Amygdalin (Vitamin B17) pretreatment attenuates experimentally induced acute autoimmune hepatitis through reduction of CD4+ cell infiltration.

BACKGROUND: Autoimmune hepatitis (AIH) is an immune-mediated inflammation of the liver characterized by disorganized hepatic parenchyma and inflammatory cell infiltration. Although the increased incidence of AIH, the development of novel therapeutic strategies are impeded by the poor understanding of the accompanied detailed immunopathogenic changes. CD4+ T cells are key mediators of inflammatory cell infiltration in initial phases of liver injuries like AIH. The distribution of CD4+ cells and the histopathological changes accompanying Con A-induced AIH were investigated together with the postulated protective effect of Amygdalin (Amg.). MATERIALS AND METHODS: 30 adult male mice were divided into three groups; control, AIH and AIH-Amg. groups. AIH was induced by a single intravenous injection of Concanavalin A (Con A) (15 mg/kg). The AIH-Amg. group received Amg. 5 mg/kg intraperitoneally once a week for three weeks. Blood samples were examined for ALT and AST. MDA, SOD, and GSH were determined in hepatic homogenates. Liver section stained with hematoxylin and eosin, Masson trichrome and CD4+ immune stain were examined by light and electron microscopy. RESULTS: AIH group showed a significant increase in levels of ALT, AST and MDA and a significant decline in SOD and GSH compared to the controls. The liver tissue showed distorted hepatic architecture with intercellular hemorrhage, necrosis, and inflammatory cell infiltration. The area percent of CD4+ immune staining was significantly increased. Electron microscopic examination showed massive cellular degenerative changes. Amg. pretreatment in AIH-Amg. group significantly reversed these changes. CONCLUSION: AIH induced CD4+ cells infiltration in the liver with subsequent liver tissue damage. Amg. pretreatment inhibited CD4+ cell infiltration and protected the liver tissue. This finding suggests that Amg. could be a therapeutic agent in the management of AIH.

[Protective effect of intraperitoneal transplantation of human liver-derived stem cells at different times against concanavalin A-induced acute liver injury in mice].

Objective: To investigate the protective effect of intraperitoneal transplantation of human liver-derived stem cells at different times against concanavalin A (ConA)-induced acute liver injury in mice. Methods: A total of 88 male C57BL/6 mice were randomly divided into normal control group (group C), ConA model group (group M), and human liver-derived stem cells (HYX1)+ConA group (group E); according to the interval between phosphate buffer/HYX1 injection and ConA injection, Groups M and E were further divided into 3-hour groups (M1 and E1 groups), 6-hour groups (M2 and E2 groups), 12-hour groups (M3 and E3 groups), 24-hour groups (M4 and E4 groups), and 48-hour groups (M5 and E5 groups). The levels of alanine aminotransferase (ALT), aspartate transaminase (AST), and total bilirubin (TBil) in peripheral blood were measured, liver tissue sections were used to observe pathological changes, and the Ishak score for liver inflammation was determined. The independent samples t-test was used for comparison between groups, and P < 0.05 was considered statistically significant. Results: The levels of ALT, AST, and TBil in group C were (36.25±1.16) U/L, (120.20±5.77) U/L, and (2.20±0.23) µmol/L, respectively; the levels of ALT, AST, and TBil and Ishak score were (8 721.23±837.39) U/L, (8 110.31±290.10) U/L, (8.41±0.10) µmol/L, and (13.32±1.30), respectively, in group M1, (8 334.31±666.50) U/L, (7 560.20±760.34) U/L, (10.40±0.80) µmol/L, and (12.67±0.81), respectively, in group M2, (8 960.75±551.93) U/L, (8 535.62±675.14) U/L, (10.95±1.43) µmol/L, and (14.57±0.65), respectively, in group M3, (8 618.57±886.40) U/L, (11 440.54 ± 1 327.86) U/L, (13.30±1.86) µmol/L, and (13.21±1.06), respectively, in group M4, and (10 170.13±1 112.37) U/L, (11 470.56±1 108.40) U/L, (12.75±1.55) µmol/L, and (15.07±1.58), respectively, in group M5. The levels of ALT, AST, and TBil and Ishak score were (1 016.35±163.47) U/L, (952.30±103.91) U/L, (7.77±0.62) µmol/L, and (3.50±0.21), respectively, in group E1, (42.10±6.20) U/L, (126.72±13.33) U/L, (3.41±0.53) µmol/L, and (2.01±0.40), respectively, in group E2, (44.21±4.30) U/L, (216.71±35.88) U/L, (3.47±0.44) µmol/L, and (2.13±0.25), respectively, in group E3, (2 909.69±212.14) U/L, (2 988.43±333.70) U/L, (7.03±0.93) µmol/L, and (4.70±0.50), respectively, in group E4, and (7 874.26±799.60) U/L, (10 940.54±947.35) U/L, (10.53±1.09) µmol/L, and (8.60±0.83), respectively, in group E5. Groups M1-M5 had significantly higher levels of ALT, AST, and TBil than group C (all P < 0.01), and groups M1-M4 had significantly higher levels of AST and ALT than groups E1-E4 (all P < 0.01), while there were no significant differences in the levels of AST and ALT between groups M5 and E5 (both P > 0.05). The pathological sections of liver tissue showed that compared with group M, group E had significant reductions in the degree of necrosis and Ishak score (both P < 0.05). Conclusion: Intraperitoneal transplantation of human liver-derived stem cells has a protective effect against ConA-induced acute liver injury in mice, and the injection at 6 and 12 hours in advance has the best protective effect.

