Diagnosed diabetes and premature death among middle-aged Japanese: results from a large-scale population-based cohort study in Japan (JPHC study)

OBJECTIVE

To examine the association between diabetes and premature death for Japanese general people.

DESIGN

Prospective cohort study.

SETTING

The Japan Public Health Center-based prospective study (JPHC study), data collected between 1990 and 2010.

POPULATION

A total of 46,017 men and 53,567 women, aged 40-69 years at the beginning of baseline survey.

MAIN OUTCOME MEASURES

Overall and cause specific mortality. Cox proportional hazards models were used to calculate the HRs of all cause and cause specific mortality associated with diabetes.

RESULTS

The median follow-up period was 17.8 years. During the follow-up period, 8223 men and 4640 women have died. Diabetes was associated with increased risk of death (856 men and 345 women; HR 1.60, (95% CI 1.49 to 1.71) for men and 1.98 (95% CI 1.77 to 2.21) for women). As for the cause of death, diabetes was associated with increased risk of death by circulatory diseases (HR 1.76 (95% CI 1.53 to 2.02) for men and 2.49 (95% CI 2.06 to 3.01) for women) while its association with the risk of cancer death was moderate (HR 1.25 (95% CI 1.11 to 1.42) for men and 1.04 (95% CI 0.82 to 1.32) for women). Diabetes was also associated with increased risk of death for 'non-cancer, non-circulatory system disease' (HR 1.91 (95% CI 1.71 to 2.14) for men and 2.67 (95% CI 2.25 to 3.17) for women).

CONCLUSIONS

Diabetes was associated with increased risk of death, especially the risk of death by circulatory diseases.

Hemoglobin a1c levels and the risk of cardiovascular disease in people without known diabetes: a population-based cohort study in Japan

High hemoglobin A1c (HbA1c) levels are strongly associated with an increased risk of cardiovascular disease (CVD) in people with and without diabetes. However, information regarding the relationship between low HbA1c levels and the risk of CVD among people without known diabetes is limited. The aim of this large-scale, prospective, population-based cohort study was to clarify the association between HbA1c levels and CVD risk among people without known diabetes.We followed-up 10,980 men and 18,079 women (46-80 years old and free of CVD and cancer at baseline) in the Japan Public Health Center-based Prospective Study. Using Cox models, we estimated the hazard ratios for CVD risk with adjustments for age, sex, geographic areas, body mass index, smoking status, sports and physical exercise, alcohol intake, systolic blood pressure, non-high-density lipoprotein cholesterol, and high-density lipoprotein cholesterol.During the median follow-up of 9.4 years, 935 CVD events (770 strokes and 165 coronary heart diseases) occurred. We observed a nonlinear association between HbA1c levels and CVD risk in participants without known diabetes. Compared with HbA1c levels of 5.0 to 5.4% (31-36 mmol/mol), the hazard ratios for CVD in participants without known diabetes were 1.50 (95% confidence interval: 1.15-1.95), 1.01 (0.85-1.20), 1.04 (0.82-1.32), and 1.77 (1.32-2.38) for HbA1c levels of <5.0% (<31 mmol/mol), 5.5 to 5.9% (37-41 mmol/mol), 6.0 to 6.4% (42-47 mmol/mol), and ≥6.5% (≥48 mmol/mol), respectively (P value for nonlinear trend: <0.001). In addition, the hazard ratio for CVD was 1.81 (1.43-2.29) in patients with known diabetes compared with participants with HbA1c levels of 5.0 to 5.4% and without known diabetes. This nonlinear relation persisted after excluding people with kidney dysfunction, liver dysfunction, anemia, body mass index <18.5 kg/m, or early events within 3 years of follow-up (P value for nonlinear trend: <0.01 for all tests).In conclusion, both low and high levels of HbA1c were associated with a higher risk of CVD in a Japanese general population without known diabetes.

