A Preliminary Study of Constructing the Tissue-Engineered Corpus Cavernosum With Autologous Adipose Stem Cells In Vivo

Introduction

The autologous skin flap is still the mainstream method for penile reconstruction, but it is very difficult to reconstruct a functional corpus cavernosum. Tissue engineering provides a new idea aiming to restore the damaged or absent corpus cavernosum.

Aim

To assess the feasibility of constructing the tissue-engineered corpus cavernosum with autologous adipose stem cells in a rabbit model.

Methods

A total of 30 New Zealand male white rabbits. Among them, 20 rabbits were used to obtain the original corpus cavernosum which were used to prepare the acellular corporal scaffolds (ACSs). The others were used for acquiring autologous adipose stem cells (ADSCs) and constructing tissue-engineered corpus cavernosum in vivo.

Outcome

ACSs were obtained from rabbit penile tissues through an established decellularization procedure. Rabbit autologous ADSCs as seed cells were harvested and expanded. The ADSCs seeded and unseeded ACSs were implanted back into the intramuscular and subcutaneous site in vivo, and the tissue-engineered corpus cavernosum was harvested and analyzed with gross morphology, histological staining, and real-time PCR assay after 1, 3, and 6 months.

Results

ACSs were successfully prepared. The cell non-cytotoxicity and integrity of micro-architecture of ACSs was confirmed in vitro. The cell-seeded scaffold in the intramuscular group was considered as the better strategy for constructing the tissue-engineered corpus cavernosum compared with the other groups. Some α-SMA and CD31 positive cells were detected and identified by immunofluorescent staining and real-time PCR assay in the tissue-engineered corpus cavernosum.

Clinical Translation

This study provides a new method for constructing the tissue-engineered corpus cavernosum.

Strengths and Limitations

First, it is urgent to improve the transformation rate of the endothelial cells and smooth muscle cells from ADSCs. Second, the scaffold harvested in this study was not a complete matrix. Third, further study is needed to explore the potential mechanism of which scaffolds are more suitable for living in intramuscular rather than subcutaneous environment.

Conclusion

In this study, we used the autologous ADSCs as seed cells, the acellular corpus cavernosum as scaffolds, and implanted the grafts back into the rabbit model to preliminarily construct the tissue-engineered corpus cavernosum. This study would provide help for further development in tissue-engineered corpus cavernosum.

Cao Z, Liu L, Jiao H, et al. A Preliminary Study of Constructing the Tissue-Engineered Corpus Cavernosum With Autologous Adipose Stem Cells In Vivo. Sex Med 2022;10:100563.

Biomaterial strategies for the application of reproductive tissue engineering

Human reproductive organs are of vital importance to the life of an individual and the reproduction of human populations. So far, traditional methods have a limited effect in recovering the function and fertility of reproductive organs and tissues. Thus, aim to replace and facilitate the regrowth of damaged or diseased tissue, various biomaterials are developed to offer hope to overcome these difficulties and help gain further research progress in reproductive tissue engineering. In this review, we focus on the biomaterials and their four main applications in reproductive tissue engineering: in vitro generation and culture of reproductive cells; development of reproductive organoids and models; in vivo transplantation of reproductive cells or tissues; and regeneration of reproductive tissue. In reproductive tissue engineering, designing biomaterials for different applications with different mechanical properties, structure, function, and microenvironment is challenging and important, and deserves more attention.

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Various biomaterials have been developed and used in reproductive tissue engineering.

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3D culture systems can lead to better cell-cell interactions for in vitro production of reproductive cells.

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Reproductive organoids and models are formed by biomaterials to simulate the environment of natural reproductive organs.

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Biomaterials should promote vascular regeneration and resist inflammation for in-situ reproductive tissue regeneration.

Cavernous Nerve Injury Resulted Erectile Dysfunction and Regeneration

Erectile dysfunction (ED) is an important cause of reduced quality of life for men and their partners. Recent studies have found that cavernous nerve injury (CNI) during prostate cancer surgery and other pelvic surgery results in medically induced CNIED in more than 80% of patients. The efficacy of first- and second-line treatment options for ED is poor. A great deal of research has been devoted to exploring new methods of neuroprotection and nerve regeneration to save erectile function in patients with CNIED, especially in patients with cavernous nerve injury after prostate cancer surgery. In addition, such as neuromodulatory proteins, proimmune ligands, gene therapy, stem cell therapy, and the current cutting-edge low-energy shock wave therapy have shown advantages in basic research and limited clinical studies. In the context of today's modern medicine, these new therapeutic techniques are expected to be new tools in the treatment of cavernous nerve injury erectile dysfunction. This article presents the main causes, mechanisms, and treatment of cavernous nerve injury erectile dysfunction and combines them with new treatment strategies.

Co-culture of smooth muscle cells and endothelial cells on three-dimensional bioprinted polycaprolactone scaffolds for cavernosal tissue engineering

PURPOSE

In vitro evaluation of polycaprolactone (PCL) scaffolds fabricated by a three-dimensional (3D) printing technique for tissue engineering applications in the corpus cavernosum.

