A biomechanical assessment of tissue-engineered polymer neo-uteri after orthotopic implantation.

OBJECTIVE: To assess the in vivo biomechanical maturation of tissue-engineered neo-uteri that have previously supported live births in a rabbit model. DESIGN: Nonclinical animal study. SETTING: University-based research laboratory. ANIMALS: Eighteen adult female rabbits. INTERVENTION: Biodegradable poly-DL-lactide-co-glycolide-coated polyglycolic acid scaffolds seeded with autologous uterine-derived endometrial and myometrial cells. Nonseeded scaffolds and seeded, tissue-engineered neo-uteri were implanted into one uterine horn of rabbits for 1, 3, or 6 months, excised, and biomechanically assessed in comparison to native uterine tissue. MAIN OUTCOME MEASURES: Tensile stress-relaxation testing, strain-to-failure testing, and viscoelastic modeling. RESULTS: By evaluating the biomechanical data with several viscoelastic models, it was revealed that tissue-engineered uteri were more mechanically robust than nonseeded scaffolds. For example, the 10% instantaneous stress of the tissue-engineered neo-uteri was 2.1 times higher than the nonseeded scaffolds at the 1-month time point, 1.6 times higher at the 3-month time point, and 1.5 times higher at the 6-month time point. Additionally, as the duration of implantation increased, the engineered constructs became more mechanically robust (e.g., 10% instantaneous stress of the tissue-engineered neo-uteri increased from 22 kPa at 1 month to 42 kPa at 6 months). Compared with native tissue values, tissue-engineered neo-uteri achieved or surpassed native tissue values by the 6-month time point. CONCLUSION: The present study evaluated the mechanical characteristics of novel tissue-engineered neo-uteri that have previously been reported to support live births in the rabbit model. We demonstrate that the biomechanics of these implants closely resemble those of native tissue, giving further credence to their development as a clinical solution to uterine factor infertility.

Chemokine Therapy in Cats With Experimental Renal Fibrosis and in a Kidney Disease Pilot Study.

Background: Chronic tubulointerstitial fibrosis is a common final pathway leading to end stage kidney disease in cats and has no effective treatment. The use of cell-based molecules to treat kidney fibrosis may be a promising approach. The objectives were to test the effects of intra-renal chemokine CXCL12 injection in a pre-clinical cat model of unilateral ischemia/reperfusion (I/R)-induced kidney fibrosis and then, within a clinical pilot study, test the safety/feasibility of CXCL12 injection in cats that might have early chronic kidney disease (CKD). Methods: Pre-clinical: Thirty cats received intra-renal injection of 100, 200, or 400 ng of recombinant human CXCL12, or sterile saline, into the I/R kidney 70 days post-injury, or were non-injured, non-injected controls (n = 6/group). Kidney collagen content was quantified 4 months post-treatment using Masson's Trichrome and Picrosirius Red (PSR) stained tissues. In a separate study (n = 2) exploring short-term effects of CXCL12, 200 ng CXCL12 was injected into I/R kidneys and then harvested either 30 min (n = 1) or 1 month (n = 1) post-injection. Kidney concentrations of CXCL12, matrix metalloproteinase 1 (MMP-1), and lysyl oxidase-like enzyme 2 (LOXL-2) were quantified via ELISA. Clinical Pilot: 14 client-owned cats with potential early kidney disease received a single-treatment, bilateral intra-renal injection of 200 ng CXCL12 (n = 7), or received no injection (n = 7). Blood/urine samples were collected monthly for 9 months to assess renal function and CKD staging. Results: Pre-clinical: I/R increased the affected kidney collagen content, which both mid and high doses of CXCL12 restored to normal (ps < 0.05 vs. untreated). I/R increased collagen fiber width, which both mid and high doses of CXCL12 restored to normal (p < 0.001 vs. untreated). Early changes in kidney MMP-1, associated with collagen breakdown, and subsequent decreases in LOXL-2, associated with collagen cross-linking, in response to CXCL12 treatment may contribute to these findings. Clinical Pilot: Bilateral intra-renal injection of CXCL12 using ultrasound guidance in cats with CKD was feasible and safe in a general practice clinical setting with no obvious side effects noted during the 9-month follow-up period. Conclusions: Intra-renal injection of CXCL12 may prove to be an effective treatment for kidney fibrosis in cats with CKD. Additional mechanistic and clinical evaluations are needed.

A tissue-engineered uterus supports live births in rabbits.

Bioengineered uterine tissue could provide a treatment option for women with uterine factor infertility. In large animal models, reconstruction of the uterus has been demonstrated only with xenogeneic tissue grafts. Here we use biodegradable polymer scaffolds seeded with autologous cells to restore uterine structure and function in rabbits. Rabbits underwent a subtotal uterine excision and were reconstructed with autologous cell-seeded constructs, with nonseeded scaffolds or by suturing. At 6 months postimplantation, only the cell-seeded engineered uteri developed native tissue-like structures, including organized luminal/glandular epithelium, stroma, vascularized mucosa and two-layered myometrium. Only rabbits with cell-seeded constructs had normal pregnancies (four in ten) in the reconstructed segment of the uterus and supported fetal development to term and live birth. With further development, this approach may provide a regenerative medicine solution to uterine factor infertility.