A clinicopathological study of perineural invasion and vascular invasion in oral tongue squamous cell carcinoma

The risk factors for recurrence of head and neck cancer are classified as being of high or intermediate risk. Those of intermediate risk include multiple positive nodes without extracapsular nodal spread, perineural/vascular invasion, pT3/T4 primary tumours, and positive level IV/V nodes. However, little evidence is available to validate these intermediate risk factors. We analyzed perineural/vascular invasion in 89 patients who underwent radical surgery for oral tongue squamous cell carcinoma, whose records were reviewed retrospectively. Perineural invasion was found in 27.0% of cases and vascular invasion in 23.6%; both had a strong relationship with histopathological nodal status (P = 0.005). The 5-year disease-specific survival (DSS) and overall survival rates of patients with perineural invasion were significantly lower than those of patients without perineural invasion (P < 0.001 and P = 0.002, respectively). The 5-year DSS of UICC stage I and II cases with perineural/vascular invasion was significantly lower than those without (P < 0.001 and P = 0.008, respectively). Perineural invasion and vascular invasion are risk factors for regional metastasis and a poor prognosis. We recommend elective neck dissection when perineural/vascular invasion is found in clinical stage I and II cases. The accumulation of further evidence to consider intermediate risks is required.

Loss of p53 in stromal fibroblasts enhances tumor cell proliferation through nitric-oxide-mediated cyclooxygenase 2 activation

Overexpression of cyclooxygenase 2 (COX-2) by stromal fibroblasts plays a critical role in the early stage of carcinogenesis. COX-2 expression is thought to be positively or negatively regulated by inflammatory chemical mediators or tumor suppressors. In this study, the contributions of inducible nitric oxide synthase (iNOS) and p53 to COX-2 expression were examined using mouse embryonic fibroblasts (MEFs) from wild-type, p53-deficient, iNOS-deficient, and p53/iNOS-deficient mice. These MEFs were treated with 1 μg/mL of lipopolysaccharide and 100 IU/mL of interferon gamma for up to 72 h. iNOS and COX-2 expression were analyzed by Western blotting. iNOS was induced earlier (16 h) in p53-deficient MEFs than in wild-type MEFs (48 h). Elevated expression of COX-2 was sustained for a longer duration in the p53-deficient MEFs. In contrast, COX-2 expression was reduced earlier in the iNOS-deficient MEFs. Addition of an exogenous NO donor (0.8 mM of S-nitroso-l-glutathione) to the iNOS-deficient MEFs augmented COX-2 expression. Co-culture with stimulated p53-deficient MEFs promoted cell proliferation of mouse rectal polyploid carcinoma CMT93 cells, but treatment with a COX-2-specific inhibitor counteracted this effect. These results suggest that loss of function of the p53 gene in stromal fibroblasts enhances COX-2 expression by enhancing iNOS expression and the resultant production of NO, contributing to the promotion of tumor growth.

Roles of extracellular Ca(2+) in the occurrence of full-type hyperactivation in boar ejaculated spermatozoa pre-incubated to induce the cAMP-triggered events

There are species differences in the regulatory system for sperm capacitation and subsequent hyperactivation between livestock and laboratory animals. In livestock spermatozoa, it is poorly understood when and how extracellular Ca(2+) is necessary for hyperactivation, although it has been demonstrated that the [Ca(2+) ]i increase is indispensable to occurrence of hyperactivation. In this study, we examined necessity of extracellular Ca(2+) for the initiation and maintenance of hyperactivation and then sought possible target molecule of Ca(2+) that was involved in hyperactivation of boar spermatozoa. Boar ejaculated spermatozoa were pre-incubated with a cell-permeable cyclic adenosine monophosphate (cAMP) analog 'cBiMPS' and without CaCl2 to induce the cAMP-triggered events including capacitation-associated changes. Subsequently, they were incubated with CaCl2 to induce hyperactivation and then used for motility assessment. Many of the spermatozoa after the incubation exhibited full-type hyperactivation which was characterized by high-amplitude and extremely asymmetrical beating of whole middle piece and principal piece. The initiation of full-type hyperactivation required the millimolar concentration of CaCl2 in the medium. However, CaCl2 of the medium was less necessary for maintenance than initiation of full-type hyperactivation, as hyperactivated spermatozoa were barely affected by the incubation with the Ca(2+) -chelating reagent. On the other hand, the pre-treatment with the inhibitor for Ca(2+) -dependent protease 'calpain 1 and 2' clearly suppressed the occurrence of CaCl2 -induced hyperactivation without influences on the percentages of motile spermatozoa. Western blotting and indirect immunofluorescence showed distribution of calpain 2 in the middle and principal pieces in which full-type hyperactivated spermatozoa exhibited extremely asymmetrical beating. On the basis of these results, we conclude that the millimolar concentration of extracellular Ca(2+) is necessary for the initiation, but not for the maintenance of full-type hyperactivation in boar spermatozoa that beforehand undergo the cAMP-triggered events including capacitation-associated changes. Moreover, we suggest possible involvement of calpain 2 in the intracellular Ca(2+) signal transduction leading to full-type hyperactivation.

