Methylation of cyclin-dependent kinase inhibitors, XAF1, JUNB, CDH13 and soluble Wnt inhibitors in essential thrombocythaemia

Background: Methylation of genes regulating cell-cycle check-point (INK4 cyclin-dependent kinase inhibitors), apoptosis (XAF1), adhesion (CDH13), JUNB and Wnt signalling (soluble Wnt inhibitors) has been implicated in pathogenesis of haematological and epithelial cancers. Method The authors studied the methylation status of CDKN2A, CDKN2B, XAF1, CDH13, JUNB and a panel of soluble Wnt inhibitors including WIF1, DKK3, APC, SFRP1, SFRP2, SFRP4 and SFRP5 by methylation-specific PCR in 31 bone marrow and 21 peripheral blood samples of patients with essential thrombocythaemia. Results and discussion: There was no evidence of hypermethylation of all these genes in both the BM and PB samples. Therefore, in contrast to myeloid leukaemias, methylation of these genes regulating the cell cycle, apoptosis, adhesion and Wnt signalling does not play an important role in the pathogenesis of myeloproliferative diseases. Whether differential methylation may occur in the progenitor or mature blood cell compartments remains to be verified. Our study contributes to the literature on methylation in chronic myeloproliferatve diseases.published_or_final_versio

Neuroprotective effects of Lycium barbarum polysaccharides against rat hippocampal apoptosis induced by chronic intermittent hypoxia

Poster presentationWe have shown neuronal apoptosis in the hippocampus of rats exposed to chronic intermittent hypoxia mimicking severe conditions of obstructive sleep apnea (OSA) syndrome in patients [1]. Lycium barbarum polysaccharides (LBP), active biological ingredients of traditional Chinese herbal medicine Goji, have been shown to possess cytoprotective properties [2]. The aim of this study was to examine the protective effects of LBP against neuronal apoptosis in the hippocampus in a severe OSA rodent model. We hypothesized that oral administration of LBP ameliorates neuronal apoptosis in the rat hippocampus induced by chronic intermittent hypoxia. Adult SD rats were randomly divided into 4 experimental groups, namely: (i) normoxic control (Nx); (ii) Nx treated with LBP; hypoxic groups treated with either (iii) LBP or (iv) vehicle. The hypoxic groups were kept in a normobaric chamber with inspired oxygen alternating from 21 to 5 ± 0.5% oxygen per minute for 8 hr/day for 7 days, whereas Nx groups was maintained in room air for 7 days. LBP (1mg/kg) were orally fed to the rats 2 hours prior the daily hypoxic treatment. Rats were sacrificed and the hippocampus was harvested for measurements of oxidative marker, malondialdehyde (MDA), apoptotic cell death using TUNEL assay, protein expression levels of antioxidant enzymes, and inflammatory cytokines by Western blot. There were significantly more TUNEL positive –labeling cells in the CA regions and dentate gyrus of the hippocampus in the vehicle-treated hypoxic group than those of the Nx control and LBP-treated groups. In addition, levels of MDA and the protein expressions of cleaved caspase 3 and inflammatory cytokines were increased in the vehicle-treated hypoxic group when compared to the Nx groups and were lowered by the LBP treatment. Intriguingly, there were significantly more PCNA-labeling cells in the dentate gyrus of the hippocampus in the LBP-treated hypoxic groups than those of the other groups. Also, the protein expression of cyclin D1 was increased in the hypoxic groups when compared to the Nx groups. In conclusion, oral administration of LBP significantly ameliorates oxidative stress, inflammation and neuronal apoptosis with enhanced proliferative activities in the hippocampus of rats exposed to chronic intermittent hypoxia. Thus, LBP may be proposed as a health supplement to mitigate neurological deficits in OSA patients, for which awaits future studies to delineate the neuroprotective mechanism of LBP. [Studies supported by research grants (HKU 7510/06M, HKU 766110M) from RGC and funding (201007176007, SFPBR 200911159072) from HKU] [1] Hung, M.W., et al. (2008) J Pineal Res 44: 214-221. [2] Chang, R.C., et al. (2008). Cell Mol Neurobiol 28: 643-652.published_or_final_versio

