Glioblastoma Microenvironment and Cellular Interactions.

The central nervous system (CNS) represents a complex network of different cells, such as neurons, glial cells, and blood vessels. In tumor pathology, glial cells result in the highest number of cancers, and glioblastoma (GB) is considered the most lethal tumor in this region. The development of GB leads to the infiltration of healthy tissue through the interaction between all the elements of the brain network. This results in a GB microenvironment, a complex peritumoral hallo composed of tumor cells and several non-tumor cells (e.g., nervous cells, stem cells, fibroblasts, vascular and immune cells), which might be the principal factor for the ineffective treatment due to the fact that the microenvironment modulates the biologic status of the tumor with the increase in its evasion capacity. Crosstalk between glioma cells and the brain microenvironment finally inhibits the beneficial action of molecular pathways, favoring the development and invasion of the tumor and its increasing resistance to treatment. A deeper understanding of cell-cell interactions in the tumor microenvironment (TME) and with the tumor cells could be the basis for a more efficient therapy.

Multiple Faces of the Glioblastoma Microenvironment.

The tumor microenvironment is a highly dynamic accumulation of resident and infiltrating tumor cells, responsible for growth and invasion. The authors focused on the leading-edge concepts regarding the glioblastoma microenvironment. Due to the fact that the modern trend in the research and treatment of glioblastoma is represented by multiple approaches that target not only the primary tumor but also the neighboring tissue, the study of the microenvironment in the peritumoral tissue is an appealing direction for current and future therapies.

Partnering bevacizumab with irinotecan as first line-therapy of metastatic colorectal cancer improves progression free survival-A retrospective analysis.

Colorectal cancer remains one of the most frequent malignancies (third place at both genders) worldwide in the last decade, owing to significant changes in modern dietary habits. Approximately half of the patients develop metastases during the course of their disease. The available therapeutic armamentarium is constantly evolving, raising questions regarding the best approach for improving survival. Bevacizumab remains one of the most widely used therapies for treating metastatic colorectal cancer and can be used after progression. This study aimed to identify the best chemotherapy partner for bevacizumab after progression. We performed a retrospective analysis of patients with metastatic colorectal cancer who were treated with bevacizumab as first- and second-line chemotherapy. Data were collected for 151 patients, 40 of whom were treated with double-dose bevacizumab after the first progression. The two standard chemotherapy regimens combined with bevacizumab were FOLFIRI/CAPIRI and FOLFOX4/CAPEOX. The initiation of first-line treatment with irinotecan-based chemotherapy improved progression-free survival and time to treatment failure but not overall survival. After the first progression, retreatment with the same regimen as that used in the induction phase was the best approach for improving overall survival (median overall survival: 46.5 vs. 27.0 months for the same vs. switched strategy, respectively). No correlations were observed between the dose intensity of irinotecan, oxaliplatin, 5-fluorouracil, or bevacizumab and the overall survival, progression-free survival in the first-/second-line treatment, and time to treatment failure. Interaction between an irinotecan-based regimen as a second-line treatment and double-dose bevacizumab after progression was associated with an improved overall survival (p = 0.06). Initiating systemic treatment with an irinotecan-based regimen in combination with bevacizumab improved the progression-free survival in the first-line treatment and time to treatment failure. In terms of overall survival, bevacizumab treatment after the first progression is better partnered with the same regimen as that used in the induction phase.

Interplay between metabolic and thyroid parameters in obese pubertal children. Does visceral adipose tissue make the first move?

Objectives: The mechanisms of obesity-associated thyroid dysfunction in children are incompletely deciphered. We aimed to evaluate whether visceral adipose tissue (VAT), insulin resistance (IR), inflammation, oxidative stress (OS) are involved in thyroid morpho-functional changes in pubertal obese children. Methods: We recruited 43 obese pubertal children without history of thyroid pathology. Metabolic and thyroid parameters (visceral fat thickness [VFT], waist/hip ratio [WHR], waist/height ratio [WHtR], insulin, glucose, liver parameters, thyroid stimulation hormone [TSH], free thyroxine [FT4], free triiodothyronine [FT3], thyroid and abdominal ultrasonography) were evaluated. Serum monocyte chemoattractant protein-1 (MCP-1) and malondialdehyde (MDA) levels were quantified as markers of inflammation and OS. Results: VFT correlated positively both with WHR (p= 0.034) and the presence of thyroid nodules (p= 0.036). WHR associated with TSH (p= 0.005), FT3/FT4 (p= 0.033) and was independently associated with FT3/FT4 increase (p< 0.001). HOMA-IR increased with visceral obesity (waist circumference, p= 0.001; WHR, p= 0.018; WHtR: p< 0.001), hepatic impairment (alanine aminotransferase, p= 0.019) and hepatic steatosis (HS; p= 0.013) and correlated positively with FT3/FT4 (p= 0.036). TSH was significantly higher in subjects with HS versus those without HS (p= 0.007) and logistic regression analysis identified TSH as a risk factor for HS (p= 0.014). MDA correlated positively with MCP-1 (p= 0.021). Conclusion: VAT and IR may be responsible for changes in thyroid parameters associated with obesity: elevated TSH, FT3/FT4 levels and increased prevalence of thyroid nodules. WHR was predictive of increased FT3/FT4. In obese children, there is an interdependent relationship between HS and thyroid function.