Investigation of dyeing behavior of oxidative dye in fine structures of the human hair cuticle by nanoscale secondary ion mass spectrometry

BACKGROUND/PURPOSE

In oxidative coloring, the hair cuticle layers are not only the penetration pathway for active ingredients but also one of the most important dyeing regions. The dyeing mechanism of oxidative dyes in fine structures of the cuticle remains unclear. To investigate the dyeing behavior of oxidative dyes in fine structures of the cuticle, hair cross-sections were analyzed by nanoscale secondary ion mass spectrometry (NanoSIMS).

METHODS

The preparation method of hair cross-section for NanoSIMS measurement was improved. Improved hair cross-sections were analyzed using NanoSIMS.

RESULTS

The cuticle layer thickness of the hair cross-section could be widened. It was confirmed that (12) C(-) ions were more strongly detected from endocuticle than from other fine structures of cuticle. The NanoSIMS (12) C(-) image and hue saturation intensity (HSI) D(-) /(1) H(-) ratio image of the hair, dyed with deuterium-labeled oxidative dye, indicated that the endocuticle had a higher D(-) /(1) H(-) ratio than the other fine structures of the cuticle. It was substantiated that more colored chromophores were fixated in the endocuticle than in other fine structures of the cuticle.

CONCLUSION

The dyeing behavior of oxidative dyes in fine structures of hair cuticle was substantiated by NanoSIMS analysis using the improved hair cross-section preparation method.

Descriptive epidemiology of diabetes prevalence and HbA1c distributions based on a self-reported questionnaire and a health checkup in the JPHC diabetes study

Background

The present study examined the prevalence of diabetes in Japan during the late 1990s and early 2000s using the Japan Public Health Center-based Prospective Diabetes cohort. We also investigated the distributions of HbA1c values in noncompliant diabetic participants in the cohort.

Methods

A total of 28 183 registered inhabitants aged 46–75 years from 10 public health center areas were included in the initial survey. The 5-year follow-up survey included 20 129 participants. The prevalence of diabetes was estimated using both a self-reported questionnaire and laboratory measurements. Among the participants who reported the presence of diabetes on the questionnaire (self-reported diabetes), the distributions of HbA1c values were described according to their treatment status.

Results

The age-standardized prevalence of diabetes in 55- to 74-year-old adults was 8.2% at the initial survey and 10.6% at the 5-year follow-up. At the initial survey, among participants with self-reported diabetes, the mean HbA1c values in the participants who had never and who had previously received diabetes treatment were 7.01% (standard deviation [SD] 1.56%) and 6.56% (SD 1.46%), respectively. Approximately 15% of the participants who had self-reported diabetes but had never received diabetes treatment had an HbA1c ≥ 8.4%.

Conclusions

The prevalence of diabetes increased in the JPHC cohort between the late 1990s and early 2000s. A certain proportion of participants who were aware of their diabetes but were not currently receiving treatment had poor diabetic control. Efforts to promote continuous medical attendance for diabetes care may be necessary.

Systematic fine-mapping of association with BMI and type 2 diabetes at the FTO locus by integrating results from multiple ethnic groups

BACKGROUND/OBJECTIVE

The 16q12.2 locus in the first intron of FTO has been robustly associated with body mass index (BMI) and type 2 diabetes in genome-wide association studies (GWAS). To improve the resolution of fine-scale mapping at FTO, we performed a systematic approach consisting of two parts.

METHODS

The first part is to partition the associated variants into linkage disequilibrium (LD) clusters, followed by conditional and haplotype analyses. The second part is to filter the list of potential causal variants through trans-ethnic comparison.

RESULTS

We first examined the LD relationship between FTO SNPs showing significant association with type 2 diabetes in Japanese GWAS and between those previously reported in European GWAS. We could partition all the assayed or imputed SNPs showing significant association in the target FTO region into 7 LD clusters. Assaying 9 selected SNPs in 4 Asian-descent populations--Japanese, Vietnamese, Sri Lankan and Chinese (n≤26,109 for BMI association and n≤24,079 for type 2 diabetes association), we identified a responsible haplotype tagged by a cluster of SNPs and successfully narrowed the list of potential causal variants to 25 SNPs, which are the smallest in number among the studies conducted to date for FTO.

