Bioinformatics analysis of gene expression profiles in the rat cerebral cortex following traumatic brain injury

BACKGROUND

Traumatic brain injury (TBI) is a serious neurodisorder commonly caused by sports related events or violence. It is the leading cause of disability in people under 40.

AIM

In order to elucidate the molecular mechanism of the secondary injury after TBI.

MATERIALS AND METHODS

In this study, we downloaded gene expression profile on TBI model with sham controls for gene set enrichment analysis and pathway analysis.

RESULTS

At a q-value of 5%, 361 genes were up-regulated and 373 were down-regulated in samples obtained at 48 hours after TBI. Functional analyses revealed that steroid biosynthesis, cell cycle, metal ion transport, inflammation and apoptosis were significantly dysregulated during the late period after trauma. In addition, MAPK3 (mitogen-activated protein kinase 3), was identified as the hub node in the protein-protein interaction (PPI) network constructed by the differentially expressed genes (DEGs).

CONCLUSIONS

Further elucidation of genes and proteins in our study may reveal their potential as novel therapeutic targets.

Androgens regulate prostate cancer cell growth via an AMPK-PGC-1α-mediated metabolic switch

Prostate cancer is the most commonly diagnosed malignancy among men in industrialized countries, accounting for the second leading cause of cancer-related deaths. Although we now know that the androgen receptor (AR) is important for progression to the deadly advanced stages of the disease, it is poorly understood what AR-regulated processes drive this pathology. Here we demonstrate that AR regulates prostate cancer cell growth via the metabolic sensor 5'-AMP-activated protein kinase (AMPK), a kinase that classically regulates cellular energy homeostasis. In patients, activation of AMPK correlated with prostate cancer progression. Using a combination of radiolabeled assays and emerging metabolomic approaches, we also show that prostate cancer cells respond to androgen treatment by increasing not only rates of glycolysis, as is commonly seen in many cancers, but also glucose and fatty acid oxidation. Importantly, this effect was dependent on androgen-mediated AMPK activity. Our results further indicate that the AMPK-mediated metabolic changes increased intracellular ATP levels and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α)-mediated mitochondrial biogenesis, affording distinct growth advantages to the prostate cancer cells. Correspondingly, we used outlier analysis to determine that PGC-1α is overexpressed in a subpopulation of clinical cancer samples. This was in contrast to what was observed in immortalized benign human prostate cells and a testosterone-induced rat model of benign prostatic hyperplasia. Taken together, our findings converge to demonstrate that androgens can co-opt the AMPK-PGC-1α signaling cascade, a known homeostatic mechanism, to increase prostate cancer cell growth. The current study points to the potential utility of developing metabolic-targeted therapies directed toward the AMPK-PGC-1α signaling axis for the treatment of prostate cancer.

Anti-tumour necrosis factor therapy enhances mucosal healing through down-regulation of interleukin-21 expression and T helper type 17 cell infiltration in Crohn's disease

Anti-tumour necrosis factor (TNF) monoclonal antibody (mAb) (infliximab, IFX) has been shown to be highly effective in the management of Crohn's disease (CD). Herein we investigated the potential role of IFX in inducing clinical remission and regulating interleukin (IL)-21 expression and T helper type 17 (Th17) cell infiltration in the intestinal mucosa of CD patients. Twenty-six CD patients were treated with IFX at weeks 0, 2 and 6. Clinical response, mucosal healing, serum C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) were evaluated at week 10 after IFX administration. Expression of IL-21, IL-17A and retinoic acid-related orphan receptor C (RORC) in intestinal mucosa were analysed by quantitative real-time polymerase chain reaction (PCR) and immunohistochemistry. Peripheral blood and lamina propria CD4(+) T cells were stimulated with anti-CD3 and anti-CD28 mAbs in the presence of IFX. Cytokine profiles and RORC were determined with enzyme-linked immunosorbent assay (ELISA) and real-time PCR. IL-21 and Th17 cells were found to be expressed highly in inflamed mucosa of active CD patients compared with healthy controls. Ten weeks after IFX infusion, CD activity index, ESR, CRP and intestinal mucosal healing were improved markedly in CD patients, and IL-21 expression and Th17 cell infiltration were decreased significantly compared with those before IFX therapy. In-vitro study demonstrated that IFX treatment could suppress IL-21, IL-17A and RORC expression in cultured CD biopsies. Moreover, IFX was also observed to down-regulate markedly IL-17A, IL-21 and RORC expression by CD CD4(+) T cells. IFX is highly effective in inducing clinical remission and promoting intestinal mucosal healing in CD patients through down-regulation of IL-21 expression and Th17 cell infiltration in intestinal mucosa.