State of the art in human adipose stem cells and their role in therapy.

Nowadays, adipose tissue appears to be the most valuable source in regenerative cell therapy, due to the following characteristics: high accessibility, high expression in a large number of individuals, high self-renewal and ability to differentiate, and hematopoietic support to the implant area. Its therapeutic potential has been experimentally observed in a broad spectrum of diseases with high population impact: diabetes, myocardial infarction, Parkinson disease, bone fractures, facial reconstruction or loss of subcutaneous tissue due to congenital abnormalities (e.g., hemifacial microsomy), trauma, burns, and tumors. Over 130 clinical trials using adipose-derived stem cells (ASCs), majority phase I or phase II, have been registered with the National Institutes of Health (NIH), and in the short term no adverse reactions or significant risks were identified. Parallel with regulatory frameworks that control their safety and assess their efficacy, phase III trials are being developed. Although transplantation with adipose tissue is becoming more and more popular, there are still important drawbacks and technical challenges to be addressed, and clinical strategies to be developed. This review explores in a concise manner the present body of knowledge concerning ASCs and their implication in therapy.

Vitamin D deficiency, insulin resistance and thyroid dysfunction in obese patients: is inflammation the common link?

The aim of this article is to study the possible relation of serum vitamin D concentrations to body mass index (BMI), visceral fat thickness (VFT), insulin resistance (IR), inflammation (serum monocyte chemoattractant protein-1 - MCP-1) and thyroid parameters in obese patients. A total of 158 non-diabetic, obese patients aged 19-68 without a history of thyroid pathology were recruited. Biochemical markers, insulin, 25-OH vitamin D, thyroid parameters (TSH, FT3, FT4, TPO antibodies, TG antibodies) and VFT were measured. Serum MCP-1 evaluated the inflammation. A HOMA-IR cut-off value of 2.5 defined IR. Most patients had severe (70.3%) or moderate (25.3%) vitamin D deficiency. Vitamin D level was negatively associated with BMI (p = .043) and during the cold season with VFT (p = .009). Vitamin D deficiency correlated with Hashimoto's thyroiditis prevalence during the warm season (p = .047) and was a risk factor for its occurrence (p = .021). At 15 ng/mL cut-off value, vitamin D was negatively correlated with MCP-1 (p = .0006). Also, MCP-1 was positive correlated with HOMA- IR (p = .042), TPO-Ab levels (p = .011) and with Hashimoto's thyroiditis (p = .027). MCP-1 was a risk factor for vitamin D deficiency (p < .0001). Our study supports a bidirectional interaction between vitamin D and systemic inflammation in obese patients. Moreover, systemic inflammation is related to the severity and frequency of Hashimoto's thyroiditis. Vitamin D deficiency is the single independent factor associated with Hashimoto's thyroiditis in obese patients.

Genotype-phenotype Analysis of Paraoxonase 1 in Schizophrenic Patients Treated with Atypical Antipsychotics.

OBJECTIVE: Recent studies suggest a possible involvement of low paraoxonase 1 (PON1) enzyme activities in the association between schizophrenia, treatment with atypical antipsychotics and increased cardiovascular (CVD) risk. In the present study, we aimed at investigating the PON1 status in a group of schizophrenic patients treated with either olanzapine or other antipsychotic, as compared to a group of healthy control participants. METHODS: We assessed the arylesterase (AREase) and paraoxonase (POase) activities of PON1, as well as three common polymorphisms of PON1 gene (Q192R, L55M, -108C＞T). RESULTS: We found significantly lower (-13.3%) AREase activity in schizophrenic patients, along with significantly lower (-18.2%) POase activity in olanzapine-treated patients with QQ genotype. Furthermore, we found a significant difference between groups in L55M polymorphism distribution, whereas Q192R and -108C＞T polymorphisms distributions were similar. CONCLUSION: We identified the olanzapine-treated patients with QQ genotype as having the lowest PON1 (POase) activity, providing a possible way of identifying schizophrenic patients exposed to the greatest risk of CVD.

