Genitourinary vascularized composite allotransplantation: a review of penile transplantation

Exploring Costimulatory Blockade-Based Immunologic Strategies in Transplantation: Are They a Promising Immunomodulatory Approach for Organ and Vascularized Composite Allotransplantation?

The field of transplantation, including the specialized area of vascularized composite allotransplantation (VCA), has been transformed since the first hand transplant in 1998. The major challenge in VCA comes from the need for life-long immunosuppressive therapy due to its non-vital nature and a high rate of systemic complications. Ongoing research is focused on immunosuppressive therapeutic strategies to avoid toxicity and promote donor-specific tolerance. This includes studying the balance between tolerance and effector mechanisms in immune modulation, particularly the role of costimulatory signals in T lymphocyte activation. Costimulatory signals during T cell activation can have either stimulatory or inhibitory effects. Interfering with T cell activation through costimulation blockade strategies shows potential in avoiding rejection and prolonging the survival of transplanted organs. This review paper aims to summarize current data on the immunologic role of costimulatory blockade in the field of transplantation. It focuses on strategies that can be applied in vascularized composite allotransplantation, offering insights into novel methods for enhancing the success and safety of these procedures.

Genitourinary vascularized composite allotransplantation for gender affirmation in trans men: An anatomical feasibility study

PURPOSE

Gender affirmation in trans men requires multiple staged procedures. The final masculinizing step involves phalloplasty or metoidioplasty and further incorporation of penile and testicular prostheses. However, these are functionally suboptimal and associated with high complication rates. Therefore, we sought to investigate the anatomical feasibility of one-stage genitourinary vascularized composite allotransplantation (GUVCA) for such gender-affirming surgeries.

METHODS

Twenty fresh cadaveric dissections were performed to delineate the neurovascular anatomy of the proposed GUVCA. Specifically, in donors (n = 14), besides the penis and scrotum, the GUVCA included an inferior bladder patch with the urinary sphincter, prostate, seminal vesicles, as well as a strip of the pubic bone. In trans men recipients, osteotomies of the pubic bone to match that of the donor GUVCA were required. Five cadaveric GUVCA transplants were then performed to simulate one-stage gender affirmation surgery.

RESULTS

The GUVCA required (1) vascular anastomoses between the recipient's deep inferior epigastric, external pudendal, and superficial circumflex iliac (or superficial inferior epigastric) vessels to the donor's internal pudendal, external pudendal and genitofemoral vessels respectively; (2) neurosynthesis between the recipient pudendal and dorsal clitoral nerves to the donor pudendal and genitofemoral nerves; and (3) urinary bladder anastomosis at the bladder neck, upstream of the urinary sphincter. Average donor measurements (length (cm), diameter (mm)) were: external pudendal artery (2.5, 2.0) and vein (2.0, 3.5), internal pudendal artery (15.0, 4.0), pudendal (15.0, 3.0) and genitofemoral nerves (8.0, 2.0).

CONCLUSIONS

We have described the anatomical basis for a one-stage GUVCA in trans masculine genitourinary reconstruction.

Functional and surgical outcomes after phalloplasty in cis men

PURPOSE

Evaluate the surgical outcomes along with a comprehensive assessment of functional outcomes in cis men (non-trans) who underwent phalloplasty.

METHODS

All consecutive cis men who underwent phalloplasty from 2008 to 2018 for penile insufficiency due to various causes were included. These underwent phalloplasty by either a radial forearm free flap (RFFF) or suprapubic phalloplasty (SPP). Data were collected from medical files. A questionnaire was sent a minimum of 1 year after surgery to each patient to evaluate sexual function and self-esteem, satisfaction with genitals, and urinary function.

RESULTS

Among the 19 patients included, 12 underwent RFFF and 7 SPP; 25% of those who had RFF and 14.3% of those with SPP had a Clavien-Dindo ≥ 2 complication. A total of 16 patients had a urethroplasty procedure, 50.0% of whom had a Clavien-Dindo ≥ 2 complication. Penile prostheses were implanted in 14 patients; 64.3% of whom had a complication. Seven patients answered the questionnaire (36.8%); the relationship satisfaction score was 89.5/100 and the confidence score was 100/100. Among the 5 patients who had a sexual relationship, all reported having a lot of pleasure during sexual intercourse and reached orgasm at least "regularly". At least 66.7% of the patients were "satisfied" or "very satisfied" about the size and the appearance of genitals. Among the 5 patients who answered questions regarding urinary function, 60.0% had standing micturition, and 80.0% reported being comfortable in public toilets.

CONCLUSION

Despite the high frequency of complications and the need for revision surgery, phalloplasty seems to allow a satisfying psychosexual and urinary functions for cis men suffering from penile insufficiency.