Role of T cell recruitment and chemokine-regulated intra-graft T cell motility patterns in corneal allograft rejection

Keratoplasty is the primary treatment to cure blindness due to corneal opacification. However, immune-mediated rejection remains the leading cause of keratoplasty failure. Here, we utilize an in vivo imaging approach to monitor, track, and characterize in real-time the recruitment of GFP-labeled allo-specific activated (Bonzo) T cells during corneal allograft rejection. We show that the recruitment of effector T cells to the site of transplantation determined the fate of corneal allografts, and that local intra-graft production of CCL5 and CXCL9/10 regulated motility patterns of effector T cells in situ, and correlated with allograft rejection. We also show that different motility patterns associate with distinct in vivo phenotypes (round, elongated, and ruffled) of graft-infiltrating effector T cells with varying proportions during progression of rejection. The ruffled phenotype was characteristic of activated effectors T cells and predominated during ongoing rejection, which associated with significantly increased T cell dynamics within the allografts. Importantly, CCR5/CXCR3 blockade decreased the motility, size, and number of infiltrating T cells and significantly prolonged allograft survival. Our findings indicate that chemokines produced locally within corneal allografts play an important role in the in situ activation and dynamic behavior of infiltrating effector T cells, and may guide targeted interventions to promote graft survival.

Relationship between diffusion-weighted imaging and Bcl-2 expression in rabbit models of hepatic VX2 tumors after radiotherapy

The paper aims to study diffusion-weighted imaging (DWI) and Bcl-2 gene expression in hepatic VX2 tumors after three-dimensional conformal radiotherapy (3D-CRT), we successfully developed 40 rabbit models with hepatic VX2 tumors. 3D-CRT was performed on 28 rabbit hepatic VX2 tumors, which were then randomly and evenly divided into four groups. The remaining 12 controls did not receive radiotherapy. Conventional and DWI was performed at 1, 5, 10, and 15 days following radiation therapy. We measured apparent diffusion coefficients (ADCs) in both a region of interest (ROI) of the VX2 tumor tissue and normal liver tissue and then calculated the ratio between them. RT-PCR was performed to detect the expression of the anti-apoptotic gene Bcl-2. On days 5 and 10, the ADC ratios of the radiotherapy groups were 1.322+-0.270 and 0.964+-0.341, respectively. On days 5, 10, and 15, Bcl-2 gene expression in the radiotherapy group was 0.563+-0.284, 0.421+-0.242, and 0.314+-0.152, respectively. For all three days, the gene expression values from the radiotherapy group were significantly lower than that in the control group (P less than 0.01). Statistical analysis revealed that ADC ratio and Bcl-2 gene expression were significantly negatively correlated (r=-0.493, P less than 0.01). Our results demonstrated that DWI sequence can reflect molecular changes at different time points for hepatic VX2 tumors following radiotherapy.

Diabetic retinopathy in predicting diabetic nephropathy in patients with type 2 diabetes and renal disease: a meta-analysis

AIMS/HYPOTHESIS

The aim of this meta-analysis is to determine the predictive value of diabetic retinopathy in differentiating diabetic nephropathy from non-diabetic renal diseases in patients with type 2 diabetes and renal disease.