CONCLUSIONS

Our data support that the power to resolve the causal variants from those in strong LD increases consistently when three distant populations--Europeans, Asians and Africans--are included in the follow-up study. It has to be noted that this fine-mapping approach has the advantage of applicability to the existing GWAS data set in combination with direct genotyping of selected variants.

Diabetes mellitus defined by hemoglobin A1c value: Risk characterization for incidence among Japanese subjects in the JPHC Diabetes Study

Aims/Introduction:  Although several risk factors for type 2 diabetes have been identified, most of them have been identified in studies on Western populations, and they should be evaluated in a Japanese population. In 2010, new diagnostic criteria for diabetes mellitus using hemoglobin A1c (HbA1c) were released and its use in epidemiological studies has many advantages. The aim of the present study was to evaluate risk factors for type 2 diabetes defined based on HbA1c values in a Japanese population.

MATERIALS AND METHODS

  A total of 9223 subjects (3076 men and 6147 women) were followed up for 5 years. Diabetes was defined based on self-report or HbA1c value. Risk factors for diabetes were evaluated as odds ratios adjusted for potential confounding factors by logistic regression.

RESULTS

  During the 5-year follow-up period, we documented 518 incident cases of diabetes (232 men and 286 women). Of the 518 incident cases, 310 cases were diagnosed by HbA1c alone. Among the men, age, smoking (both past smoking and current smoking) and family history of diabetes significantly increased the risk of diabetes. Among the women, body mass index, family history of diabetes and hypertension significantly increased the risk of diabetes. These results did not change markedly after adjustment for the baseline HbA1c values, and the baseline HbA1c value itself was a significant risk factor for diabetes mellitus.

CONCLUSIONS

  Known risk factors for diabetes established in Western populations also increased the risk of diabetes in a Japanese population defined on the basis of HbA1c values. (J Diabetes Invest, doi: 10.1111/j.2040-1124.2011.00119.x, 2011).

How can waist circumference predict the body composition?

BACKGROUND

Waist circumference (WC) is used as a risk assessment for metabolic syndrome, diabetes, and cardiovascular disease (CVD). WC consists of visceral fat area (VFA), subcutaneous fat area (SFA), muscle, intramuscular fat, viscera, and bone. Each component of the WC may differ between the sexes and generations, even if they have the same WC. However, this has not been measured in an epidemiological study.

METHODS

Between 2004 to 2009, employees and their spouses working at a Japanese company underwent a health examination after more than 12 hours of fasting. We analyzed the data of 11,570 subjects (9,874 men and 1,696 women), aged from 20 to 76 years, who underwent a computed tomography (CT) examination. VFA, SFA, WC, muscle, intramuscular fat, viscera, and bone were measured using a CT scanner. We conducted stratified analyses by generational age, and calculated the Pearson's correlation coefficients between the VFA and WC, BMI, and VFA plus SFA. To establish the equations for converting the WC to the corresponding VFA and VFA plus SFA, linear regression analyses were used to obtain the regression coefficients and intercepts.

RESULTS

As the generations increased in age, the VFA tended to increase. However, the differences in the WC values of each generation did not coincide with the VFA values in men (r = -0.275 and 0.979 for men and women, n = 5 generations), but did correlate with the difference in the sum of the VFA plus SFA for both sexes (r = 0.915 and 0.996 for men and women, n = 5 generations). Older generations had lower WC values when they had the same VFA values as the younger generations.

CONCLUSIONS

The WC value corresponding to a certain VFA value differed significantly by generational age. Thus, revised optimal cutoff values for the WC may be needed for each generation.

New members of layered oxychloride perovskites with square planar coordination: Sr2MO2Cl2 (M = Mn, Ni) and Ba2PdO2Cl2

We have demonstrated high-pressure syntheses of Ruddlesden–Popper type layered oxychloride perovskites, Sr₂MnO₂Cl₂, Sr₂NiO₂Cl₂ and Ba₂PdO₂Cl₂, with a square planar coordination around the transition metal centres.

Adiponectin and visceral fat associate with cardiovascular risk factors

OBJECTIVE

To examine the combined effect of CT-measured visceral fat area (VFA) and adiponectin level against the clustering of metabolic risk factors.