Low Retinal Dehydrogenase 1 (RALDH1) Level in Prepubertal Boys with Autism Spectrum Disorder: A Possible Link to Dopamine Dysfunction?

OBJECTIVE: Retinal dehydrogenase 1 (RALDH1) is a cytosolic enzyme which acts both as a source of retinoic acid (RA) and as a detoxification enzyme. RALDH1 has key functions in the midbrain dopaminergic system, which influences motivation, cognition, and social behavior. Since dopamine has been increasingly linked to autism spectrum disorder (ASD), we asked whether RALDH1 could contribute to the autistic phenotype. Therefore, we investigated for the first time the levels of RALDH1 in autistic patients. To further assess the detoxification function of RALDH1, we also explored 4-hydroxynonenal protein adducts (4-HNE PAs) and reduced glutathione (GSH) levels. Moreover, considering the effect of testosterone on RALDH1 expression, we measured the second to fourth digit ratio (2D:4D ratio) for both hands, which reflects exposure to prenatal testosterone. METHODS: Male patients with ASD (n=18; age, 62.9±4.3 months) and healthy controls (n=13; age, 78.1±4.9 months) were examined. Erythrocyte RALDH1, serum 4-HNE PAs and erythrocyte GSH levels were measured using colorimetric assays, and digit lengths were measured using digital calipers. RESULTS: We found significantly lower (-42.9%) RALDH1 levels in autistic patients as compared to controls (p=0.032). However, there was no difference in 4-HNE PAs levels (p=0.368), GSH levels (p=0.586), or 2D:4D ratios (p=0.246 in the left hand, p=0.584 in the right hand) between healthy controls and autistic subjects. CONCLUSION: We concluded that a subset of autistic patients had a low RALDH1 level. These results suggest that low RALDH1 levels could contribute to the autistic phenotype by reflecting a dopaminergic dysfunction.

Chondroprotective effects of pulsed shortwave therapy in rabbits with experimental osteoarthritis.

INTRODUCTION: Osteoarthritis (OA) represents a public health challenge since the pathogenic treatment, able to induce cartilage regeneration, still remains unknown. Ageing of the population and increasing OA prevalence have led to a lot of research, aiming to identify treatments acting on chondrocytes that play a determinant role in cartilage degeneration÷regeneration balance. Pulsed shortwave therapy (with the classical application form - Diapulse) is a physiotherapy method with anabolic effects demonstrated on nervous, conjunctive and vascular tissues, but its effects on OA cartilage are not known. AIM: Our aim was to demonstrate the effects of Diapulse on the cartilage in experimental induced OA. MATERIALS AND METHODS: Experimental OA was induced in 10 mature female rabbits by anterior cruciate ligament transection (ACLT). Ten weeks after ACLT, rabbits were randomized in a treatment group and a control group. Treatment group was exposed to Diapulse at a frequency of 27.12 MHz, pulse length of 65 µs, pulse frequency of 300 pulses÷s (300 Hz) for 10 minutes÷day. Control group was exposed to sham therapy. After treatment, rabbits were sacrificed and the cartilage was evaluated by histopathological examinations with Hematoxylin-Eosin (HE) staining and transmission electron microscopy (TEM). RESULTS: OA characteristic changes were found in both groups. In the treatment group, we found that Diapulse influenced the degenerative process in the OA cartilage by improving the chondrocyte viability and the capacity to maintain cellular matrix integrity and structure. CONCLUSIONS: Diapulse can be considered a disease modifying therapeutic procedure and could be a reliable option for treatment of OA patients.

Solitary Langerhans histiocytosis of the orbit: case report and review of the literature.

Langerhans cell histiocytosis (LCH), previously known as "histiocytosis X", is a clinical entity characterized by abnormal proliferation of Langerhans cells, which exert a mass effect. Orbital involvement due to LCH is rare as a unifocal disease, seldom occurring outside the pediatric population. We report a case of a 21-year-old man with solitary LCH of the orbit depicted by magnetic resonance imaging (MRI) and diagnosed by histopathological examination.

Paraoxonase-1 activities in children and adolescents with type 1 diabetes mellitus.