METHODS

Medline and Embase databases were searched from inception to February 2012. Renal biopsy studies of participants with type 2 diabetes were included if they contained data with measurements of diabetic retinopathy. Pooled sensitivity, specificity, positive predictive value, negative predictive value and other diagnostic indices were evaluated using a random-effects model.

RESULTS

The meta-analysis investigated 26 papers with 2012 patients. The pooled sensitivity and specificity of diabetic retinopathy to predict diabetic nephropathy were 0.65 (95% CI 0.62, 0.68) and 0.75 (95% CI 0.73, 0.78), respectively. The pooled positive and negative predictive value of diabetic retinopathy to predict diabetic nephropathy were 0.72 (95% CI 0.68, 0.75) and 0.69 (95% CI 0.67, 0.72), respectively. The area under the summary receiver operating characteristic curve was 0.75, and the diagnostic odds ratio was 5.67 (95% CI 3.45, 9.34). For proliferative diabetic retinopathy, the pooled sensitivity was 0.25 (95% CI 0.16, 0.35), while the specificity was 0.98 (95% CI 0.92, 1.00). There was heterogeneity among studies (p < 0.001), and no publishing bias was identified.

CONCLUSIONS/INTERPRETATION

Diabetic retinopathy is useful in diagnosing or screening for diabetic nephropathy in patients with type 2 diabetes and renal disease. Proliferative diabetic retinopathy may be a highly specific indicator for diabetic nephropathy.

The association between lysosomal protein glucocerebrosidase and Parkinson's disease

BACKGROUND

In recent years, mutations in glucocerebrosidase gene (GBA), which encodes the lysosomal enzyme glucocerebrosidase (GCase) deficient in Gaucher disease (GD), were found to be the most widespread genetic for the development of Parkinson disease.

AIM

In this work, we investigated the possibility of a biological linkage between GCase and alpha-synuclein.

MATERIALS AND METHODS

siRNA was used to knockdown the GBA, then the related proteins such as alpha-synuclein were detected, additionally, the mutations of GBA were also detected. We also provide evidence that a mouse model of Gaucher disease (GBAD409H/D409H) to detect the gene types of GBA.

RESULTS

The results showed functional knockdown (KD) of GBA in neuroblastoma cells culture causes a significant accumulation of alpha-synuclein and alpha-synuclein-mediated neurotoxicity. Furthermore, KD of GBA in rat primary neurons expressing the A53T mutation of alpha-synuclein, decreases cell viability. In addition, we observed that overexpression of several GBA mutants (N370S, L444P, D409H, D409V) significantly raised human alpha-syn levels of vector control. Glucosylceramide (GlcCer), the GCase substrate, influenced formation of purified a-syn by stabilizing soluble oligomeric intermediates. We also provide evidence that a mouse model of Gaucher disease (GBAD409H/D409H) exhibited alpha-syn aggregates in substantia nigra, cortex and hippocampus regions. ELISA analysis showed a significant rise in membrane-associated α-syn and western blot analysis showed that two forms of alpha-syn oligomers were present in brain homogenates from the hippocampus D409H mice.

CONCLUSIONS

These studies support the contention that both WT and mutant GBA can cause Parkinson disease-like alpha-synuclein pathology.

Temperature-sensitive poly(N-isopropylacrylamide-co-butyl methylacrylate) nanogel as an embolic agent: distribution, durability of vascular occlusion, and inflammatory reactions in the renal artery of rabbits

BACKGROUND AND PURPOSE

We have developed a new thermosensitive liquid embolic agent, PIB nanogel, that can be solidified at body temperature. We thus further investigated the distribution, durability of vascular occlusion, and inflammatory reactions of PIB in embolization of the renal artery of rabbits.

