The liver, located in the upper right abdomen, plays a central role in maintaining overall body health. Its primary functional cells are hepatic parenchymal cells, or hepatocytes, which constitute about 70-80% of the liver’s mass. These cells are the main working units of the liver, responsible for a wide array of biochemical processes.
The Liver’s Workhorses
Hepatic parenchymal cells perform diverse and complex functions to maintain the body’s internal balance. They are involved in metabolism, processing carbohydrates, fats, and proteins. For example, these cells synthesize glucose from non-carbohydrate sources like amino acids, a process called gluconeogenesis that regulates blood sugar. They also form fatty acids from carbohydrates and synthesize triglycerides, assembling and exporting lipoproteins like VLDL and HDL.
These cells are also specialized in detoxification, breaking down harmful substances. This includes metabolizing drugs, alcohol, and various toxins, converting them into less harmful forms for excretion. A key detoxification function involves modifying ammonia into urea for excretion.
Hepatic parenchymal cells produce bile, a digestive fluid that aids in fat breakdown and absorption in the small intestine, and helps remove waste products. They also synthesize numerous proteins, such as albumin, which regulates fluid balance, and various clotting factors necessary for blood coagulation.
What Harms Hepatic Parenchymal Cells
Several factors can damage hepatic parenchymal cells, disrupting their normal operations. Viral infections, particularly hepatitis B and C, are common culprits, causing persistent inflammation. Hepatitis A can also lead to liver inflammation, though it is often milder.
Excessive alcohol consumption is another cause of damage, leading to alcoholic liver disease, which can manifest as alcoholic hepatitis or cirrhosis. Certain medications, especially in overdose situations like acetaminophen, can induce liver injury.
Non-alcoholic fatty liver disease (NAFLD), characterized by fat accumulation, can progress to non-alcoholic steatohepatitis (NASH), causing inflammation and damage. Autoimmune conditions, such as autoimmune hepatitis, involve the body’s immune system attacking its own liver cells.
Metabolic disorders like hemochromatosis (excessive iron accumulation) and Wilson’s disease (copper buildup) can also harm these cells. Exposure to environmental toxins, including heavy metals, can induce oxidative stress and mitochondrial dysfunction.
How Damage Affects Liver Health
When hepatic parenchymal cells are damaged, the liver’s functions are impaired. This injury can trigger inflammation (hepatitis) or fat accumulation (steatosis). Persistent damage leads to scar tissue formation, known as fibrosis.
Severe scarring can develop into cirrhosis, replacing normal liver tissue with non-functional scar tissue. This obstructs blood flow, leading to increased pressure in the portal vein system (portal hypertension).
These conditions reduce the liver’s capacity to detoxify, synthesize proteins, and produce bile. Symptoms include fatigue, jaundice, abdominal discomfort, and fluid retention.
The Liver’s Remarkable Ability to Heal
The liver possesses a capacity for regeneration, allowing its hepatic parenchymal cells to multiply and replace damaged tissue. Even after significant tissue loss, such as a partial hepatectomy where up to 70% of the liver is removed, the remaining liver can regrow to nearly its original size within weeks.
This regenerative process involves the proliferation of existing hepatocytes, which divide to restore liver mass. This ensures the liver can recover from various injuries.
However, this healing ability has limits, particularly in cases of chronic and severe damage like advanced cirrhosis, where extensive scarring can impede effective regeneration. The healing process is supported by removing the damaging agent, such as stopping alcohol consumption or treating viral infections. Maintaining a healthy lifestyle, including a balanced diet and regular exercise, also supports liver health.