Genetic deficiency of aldose reductase counteracts the development of diabetic nephropathy in C57BL/6 mice

AIMS/HYPOTHESIS

The aim of the study was to investigate the effects of genetic deficiency of aldose reductase in mice on the development of key endpoints of diabetic nephropathy.

METHODS

A line of Ar (also known as Akr1b3)-knockout (KO) mice, a line of Ar-bitransgenic mice and control C57BL/6 mice were used in the study. The KO and bitransgenic mice were deficient for Ar in the renal glomeruli and all other tissues, with the exception of, in the bitransgenic mice, a human AR cDNA knockin-transgene that directed collecting-tubule epithelial-cell-specific AR expression. Diabetes was induced in 8-week-old male mice with streptozotocin. Mice were further maintained for 17 weeks then killed. A number of serum and urinary variables were determined for these 25-week-old mice. Periodic acid-Schiff staining, western blots, immunohistochemistry and protein kinase C (PKC) activity assays were performed for histological analyses, and to determine the levels of collagen IV and TGF-β1 and PKC activities in renal cortical tissues.

RESULTS

Diabetes-induced extracellular matrix accumulation and collagen IV overproduction were completely prevented in diabetic Ar-KO and bitransgenic mice. Ar deficiency also completely or partially prevented diabetes-induced activation of renal cortical PKC, TGF-β1 and glomerular hypertrophy. Loss of Ar results in a 43% reduction in urine albumin excretion in the diabetic Ar-KO mice and a 48% reduction in the diabetic bitransgenic mice (p < 0.01).

CONCLUSIONS/INTERPRETATION

Genetic deficiency of Ar significantly ameliorated development of key endpoints linked with early diabetic nephropathy in vivo. Robust and specific inhibition of aldose reductase might be an effective strategy for the prevention and treatment of diabetic nephropathy.

Copy number variations of the human histamine H4 receptor gene are associated with systemic lupus erythematosus

BACKGROUND

Systemic lupus erythematosus (SLE) is a complex genetic disease; the histamine H4 receptor (HRH4) has been shown to be related to different kinds of autoimmune disorders; and copy number variations (CNVs) have been found to be associated with various types of diseases.

OBJECTIVES

To explore a possible association between HRH4 (formerly H4R) CNVs and the risk of SLE.

METHODS

Genomic DNA and RNA from 340 patients with SLE and 392 healthy controls were extracted, and CNVs and mRNA levels of HRH4 were examined.

RESULTS

The expression of HRH4 mRNA was significantly increased in patients with SLE compared with controls. Amplification of HRH4 copy numbers significantly increased the risk of SLE [P < 0·001, odds ratio (OR) 2·26, 95% confidence interval (CI) 1·50-3·40]. HRH4 amplifications also positively correlated with the incidence of arthritis (P = 0·019, OR 1·96, 95% CI 1·11-3·47), and proteinuria (P < 0·001, OR 2·95, 95% CI 1·73-5·00) and antinuclear antibody abnormalities (P < 0·001, OR 2·97, 95% CI 1·66-5·33). Deletions of HRH4 copy numbers were protective against proteinuria (P = 0·03, OR 0·50, 95% CI 0·26-0·94).

CONCLUSION

CNVs of the HRH4 gene are associated with SLE.

Randomized clinical trial of splenic radiofrequency ablation versus splenectomy for severe hypersplenism

BACKGROUND

Radiofrequency ablation (RFA) is a relatively new treatment for hypersplenism. The results of a randomized clinical trial comparing RFA and splenectomy with 5 years of follow-up are reported.

METHODS

Fifty-seven patients with hypersplenism due to liver cirrhosis were assigned randomly (in a 1 : 2 ratio) to splenectomy (19 patients) or RFA (38). The RFA group was subdivided according to the percentage of the spleen ablated: less than 50 per cent (9 patients), 50-70 per cent (18) or over 70 per cent (11). Routine blood tests were performed before and after operation, and total spleen volume and ablated volume were measured by contrast-enhanced computed tomography. The primary endpoint of the trial was recurrence of hypersplenism, assessed as platelet and white cell counts, at 5 years after surgery.

RESULTS

White cell and platelet counts increased rapidly after intervention in both groups. By 36 months after operation peripheral platelet and white cell counts had decreased significantly in the RFA group compared with the splenectomy group, and declined to baseline levels by 48 months. Hypersplenism recurred after 6 months in patients with less than 50 per cent of the spleen ablated. Blood cell count in the splenectomy group and in patients with more than 50 per cent of the spleen ablated decreased with time after operation, but to levels that remained significantly higher than those before operation (P < 0·050). Splenic volume reached its nadir 12 months after RFA and then increased with time.