Methylation of TET2, CBL and CEBPA in Ph-negative myeloproliferative neoplasms

A loss-of-function mutation of TET2, CBL and CEBPA has been implicated in the pathogenesis or leukaemic transformation of myeloproliferative neoplasm. As tumour suppressor genes may potentially be inactivated by promoter hypermethylation, the authors studied the methylation status of these genes in three cell lines and diagnostic marrow samples from 45 patients with myeloproliferative neoplasm (MPN) (essential thrombocythaemia, N=34; polycythaemia vera, N=7 and primary myelofibrosis, N=4) by methylation-specific PCR. TET2 was heterozygously methylated in MEG-01 and K562 but completely unmethylated in HEL. On the other hand, both CBL and CEBPA were completely unmethylated in all three cell lines. In the primary marrow samples, methylation of TET2 occurred in two (5.9%) patients with essential thrombocythaemia (4.4% of all patients), both without JAK2 V617 mutation, but not in polycythaemia vera or primary myelofibrosis. There was no association between TET2 methylation with the type of MPN (p=0.713). Hypermethylation of CBL or CEBPA was not detected in any patients. In summary, methylation of TET2, CBL and CEBPA is infrequent in MPN at diagnosis. The role of methylation of these genes at the time of leukaemic transformation warrants further study.published_or_final_versio

Electronic clinical practice guidelines: Current status and future prospects in Hong Kong

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M30 Antagonizes Indoleamine 2,3-Dioxygenase Activation and Neurodegeneration Induced by Corticosterone in the Hippocampus

Monoamine oxidases (MAO), downstream targets of glucocorticoid, maintain the turnover and homeostasis of monoamine neurotransmitters; yet, its pathophysiological role in monoamine deficiency, oxidative stress and neuroinflammation remains controversial. Protective effects of M30, a brain selective MAO inhibitor with iron-chelating antioxidant properties, have been shown in models of neurodegenerative diseases. This study aims to examine the neuroprotective mechanism of M30 against depressive-like behavior induced by corticosterone (CORT). Sprague-Dawley rats were given CORT subcutaneous injections with or without concomitant M30 administration for two weeks. CORT-treated rats exhibited depressive-like behavior with significant elevated levels of MAO activities, serotonin turnover, oxidative stress, neuroinflammation and apoptosis in the hippocampus with significant losses of synaptic proteins when compared to the control. The expression and activity of cytokine-responsive indoleamine 2,3-dioxygenase (IDO-1), a catabolic enzyme of serotonin and tryptophan, was significantly increased in the CORT-treated group with lowered levels of serotonin. Besides, CORT markedly reduced dendritic length and spine density. Remarkably, M30 administration neutralized the aberrant changes in the hippocampus and prevented the induction of depressive-like behavior induced by CORT. Our results suggest that M30 is neuroprotective against CORT-induced depression targeting elevated MAO activities that cause oxidative stress and neuroinflammation, resulting in IDO-1 activation, serotonin deficiency and neurodegeneration.published_or_final_versio

Monoamine oxidase A upregulated by chronic intermittent hypoxia activates indoleamine 2,3-dioxygenase and neurodegeneration

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Neuroprotective Mechanism of Lycium barbarum Polysaccharides against Hippocampal-Dependent Spatial Memory Deficits in a Rat Model of Obstructive Sleep Apnea

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Methylation of miR-34a, miR-34b/c, miR-124-1 and miR-203 in Ph-negative myeloproliferative neoplasms