Hepatic serum amyloid A1 aggravates T cell-mediated hepatitis by inducing chemokines via Toll-like receptor 2 in mice.

Serum amyloid A is a proinflammatory molecule that induces leukocyte infiltration and promotes neutrophil adhesion to endothelial cells under inflammatory conditions. The aim of this study was to examine whether Saa1 aggravates T cell-mediated hepatitis by inducing chemokines in a liver-specific, Saa1-overexpressing, transgenic (TG) mouse model. We generated TG mice in which Saa1 was overexpressed specifically in liver tissue. The chemokines monocyte chemotactic protein 1 (MCP1), MIP1α, MIP1ß, interferon γ-induced protein 10 (IP-10), and eotaxin were induced in Saa1 TG mice. After concanavalin A treatment, Saa1 expression was higher in Saa1 TG mice than in WT mice. More severe liver injury, increased hepatocyte apoptosis, and higher levels of hepatic enzymes were observed in Saa1 TG mice than in WT mice. Liver infiltration of CD4(+) T cells and macrophages increased after inducing hepatitis. Activation of T cells was higher in Saa1 TG mice than in WT mice, and the populations of Th17 cells and regulatory T cells were altered by overexpressing Saa1 in TG mice. Secretion of various cytokines, such as interferon γ, tumor necrosis factor α, and interleukin 6, increased in Saa1 TG mice. Injecting a Toll-like receptor 2 (TLR2) antagonist in vivo inhibited chemokine expression and IκBα phosphorylation and showed that the induction of chemokines by Saa1 was dependent on TLR2. Hepatic Saa1 accelerated T cell-mediated hepatitis by inducing chemokine production and activating T cells by TLR2. Therefore, Saa1 might be a novel inflammatory factor that acts as a chemokine modulator in hepatitis.

Morphological and functional changes in the spleen of mice offspring at different stages of postnatal development after a single immunostimulating impact on maternal organism in early pregnancy.

We studied the effect of short-term activation of the maternal immune system with T-cell mitogen concanavalin A at the early terms of pregnancy on the postnatal development of the spleen in the offspring. It was found that single immunostimulatory exposure prior to the formation of the fetal immune system delays the postnatal development of the spleen until the beginning of puberty and impairs the formation of splenic lymphatic nodules with the predominant development of germinal centers as well as increases the number of mast cells in this organ.