BACKGROUND: Paraoxonase-1 is an HDL-associated esterase that acts as an anti-atherogenic agent by protecting LDL from oxidation. This study investigates paraoxonase-1 activities in children and adolescents with type 1 diabetes mellitus and possible associations with other biochemical markers. PATIENTS AND METHODS: The study enrolled 82 children and adolescents with type 1 diabetes mellitus and 41 controls with similar age and gender distribution. Serum paraoxonase-1 arylesterase and salt-stimulated paraoxonase activities were assessed by measuring the rates of phenyl acetate and paraoxon hydrolysis, respectively; paraoxonase-1 lactonase activity and oxidized LDL were assessed by a pH-sensitive colorimetric assay and ELISA, respectively. Glycated haemoglobin HbA1c and lipid profile were assayed with an immunoturbidimetric method and commercially available kits, respectively. RESULTS: We found lower paraoxonase-1 activities in diabetics when compared to controls. The decrease was statistically significant only for the lactonase activity, the difference being higher when referring to the subgroup with poor glycaemic control. The lactonase activity/HDL ratio was also lower in diabetics vs. controls, but without statistical significance. Both lactonase and arylesterase activities were negatively correlated with HbA1c in diabetics, but only the latter was statistically significant (ρ = -0.21, P = 0.055; ρ = -0.24, P = 0.03, respectively). A correlation coefficient of ρ = 0.196 (P = 0.078) was found between oxidized LDL and HbA1c. CONCLUSION: All paraoxonase-1 activities were lower in diabetic children and adolescents, but only the decrease in the lactonase activity was statistically significant. Although lipid profile and glycaemic control were altered in diabetics, no differences were observed between groups regarding oxidized LDL level.

Evaluation of whole blood zinc and copper levels in children with autism spectrum disorder.

Zinc (Zn) and copper (Cu) are important trace elements for cognitive development and normal neurological functioning. Autism spectrum disorder (ASD) is a common neurological disorder, which has previously been associated with the levels of some trace elements in the blood. However, clinical data regarding the potential implication of Zn and Cu in patients with ASD are still insufficient. Therefore, the aim of the present study was to investigate the whole blood levels of Zn and Cu in a cohort of 28 children with ASD and 28 age- and gender-matched healthy controls. Whole blood Zn and Cu levels were assessed using inductively-coupled plasma-sector field mass spectrometry. Both in the control and in the ASD group, the values of whole blood Cu and Zn were characterized by a Gaussian distribution. The results indicate that the ASD children were characterized by ~10 % (p = 0.005) and ~12 % (p = 0.015) lower levels of whole blood Zn and Zn/Cu ratio, respectively, in comparison to controls. No significant difference in whole blood Cu was observed. However, Cu/Zn ratio was ~15 % (p = 0.008) higher in ASD children than that in the control ones. The results of the present study may be indicative of Zn deficiency in ASD children. Taking into account Zn-mediated up-regulation of metallothionein (MT) gene expression, these findings suggest a possible alteration in the functioning of the neuroprotective MT system. However, further investigations are required to test this hypothesis.

Paraoxonase 1 genotype-phenotype correlation in patients with metabolic syndrome.

The aim of the study was to investigate the influence of three single nucleotide polymorphisms (SNPs) (-108C>T, -162A>G and -909G>C) from the promoter region of paraoxonase 1 (PON1) gene on the enzyme activity, in patients with metabolic syndrome (MS). The study group consisted of 61 individuals with MS and the control group of 73 individuals without MS, matched for age and gender. For each individual, clinical and genetic parameters with possible influence on PON1 activities (paraoxonase, arylesterase and lactonase) were measured. PON1 genotyping was performed with PCR-RFLP, using specific primers and restriction enzymes. We found no differences for distribution of PON1 -108C>T, -162A>G and -909G>C polymorphisms, between the two groups (p-NS). The -108C>T and -909G>C polymorphisms were associated with paraoxonase (p=0.03, p=0.006, respectively), arylesterase (p<0.001, p<0.001, respectively) and lactonase (p<0.001, p<0.001, respectively) activities. The -162A>G polymorphism was not associated with paraoxonase (p-NS) or lactonase (p-NS) activities, but influenced the arylesterase activity (p=0.03). PON1 activities were influenced by all three polymorphisms, regardless of the presence of MS.

Serum homocysteine levels, oxidative stress and cardiovascular risk in non-alcoholic steatohepatitis.