MATERIALS AND METHODS

The bilateral renal arteries of 9 rabbits were first embolized with PIB at different injection rates. The distribution pattern of PIB was investigated by contact radiography and histology 1 hour after embolization. The right renal arteries of 20 rabbits were then embolized with PIB at the proper injection rate. Angiography and pathologic examination of the kidneys were performed at 1 week and 1, 2, and 3 months after embolization to evaluate the long-term outcomes.

RESULTS

With the injection rate increasing, PIB could reach the more distal branch of the renal artery. The proper injection rate was chosen as 0.10 mL/s due to the homogeneous distribution of PIB from the main renal artery to the precapillary level at this rate. During a 3-month follow-up observation period, no angiographic recanalization was observed. Histologically, we found no disruption of the vessel wall or subintimal bleeding, no extravasation of PIB, and no evidence of neovascularization. Moreover, there was only a mild inflammatory response, manifested by few lymphocytic and monocellular infiltration, without foreign body granuloma formation.

CONCLUSIONS

Embolization of the renal artery with PIB was easy and controllable, which could lead to a homogeneous and persistent occlusion without severe inflammatory changes. PIB might be a suitable material for intravascular embolization.

Thyroid Hormone Analogue Stimulates Keratinocyte Proliferation but Inhibits Cell Differentiation in Epidermis

Gross clinical manifestations of thyroid hormone (TH) imbalance are often first seen in the skin where TH plays an integral role in sustaining natural function. Although mounting evidence suggests that TH plays an important role in epidermal proliferation and wound healing, the physiologic role of thyroid hormone in skin is not well understood. In the current study, we investigated the effect of a natural thyroid hormone analogue-3, 3', 5-triiodo-thyroacetic acid (TRIAC) on regulating proliferation and differentiation and its possible molecular mechanism in normal human epidermal keratinocytes and C57BL/6 mice. We determined that TRIAC could stimulate epidermal thickening in mice and promote human keratinocyte proliferation by activating Cyclin D1 expression and promoting entrance into S phase. Moreover, TRIAC might inhibit cell differentiation through repressing the expression of Casein Kinase 1 (CK1), which is a key regulatory protein involved in the control of cell differentiation. Taken together, our data explored the physiologic effect of TRIAC on skin and the possible molecular mechanism of TRIAC, which might be an interesting compound for the treatment of hyperkeratotic skin disorders.

Blocking p55PIK signaling inhibits proliferation and induces differentiation of leukemia cells

p55PIK, a regulatory subunit of phosphatidylinositol 3-kinases, promotes cell cycle progression by interacting with cell cycle modulators such as retinoblastoma protein (Rb) via its unique amino-terminal 24 amino-acid residue (N24). Overexpression of N24 specifically inhibits these interactions and leads to cell cycle arrest. Herein, we describe the generation of a fusion protein (Tat transactivator protein (TAT)-N24) that contains the protein transduction domain and N24, and examined its effects on the proliferation and differentiation of leukemia cells. TAT-N24 not only blocks cell proliferation but remarkably induces differentiation of leukemia cells in vitro and in vivo. Systemically administered TAT-N24 also significantly decreases growth of leukemia cell tumors in animal models. Furthermore, overexpression of p55PIK in leukemia cells leads to increased proliferation; however, TAT-N24 blocks this effect and concomitantly induces differentiation. There is significant upregulation of p55PIK mRNA and protein expression in leukemia cells from patients. TAT-N24 inhibits cell cycle progression and induces differentiation of bone marrow cells derived from patients with several different types of leukemia. These results show that cell-permeable N24 peptide induces leukemia cell differentiation and suggest that p55PIK may be a novel drug target for the treatment of hematopoetic malignancies.

Daidzein improves insulin resistance in ovariectomized rats

OBJECTIVE

To determine whether daidzein improves insulin resistance by modifying weight gain, visceral fat accumulation, blood lipids and serum cytokines levels in ovariectomized Sprague-Dawley rats.