The critical role of myeloid-derived suppressor cells and FXR activation in immune-mediated liver injury.

The immunobiology of FXR has attracted significant attention in immune regulation and innate immunity. We have studied the mechanism of action of FXR activation on two models of acute hepatitis, inflammation mediated by Con A and α-GalCer and focused on the interactions of FXR activation and expression of PIR-B, both in vivo and in vitro using luciferase reporter and CHIP assays. In addition, based upon our data, we studied the role of FXR activation on the immunobiology of myeloid-derived suppressor cells (MDSCs). Importantly, we report herein that FXR activation reduces the inflammatory insult induced by either α-GalCer or Con A; such treatment expands CD11b(+)Ly6C(+) MDSCs. The protective effect of FXR activation is dependent on expansion of MDSCs, particularly liver CD11b(+)Ly6C(high) cells. Indeed, FXR activation enhances the suppressor function of MDSCs through upregulation of PIR-B by binding the PIR-B promoter. FXR activation drives the accumulation of MDSCs to liver through upregulation of S100A8. FXR activation facilitates homing and function of MDSCs, which function as a critical negative feedback loop in immune-mediated liver injury. The novel mechanisms defined herein emphasize not only the importance of liver lymphoid subpopulations, but also the potential roles of modulating FXR in autoimmune liver disease.

STAT4 knockout mice are more susceptible to concanavalin A-induced T-cell hepatitis.

STAT4, which is activated mainly by IL-12, promotes inflammatory responses by inducing Th1 and Th2 cytokines. Recent genome-wide association studies indicate that STAT4 gene variants are associated with risk of various types of liver diseases, but how STAT4 contributes to liver disease pathogenesis remains obscure. In this study, STAT4 activation was detected in liver immune cells from patients with viral hepatitis and autoimmune hepatitis, as well as in a mouse model of concanavalin A (Con A)-induced hepatitis. Such STAT4 activation was detected mainly in T cells, natural killer T cells, and macrophages and Kupffer cells, and was diminished in Il12a(-/-) and Il12b(-/-) mice. As expected, disruption of the Stat4 gene reduced production of Th1 and Th2 cytokines, but surprisingly exacerbated Con A-induced liver injury. Similarly, disruption of Il12a or Il12b also augmented Con A-induced hepatocellular damage. Further studies showed that hepatic natural killer T (NKT) cells from Con A-treated Stat4(-/-) mice had higher levels of FasL expression and increased cytotoxicity against hepatocytes than those from Con A-treated WT mice. In vitro, blocking FasL attenuated Stat4(-/-) NKT cytotoxicity against hepatocytes. In conclusion, despite up-regulation of proinflammatory cytokines, STAT4 protects against acute T-cell hepatitis, which is mediated by direct or indirect down-regulation of FasL expression on NKT cells.

Long-term estradiol exposure is a direct mitogen for insulin/EGF-primed endometrial cells and drives PTEN loss-induced hyperplasic growth.

Loss of tumor-suppressor PTEN is the most common alteration in endometrial carcinoma. However, the relationship between loss of PTEN, growth factors [eg, insulin/insulin-like growth factor (IGF)-1], epidermal growth factor (EGF), and hyperestrogenism in the development of endometrial carcinoma is still controversial. By using three-dimensional (3D) cultures of PTEN(+/+) and PTEN(+/-) endometrial epithelial cells, we investigated the effects of EGF, insulin/IGF, and estradiol in endometrial cell proliferation. We have previously demonstrated that 3D cultures of endometrial cells require EGF and insulin/IGF to proliferate. Herein, we demonstrate that, in the presence of EGF and insulin/IGF, long-term estradiol treatment directly induces proliferation of 3D cultures. Moreover, we show that the mitogenic effects of estradiol require the presence of insulin/IGF and EGF, because withdrawal of such factors completely abolishes estradiol-induced proliferation. In the presence of EGF and insulin/IGF, PTEN(+/-) and PTEN(+/+) spheroids display a similar rate of proliferation. However, the addition of estradiol causes an exaggerated proliferation of PTEN(+/-) cultures, leading to formation of complex structures, such as those observed in endometrial hyperplasia or carcinoma. In summary, we demonstrate that EGF and insulin/IGF prime endometrial epithelial cells to direct the mitogenic effects of estradiol. Furthermore, PTEN deficiency results in enhanced responsiveness to this combination, leading to the development of hyperplasia of endometrial cells in culture.