INTRODUCTION: Hyperhomocysteinemia is considered an independent risk factor for cardiovascular disease. Oxidative stress is one of the major pathogenic mechanisms in non-alcoholic fatty liver disease and atherosclerosis. AIM: Our study aimed to evaluate serum homocysteine levels and oxidative stress in patients with biopsy-proven non-alcoholic steatohepatitis and possible association with cardiovascular risk measured by carotid artery intima-media thickness (c-IMT). PATIENTS AND METHODS: 50 patients with non-alcoholic steatohepatitis and 30 healthy controls, age and gender matched, were recruited. Lipid profile, liver biochemical markers, serum homocysteine, vitamins B6 and B12, folic acid, glutathione (reduced and total), erythrocyte superoxide dismutase, whole blood glutathione peroxidase, malondialdehyde and carotid intima-media thickness were assayed. RESULTS: Patients had an altered lipid profile and liver biochemical markers; carotid intima-media thickness and serum homocysteine levels were significantly higher compared to controls, but there were no differences in folate, B12 and B6 vitamins levels. Patients had significantly lower levels of glutathione peroxidase activity, total and reduced glutathione and higher levels of malondialdehyde, but unchanged superoxide dismutase activity compared to control group. Also, serum homocysteine level showed significant positive correlation with waist circumference, body mass index, free cholesterol, triglycerides, LDL-cholesterol, amino transferases and negative correlation with reduced and total glutathione, superoxide dismutase and γ-GT. CONCLUSION: Non-alcoholic steatohepatitis is an independent cardiovascular risk factor, associated with elevated homocysteine levels, oxidative stress and c-IMT. c-IMT could be used as an indicator of early atherosclerotic changes initiated by dyslipidemia and oxidative stress, while higher level of homocysteine might be an effect of liver damage.

Diagnostic correlation between RET proto-oncogene mutation, imaging techniques, biochemical markers and morphological examination in MEN2A syndrome: case report and literature review.

Multiple endocrine neoplasia type 2 (MEN2) is a rare autosomal dominant monogenic disorder caused mostly by missense mutations in the RET (REarranged during Transfection) proto-oncogene on chromosome 10q11.2. MEN2A represents more than 50% of all MEN2 cases, having a regular pattern with medullary thyroid carcinoma (MTC) incidence of 90-100%, bilateral pheochromocytoma (PCC) incidence of 40-50% and primary hyperparathyroidism (HPT) incidence of 10-25%. Until recently, the diagnosis of MTC was most frequently based on fine-needle aspiration of thyroid nodules, after an ultrasound examination and endocrine evaluation of serum calcitonin levels. Nowadays, RET gene screening (starting with exons 10 and 11) is a mandatory test used for identification of both symptomatic and non-symptomatic MTC carriers or for exclusion of healthy individuals from subsequent periodical clinical/biochemical screening. In this context, and in the idea of PCC preceding MTC, the early detection of germline RET mutations are highly suggestive for hereditary disease. PCC diagnosis is established in classical manner by abdominal ultrasound imaging or computed tomography confirming the presence of adrenal gland masses, elevated plasma metanephrines and normetanephrines values and histopathological examination. Additional HPT diagnosis is acknowledged by serum ionized calcium and parathormone levels. Here we report a hereditary case of MEN2A in a two-generation Romanian family, along with data presenting the importance of correlative plurifactorial diagnostic scheme in this syndrome and a short literature review.

Paraoxonase 1 activities and polymorphisms in autism spectrum disorders.

Autism spectrum disorders (ASD) comprise a complex and heterogeneous group of conditions of unknown aetiology, characterized by significant disturbances in social, communicative and behavioural functioning. Recent studies suggested a possible implication of the high-density lipoprotein associated esterase/lactonase paraoxonase 1 (PON1) in ASD. In the present study, we aimed at investigating the PON1 status in a group of 50 children with ASD as compared to healthy age and sex matched control participants. We evaluated PON1 bioavailability (i.e. arylesterase activity) and catalytic activity (i.e. paraoxonase activity) in plasma using spectrophotometric methods and the two common polymorphisms in the PON1 coding region (Q192R, L55M) by employing Light Cycler real-time PCR. We found that both PON1 arylesterase and PON1 paraoxonase activities were decreased in autistic patients (respectively, P < 0.001, P < 0.05), but no association with less active variants of the PON1 gene was found. The PON1 phenotype, inferred from the two-dimensional enzyme analysis, had a similar distribution in the ASD group and the control group. In conclusion, both the bioavailability and the catalytic activity of PON1 are impaired in ASD, despite no association with the Q192R and L55M polymorphisms in the PON1 gene and a normal distribution of the PON1 phenotype.