BACKGROUND: MicroRNA (miR) miR-34a, -34b/c, -124-1 and -203 are tumor suppressor miRs implicated in carcinogenesis. METHODS: We studied DNA methylation of these miRs in Philadelphia-negative (Ph-ve) myeloproliferative neoplasms (MPNs). Methylation-specific PCR (MSP), verified by direct sequencing of the methylated MSP products, was performed in cell lines, normal controls and diagnostic marrow samples of patients with MPNs. RESULTS: Methylation of these miRs was absent in the normal controls. miR-34b/c were homozygously methylated in HEL cells but heterozygously in MEG-01. In HEL cells, homozygous miR-34b/c methylation was associated with miR silencing, and 5-aza-2'-deoxycytidine treatment led to re-expression of both miR-34b and miR-34c, consistent with that both miRs are under the regulation of the same promoter CpG island. miR-34a was heterozygously methylated in MEG-01 and K-562. miR-203 was completely unmethylated in K-562 and SET-2 but no MSP amplification was found in both HEL and MEG-01, suggestive of miR deletion. In primary samples, four each had miR-34b/c and -203 methylation, in which two had concomitant methylation of miR-34b/c and -203. miR-34a was methylated in one patient and none had methylation of miR-124-1. Seven patients (15.6%) had methylation of at least one of the four miRs. miR methylation did not correlate with clinical parameters, disease complications or JAK2 V617F mutation. CONCLUSION: This is the first report of miR hypermethylation in MPNs. miR-203 hypermethylation is not specific to Ph+ve leukemias but also present in Ph-ve MPNs. miR-34b/c methylation was associated with reversible miR silencing. There was no correlation of miR methylation with clinical demographic data or outcome.published_or_final_versio

Antihypertensive drug class and impaired fasting glucose: a risk association study among Chinese patients with uncomplicated hypertension

<b>Background</b> There is a scarcity of studies addressing the factors associated with impaired fasting glucose in Chinese patients with uncomplicated hypertension. We included 1,218 patients newly prescribed a single antihypertensive drug in the public primary healthcare setting in Hong Kong, where their fasting glucose levels were measured 6–7 weeks after the first-ever antihypertensive prescription.<p></p> <b>Methods</b> The odds ratios of having above borderline (≥ 6.1 mmol/l) and adverse (≥ 7.0 mmol/l) glucose levels, respectively, were studied according to patient age, gender, socioeconomic status, clinic types and antihypertensive drug classes by multivariable regression analyses.<p></p> <b>Results</b> The fasting glucose levels were statistically similar (p = 0.786) among patients prescribed thiazide diuretics (5.48 mmol/l, 95%, 5.38, 5.59), calcium channel blockers (5.46 mmol/l, 95% C.I. 5.37, 5.54), β-blockers (5.42 mmol/l, 95% C.I. 5.34, 5.51) and drugs acting on the renin angiotensin system (RAS) [5.41 mmol/l, 95% C.I. 5.20, 5.61]. Multivariate analyses reported no significant associations between antihypertensive drug class and impaired fasting glucose. Elderly patients and male gender were significantly more likely to present with above borderline and adverse readings respectively.<p></p> <b>Conclusion</b> Clinicians should be aware of the increased risk of impaired fasting glucose in these groups, and use of thiazides should not in itself deter its use as a first-line antihypertensive agent among ethnic Chinese patients

Chronic intermittent hypoxia induces depressive-like behavior in rats

Obstructive sleep apnea (OSA) causes recurrent oxygen desaturation (chronic intermittent hypoxia, CIH) and is associated with depression in patients. However, the relationship between OSA and depression is unclear. Synaptic degeneration, microtubule instability and monoamine deficiency are the common pathological features exhibited in both patients and depression animal models. We hypothesized that CIH induces depressive-like behavior by triggering synaptic degeneration, microtubule instability, and reducing monoamine downstream signaling deficits in the hippocampus. Adult male SD rats were exposed to air (normoxic) control or CIH treatment (8 hours/day) for 7 days. Hippocampus was harvested for the measurement of markers for synaptic vesicle protein ...postprin