[An experimental study of the anti-inflammatory action of noopept and its effect on the level of cytokines].

The anti-inflammatory effects of noopept (dipeptide analog of piracetam) upon a single intraperitoneal (i.p.) administration at doses of 1, 5, and 10 mg/kg in comparison to the reference drug diclofenac (10 mg/kg, i.p.) have been studied on a model of acute exudative inflammation induced by carrageenan in outbred rats and concanavalin A (Con A) in CBA mice. The level of cytokines was studied on the lipopolysaccharide (LPS) model (single administration, 100 mg/kg, i.p.) with 5-day administration of noopept at a dose of 5 mg/kg (i.p., before endotoxin injection) in C57BL/6 mice. The administration of noopept led to a significant suppression of the inflammatory response to both carrageenan and Con A. The administration of Con A caused a 16-fold increase in the level of IL-6 interleukin in the blood serum of mice as compared to control. Noopept (5 mg/kg) reduced the level of IL-6 by a factor of 1.8 in the inflammatory response to Con A. The administration of LPS led to pronounced increase in the levels ofpro-inflammatory IL-6 and TNF-alpha in the blood serum of test mice as compared to intact animals. The course administration of noopept (5 mg/kg) significantly decreased the level of IL-6 and reduced by half the level of TNF-alpha.

NCPP treatment alleviates ConA-induced hepatitis via reducing CD4+T activation and NO production.

Corynebacterium parvum (CP), a kind of immunomodulator, has been well documented in many diseases. Non-cell C. parvum product (NCPP) is a newly-found nano-preparation. To investigate the effect of NCPP on Con A-induced murine severe hepatitis, we pretreated mice with NCPP intraperitoneally. After 12 h, ConA (25 µg/g body wt) was injected intravenously to provoke severe hepatitis and the degree of liver injury was evaluated by serum transaminase analysis and heptatic tissue pathology. Results have shown that levels of serum transaminase and degree of liver injury in ConA/NCPP groups had significantly declined than those in ConA/PBS groups. Notably, results of flow cytometry have demonstrated that activation of CD4+T cells in ConA/NCPP groups has been down-regulated, compared with ConA/PBS groups. Further, levels of serum and KC-related nitric oxide (NO) was displayed significantly lower in ConA/NCPP groups than those in ConA/PBS groups. The results indicate that NCPP may alleviate ConA-induced hepatitis by reducing CD4+T activation and NO production.

Adenovirus-mediated viral interleukin-10 gene transfer prevents concanavalin A-induced liver injury.