CONCLUSION

Splenic RFA represents an attractive alternative treatment for hypersplenism induced by liver cirrhosis, particularly when more than 50 per cent of the spleen is ablated.

Acidic stress promotes a glioma stem cell phenotype

Malignant gliomas are lethal cancers that display cellular hierarchies with cancer stem cells at the apex. Glioma stem cells (GSCs) are not uniformly distributed, but rather located in specialized niches, suggesting that the cancer stem cell phenotype is regulated by the tumor microenvironment. Indeed, recent studies show that hypoxia and its molecular responses regulate cancer stem cell maintenance. We now demonstrate that acidic conditions, independent of restricted oxygen, promote the expression of GSC markers, self-renewal and tumor growth. GSCs exert paracrine effects on tumor growth through elaboration of angiogenic factors, and low pH conditions augment this expression associated with induction of hypoxia inducible factor 2α (HIF2α), a GSC-specific regulator. Induction of HIF2α and other GSC markers by acidic stress can be reverted by elevating pH in vitro, suggesting that raising intratumoral pH may be beneficial for targeting the GSC phenotype. Together, our results suggest that exposure to low pH promotes malignancy through the induction of a cancer stem cell phenotype, and that culturing cancer cells at lower pH reflective of endogenous tumor conditions may better retain the cellular heterogeneity found in tumors.

Does using lower limit of normal values enhance the ability of a single bone mineral density measure to predict fractures?

Using a single bone mineral density (BMD) measure, we demonstrated that the lower limit of normal (LLN) method is more consistent in predicting osteoporosis fractures than the T-score in white menopausal women from the Study of Osteoporosis Fracture (SOF).

INTRODUCTION

In order to circumvent the inconsistencies and limitations with using the T-score when defining osteoporosis, we propose using 95% LLN values derived from centered polynomial models using the NHANES III BMD measures. The main aim of this study was to compare the two methods in prediction of fracture and agreement in osteoporosis classification using cohort data.

METHODS

We compared the fracture prediction ability of the two methods using a single BMD measurement in 4,948 white women aged 67-74 years in the SOF employing kappa statistics, sensitivity, and specificity.

RESULTS

The T-score provided inconsistent osteoporosis classification (46.6%) across the five hip regions of interest (ROIs) and this was significantly (p<0.0001) reduced when using the LLN method (36.5%). Kappa statistics of incident fracture during 12 years of follow-up related to the prevalence of osteoporosis at baseline was significantly improved using the LLN method compared to using T-score. Sensitivity and specificity for fracture based on a single BMD measurement of different hip ROIs were more consistent using the LLN method.

CONCLUSION

The LLN method provides a more consistent and efficient method for osteoporosis fracture prediction than the T-score in 67- to 74-year-old white women.

All-trans retinoic acid attenuates cardiac allograft vasculopathy in rats

OBJECTIVE

We sought to study the inhibitory effects of all-trans retinoic acid (ATRA) on cardiac allograft vasculopathy in rats.

METHODS

Inbred Wistar and Sprague-Dawley rats were used as donors and recipients, respectively. After abdominal heterotopic heart transplantation, animals were randomized to a cyclosporine (CsA) group versus a CsA+ATRA group: 10 mg/kg/d CsA versus the same CsA dose plus 10 mg/kg/d ATRA. Transplanted hearts were analyzed at 60 days. Cardiac allograft sections were treated with Van Giesson stain to examine vascular luminal occlusion, with immunohistochemistry for CD68 and proliferating cell nuclear antigen (PCNA), and with reverse-transcription polymerase chain reaction (RT-PCR) for platelet-derived growth factor A (PDGF-A) mRNA.

RESULTS

Luminal occlusion in the CsA+ATRA group was significantly less than that in the CsA group (40.10 +/- 8.20% vs 62.86 +/- 17.18%; P < .01). The CsA+ATRA group showed a marked reduction in PCNA- and CD68-positive cells: namely, 33.96 +/- 8.65% versus 60.17 +/- 17.74% (P < .01) and 17.63 +/- 4.24% versus 32.13 +/- 9.26 (P < .01), respectively. RT-PCR analysis showed that relative PDGF-A mRNA content in the CsA+ATRA group was significantly decreased compared with the CsA group (0.46 +/- 0.08 vs 0.94 +/- 0.11; P < .01).

CONCLUSION

ATRA may attenuate rat cardiac allograft vasculopathy by inhibiting macrophage infiltration and cell proliferation.