Video Messaging to Increase Vascularized Composite Allograft Donation Willingness in United States Military Veterans

Expansion of vascularized composite allograft (VCA) transplantation depends on the public's willingness to donate VCA organs, including face, extremities, and genitourinary organs. This study evaluated the effectiveness of video messaging on VCA donation willingness in US military veterans, a key stakeholder in VCA transplantation.

Methods

Participants (n = 556) were randomized to 1 of 3 VCA video messaging interventions (informational, testimonial, or blended), a general (non-VCA) organ donation video message, or a control (nondonation) video message. Questionnaires were completed at pre- and postintervention and at 3-wk follow-up.

Results

Veterans exposed to any VCA video messaging were more likely to express VCA donation willingness (69%, n = 203/296) than those exposed to general donation messaging (53%, n = 47 of 89; P = 0.006) or No Donation Messaging (37%, n = 36 of 97; P < 0.001). A significantly higher proportion of participants who received Blended VCA Messaging were willing to be VCA donors, compared with the Informational VCA Messaging group (79% versus 61%, P = 0.006). Each VCA messaging video resulted in a significant pre- to postintervention increase in the proportion of participants willing to donate their own face, hands, and legs (P < 0.03).

Conclusions

Brief educational videos focused on VCA transplantation can have a demonstrable and verifiable impact on rates of VCA donation willingness in veterans.

Ethical stakes of penile transplantation: A literature review

BACKGROUND

Vascularized composite allotransplantation has become an alternative reconstruction technique for patients with a severe loss of substance. Today, five human penile transplantations have been reported. The objective of this literature review is to offer an updated overview of the technical and ethical questions surrounding penile transplantation compared with conventional phalloplasty.

MATERIAL AND METHODS

A systematic review was conducted of the literature from 2000 to 2020. A search of PubMed was performed using the keywords: "penile transplantation," "penis transplantation," and "penile vascularized composite allotransplantation." The criteria for the analysis were the type of study, surgical techniques, and ethical concerns.

RESULTS

Thirty-six articles were selected. These articles include reviews, case report, editorials, and preclinical studies. The first article was published in 2003, but the number of articles has increased after the second human transplantation in South Africa in 2014. Surgical techniques and the medication management specific to each team were successful in the 5 transplant cases, but several complications were noted.

CONCLUSION

Two decades of successful penile transplantations have proven the technique to be a viable solution to treat a penile amputation, allowing for a better esthetic and sensitive outcome paired with the possibility of natural urinary and erectile functions. Psychological impact of penile transplantation, selection of patients, complications of immunosuppressive therapies, and surgical technicity are the biggest penile transplantation challenges. Further experimental studies are necessary to produce standardized protocols to safely include penile transplantation in the conventional treatment of a penile amputation.

Induction of Endotoxin Tolerance Delays Acute Rejection in a Hindlimb Transplantation Model in Rats

BACKGROUND

Acute rejection is seen in 85 percent of composite vascular allogeneic transplants despite long-term immunosuppression. Recently, it was reported that the induction of endotoxin tolerance prolonged heart allograft survival in mice. However, it produced side effects in all the animals secondary to the inflammatory reaction. Galactomannan has shown endotoxin tolerance without this side effect in vitro. The authors hypothesized that galactomannan-induced endotoxin tolerance delays acute rejection in vascular allogeneic transplantation without the side effects produced by lipopolysaccharide.

METHODS

Twenty-four rat hindlimb transplants were divided into four groups according to the preconditioning received: control, lipopolysaccharide (0.16 ml/kg), galactomannan 72 hours before (galactomannan-72) (8 ml/kg), and galactomannan 24 hours before (galactomannan-24) (8 ml/kg). Median acute rejection time, weight loss, and diarrheal episodes were monitored. Blood samples were collected at 0, 7, 21, 30, 45, and 60 days. Plasma cytokines (i.e., tumor necrosis factor alpha, interferon gamma), peripheral chimerism, and lymphocyte percentages were analyzed.

RESULTS

Median allograft survival was 40 days (range, 40 to 44 days) in the control group, 68 days (range, 61 to 71 days) in the lipopolysaccharide group, and 70 days (range, 69 to 73 days) in both galactomannan groups (p = 0.001). Weight loss was higher in the lipopolysaccharide group (p < 0.001), as was the 83.3 percent rate of diarrheal episodes (control, 0 percent, p = 0.015; galactomannan-72, 0 percent, p = 0.015; and galactomannan-24, 16.7 percent, p = 0.02). Preconditioned rats had higher peripheral blood chimerism (lipopolysaccharide, 2.30 ± 0.13 percent; galactomannan-72, 2.63 ±1.46 percent; and galactomannan-24, 2.47 ± 0.19 percent) compared to the control group (2.06 ± 0.36 percent) (lipopolysaccharide, p = 0.04; galactomannan-72, p = 0.002; and galactomannan-24, p = 0.002).