BACKGROUND AND AIM: Liver injury is closely associated with immune inflammation. Lacking immunostimulatory functions, viral interleukin-10 (vIL-10), a cellular IL-10 homologue, has been an attractive molecule for immunomodulatory therapy. We aimed to reveal a protective effect of the gene transfer of an adenoviral vector encoding vIL-10 on liver injury induced by concanavalin A. METHODS: C57BL/6J mice were intravenously injected with adenoviral vector encoding vIL-10 before concanavalin A challenge. Liver injury was assessed. Interferon-γ and interleukin-4 levels were measured by ELISA. The activation of splenic and hepatic immune cells was analysed using an MTT assay. RESULTS: Adenoviral vector encoding vIL-10 pretreatment significantly decreased concanavalin A-mediated elevations in serum alanine aminotransaminase and aspartate aminotransaminase activity, and necrotic area in liver tissues. The protective effect of adenoviral vector encoding vIL-10 was attributed to its inhibition of T cell activation, and production of interferon-γ and interleukin-4 by the immune cells. Recombinant mouse IL-10, a high homologous cytokine to vIL-10, effectively downregulated interferon-γ and interleukin-4 release by hepatic mononuclear cells. CONCLUSION: Adenovirus vector-mediated vIL-10 gene transfer can prevent concanavalin A-induced hepatic injury, minimise pro-inflammatory cytokine release, and inhibit the activation of T lymphocytes.

Insulin X10 revisited: a super-mitogenic insulin analogue.

The molecular safety of insulin analogues has received a great deal of attention over the last year. In particular, attention has been directed to the mitogenic properties of insulin analogues as compared with human insulin. Understanding the mechanisms implicated in mediating mitogenic effects of insulin is therefore of particular interest. In this review we detail the story of the rapid-acting insulin analogue known as X10, which was the first insulin analogue in clinical development, but ended up being discontinued at an early clinical development stage following findings of mammary tumours in female Sprague-Dawley rats. The molecular characteristics of insulin X10, along with its interaction at both the IGF-1 receptor and the insulin receptor, have provided us with important insights into mechanisms implicated in metabolic and mitogenic signalling of insulin analogues.

Breast tissue composition and susceptibility to breast cancer.

Breast density, as assessed by mammography, reflects breast tissue composition. Breast epithelium and stroma attenuate x-rays more than fat and thus appear light on mammograms while fat appears dark. In this review, we provide an overview of selected areas of current knowledge about the relationship between breast density and susceptibility to breast cancer. We review the evidence that breast density is a risk factor for breast cancer, the histological and other risk factors that are associated with variations in breast density, and the biological plausibility of the associations with risk of breast cancer. We also discuss the potential for improved risk prediction that might be achieved by using alternative breast imaging methods, such as magnetic resonance or ultrasound. After adjustment for other risk factors, breast density is consistently associated with breast cancer risk, more strongly than most other risk factors for this disease, and extensive breast density may account for a substantial fraction of breast cancer. Breast density is associated with risk of all of the proliferative lesions that are thought to be precursors of breast cancer. Studies of twins have shown that breast density is a highly heritable quantitative trait. Associations between breast density and variations in breast histology, risk of proliferative breast lesions, and risk of breast cancer may be the result of exposures of breast tissue to both mitogens and mutagens. Characterization of breast density by mammography has several limitations, and the uses of breast density in risk prediction and breast cancer prevention may be improved by other methods of imaging, such as magnetic resonance or ultrasound tomography.

Effect of feeding a formula supplemented with long-chain polyunsaturated fatty acids for 14 weeks improves the ex vivo response to a mitogen and reduces the response to a soy protein in infants at low risk for allergy.

BACKGROUND AND OBJECTIVE: Feeding long-chain polyunsaturated fatty acids (LCP) influences immunity in adults; however, less is known about their effect during development. The aim of the study was to determine the effect of feeding LCP on immunity in healthy infants during the first 4 months of life. PATIENTS AND METHODS: Formula-fed infants were randomized at

The novel non-mitogenic anti-CD3 antibody, mini-yCD3, delivers a partial TCR signal.