DESIGN AND METHODS

The subjects were 6,996 Japanese. The subjects were divided according to the combinations of VFA and adiponectin level quartiles and the odds ratio for multiple risk factors of metabolic syndrome were calculated (adjusted for age and lifestyle factors using logistic regression analyses). Group with the lowest VFA and the highest adiponectin level was used as a reference. The correlation between adiponectin level and each metabolic risk factor was evaluated.

RESULTS

The strongest correlation was observed between adiponectin level and high-density lipoprotein cholesterol levels (r = 0.369 and 0.439 for men and women). Both VFA and adiponectin level were independently associated with the clustering of metabolic risk factors (interaction P = 0.58 and 0.11 for men and women). The odds ratio for the clustering of metabolic risk factors in the group with the highest VFA and the lowest adiponectin level, compared with the group with the lowest VFA and the highest adiponectin level, was 12.7 (9.7-16.6) for men and 13.5 (6.0-30.2) for women.

CONCLUSION

The ability to detect metabolic syndrome could be improved by examining adiponectin level in conjunction with VFA.

Secretory units of islets in transplantation index is a useful predictor of insulin requirement in Japanese type 2 diabetic patients

AIMS/INTRODUCTION

The objective of the present study was to clarify the validity of β-cell function-related parameters for predicting the insulin requirement of Japanese type 2 diabetic patients.

MATERIALS AND METHODS

In 188 patients with type 2 diabetes who had been admitted to the University of Toyama Hospital (Toyama, Japan) without receiving insulin therapy, we carried out a cross-sectional study examining the relationship between the homeostasis model assessment of β-cell function (HOMA-β) and C-peptide-based indices, and also carried out a retrospective study to examine the utility for predicting insulin requirement of several β -cell function-related indices using a receiver operating characteristic (ROC) curve analysis.

RESULTS

The secretory units of islets in transplantation index (SUIT) had the strongest correlation with HOMA-β, followed by the fasting serum C-peptide immunoreactivity index (CPI); the fasting serum C-peptide immunoreactivity itself (F-CPR) had the least correlation. The CPI, HOMA-β and SUIT were significantly lower in the insulin-requiring group than in the non-insulin-requiring group, even after adjustments for confounding factors (P < 0.01). The areas under the ROC curve for insulin requirement were 0.622, 0.774, 0.808, and 0.759 for F-CPR, CPI, SUIT, and HOMA-β, respectively. The cut-off values of SUIT, CPI, and HOMA-β for an over 80% specificity for the prediction of insulin therapy were 23.5, 1.00, and 14.9, respectively.

CONCLUSIONS

The present study shows that SUIT is the best predictor of insulin requirement among these β-cell function-related markers.

Fractionated stereotactic radiotherapy using CyberKnife for the treatment of large brain metastases: a dose escalation study

AIMS

To evaluate the toxicity and efficacy of fractionated stereotactic radiotherapy (FSRT) with doses of 18-30 Gy in three fractions and 21-35 Gy in five fractions against large brain metastases.

MATERIALS AND METHODS

Between 2005 and 2012, 61 large brain metastases (≥ 2.5 cm in maximum diameter) of a total of 102 in 54 patients were treated with FSRT as a first-line therapy. Neurological symptoms were observed in 47 of the 54 patients before FSRT. Three fractions were applied to tumours with a maximum diameter ≥ 2.5 cm and <4 cm, and five fractions were used for brain metastases ≥ 4 cm. After ensuring that the toxicities were acceptable (≤ grade 2), doses were escalated in steps. Doses to the large brain metastases were as follows: level I, 18-22 Gy/three fractions or 21-25 Gy/five fractions; level II, 22-27 Gy/three fractions or 25-31 Gy/five fractions; level III, 27-30 Gy/three fractions or 31-35 Gy/five fractions. Level III was the target dose level.

RESULTS

Overall survival rates were 52 and 31% at 6 and 12 months, respectively. Local tumour control rates of the 102 total brain metastases were 84 and 78% at 6 and 12 months, respectively. Local tumour control rates of the 61 large brain metastases were 77 and 69% at 6 and 12 months, respectively. Grade 3 or higher toxicities were not observed.

CONCLUSIONS

The highest dose levels of 27-30 Gy/three fractions and 31-35 Gy/five fractions seemed to be tolerable and effective in controlling large brain metastases. These doses can be used in future studies on FSRT for large brain metastases.