CONCLUSIONS

Induction of endotoxin tolerance delays acute rejection in the rat hindlimb transplantation model. Galactomannan preconditioning has no lipopolysaccharide side effects and was equally effective in delaying acute rejection.

CLINICAL RELEVANCE STATEMENT

The contributions of this experimental work are very incipient. Although the use of galactomannan in clinical practice requires more studies to assess its safety, there is no doubt that immunomodulation may be one of the responses that solve the problem of long-term immunosuppression.

Vascularized composite allotransplantation of the penis: current status and future perspectives

Given the multifunctional role of the penis in daily life, penile loss can be a physically and emotionally devastating injury. Options to restore penile loss have traditionally relied on autogenous free flap, local flaps, and skin grafts. These techniques provide satisfactory outcomes but carry high rates of urologic and prosthesis-related complications. Vascularized composite allotransplantation may offer a novel solution for these patients through reconstruction with true penile tissue. Still, penile transplants pose ethical, logistical, and psychosocial challenges. These obstacles are made more complex by the limited cases detailed in published literature. A review of the literature was conducted to assay current practices for penile reconstruction. Most modern complex penile reconstructions utilize autogenous pedicled or free tissue flaps, which may be harvested from a variety of donor sites. A total of five penile transplants have been described in the literature. Of these, four report satisfactory outcomes. The advent of genital allotransplantation has recently broadened the landscape of treatment for penile loss. Reconstruction using true penile tissue through vascularized penile allotransplantation has the possibility to engender increased penile function, sensation, and overall quality of life.

Attitudes Toward Organ, Tissue, and Vascularized Composite Allograft (VCA) Donation and Transplantation: A Survey of United States Military Veterans

BACKGROUND

There are 20 million living US armed forces veterans; however, the organ donation attitudes of veterans have not been examined.

METHODS

Over a 17-month period, a convenience sample of 1517 veterans in New England completed a survey to assess attitudes about organ, tissue, and vascularized composite allograft (VCA) donation.

RESULTS

Most veterans (96%) supported the donation of organs and tissue for transplantation, and 59% were registered as an organ and tissue donor. Being younger (adjusted odds ratio [aOR]: 0.960.970.98; P = 0.01), female (aOR: 1.061.462.03; P = 0.02), non-Hispanic white (aOR: 1.302.073.30; P = 0.01), Hispanic (aOR: 1.282.434.61; P = 0.01), and having more trust that the transplant process is fair and equal (aOR: 1.191.401.65; P = 0.01) were predictive of donor registration. Also, most veterans were willing to donate their face (57%), hands/arms (81%), legs (81%), penis (men: 61%), and uterus (women: 76%) at time of death; donation willingness was higher for upper and lower limbs than for face or genitourinary organs (P < 0.001). Those unwilling to donate VCA organs expressed concerns about identity loss, psychological discomfort of self and others, body integrity, funeral presentation, and religious beliefs. Most (54%) felt that VCA donation should require permission of legal next-of-kin at the time of one's death, even if the decedent was a registered donor.

CONCLUSIONS

There is a high level of support for organ, tissue, and VCA transplantation and donation among veterans, despite limited educational campaigns targeting this population. There is high potential among veterans to further increase donor registry enrollment and raise awareness about VCA benefits for severely injured service members.

Intergender Hand Transplant: A Sex Congruent Hand Transformation

ABSTRACT

Hand and upper-extremity transplantation restore severely damaged limbs that cannot be repaired with conventional surgical techniques. Over the past 20 years, more than 200 vascularized composite allotransplantations have been performed worldwide, among them 7 were cases of sex unmatched hand transplants. The long term effects of recipient sex hormones and nerve regeneration on the sexually dimorphic physical features of donor upper extremity have not been described previously. We report a case of sex congruent transformation of hand morphology in an intergender hand transplant.

Limitations and limits and of vascularized composite allotransplantations: can we reach the holy grail?

PURPOSE OF REVIEW

In recent times, vascularized composite allotransplantation (VCA) have been gaining more attention and applications. Currently, VCA are at the highest level of the reconstruction pyramid, and thus the effects expected after them are intended to outweigh what the 'classical' reconstructive surgery can offer us, including even the most advanced microsurgical techniques.

RECENT FINDINGS

Over 40 patients have received a partial or full-face transplant. Others have received penis, uterus, larynx, abdominal wall, and lower extremity transplants. Each type of VCA has its own problems and limitations. However, resolving the limits defined by immunosuppression and improved donor selection would revolutionize all of them.

SUMMARY

Defining the limits and limitations of given procedures will not only allow for better preparation of transplant teams but will also help in determining the direction of future research.

The histocompatibility and immunogenetics of hand transplantation

This short review will be concerned with the literature that has developed connected with the immunogenetic and tissue compatibility aspects of hand transplantation and will also draw on connected work in the more general area of vascularized composite allotransplantation (VCA) which includes face, abdominal wall uterus and larynx.