One carbon metabolism disturbances and the C677T MTHFR gene polymorphism in children with autism spectrum disorders.

Autism spectrum disorders (ASDs), which include the prototypic autistic disorder (AD), Asperger's syndrome (AS) and pervasive developmental disorders not otherwise specified (PDD-NOS), are complex neurodevelopmental conditions of unknown aetiology. The current study investigated the metabolites in the methionine cycle, the transsulphuration pathway, folate, vitamin B(12) and the C677T polymorphism of the MTHFR gene in three groups of children diagnosed with AD (n= 15), AS (n= 5) and PDD-NOS (n= 19) and their age- and sex-matched controls (n= 25). No metabolic disturbances were seen in the AS patients, while in the AD and PDD-NOS groups, lower plasma levels of methionine (P= 0.01 and P= 0.03, respectively) and alpha-aminobutyrate were observed (P= 0.01 and P= 0.001, respectively). Only in the AD group, plasma cysteine (P= 0.02) and total blood glutathione (P= 0.02) were found to be reduced. Although there was a trend towards lower levels of serine, glycine, N, N-dimethylglycine in AD patients, the plasma levels of these metabolites as well as the levels of homocysteine and cystathionine were not statistically different in any of the ASDs groups. The serum levels of vitamin B(12) and folate were in the normal range. The results of the MTHFR gene analysis showed a normal distribution of the C677T polymorphism in children with ASDs, but the frequency of the 677T allele was slightly more prevalent in AD patients. Our study indicates a possible role for the alterations in one carbon metabolism in the pathophysiology of ASDs and provides, for the first time, preliminary evidence for metabolic and genetic differences between clinical subtypes of ASDs.

[Hyperhomocysteinemia, risk factor in deep venous thrombosis: a case-control study]. / Hiperhomocisteinemia--factor de risc în trombozele venoase profunde. Un studiu de tip case-control.

UNLABELLED: Hyperhomocysteinemia, an established cardiovascular risk factor, has been recently associated with deep venous thrombosis. MATERIAL AND METHOD: A matched case-control study was designed to assess homocysteinemia as well as the acquired risk factors in deep venous thrombosis (DVT). We enrolled 227 subjects, 127 with DVT confirmed by Doppler ultrasonography and 100 controls. Homocysteinemia was measured using reverse-phase high pressure liquid chromatography. RESULTS: We found a significant association between hyperhomocysteinemia and DVT; the associated risk was weak (p = 0.025, OR: 1.7). Other risk factors significantly associated with DVT were: obesity (p = 0.04, OR for DVT: 2.9), varicose veins (p = 0.023, OR: 3.13), prolonged immobility (p = 0.015, OR: 3.1), history of DVT (p = 0.01, OR: 5.59). All these factors were found to be independent risk factors using multivariate logistic regression. CONCLUSION: hyperhomocysteinemia is an independent risk factor for DVT; the risk is not associated with the severity of hyperhomocysteinemia.

High levels of homocysteine and low serum paraoxonase 1 arylesterase activity in children with autism.

Autism is a behaviorally defined disorder of unknown etiology that is thought to be influenced by genetic and environmental factors. High levels of homocysteine and oxidative stress are generally associated with neuropsychiatric disorders. The purpose of this study was to compare the level of homocysteine and other biomarkers in children with autism to corresponding values in age-matched healthy children. We measured total homocysteine (tHcy), vitamin B(12), paraoxonase and arylesterase activities of human paraoxonase 1 (PON1) in plasma and glutathione peroxidase (GPx) activity in erythrocytes from 21 children: 12 with autism (age: 8.29 +/- 2.76 years) and 9 controls (age: 8.33 +/- 1.82 years). We found statistically significant differences in tHcy levels and in arylesterase activity of PON1 in children with autism compared to the control group: 9.83 +/- 2.75 vs. 7.51 +/- 0.93 micromol/L (P < or =0.01) and 72.57 +/- 11.73 vs. 81.83 +/- 7.39 kU/L (P < or =0.005). In the autistic group there was a strong negative correlation between tHcy and GPx activity and the vitamin B(12) level was low or suboptimal. In conclusion, our study shows that in children with autism there are higher levels of tHcy, which is negatively correlated with GPx activity, low PON1 arylesterase activity and suboptimal levels of vitamin B(12).