Previous studies indicated that a partial T-cell receptor signal delivered by non-mitogenic anti-CD3 antibodies is critical for dampening the activated T-cell response. The mini-yCD3 is a novel non-mitogenic anti-CD3 antibody based on a murine anti-human CD3 antibody yCD3. However, the mechanism by which mini-yCD3 suppresses immune responses mediated by activated T-cells remains unknown. To elucidate its mechanism, we examined the effects of the mini-yCD3 on early signaling events in T-cells. Similar to the mitogenic anti-CD3 mAb, mini-yCD3 triggered changes in the T-cell receptor (TCR). However, unlike the mitogenic anti-CD3 stimulation, mini-yCD3 was ineffective at inducing the highly phosphorylated zeta chain and tyrosine phosphorylation of the associated tyrosine kinase ZAP-70. This proximal signaling deficiency failed to mobilize detectable Ca(2+) and translocate NF-AT into the nucleus. Additionally, the non-mitogenic anti-CD3 appeared insufficient for the redistribution of TCRs into an aggregated cap, which correlated with T-cell activation.

Genetic delineation of the pathways mediated by bid and JNK in tumor necrosis factor-alpha-induced liver injury in adult and embryonic mice.

Tumor necrosis factor-alpha (TNFalpha)-induced hepatocyte death and liver injury can be mediated by multiple mechanisms, which could be evaluated by different animal models. Previous studies have defined the importance of Bid in mitochondrial apoptosis activation in adult mice treated with lipopolysaccharides in the presence of galactosamine (GalN), which suppresses NF-kappaB activation, but not in embryonic mice in which NF-kappaB activation is suppressed by genetic deletion of p65RelA. JNK has also been found important in TNFalpha-induced mitochondria activation and liver injury in the lipopolysaccharide/GalN and concanavalin A (ConA)/GalN models, but not in a ConA-only model in which NF-kappaB activation was not suppressed. To determine the mechanistic relationship of pathways mediated by Bid and JNK, we investigated these two molecules in TNFalpha injury models that had not been previously examined. Most importantly, we created and studied mice deficient in both Bid and JNK. We found that, like JNK, Bid was also required for TNFalpha-induced injury induced by concanavalin A/GalN but not by ConA alone. Furthermore, our results indicate that these two molecules function in a largely overlapped manner, with Bid being downstream of JNK in the adult livers. However, JNK, but not Bid, was able to contribute to the TNFalpha-induced liver apoptosis in RelA-deficient embryos. The Bid-independent role of JNK was also observed in the adult mice, mainly in the promotion of the lethal progression of the TNFalpha injury. This work defined both linear and parallel relationships of Bid and JNK in TNFalpha-induced hepatocyte apoptosis and liver injury.

Orally administrated Juzen-taiho-to/TJ-48 ameliorates erythropoietin (rHuEPO)-resistant anemia in patients on hemodialysis.

Maintenance of the red blood cell volume is a fundamental aspect of ensuring oxygen supply to the tissue. Recombinant human erythropoietin (rHuEPO) was approved for marketing in Japan in 1990 for the treatment of anemia in patients on dialysis. Recombinant human erythropoietin caused a significant increase in hemoglobin (Hb) levels in patients on dialysis. However, not all have a good response to rHuEPO therapy; the causes of rHuEPO failure include iron deficiency, infection, uremia, and interaction of some drugs. Juzen-taiho-to (TJ-48), a mixture of extracts from 10 medicinal herbs, has been used traditionally to treat patients with anemia, anorexia, or fatigue. To clarify the effect of TJ-48 on erythropoietin-resistant anemia, we studied the effect of TJ-48 in patients on hemodialysis with erythropoietin-resistant anemia. We divided 42 end-stage renal disease patients on hemodialysis with erythropoietin-resistant anemia (Hb<10.0 g/dL with rHuEPO 9000 U/wk or 15 U/kg/wk treatment) into 2 groups as follows: a TJ-48-treated group (TJ-48 group, 7.5 g/d, n=22) and a TJ-48 nontreated (control group, n=20). At the beginning of this study, there was no significant difference between the groups in age, sex, serum creatinine, blood urea nitrogen, serum iron, and ferritin. After 12 weeks of treatment, the Hb level had significantly increased from 8.4 +/- 1.1 to 9.5 +/- 1.3 g/dL (P=0.0272) in the TJ-48 group. C-reactive protein (CRP) had significantly decreased from 1.4 +/- 1.7 to 0.6 +/- 0.8 mg/dL (P=0.0438). There was a significant negative correlation between Hb and CRP in the TJ-48 group (r(2)=0.121, P=0.0066). In contrast, in the control group, Hb and CRP showed no significant changes throughout this study. Nor was there a significant correlation between Hb and CRP in the control group. In conclusion, TJ-48 was effective in improving erythropoietin-resistant anemia in end-stage renal disease patients. This effect was, at least in part, due to the anti-inflammatory effect of TJ-48 in patients on hemodialysis.