MATERIALS AND METHODS

PCL scaffolds were fabricated by use of a 3 D bioprinting system. The 3D-printed scaffolds had interconnected structures for cell ingrowth. Human aortic smooth muscle cells (haSMCs) were seeded on the scaffold and cultured for 5 days, and then human umbilical vein endothelial cells (HUVECs) were also added on the scaffolds and co-cultured with haSMCs for up to 7 days. The ability of these scaffolds to support the growth of HUVECs and haSMCs was investigated in vitro. 3 D strand-deposited scaffolds were characterized by scanning electron microscopy (SEM) images and porosity measurement.

RESULTS

SEM images showed the surface of the PCL scaffolds to be well covered by HUVECs and haSMCs. Immunofluorescent staining of α-flk1 and α-smooth muscle actin on the HUVECs and haSMCs seeded scaffolds confirmed that the cells remained viable and proliferated throughout the time course of the culture.

CONCLUSION

3 D bioprinting of a PCL scaffold is feasible for co-culturing of HUVECs and haSMCs. This was a preliminary study to investigate the possibility of fabrication of tissue-engineered corpus cavernosum.

Functional reconstruction of injured corpus cavernosa using 3D-printed hydrogel scaffolds seeded with HIF-1α-expressing stem cells

Injury of corpus cavernosa results in erectile dysfunction, but its treatment has been very difficult. Here we construct heparin-coated 3D-printed hydrogel scaffolds seeded with hypoxia inducible factor-1α (HIF-1α)-mutated muscle-derived stem cells (MDSCs) to develop bioengineered vascularized corpora. HIF-1α-mutated MDSCs significantly secrete various angiogenic factors in MDSCs regardless of hypoxia or normoxia. The biodegradable scaffolds, along with MDSCs, are implanted into corpus cavernosa defects in a rabbit model to show good histocompatibility with no immunological rejection, support vascularized tissue ingrowth, and promote neovascularisation to repair the defects. Evaluation of morphology, intracavernosal pressure, elasticity and shrinkage of repaired cavernous tissue prove that the bioengineered corpora scaffolds repair the defects and recover penile erectile and ejaculation function successfully. The function recovery restores the reproductive capability of the injured male rabbits. Our work demonstrates that the 3D-printed hydrogels with angiogenic cells hold great promise for penile reconstruction to restore reproductive capability of males.

Injury of corpus cavernosa results in erectile dysfunction, and repair leading to restoration of function is difficult. Here the authors construct 3D printed hydrogel constructs seeded with HIF-1α-expressing muscle derived stem cells to restore corpus function in a rabbit model.

Construction of engineered corpus cavernosum with primary mesenchymal stem cells in vitro

Various methods have been used to reconstruct the penis. The objective of this study was to investigate the feasibility of constructing engineered corpus cavernosum with primary mesenchymal stem cells (MSCs) in a rabbit model in vitro. Acellular corporal matrices (ACMs) were obtained from adult rabbit penile tissues through an established decellularization procedure. MSCs were separated, purified, and then seeded on ACMs to construct engineered corpus cavernosum. The seeded ACMs were subsequently cultured in an incubator for 14 days. Histological analyses showed that MSCs seeded on the ACMs had proliferated and were well distributed. Detection of CD31, vWF, smooth muscle actin (SMA), and myosin protein as well as vWF and myosin mRNA revealed that the MSCs had differentiated into endothelial cells and smooth muscle cells. In addition, cell morphology of the engineered corpus cavernosum was directly observed by transmission electron microscopy. This study demonstrated that engineered corpus cavernosum could be successfully constructed using primary MSCs in vitro. This technology represents another step towards developing engineered corpus cavernosum in vitro.

Emerging tools for erectile dysfunction: a role for regenerative medicine

Erectile dysfunction (ED) is the most common sexual disorder reported by men to their health-care providers and the most investigated male sexual dysfunction. Currently, the treatment of ED focuses on 'symptomatic relief' of ED and, therefore, tends to provide temporary relief rather than providing a cure or reversing the cause. The identification of a large population of "difficult-to-treat" patients has triggered researchers to identify novel treatment approaches, which focus on cure and restoration of the underlying cause of ED. Regenerative medicine has developed extensively in the past few decades and preclinical trials have emphasized the benefit of growth factor therapy, gene transfer, stem cells and tissue engineering for the restoration of erectile function. Development of clinical trials involving immunomodulation in postprostatectomy ED patients and the use of maxi-K channels for gene therapy are illustrative of the advances in the field. However, the search for novel treatment targets and a wealth of preclinical studies represent a dynamic and continuing field of enquiry.

Regenerative medicine in urology

The term 'regenerative medicine' encompasses strategies for restoring or renewing tissue or organ function by: (i) in vivo tissue repair by in-growth of host cells into an acellular natural or synthetic biomaterial, (ii) implantation of tissue 'engineered'in vitro by seeding cultured cells into a biomaterial scaffold, and (iii) therapeutic cloning and stem cell-based tissue regeneration. In this article, we review recent developments underpinning the emerging science of regenerative medicine and critically assess where successful implementation of novel regenerative medicine approaches into urology practice might genuinely transform the quality of life of affected individuals. We advocate the need for an evidence-based approach supported by strong science and clinical objectivity.