Elissa Elia

Urethral reconstruction is required for a variety of congenital and acquired conditions. Current grafting techniques rely on autologous tissues such as buccal mucosa, which are often limited by donor-site morbidity. Biomaterials could be an alternative. However, they may present immunological risks and inconsistent surgical outcomes. The tissue-engineering self-assembly approach, which uses autologous patient cells to generate tissue constructs without exogenous biomaterials, offers a promising alternative by improving graft integration. Such natural tissue-engineered constructs exhibit promising histological similarity to native urethral tissue and hold potential for clinical application. However, graft selection for surgery remains subjective, lacking standardized mechanical criteria to ensure consistent quality. Previous efforts to quantify graft properties through uniaxial tensile testing have proven informative but require cutting the tissue into standardized specimens and are therefore not readily suited to routine quality-control workflows. To address this, we investigated puncture testing as a simpler practical alternative that does not require tissue cutting and assessed its correlation with tensile testing and surgeon-based evaluation. Self-assembled dermal and urethral constructs were evaluated using uniaxial tensile and puncture tests, and results were correlated with the surgeon’s qualitative assessments during graft handling. Our findings reveal a strong linear relationship between two mechanical testing techniques. Puncture testing also showed a strong relationship with surgeon-based qualitative assessments of graft handling. This study highlights the potential of puncture testing as a practical mechanical assessment tool for characterizing graft mechanical behavior in the context of surgical handling, and offers a pathway toward the development of standardized, objective quality control protocols for tissue-engineered urethral grafts prior to implantation.

Trans-epithelial permeability is a critical functional parameter for reconstructed tissues, particularly in genitourinary tissue engineering, where urine leakage must be avoided. Although Franz diffusion cells are considered the gold standard for permeability measurements, their cost and limited accessibility restrict their widespread use. In parallel, the reliable quantification of urea in culture media remains challenging due to protein interference and assay cost. The Inexpensive Trans-Epithelial Permeability (I-TEP) test is a simple and a low-cost Franz-like permeability system which can be combined with an optimized diacetyl monoxime–thiosemicarbazide (DAMO–TSC) colorimetric urea assay. I-TEP system relies on readily available laboratory components to create physically separate donor and receiver compartments, with the tissue acting as the sole diffusion interface. The DAMO–TSC assay was optimized through systematic evaluation of deproteinization, incubation time, storage conditions, and serum interference. The I-TEP test showed a strong correlation with conventional Franz diffusion cells when testing similar tissue samples. Deproteinization was identified as a mandatory step for accurate urea quantification in serum-containing media. The combined approach was successfully applied on engineered genitourinary tissues, demonstrating sensitivity to tissue maturation and cellular composition. This protocol provides a proof of concept for an affordable, robust, and autonomous method for routine permeability assessment, bridging the gap between costly commercial systems and high-throughput experimental needs.

Urethral reconstruction remains a challenge. Indeed, the use of oral mucosa, the reference biomaterial for urethroplasty, is associated with two main drawbacks: the limited availability of autologous tissues and potential short- and long-term complications, especially for patients with recurrences or severe anomalies. Therefore, the development of alternative approaches, such as urethral tissue engineering, is necessary. A new type of human urethral substitute devoid of exogenous biomaterials has been reconstructed in vitro. It presented sufficient mechanical strength and had histological and functional properties comparable to native tissues. These reconstructed tissues were implanted in vivo to repair hypospadias induced in tacrolimus-immunosuppressed rabbits via a two-stage urethroplasty. In the first stage, the distal part of the native urethra was removed, and a flat graft was implanted, leaving the urethra open proximally. Twelve weeks later, the graft was tubularized to create a neourethra, reproducing the usual clinical scenario. The results obtained for the experimental group were less effective than for the control group, with a success rate of 50% after excluding the animal affected by unwanted events unrelated to urethroplasty, and it is possible that the animal model or surgical technique used was not suitable and should be modified. Nevertheless, half of the urethral substitutes grafted on rabbits showed successful integration. These self-assembled artificial tissues represent promising substitutes for urethroplasty.

The penis is a complex organ with a development cycle from the fetal stage to puberty. In addition, it may suffer from either congenital or acquired anomalies. Penile surgical reconstruction has been the center of interest for many researchers but is still challenging due to the complexity of its anatomy and functionality. In this review, penile anatomy, pathologies, and current treatments are described, including surgical techniques and tissue engineering approaches. The self-assembly technique currently applied is emphasized since it is considered promising for an adequate tissue-engineered penile reconstructed substitute.

Congenital vaginal anomalies and pelvic organ prolapse affect different age groups of women and both have significant negative impacts on patients’ psychological well-being and quality of life. While surgical and non-surgical treatments are available for vaginal defects, their efficacy is limited, and they often result in long-term complications. Therefore, alternative treatment options are urgently needed. Fortunately, tissue-engineered scaffolds are promising new treatment modalities that provide an extracellular matrix (ECM)-like environment for vaginal cells to adhere, secrete ECM, and be remodeled by host cells. To this end, ECM-based scaffolds or the constructs that resemble ECM, generated by self-assembly, decellularization, or electrospinning techniques, have gained attention from both clinicians and researchers. These biomimetic scaffolds are highly similar to the native vaginal ECM and have great potential for clinical translation. This review article aims to discuss recent applications, challenges, and future perspectives of these scaffolds in vaginal reconstruction or repair strategies.

The gastrointestinal and genitourinary tracts share several similarities. Primarily, these tissues are composed of hollow structures lined by an epithelium through which materials need to flow with the help of peristalsis brought by muscle contraction. In the case of the gastrointestinal tract, solid or liquid food must circulate to be digested and absorbed and the waste products eliminated. In the case of the urinary tract, the urine produced by the kidneys must flow to the bladder, where it is stored until its elimination from the body. Finally, in the case of the vagina, it must allow the evacuation of blood during menstruation, accommodate the male sexual organ during coitus, and is the natural way to birth a child. The present review describes the anatomy, pathologies, and treatments of such organs, emphasizing tissue engineering strategies.

The gastrointestinal and genitourinary tracts share several similarities. Primarily, these tissues are composed of hollow structures lined by an epithelium through which materials need to flow with the help of peristalsis brought by muscle contraction. In the case of the gastrointestinal tract, solid or liquid food must circulate to be digested and absorbed and the waste products eliminated. In the case of the urinary tract, the urine produced by the kidneys must flow to the bladder, where it is stored until its elimination from the body. Finally, in the case of the vagina, it must allow the evacuation of blood during menstruation, accommodate the male sexual organ during coitus, and is the natural way to birth a child. The present review describes the anatomy, pathologies and treatments of such organs, emphasizing tissue engineering strategies.