Natural killer T cell dysfunction in CD39-null mice protects against concanavalin A-induced hepatitis.

UNLABELLED: Concanavalin A (Con A)-induced injury is an established natural killer T (NKT) cell-mediated model of inflammation that has been used in studies of immune liver disease. Extracellular nucleotides, such as adenosine triphosphate, are released by Con A-stimulated cells and bind to specific purinergic type 2 receptors to modulate immune activation responses. Levels of extracellular nucleotides are in turn closely regulated by ectonucleotidases, such as CD39/NTPDase1. Effects of extracellular nucleotides and CD39 on NKT cell activation and upon hepatic inflammation have been largely unexplored to date. Here, we show that NKT cells express both CD39 and CD73/ecto-5'-nucleotidase and can therefore generate adenosine from extracellular nucleotides, whereas natural killer cells do not express CD73. In vivo, mice null for CD39 are protected from Con A-induced liver injury and show substantively lower serum levels of interleukin-4 and interferon-gamma when compared with matched wild-type mice. Numbers of hepatic NKT cells are significantly decreased in CD39 null mice after Con A administration. Hepatic NKT cells express most P2X and P2Y receptors; exceptions include P2X3 and P2Y11. Heightened levels of apoptosis of CD39 null NKT cells in vivo and in vitro appear to be driven by unimpeded activation of the P2X7 receptor. CONCLUSION: CD39 and CD73 are novel phenotypic markers of NKT cells. In turn, CD39 expression [corrected] modulates nucleotide-mediated cytokine production by, and limits apoptosis of, hepatic NKT cells. Deletion of CD39 is protective in [corrected] Con A-induced hepatitis. This study illustrates a [corrected] role for purinergic signaling in NKT-mediated mechanisms that result in liver immune injury.

Increased micronucleus frequency in phytohaemagglutinin-stimulated blood cells of patients with vitiligo.

BACKGROUND: Vitiligo is a relatively common, acquired pigmentary disorder characterized by areas of depigmented skin resulting from loss of melanocytes in the epidermis. Although several hypotheses have been proposed for the aetiology and pathogenesis of vitiligo, the cause of vitiligo remains unclear. OBJECTIVE: To evaluate spontaneous micronucleus (MN) frequency using the cytokinesis block MN assay to determine damages at the DNA or chromosome level in phytohaemagglutinin (PHA)-stimulated blood cells of patients with vitiligo and healthy control subjects. METHODS: Peripheral blood samples were obtained and cultured from 21 patients with vitiligo (mean age: 21.48 +/- 9.78 years) and 21 age- and sex-matched healthy control subjects (mean age: 21.52 +/- 9.80 years). MN values were scored in binucleated cells obtained from whole-blood cultures of patients and control subjects. RESULTS: MN frequencies (mean +/- SD) in PHA-stimulated blood cells of patients with vitiligo and control subjects were 0.94 +/- 0.58 and 0.58 +/- 0.32, respectively. Compared with control subjects, MN frequencies of patients with vitiligo were found significantly higher than those of the control subjects (P = 0.012). CONCLUSION: Our results indicate unexpectedly some chromosomal/DNA damage in whole-blood cultures of patients with vitiligo. We do not know, however, if these chromosome/DNA instabilities observed in the cells of vitiligo patients resulted from the cause or from the consequences of the disorder.