Compromised Neurotrophic and Angiogenic Regenerative Capability during Tendon Healing in a Rat Model of Type-II Diabetes.

Metabolic diseases such as diabetes mellitus type-II (DM-II) may increase the risk of suffering painful connective tissue disorders and tendon ruptures. The pathomechanisms, however, by which diabetes adversely affects connective tissue matrix metabolism and regeneration, still need better definition. Our aim was to study the effect of DM-II on expressional changes of neuro- and angiotrophic mediators and receptors in intact and healing Achilles tendon. The right Achilles tendon was transected in 5 male DM-II Goto-Kakizaki (GK) and 4 age-matched Wistar control rats. The left Achilles tendons were left intact. At week 2 post-injury, NGF, BDNF, TSP, and receptors TrkA, TrkB and Nk1 gene expression was studied by quantitative RT-PCR (qRT-PCR) and their protein distribution by immunohistochemistry in intact and injured tendons. The expression of tendon-related markers, Scleraxis (SCX) and Tenomodulin (TNMD), was evaluated by qRT-PCR in intact and injured tendons. Injured tendons of diabetic GK rats exhibited significantly down-regulated Ngf and Tsp1 mRNA and corresponding protein levels, and down-regulated Trka gene expression compared to injured Wistar controls. Intact tendons of DM-II GK rats displayed reduced mRNA levels for Ngf, Tsp1 and Trkb compared to corresponding intact non-diabetic tendons. Up-regulated Scx and Tnmd gene expression was observed in injured tendons of normal and diabetic GK rats compared to intact Wistar controls. However, these molecules were not up-regulated in injured DM-II GK rats compared to their corresponding controls. Our results suggest that DM-II has detrimental effects on neuro- and angiotrophic pathways, and such effects may reflect the compromised repair seen in diabetic Achilles tendon. Thus, novel approaches for regeneration of injured, including tendinopathic, and surgically repaired diabetic tendons may include therapeutic molecular modulation of neurotrophic pathways such as NGF and its receptors.

Rapid Antimicrobial Susceptibility Testing Using Forward Laser Light Scatter Technology.

The delayed reporting of antimicrobial susceptibility testing remains a limiting factor in clinical decision-making in the treatment of bacterial infection. This study evaluates the use of forward laser light scatter (FLLS) to measure bacterial growth for the early determination of antimicrobial susceptibility. Three isolates each (two clinical isolates and one reference strain) of Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa were tested in triplicate using two commercial antimicrobial testing systems, the Vitek2 and the MicroScan MIC panel, to challenge the BacterioScan FLLS. The BacterioScan FLLS showed a high degree of categorical concordance with the commercial methods. Pairwise comparison with each commercial system serving as a reference standard showed 88.9% agreement with MicroScan (two minor errors) and 72.2% agreement with Vitek (five minor errors). FLLS using the BacterioScan system shows promise as a novel method for the rapid and accurate determination of antimicrobial susceptibility.

Expressional changes in growth and inflammatory mediators during Achilles tendon repair in diabetic rats: new insights into a possible basis for compromised healing.

Dysregulation of growth and inflammatory mediators might contribute to defective tissue homeostasis and healing, as commonly observed in sedentary lifestyles and in conditions such as diabetes mellitus type-2. The present study aims to assess expression changes in growth and inflammatory mediators in the intact and healing Achilles tendon of type-2 diabetic rats. The study utilized 11 male diabetic Goto-Kakizaki (GK) and 10 age- and sex-matched Wistar control rats. The right Achilles tendon was transected in all animals, whereas the left Achilles tendon remained intact. At 2 weeks post-injury, intact and injured tendons were assessed for gene expression for VEGF, Tß-4, TGF-ß1, IGF-1, COX-2, iNOS, HIF-1α, and IL-1ß by quantitative reverse transcription plus the polymerase chain reaction, and their protein distribution was studied by immunolocalization. In injured tendons of diabetic GK rats, VEGF and Tß-4 mRNA and corresponding protein levels were significantly down-regulated compared with those of injured Wistar controls. Compared with intact tendons of diabetic GK rats, TGF-ß1, IGF-1, and COX-2 RNA levels were higher, whereas iNOS mRNA levels were lower in injured tendons of diabetic GK rats. Within Wistar controls, healing at 2 weeks post-injury led to significantly down-regulated VEGF and iNOS mRNA levels in injured tendons, whereas TGF-ß1 and HIF-1α mRNA levels increased compared with intact tendons. Thus, dysregulation of inflammatory and growth mediators occurs in type-2 diabetes injured tendons. Our data suggest that therapeutic modulation of Tß-4 and VEGF represent a new regenerative approach in operated, injured, or degenerative tendon diseases in diabetes.

