Does a transplanted area become denervated?

From the Guidelines

Yes, a transplanted area becomes denervated during the transplantation process, resulting in the loss of direct neural connections between the transplanted organ and the recipient's central nervous system. This denervation occurs because the nerves connecting the organ to the central nervous system are severed during the harvesting process, affecting all transplanted organs, including the heart, liver, kidney, lung, and pancreas 1. The lack of nerve connections means the transplanted organ cannot receive direct neural signals from the recipient's brain and spinal cord. Despite this denervation, most transplanted organs can still function effectively because many organ functions are regulated by hormonal signals, local control mechanisms, and intrinsic properties of the organ itself. For example, a transplanted heart can still pump blood effectively due to its intrinsic pacemaker activity, though it typically beats at a higher resting rate due to the absence of vagal tone.

Some studies have shown that denervation can lead to various complications, such as biliary complications in liver transplant patients, including bile leaks, bilomas, anastomotic strictures, and Sphincter of Oddi dysfunction 1. These complications can be related to the denervation of the transplanted organ and the subsequent loss of neural control over its functions. However, with careful monitoring and specialized medical management, transplant recipients can still achieve a good quality of life and functional status.

Key points to consider include:

• Denervation of the transplanted organ occurs during the harvesting process
• Loss of direct neural connections between the transplanted organ and the recipient's central nervous system
• Transplanted organs can still function effectively due to hormonal signals, local control mechanisms, and intrinsic properties
• Denervation can lead to various complications, such as biliary complications in liver transplant patients
• Careful monitoring and specialized medical management are necessary to achieve a good quality of life and functional status in transplant recipients.

From the Research

Transplanted Area Denervation

• A transplanted area can become denervated due to the transplantation procedure, as seen in islet transplantation where grafted islets become denervated 2.
• However, reinnervation of the transplanted area is possible, as shown in a study where islet grafts in the liver, spleen, and under the kidney capsule in rats became reinnervated following transplantation 2.
• Denervation can also occur in other types of transplants, such as heart transplants, where the transplanted heart exhibits an up-regulation of functional beta 2-adrenergic receptors 3.
• In some cases, denervation can lead to complications, such as airway obstruction in lung transplants, which can be caused by operative denervation rather than immunosuppression or rejection 4.

Reinnervation of Transplanted Areas

• Reinnervation of transplanted areas can occur through the growth of new nerve fibers, as seen in a study where muscle reinnervation was achieved by transplanting embryonic ventral spinal cord cells into a nearby peripheral nerve 5.
• The rate and extent of reinnervation can vary depending on factors such as the type of transplant, the location of the transplant, and the presence of growth factors 2, 5.
• Reinnervation can lead to functional recovery of the transplanted area, as seen in a study where reinnervated muscles showed improved contraction thresholds and muscle area 5.

Effects of Denervation on Transplanted Areas

• Denervation can lead to changes in the functional properties of the transplanted area, such as altered heart rate responses to edrophonium in cardiac transplant patients 6.
• Denervation can also lead to histologic changes, such as those seen in lung transplants where denervation causes small airway obstruction 4.
• The effects of denervation on transplanted areas can be influenced by various factors, including the type of transplant, the duration of denervation, and the presence of underlying diseases 3, 6.