MATERIALS AND METHODS

Twenty-eight 12-week-old female rats were divided into three groups: the sham-operated group (SHAM) (n =10), the ovariectomized group receiving daidzein therapy (DAID) (n =10), and the ovariectomized control group (Control) (n =8). The rats in the DAID group received 50 mg/kg daidzein via gavage daily. Weight and food intake were recorded every 2 weeks. All of the animals were euthanized 12 weeks after ovariectomy, after which their fasting insulin, glucose, blood lipids, estradiol, interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), adiponectin and leptin levels were measured.

RESULTS

After 12 weeks, the ovariectomized rats demonstrated an increase in their body weight and visceral fat; compared to the SHAM rats, the ovariectomized rats also experienced a significant increase in their serum IL-6 levels and insulin resistance, which was calculated using the homeostatic model assessment of insulin resistance (HOMA-IR) (p <0.05). Daidzein therapy decreased weight gain, visceral fat, the HOMA-IR index and IL-6 levels that were induced by ovariectomy. Rats which had received daidzein therapy had lower levels of TNF-α, leptin and blood lipids (except for high density lipoprotein cholesterol) than the other two groups. IL-6 levels positively correlated with the HOMA-IR index in all of the rats after adjustment for body weight (r =0.495; p =0.016).

CONCLUSION

We conclude that daidzein can improve insulin resistance induced by ovariectomy by decreasing weight gain, visceral fat accumulation, blood lipids, TNF-α, leptin and IL-6 levels.

Implanted adipose-derived stem cells attenuate small-for-size liver graft injury by secretion of VEGF in rats

Graft injury after small-for-size liver transplantation impairs graft function and threatens the survival of the recipients. The use of adipose-derived stem cells (ADSCs) for liver injury protection and repair is promising. Our aim was to investigate the role of vascular endothelial growth factor (VEGF) secreted by ADSCs in the treatment of small-for-size liver graft injury. Studies were performed using ADSCs with VEGF secretion blocked by RNA interference. In vitro, ADSCs prevented apoptosis of freshly isolated liver sinusoidal endothelial cells (LSECs) by secretion of VEGF. Syngeneic 35% orthotopic liver transplantation followed by implantation of syngeneic ADSCs through the portal vein system was performed using Wistar rats. We found VEGF secreted by implanted ADSCs improved graft microcirculatory disturbances, serum liver function parameters and survival. The improved microcirculatory status was also reflected by reduced hepatocellular damage, especially LSEC apoptosis and improved liver regeneration. These effects were accompanied by decreased expression of endothelin receptor type A, increased Bcl-2/Bax ratio, decreased expression of Bad and elevated proportion of phosphorylated Bad. In conclusion, implanted syngeneic ADSCs attenuated small-for-size liver graft injuries and subsequently enhanced liver regeneration in a rat 35% liver transplantation model. The VEGF secreted by implanted ADSCs played a crucial role in this process.

Enhanced alveolar bone loss in a model of non-invasive periodontitis in rice rats

OBJECTIVE

The rice rat (Oryzomys palustris) develops periodontitis-like lesions when fed a diet rich in sucrose and casein (H-SC). We aimed to establish whether this model can accurately mimic the development of human periodontitis.

MATERIALS AND METHODS

For this purpose, 28-day-old rice rats (15/group) were assigned to standard (STD) or H-SC diets and sacrificed after 6, 12, and 18 weeks. Jaws were processed for morphometric, histometric, histologic, histomorphometric, and micro-CT analyses.

RESULTS

We found a progressive increase in horizontal alveolar bone loss (ABL) with age in maxillae of rats fed the STD diet as determined by morphometry. The H-SC diet exacerbated horizontal ABL at the palatal surface at 12 and 18 weeks. Furthermore, increased vertical ABL was detected in mandibles and maxillae of rats fed the H-SC diet for 12 and/or 18 weeks by histometry and micro-CT. Remarkably, the H-SC diet significantly increased bone remodeling at the interproximal alveolar bone of mandibles from rats fed for 6 weeks, but not in those fed for longer periods.

