Human biology - liver regeneration after laprascopic segmentectomy

Question

I am trying to understand to what extent human patients can regenerate liver mass after laprascopic segmentectomy: what part of liver will be regenerated and how fully.

My work with sources is not very good, but here is what I have found so far:

Michalopoulos, G. K., & DeFrances, M. (2005). Liver regeneration. Advances in biochemical engineering/biotechnology, 93, 101–134.:

"Following surgical resection of the two anterior hepatic lobes of rodents accounting for ~68% of liver tissue, the remaining lobes undergo compensatory hyperplasia restoring the liver to its original presurgical mass" However, the article notes that:

"..PHx model doesn't apply to most common clinical scenarios.. patients who must regenerate liver mass after hepatic surgery often have cirrhosis, hepatic viral infection, steatosis.."

From this question (If the liver can regenerate why can alcohol abuse permanently damage it?) I gathered that only healthy hepatic tissue in liver can regenerate: the epithelial tissue. Cytotoxic drugs like alcohol lead to steatosis and cirrhosis. Cirrhosis is the substitution of epithelial tissue by connective tissue. This connective tissue not only can't regenerate: it doesn't perform hepatic functions.

Assuming that the patient has otherwise healthy liver tissue, if a laprascopic resection of liver segment Sg3 has been performed, what part of the liver will be regenerated?

Thank you in advance, and I would be happy to edit/update my question with more info.

Answer 1

The healthy human liver has remarkable ability to regenerate in only a few months after resection.

In a study of 98 healthy donors who underwent left lobectomy donation, Chen and colleagues found that donors started with a mean liver volume of 1154 cm³, had an average of 276 cm³ removed, and then had an average liver volume of 1065 cm³ 6 months later (2006. PMID 17100722). Thus, on average, 68% of the donated liver volume had regenerated in those 6 months.

In my research, I was unable to find a systematic study of the location or direction of regeneration. Although hyperplasia appears to be the mechanism of regeneration (Marongiu et al 2017. PMCID 5352916), intuitively, we should suspect that the remaining liver will increase in volume rather than the removed lobe suddenly re-spouting somehow like a salamander's tail.

This set of 3 CT scans from a study by Esschert and colleagues provides anecdotal evidence for this intuition (2009. PMCID 2710489):

^{Figure 1 from Esschert et al 2009 showing post-operative liver regeneration after 3 months, available here.}

In addition to the return of liver volume, donors also have no evidence of decreased liver function at least as long as 5 years post-operatively (Murad et al 2016. 27144969).

The above studies do not appear to delineate whether surgeries were performed open or laparoscopically, but I suspect that any effect of the less invasive laparoscopic procedure would only improve regeneration.

As an interesting aside, even after performing as many as 4 separate resections for patients with recurring hepatocellular carcinoma, Yamaguchi and colleagues found continued high rates of liver regeneration (over 90%) (Yamaguchi et al 2018. PMID 29947985).