A scientist revisits the atrophy-hypertrophy complex: hepatic apoptosis and regeneration

Current strategies to induce liver remnant hypertrophy before major liver resection

Hepatic resection is the gold standard for patients affected by primary or metastatic liver tumors but is hampered by the risk of post-hepatectomy liver failure. Despite recent improvements, liver surgery still requires excellent clinical judgement in selecting patients for surgery and, above all, efficient pre-operative strategies to provide adequate future liver remnant. The aim of this article is to review the literature on the rational, the preliminary assessment, the advantages as well as the limits of each existing technique for preparing the liver for major hepatectomy.

Subtotal (segment II-VIII) hepatectomy for bilateral diffuse hepatolithiasis with compensatory caudate lobe hypertrophy: a report of two cases

Background

Hepatolithiasis often leads to atrophy–hypertrophy complex due to bile duct obstruction, inflammation or infection in the affected liver segments and compensatory response in the normal segments. In severe bilateral diffuse cases, main liver can all be atrophic, leaving the caudate lobe to be extremely hypertrophic. Subtotal (segment II–VIII) hepatectomy can be an option in selected patients under such circumstances. Since rare cases have been reported, our study aims to highlight the preoperative evaluation and key points of this procedure.

Case presentation

Two patients with primary and secondary bilateral diffuse hepatolithiasis, respectively, were enrolled in this case series. The atrophy of the left and right liver with an exceeding hypertrophy of the caudate lobe were observed. Since the liver anatomy had completely been changed, contrast computed tomography, magnetic resonance imaging combined with 3D liver reconstruction were employed for comprehensive evaluation and pre-operational planning. The patients underwent standard subtotal (segment II–VIII) hepatectomy. During operation, the hepatoduodenal ligament around porta hepatis was dissected firstly to expose the hepatic artery, portal vein, bile duct and their branches successively. And then the vessels and bile duct to caudate lobe were preserved safely through cutting off the left and right hepatic artery, portal vein and bile duct at a safe point distal to the origin of the branches to caudate lobe. Operation time was 300 min and 360 min, respectively. Blood loss was 200 ml and 300 ml. No evidence of liver dysfunction, hepatolithiasis relapse or cholangitis was observed during the follow-up of 12 and 26 months.

Conclusions

Subtotal (segment II–VIII) hepatectomy may be one of several treatments possible in selected patients with compensatory caudate lobe hypertrophy caused by bilateral diffuse hepatolithiasis.

Preparing for liver surgery with "Alphabet Soup": PVE, ALPPS, TAE-PVE, LVD and RL

Future liver remnant (FLR) size and function is a critical limiting factor for treatment eligibility and postoperative prognosis when considering surgical hepatectomy. Pre-operative portal vein embolization (PVE) has been proven effective in modulating FLR and now widely accepted as a standard of care. However, PVE is not always effective due to potentially inadequate augmentation of the FLR as well as tumor progression while awaiting liver growth. These concerns have prompted exploration of alternative techniques: associating liver partition and portal vein ligation for staged hepatectomy (ALPPS), transarterial embolization-portal vein embolization (TAE-PVE), liver venous deprivation (LVD), and radiation lobectomy (RL). The article aims to review the principles and applications of PVE and these newer hepatic regenerative techniques.

Portal vein embolization for induction of selective hepatic hypertrophy prior to major hepatectomy: rationale, techniques, outcomes and future directions

The ability to modulate the future liver remnant (FLR) is a key component of modern oncologic hepatobiliary surgery practice and has extended surgical candidacy for patients who may have been previously thought unable to survive liver resection. Multiple techniques have been developed to augment the FLR including portal vein embolization (PVE), associating liver partition and portal vein ligation (ALPPS), and the recently reported transhepatic liver venous deprivation (LVD). PVE is a well-established means to improve the safety of liver resection by redirecting blood flow to the FLR in an effort to selectively hypertrophy and ultimately improve functional reserve of the FLR. This article discusses the current practice of PVE with focus on summarizing the large number of published reports from which outcomes based practices have been developed. Both technical aspects of PVE including volumetry, approaches, and embolization agents; and clinical aspects of PVE including data supporting indications, and its role in conjunction with chemotherapy and transarterial embolization will be highlighted. PVE remains an important aspect of oncologic care; in large part due to the substantial foundation of information available demonstrating its clear clinical benefit for hepatic resection candidates with small anticipated FLRs.