CONCLUSIONS

These findings indicate that the H-SC diet induced a transient increase in alveolar bone remodeling, which is followed by ABL characteristic of moderate periodontitis.

Pharmacokinetics of a novel amoxicillin/colistin suspension after intramuscular administration in pigs

An amoxicillin (AMO) or colistin (COS) oil suspension was developed and corresponding pharmacokinetics studies were conducted in pigs after i.m. injection. The combination product is a white- to cream-colored oil suspension which is easy to be re-dispersed. Settling volume ratio, syringeability and flowability of the product is well consistent with the technical standards set by the Ministry of Agriculture of People's Republic of China. Two studies were conducted to investigate the pharmacokinetics of the combination product in swine. First, the pharmacokinetics of the combination product was compared with those of the same products merely removing either AMO or COS. No significant change in the major pharmacokinetic parameters (C(max) , T(max) , MRT, t(1/2λ) , AUC and AUMC) was observed when either component was removed from the combination product, indicating that AMO and COS do not interfere with each other in their absorption and distribution in the tissue when used as a combination. Second, the pharmacokinetics of the combination product was compared with that of their respective single products. It was found that the apparent elimination half-lives (t(1/2λ) ) of AMO and COS in combination product were 6.38 and 8.09 h, which were 2.40 and 2.38 times longer than the single products, respectively. Thus, the novel AMO/COS suspension extended significantly the half-life of both drugs to maintain a longer drug residence time in pigs when compared to their single products.

Advantage of carbonate-versus citrate-based alkalinization on bone metabolism in moderately exercising aged male rats fed an acidogenic diet

This study aims to determine the effects of different alkaline supplementations on high protein diet-induced abnormalities affecting bone metabolism in rats which were also undergoing physical exercise of moderate intensity. Sixty elderly Sprague-Dawley rats were randomly divided into four groups of 10 rats each and treated for 16 weeks as follows: baseline control group fed normal food (C); acidic high-protein diet supplemented group (chronic acidosis, CA group), bicarbonate-based alkaline formula (Basenpulver, Named, Italy) supplemented chronic acidosis (BB-CA) and citrate-based alkaline supplement (CB-CA). Throughout the supplementation period, rats were put on a treadmill training mimicking a moderate level of exercise. In the CA group, 24-hour urinary calcium (Ca) and phosphorus (P) excretion were increased over 30 percent (p<0.05 vs normal diet controls). However serum Ca was not significantly changed. Femural and tibial BMD and BMC was significantly decreased in the CA group (p<0.05) but both alkaline supplementations prevented such phenomenon (p<0.05 vs CA), without significant difference between the two formulations although the BB-CA group showed significantly more preserved trabecular bone volume (p<0.05 vs CB-CA group). An increased level of over 50 percent of urinary Dpd observed in the CA group (p<0.001) was reverted to normal by both supplementations (p<0.001 vs CA group). The same applied to urinary net acid excretion (p<001) with BB-supplementation performing better than CB-supplementation (p<0.05). Moreover, while the latter did not modify Nterminal telopeptide value, BB-supplementation significantly normalized this parameter (p<0.05 vs CA group) which exercise and acidic protein diet had modified (p<0.01 vs control diet). Overall, the present study shows that a bicarbonate-based alkaline formula, when administered to a dose amenable to clinical use, may significantly protect bone structure in exercising aged animals to a greater extent than a quali/quantitavely similar citrate-based formula.