Nonhuman primate model of persistent erectile and urinary dysfunction following radical prostatectomy: Feasibility of minimally invasive therapy.

OBJECTIVE: Persistent urinary incontinence (UI) and/or erectile dysfunction (ED) occur in 30-50% of post-radical prostatectomy patients regardless of nerve sparing approaches. Identification of potential treatment options for these patients will require testing in an animal model that develops these chronic conditions. The objective was to characterize a nonhuman primate (NHP) model of persistent post-prostatectomy ED and UI and then test the feasibility of periurethral injection of the chemokine CXCL-12. METHODS: Ten adult male cynomolgus monkeys were used. Two were used for study of normal male nonhuman primate genitourinary anatomy. Five were used for measures of sexual behavior, peak intra-corporal pressure (ICP), abdominal leak point pressures (ALPP) 3 and 6-months post open radical prostatectomy (ORP). Three additional ORP animals received ultrasound-guided peri-urethral injection of chemokine CXCL12 6 weeks after ORP, and UI/ED evaluated for up to 3 months. RESULTS: The anatomy, innervation, and vascular supply to the prostate and surrounding tissues of these male NHPs are substantially similar to those of human beings. ORP resulted in complete removal of the prostate gland along with both neurovascular bundles and seminal vesicles while permitting stable restoration of vesico-urethral patency. ORP produced sustained (6 months) decreases in ALPP, ICP's, and sexual function. Transurethral injection of chemokine CXCL12 was feasible and had beneficial effects on erectile and urinary function. CONCLUSIONS: ORP in NHPs produced persistent erectile and urinary tract dysfunction. Periurethral injection of CXCL-12 was feasible and improved both urinary incontinence and erectile dysfunction and suggests that this model can be used to test new approaches for both conditions.

Kidney regeneration: Where we are and future perspectives.

In 2012, about 16487 people received kidney transplants in the United States, whereas 95022 candidates were on the waiting list by the end of the year. Despite advances in renal transplant immunology, approximately 40% of recipients will die or lose graft within 10 years. The limitations of current therapies for renal failure have led researchers to explore the development of modalities that could improve, restore, or replace the renal function. The aim of this paper is to describe a reasonable approach for kidney regeneration and review the current literature regarding cell sources and mechanisms to develop a bioengineering kidney. Due to kidneys peculiar anatomy, extracellular matrix based scaffolds are rational starting point for their regeneration. The perfusion of detergents through the kidney vasculature is an efficient method for delivering decellularizing agents to cells and for removing of cellular material from the tissue. Many efforts have focused on the search of a reliable cell source to provide enrichment for achieving stable renal cell systems. For an efficient bioengineered kidney, these cells must be attached to the organ and then maturated into the bioractors, which simulates the human body environment. A functional bioengineered kidney is still a big challenge for scientists. In the last ten years we have got many improvements on the field of solid organ regeneration; however, we are still far away from the main target. Currently, regenerative centers worldwide have been striving to find feasible strategies to develop bioengineered kidneys. Cell-scaffold technology gives hope to end-stage renal disease patients who struggle with morbidity and mortality due to extended periods on dialysis or immunosupression. The potential of bioengineered organ is to provide a reliable source of organs, which can be refunctionalized and transplanted.

Histological changes induced by Polyglycolic-Acid (PGA) scaffolds seeded with autologous adipose or muscle-derived stem cells when implanted on rabbit bladder.

PURPOSE: To evaluate the morphological and histological changes induced by PGA scaffold seeded with autologous adipose or muscle derived stem cells implanted on rabbit bladder wall. MATERIAL AND METHODS: Adipose derived stem cells (ADSCs) were obtained from the inguinal fat of eight rabbits and muscle derived stem cells (MDSCs) from the anterior tibial muscle of other eight rabbits. After culture and isolation, the cells were stained with Vybrant Red CM DiI and then implanted at third passage. Two PGA scaffolds were implanted on the bladder submucosa of each animal. On the right bladder side was implanted unseeded PGA scaffold while on the left side was implanted ADSCs or skeletal MDSCs seeded PGA scaffold. ADSCs were implanted in eight animals and MDSC in other eight animals. The animals were sacrificed at four and eight weeks. Histological evaluation was performed with Hematoxylin and Eosin, Masson's Trichrome and smooth muscle α-actin. RESULTS: We observed a mild inflammatory response in all the three groups. Seeded scaffolds induced higher lymphocytes and lower polimorphonuclear migration than controls. Fibrosis was more pronounced in the control groups. Smooth muscle α-actin was positive only in ADSC and MDSC seeded scaffolds. At four and eight weeks ADCSs and skeletal MDSCs labeled cells were found at the implant sites. CONCLUSIONS: The implantation of PGA scaffolds seeded with ADSC and MDSC induced less fibrosis than control and smooth muscle regeneration.