Increased serum leukocyte cell-derived chemotaxin 2 (LECT2) levels in obesity and fatty liver

Leukocyte cell-derived chemotaxin 2 (LECT2) is a signaling molecule expressed in the liver and regulated by Wnt/β-catenin pathways implicated in hepatic metabolism. However, the clinical relevance of LECT2 in obesity and fatty liver is unknown. The objective of this study was to determine whether serum LECT2 levels are affected by of obesity and fatty liver. A cross sectional study comprising 231 Japanese adult subjects were tested for LECT2 using a highly sensitive assay. We evaluated the associations between LECT2 and the anthropometric or clinical markers of obesity and fatty liver. The mean serum LECT2 levels were 43.5 ± 13.6 ng/mL. LECT2 positively correlated with all the anthropometric measures of obesity: body mass index, waist circumference, waist-to-hip ratio, and waist-to-height ratio (W/Ht). Multiple regression analysis revealed that LECT2 is independently related to γ-glutamyl transpeptidase (γ-GTP), triglyceride, and age in males, whereas in females it was related to the homeostasis model assessment ratio, blood urea nitrogen, high-density lipoprotein cholesterol, and γ-GTP. Receiver operating characteristics curve analyses revealed that LECT2 correlated with obesity [area under the curve (AUC) 0.655, 95% confidence interval (CI) = 0.551-0.758, p = 0.002 in males; AUC 0.670, 95% CI = 0.570-0.770, p < 0.001 in females] and fatty liver (AUC 0.646, 95% CI = 0.544-0.749, p = 0.004 in males; AUC 0.733, 95% CI = 0.621-0.844, p < 0.001 in females). The present study indicates that serum LECT2 levels are increased by obesity and fatty liver, and suggests that LECT2 is a novel obesity-related protein.

Effect of longitudinal changes in visceral fat area on incidence of metabolic risk factors: the Hitachi health study

OBJECTIVE

To examine the incidences of metabolic risk factors according to changes in visceral fat area (VFA) in a large Japanese population.

DESIGN AND METHODS

The subjects were 973 men who received a computed tomography (CT) examination in health checkups twice (2004-2005 and 2007-2008), and not having two or more of metabolic risk factors (except for the waist circumference) in 2004-2005. VFA was measured using CT. To assess the potential influence of changes in VFA for the 3-year incidences of each metabolic risk factor and clustering metabolic risk factors, logistic regression analyses were used.

RESULTS

A significant association was observed between the change in VFA and the components of the metabolic risk factors. Incidences of the components of the metabolic risk factors were significantly higher among subjects with a larger increase in VFA and were significantly lower among subjects with a larger decrease in VFA (trend P < 0.001). Significant increases in the odds ratios for the incidences of high triglycerides and low high-density lipoprotein cholesterol level were observed among subjects with ≥50 cm(2) VFA increase.

CONCLUSIONS

The adoption of a lifestyle that does not increase the VFA is important for preventing metabolic syndrome.

Epigenetic regulation of BDNF expression in the primary sensory neurons after peripheral nerve injury: implications in the development of neuropathic pain

Brain-derived neurotrophic factor (BDNF) is known to be up-regulated in the dorsal root ganglion (DRG) after peripheral nerve injury, and to contribute to neuropathic pain. Here, we found that thermal hyperalgesia and mechanical allodynia at day 7 post-injury were inhibited only when anti-BDNF antibody was intrathecally administrated at day 2 post-injury. Consistent with behavioral results, Western blot analysis showed that the expression levels of BDNF protein in the spinal dorsal horn were markedly induced during early stage post-injury. Moreover, the maximal increase in BDNF mRNA expression in the DRG was observed at day 1 post-injury, and significantly elevated levels were sustained for at least 14 days. Four of five BDNF mRNA transcripts were up-regulated after nerve injury, and the most inducible transcript was exon I. Using a chromatin immunoprecipitation (ChIP) assay, we found that nerve injury promotes histone H3 and H4 acetylation, transcriptionally active modifications, at BDNF promoter I at day 1 post-injury, and the levels of histone acetylation remain elevated for at least 7 days. Taken together, our findings suggest that an initial increase in BDNF exon I expression controlled by epigenetic mechanisms might have a crucial role in the development of neuropathic pain.