Competitive electroporation formulation for cell therapy

Established cell transfection via nucleofection relies on nucleofection buffers with unknown and proprietary makeup due to trade secrecy, inhibiting the possibility of using this otherwise effective method for developing cell therapy. We devised a three-step method for discovering an optimal formulation for the nucleofection of any cell line. These steps include the selection of the best nucleofection program and known buffer type, selection of the best polymer for boosting the transfection efficiency of the best buffer and the comparison with the optimal buffer from an established commercial vendor (Amaxa). Using this three-step selection system, competitive nucleofection formulations were discovered for multiple cell lines, which are equal to or surpass the efficiency of the Amaxa nucleofector solution in a variety of cells and cell lines, including primary adipose stem cells, muscle cells, tumor cells and immune cells. Through the use of scanning electron microscopy, we have revealed morphological changes, which predispose for the ability of these buffers to assist in transferring plasmid DNA into the nuclear space. Our formulation may greatly reduce the cost of electroporation study in laboratory and boosts the potential of application of electroporation-based cell therapies in clinical trials.

Beneficial nutraceutical modulation of cerebral erythropoietin expression and oxidative stress: an experimental study

The main object of this study is to examine the effect of Klamin®, a nutraceutical containing phenylethylamine, phycocyanins, mycosporine-like aminoacids and aphanizomenon flos aquae-phytochrome on the learning and memory ability, the oxidative status and cerebral erythropoietin and its receptor EPO/EPOR system in prematurely senescent (PS) mice. A total of 28 PS mice, selected according to a prior T-maze test, and 26 non-prematurely senescent mice (NPS) mice were chosen. PS animals were divided into 3 groups and followed for 4 weeks: A) normal chow diet; B) added with Klamin® at 20 mg/kg/day (low dose); C) added with Klamin® at 100mg/kg/day (high dose). A further group of NPS mice given either normal food (group D) or high dose Klamin® (group E) was also considered. The behavioral procedures of spatial learning ability (Morris test) showed that PS mice had significantly longer learning time as compared to their NPS counterpart (p<0.01), but this effect was prevented especially in mice supplemented with high-dose Klamin® (p<0.05) which improved performances in NPS mice (p<0.05). High-dose Klamin® supplementation restored the depleted total thiol concentration in the brain observed in PS mice while normalizing their increased malonildialdehyde level (p<0.05). Moreover, the high-dosage only caused a significant upregulation of EPO/EPOR system both in PS and in NPS animals (p<0.05). Taken together, these data suggest that this specific alga Klamath extract has considerable antioxidant and adaptogenic properties, also through a stimulatory effect of cerebral EPO/EPO system.

Escherichia coli from retail meats carry genes associated with uropathogenic Escherichia coli, but are weakly invasive in human bladder cell culture

AIMS

The aim of this study was to determine the uropathogenic potential of Escherichia coli isolated from retail meats.

METHODS AND RESULTS

Two hundred E. coli isolates recovered from retail meats, which were previously identified molecularly as extraintestinal pathogenic E. coli, were investigated for the presence of 21 uropathogenic E. coli (UPEC) virulence-associated genes. Twenty-three E. coli isolates were selected based on their serogroups and the number of virulence genes they contained, and further characterized using multilocus sequence typing, and by tissue culture assays for adherence to and invasion of T-24 human bladder cells and for their induction of interleukin (IL)-6 secretion. All virulence genes tested, except afa/dra and hlyD, were detected among the E. coli isolates. Multilocus sequence typing analysis of 23 selected isolates revealed that 17 isolates belonged to STs associated with human UPEC. Nearly all 23 isolates exhibited lower level of adherence and invasion compared to a clinical strain, UPEC CFT073.

CONCLUSIONS

These observations suggested that a small proportion of E. coli isolates from retail meats carry uropathogenic associated virulence genes and thus may serve as a reservoir of these genes to UPEC in the human intestine. Their virulence potential seemed limited as they were only weakly invasive in human bladder cell culture.

SIGNIFICANCE AND IMPACT OF THE STUDY

These findings support the hypothesis that retail meat E. coli may play a role in relation to urinary tract infection (UTI) and may be considered in development of a UTI prevention strategy.