Urinary Bladder Matrix Protects Host in a Murine Model of Bacterial-Induced Lung Infection

Use of a dynamic tissue system and biological xenograft in complex traumatic wound closure

OBJECTIVE

Asymmetrical dimensions and nonlinear margins of a multilayered traumatic wound often preclude healing via primary intention. We present the case of an otherwise healthy 21-year-old male who sustained trauma following a boating accident.

METHOD

The patient sustained three lacerations to the posterior thighs from the boat propeller. The most extensive wound measured 25×10×6cm of muscle extrusion with a divot fracture involving the posterior femur.

RESULTS

Primary closure and restoration of muscle biomechanics was achieved using a combination of a dynamic tissue system (DTS) and porcine urinary bladder matrix (PUBM) xenograft. After 24 days of treatment in hospital, the patient was discharged without the need for home health, outpatient wound care, or ongoing negative pressure wound therapy. The patient recovered full function of the legs and was cleared for participation in all activities.

CONCLUSION

This complex traumatic boat propeller injury presented many challenges, including a transverse orientation on the extremity, degree of muscle injury/extrusion, and significant soft tissue loss. The combined application of a DTS with PUBM biological xenograft achieved a primary myocutaneous closure without the need for skin graft or flap reconstruction by plastic surgery.

Treatment with a Urinary Bladder Matrix Alters the Innate Host Response to Pneumonia Induced by Escherichia coli

Escherichia coli has become the prominent cause of nosocomial pneumonia in recent years. In the meantime, some strains of E. coli have developed resistance to commonly used antibacterial drugs. The urinary bladder matrix (UBM) is a biologically derived scaffold material that has been used to promote site-appropriate tissue remodeling in a variety of body systems, partially through the modulation of the innate immune response. In this study, we seek to determine UBM efficacy in preventing bacterial pneumonia in mouse lungs using the Gram-negative bacterial strain E. coli. Our results show that the UBM prevented bacterial biofilm formation in both abiotic and biotic conditions through experimentation on polystyrene plates and culture on the apical surface of differentiated airway epithelial cells. Intratracheal treatment with UBM led to host protection from E. coli-induced respiratory infection in a murine pneumonia model. Transcriptomic analysis revealed the involvement of the enhanced host immune response in UBM-treated mice. Additionally, UBM-treated macrophages had an increased iNOS expression and enhanced phagocytosis activity. Therefore, the protection against E. coli-induced infection and the antibacterial function observed by UBM is potentially through both the anti-biofilm activity and enhanced host immunity following UBM treatment. Taken together, our results support further investigation of UBM as an alternative treatment to attenuate bacterial-induced respiratory infection.

Determination and Quantification of Bacterial Virulent Gene Expression Using Quantitative Real-Time PCR

Polymerase chain reaction (PCR) plays significant roles in modern molecular biology. However, it is relatively cumbersome and less accurate to use the traditional PCR method in quantifying gene expression because it requires first generating a standard curve with multiple input controls showing linearity with amplified control PCR products on a electrophoresis gel to compare with the abundance of the to-be-determined gene transcript PCR amplicons. Quantitative real-time PCR (qRT-PCR) is a time-efficient and reliable tool for accurate quantification and comparison of gene (RNA transcript) expression from various biological samples. Current technology has simplified and expedited the qPCR process significantly. However, proper techniques and standard protocols are required in eliminating potentially erroneous experimental outcome. Here, we provide an example from a drug-treated bacterial gene expression study with detailed protocols to demonstrate real-time qPCR with SYBR^™ Green and TaqMan^®, two of the most adapted and well-established qPCR technologies. Relative quantification of gene (RNA transcript) expression using qRT-PCR is demonstrated in detail from sample preparations to data analysis.