Protective effects of icariin on brain dysfunction induced by lipopolysaccharide in rats

In this study we examined the protective effects of icariin, a flavonol isolated from Herba epimedii, on learning and memory in a rat model with brain inflammation induced by lipopolysaccharide (LPS). Injecting LPS into the lateral ventricle caused rat brain dysfunction, as evidenced by deficits of spatial learning and memory in the Morris water maze. With administration of icariin (30, 60, 120mg/kg body wt./day) for 17 consecutive days, spatial learning and memory abilities were markedly altered. Escape latency and searching distance decreased, and the expressions of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and cyclooxygenase-2 (COX-2) of brain were significantly reduced as observed by real-time RT-PCR and immunohistochemistry. This study used ibuprofen (40mg/kg body wt./day) as positive control. In conclusion, this study suggested that icariin can improve spatial learning and memory abilities in rats with brain dysfunction induced by LPS, an effect which may be due to decreased expressions of TNF-α, IL-1β and COX-2 in the hippocampus.

Assessment of the Risk of Rupture of Intracranial Aneurysms using Three-Dimensional Cerebral Digital Subtraction Angiography

The aim of this study was to develop an improved binary logistic regression model for predicting the risk of intracranial aneurysm rupture. A cohort of patients ( n = 37) with aneurysms underwent three-dimensional digital subtraction angiography examination to measure several morphological parameters of the aneurysm. The aspect ratio (height/neck size) and the size ratio (length/mean diameter of parent vessel) were also calculated. All the morphological parameters combined with the aneurysm location and the patient's baseline data were used to derive a backward binary logistic regression model. In order to validate the model, it was applied to another independent cohort of 19 patients with aneurysms. The model had sensitivity, specificity and accuracy of 84.6%, 66.7% and 78.9%, respectively. This binary logistic regression model of aneurysm rupture risk identified the status of an aneurysm with high accuracy and could form the basis of more complex models in the future.

Depression, fracture risk, and bone loss: a meta-analysis of cohort studies

Whether depression can increase the risk of bone fractures is uncertain. This meta-analysis, which pooled results from 14 qualifying individual cohort studies, found that depression was associated with a significantly increased risk of fractures and bone loss.

INTRODUCTION

The effect of depression on the risk of bone fractures is controversial. We conducted a meta-analysis of prospective studies that examined the risk of osteoporotic fractures and bone loss associated with depression.

METHODS

We searched databases and reviewed citations in relevant articles to identify cohort studies that met prestated inclusion criteria; 14 studies were identified. Information on study design, participant characteristics, exposure and outcome measures, control for potential confounders, and risk estimates was abstracted independently by two investigators using a standardized protocol. Data were pooled by use of a random-effects model.

RESULTS

In studies that reported fracture outcomes as hazard ratios (HRs) (six studies [n = 108,157]), depression was associated with a 17% increase in fracture risk (HR = 1.17; 95% confidence interval [CI], 1.00-1.36; P = 0.05); in studies that reported risk ratios as fracture outcomes (four studies [n = 33,428]), depression was associated with a 52% increase in risk (risk ratio, 1.52; 95% CI, 1.26-1.85; P < 0.001). In studies that reported bone mineral density as an outcome (five studies [n = 8,931]), depression was associated with a reduced annualized bone loss rate of 0.25% (0.05-0.45%; P = 0.02) at the hip and 0.29% (-0.07-0.64%; P = 0.11) at the spine. The HR for the three studies (n = 14,777) that did not adjust for antidepressant treatment was 1.30 (95% CI, 1.11-1.52; P = 0.01), and the HR for the three studies (n = 93,380) that did adjust for antidepressant treatment was 1.05 (95% CI, 0.86-1.29; P = 0.6).

CONCLUSION

Evidence supports an association between depression and increased risk of fracture and bone loss that may be mediated by antidepressants.

Polymorphisms of PXK are associated with autoantibody production, but not disease risk, of systemic lupus erythematosus in Chinese mainland population

Systemic lupus erythematosus (SLE) is a complex immune disease. The genetic variation in the PXK gene was found to associate with SLE in Caucasian populations. However, the association of rs6445975 with SLE has not been extensively studied in a Chinese mainland population. A total of 288 SLE patients and 357 controls were recruited. Unlabeled probe-based high-resolution melting analysis (HRMA) was used in genotyping. HRMA with unlabeled probe successfully distinguished all genotypes. Neither genotype nor allele frequencies of SNP rs6445975 showed statistically significant differences between SLE patients and controls. The association of SNP rs6445975 with the diagnostic criteria of SLE was also examined. No obvious association was observed between rs6445975 and the incidence of clinical symptoms. However, the minor allele (G) of rs6445975 was found to significantly associate with increased abnormalities of anti-Smith (p = 0.004, odds ratio (OR) = 1.95, 95% confidence interval (CI) = 1.22-3.09), anti-Ro (p = 0.015, OR = 1.69, 95% CI = 1.10-2.58), anti-La (p = 0.008, OR = 1.86, 95% CI = 1.17-2.93) and C3C4 (p = 0.007, OR = 1.79, 95% CI = 1.17-2.74). Polymorphisms of rs6445975 in the PXK gene were associated with autoantibody production, but not disease risk, of systemic lupus erythematosus in a Chinese population.

