the association between SORL1 and AD. The influence of SORL1 variants on production of inflammatory cytokines warrants further investigation.

Tumor necrosis factor-α (TNF-α) has been implicated in the pathogenesis of atherosclerosis through influence on vascular smooth muscle cell behavior. However, little is known about the expression and function of endogenous TNF-α in the cells. Dense and sparse cultures of bovine aortic smooth muscle cells were prepared and the expression of TNF-α and regulation of collagen synthesis by endogenous TNF-α were investigated. The results indicate that dense and sparse vascular smooth muscle cells express endogenous TNF-α that suppresses the synthesis of collagen (types I and III) only when the cell density is high; suppression was also observed in human and rabbit aortic smooth muscle cells. Transforming growth factor-β stimulated collagen synthesis in bovine aortic smooth muscle cells and the stimulation was significantly suppressed by endogenous TNF-α when cell density was high. The present data suggest that vascular smooth muscle cells express endogenous TNF-α that is involved in the suppressive regulation of collagen synthesis depending on the cell density.