The Liver is one of the largest organs in the body weighing about 1.5 kgs. It is located on the right side of the abdomen, behind the right rib cage. It has two lobes, the larger right lobe and the smaller left lobe. It performs almost 500 functions- crucially the synthesis of various proteins like albumin, blood clotting proteins, regulation of metabolism as well as the metabolism of many drugs. It has immune functions too. Excretory functions include the excretion of bile from the liver to the intestines via the bile duct. Bile is important for the digestion of fats and the fat-soluble vitamins A, D, E & K. It excretes and detoxifies many substances like drugs, as well as ammonia which is produced during the metabolism of proteins.
Dr. Parimal Lawate, Gastroenterologist/Director Department of Gastro Science in Jehangir Hospital shares, “The prime causes of liver disease are alcohol, viruses, diabetes, obesity & some metabolic disorders. If the damage persists, the liver shrinks, becomes hard (fibrosis) and finally cirrhotic (disorganized structure of liver cells & blood vessels). Once cirrhotic, the liver loses its capacity to regenerate and new liver tissue cannot be formed. In acute liver disease, the damaging agent causes temporary damage leading to the loss of liver cells (hepatocytes). On removing the damaging agent, the liver gets back to full normal function thanks to the self-healing (regenerative) capacity of the liver. In chronic liver damage, however, the damage continues in a persistent manner. For example, a patient who consumed excess alcohol for years. In such instances the liver becomes cirrhotic, losing its regenerative capacity.”
Consequently, the liver is unable to function optimally. This typically leads to symptoms like swelling of the body (due to reduced albumin synthesis), bruising and bleeding (reduced formation of clotting factors) & altered consciousness (failure to detoxify ammonia).
In Greek mythology, Prometheus stole fire from the gods & gave it to humans. For doing this he was punished by being tied to a rock and by allowing eagles to feed on his liver during the daytime so that it regrew every night- ready for the eagle’s next meal.
The liver is the only organ in the human body that has the capacity to regenerate. This is akin to starfish and lizards. Starfish are able to regrow their whole body from a single arm, while lizards can grow their tailback. This is called regeneration.
Regeneration has now become an important part of research for two reasons:
1. In many patients who have liver tumours, a fairly large portion of the liver must be removed surgically (liver resection).
2. In the setting of Liver transplant, the diseased liver of a patient with cirrhosis (the recipient) is removed completely and replaced by a liver from another person (the donor).
The donour and recipient should have matching blood groups.
If the donor is brain dead (Deceased Donor Liver Transplant: DDLT), the whole liver is removed and implanted into one or rarely two recipients. If the donor happens to be a blood group matched relative (Living Donor Liver Transplant : LDLT) it follows that the whole liver of the donor cannot be removed. The larger right lobe is often removed and implanted into the recipient. The remnant liver in the donor, naturally should regenerate, so that the donor’s liver can function optimally. Conversely, the newly implanted liver too must grow into a fully functioning liver in the recipient. The concept of a Functional Liver Reserve (FLR) is now used to assess the remnant liver reserve in the live donor and patient who has had a liver resection. Advanced imaging techniques like a CT scan volumetry can now ensure an adequate FLR for the donor and the resected patient to survive.
Incredibly, the liver can regenerate to its full size in two to three weeks! Various hormones and growth factors initiate the pathways that allow the genetic machinery to rapidly form new liver cells or hepatocytes. Interestingly, the newly formed cells need scaffolding to hold on to; along with new blood vessels to sustain them and new bile ductules to expel waste products.
Only then can the newly formed cells function as a cooperative unit and restore a new, healthy, fully functioning liver, giving the patient a new lease on life!