The phenotypic and genotypic characterization of Enterobacter sakazakii strains from infant formula milk

Enterobacter sakazakii is an emerging foodborne pathogen associated with severe diseases in neonates. Infant formula milk (IFM) has been identified as one of the major contaminated sources and a transmission vehicle. To determine the phenotypic and genotypic characterization of this pathogen, 22 E. sakazakii strains isolated from IFM by an FDA-recommended method and PCR on the alpha-glucosidase gene were subtyped by random amplified polymorphic DNA (RAPD)-PCR, enterobacterial repetitive intergenic consensus (ERIC)-PCR, and antibiotic resistance patterns. At a similarity threshold of 80%, 16 ERIC-PCR fingerprint types were identified with a discriminatory power (D) of 0.933, and 18 RAPD-PCR types were identified with D of 0.973. Resistance to 9 antibiotics tested by disk diffusion assay revealed 6 antibiotic resistance patterns with D of 0.749. The comparison of characterization indicated that RAPD-PCR and ERIC-PCR have high discriminatory power showing genetic diversity of E. sakazakii isolates, and ERIC-PCR patterns showed a closer correlation than RAPD-PCR patterns to phenotypic characterization and the brands of IFM. Overall, the ERIC-PCR typing method could be used for tracing sources of E. sakazakii isolates in the food chain.

Urinary cadmium, osteopenia, and osteoporosis in the US population

SUMMARY

The association between cadmium and osteoporosis in a multiethnic population is unclear. We found that urinary cadmium is consistently associated with osteopenia and osteoporosis in the Third National Health and Nutrition Examination Survey, regardless of age, sex, race, and smoking status. Cadmium exposure may be an independent risk factor for osteoporosis.

INTRODUCTION

Our purpose was to test whether cadmium exposure is associated with a higher prevalence of osteopenia and osteoporosis in the general US population and selected subgroups.

METHODS

We used multinomial logistic regression to analyze data on 10,978 subjects (aged 30-90) from the Third National Health and Nutrition Examination Survey. We studied the association of urinary cadmium levels (adjusted for urinary creatinine) and the prevalence of osteopenia and osteoporosis as defined by the World Health Organization.

RESULTS

After adjustment for age, sex, ethnicity, body mass index, calcium intake, and physical inactivity, odds ratios (ORs) for osteopenia and osteoporosis increased dose dependently with two urinary cadmium levels (in micrograms of urinary cadmium per grams of urinary creatinine: level I, 1.00-1.99 mcg/g; level II, > or =2.00 mcg/g). Osteopenia results were as follows: level I OR, 1.49 (95% confidence interval [CI], 1.24-1.80); level II OR, 2.05 (95% CI, 1.52-2.78). Osteoporosis results were as follows: level I OR, 1.78 (95% CI, 1.26-2.52); level II OR, 3.80 (95% CI, 2.36-6.14). The association was consistent in all age, sex, race, and smoking status subgroups.

CONCLUSIONS

Cadmium exposure may be a potential risk factor for osteopenia and osteoporosis in the general US population.

High-resolution melting analysis of PCDH10 methylation levels in gastric, colorectal and pancreatic cancers

Protocadherins are celladhesion molecules with 6 or 7 cadherin motifs in their extracellular domain and various cyotoplasmic domains. PCDH10 was characterized a novel tumor suppressive gene in and was epigenetically silenced in multiple haematologic malignancies as well as some solid tumors such as gastric cancer, nasopharyngeal carcinoma and esophageal carcinoma. High-resolution melting (HRM) analysis has been used as a novel tool for analysis of promoter methylation. In our study, we used HRM analysis to detect the methylation levels of PCDH10 gene in 100 gastric cancers, 100 colorectal cancers, 70 pancreatic cancers and equal number of adjacent normal tissues. The frequency of PCDH10 methylation in all three types of cancers was significantly higher than that in normal tissues. Consistent with previous reports, expression levels of PCDH10 were inversely correlated with methylation levels. But we didn't find significant association between PCDH10 methylation status and TNM staging in all three types of cancers. In summary, application of HRM analysis to large amount of clinical samples proves to be a fast and high-throughput way to investigate the epigenetic status of PCDH10. And this is the first study to evaluate the prevalence of PCDH10 methylation based on large amount of tumor samples, showing that epigenetic regulation of PCDH10 was associated with carcinogenesis.