Type 2 diabetes impairs tendon repair after injury in a rat model.

Type 2 diabetes adversely affects the properties of native connective tissue. The underlying mechanisms, however, by which diabetes alters connective tissue metabolism, especially tendon, are poorly defined. The aim of this study was to determine the effect of type 2 diabetes on the mechanical, histological, and molecular properties of the intact and healing Achilles tendon. The right Achilles tendon was transected in 11 male diabetic Goto-Kakizaki (GK) and 10 age- and sex-matched Wistar control rats, while the left Achilles tendon was left intact. At 2 wk postinjury the intact and injured tendons were assessed by biomechanical testing and histology. The gene expression of collagen I and III, biglycan, versican, MMP-13, and MMP-3 was measured by quantitative RT-PCR, and their protein distribution was studied by immunohistochemistry. Intact tendons exhibited only small differences between the groups. In injured tendons, however, a significantly smaller transverse area and lower stiffness was found in diabetic GK compared with Wistar control rats. This correlated with impaired structural organization of collagen fibers and a reduced expression of collagen I and III in the injured tendons of the diabetic GK compared with Wistar control. Moreover, MMP-3 gene expression was downregulated in the injured diabetic GK tendons compared with injured Wistar controls. Our results indicate that in a rat model of diabetes tendon healing is impaired mainly due to altered expression of collagen and MMPs reflecting decreased degradation of matrix proteins and impaired tissue remodeling. Further our data suggest that therapeutic modulation of collagens or MMPs might be targets for new regenerative approaches in operated, injured, or maybe also degenerative tendon diseases in diabetes.

Diagnostic accuracy of the Cepheid GeneXpert vanA/vanB assay ver. 1.0 to detect the vanA and vanB vancomycin resistance genes in Enterococcus from perianal specimens.

Rapid detection of vancomycin-resistant enterococci (VRE) carriers could be useful to health care facilities to minimize transmission. To that end, we compared the performance of the Cepheid GeneXpert vanA/vanB assay with that of direct and broth-enriched culture methods for detection of VRE from perianal swabs. Enterococci were cultivated on Enterococcosel™ agar with 8 µg/mL vancomycin, Bile Esculin Azide Agar with 6 µg/mL vancomycin, and Bile Esculin Azide Enterococcosel Broth. Compared to the reference standard (combination of direct agar plating, broth-enriched culture, and clinical chart review), the sensitivity, specificity, positive predictive value, and negative predictive value of the vanA/vanB assay were 96.4%, 93.0%, 92.0%, and 96.9%, respectively (n=184). The 95% limit of detection was 100 colony-forming units (CFU)/mL for vanA and 114 CFU/mL for vanB. In summary, the GeneXpert vanA/vanB assay is a rapid and accurate method to identify vanA/vanB-colonized patients for VRE screening programs that use perianal swab specimens.

Filtration-based culture methods improve recovery of fungal pathogens in respiratory specimens.

We describe a filtration-based culture method to enhance sensitivity of routine culture for recovery of fungi from respiratory specimens. The new method resulted in an 8.3% (P = 0.0039) increase in recovery for all organisms and a 6.4% (P = 0.0391) for Candida species when compared to the conventional culture technique.