Volume change and liver parenchymal signal intensity in Gd-EOB-DTPA-enhanced magnetic resonance imaging after portal vein embolization prior to hepatectomy

Purpose. To investigate the liver volume change and the potential of early evaluation by contrast-enhanced magnetic resonance imaging (MRI) using gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) after portal vein embolization (PVE). Materials and Methods. Retrospective evaluations of computed tomography (CT) volumetry of total liver and nonembolized areas were performed before and 3 weeks after PVE in 37 cases. The percentage of future liver remnant (%FLR) and the change ratio of %FLR (%FLR ratio) were calculated. Prospective evaluation of signal intensities (SIs) was performed to estimate the role of Gd-EOB-DTPA-enhanced MRI as a predictor of hypertrophy in 16 cases. The SI contrast between embolized and nonembolized areas was calculated 1 week after PVE. The change in SI contrast before and after PVE (SI ratio) was also calculated in 11 cases. Results. %FLR ratio significantly increased, and SI ratio significantly decreased (both P < 0.01). There were significant negative correlations between %FLR and SI contrast and between %FLR and SI ratio (both P < 0.01). Conclusion. Hypertrophy in the nonembolized area after PVE was indicated by CT volumetry, and measurement of SI contrast and SI ratio in Gd-EOB-DTPA-enhanced MRI early after PVE may be useful to predict the potential for hepatic hypertrophy.

Acute iatrogenic Budd-Chiari syndrome following hepatectomy for hepatolithiasis: A report of two cases

Budd-Chiari syndrome (BCS) is defined as hepatic venous outflow obstruction at any level from the small hepatic veins to the junction of the inferior vena cava (IVC) and the right atrium, regardless of the cause of obstruction. We present two cases of acute iatrogenic BCS and our clinical management of these cases. The first case was a 43-year-old woman who developed acute BCS following the implantation of an IVC stent for the correction of stenosis in the IVC after hepatectomy for hepatolithiasis. The second case was a 61-year-old woman with complete obstruction of the outflow of hepatic veins during bilateral hepatectomy for hepatolithiasis. Acute iatrogenic BCS should be considered a rare complication following hepatectomy for hepatolithiasis. Awareness of potential hepatic outflow obstructions and timely management are critical to avoid poor outcomes when performing hepatectomy for hepatolithiasis.

Caudate lobe-sparing subtotal hepatectomy for primary hepatolithiasis

BACKGROUND

Patients with frequent and life-threatening attacks of cholangitis due to bilateral primary hepatolithiasis with atrophy of the main liver and giant hypertrophy of the caudate lobe were assessed for caudate lobe-sparing subtotal hepatectomy.

METHODS

This was a retrospective study of prospectively collected data from patients who underwent subtotal hepatectomy with sparing of the caudate lobe (resection of 7 liver segments, leaving only the caudate lobe) between March 2003 and December 2009. All patients had concomitant bile duct exploration and choledochoscopy. Perioperative and long-term outcomes were analysed.

RESULTS

Immediate stone clearance was obtained in all 12 patients enrolled in the study. Two patients had strictureplasty of the strictured caudate bile duct. There was no hospital mortality and six complications developed in three patients. At a mean follow-up of 51 months, one patient had developed recurrent stones in the caudate lobe bile ducts at 8 months and died from acute purulent cholangitis, 17 months after surgery. The remaining 11 patients were symptom-free with no further attacks of acute cholangitis.

CONCLUSION

In selected patients with bilateral primary hepatolithiasis, caudate lobe-sparing subtotal hepatectomy is a safe and effective treatment.

Portal vein embolization: rationale, outcomes, controversies and future directions

Portal vein embolization (PVE) is now considered the standard of care to improve safety for patients undergoing extensive hepatectomy with an anticipated small future liver remnant (FLR). PVE is used to induce contralateral liver hypertrophy in preparation for major liver resection. Optimal patient selection is essential to maximize the clinical benefits of PVE. Computed tomography volumetry is used to calculate a standardized FLR and determine the need for preoperative PVE. Percutaneous PVE can be performed via the transhepatic ipsilateral or contralateral approaches, depending on operator preference. Several different embolic agents are available to the interventional radiologist, all with similar effectiveness in inducing hypertrophy. When an extended hepatectomy is planned, right PVE should include segment 4, in order to maximize FLR hypertrophy. Multiple studies have demonstrated the beneficial outcomes of PVE in both patients with healthy livers and with underlying liver diseases. Novel improvements to PVE should expand its scope to patients who were previously not candidates for the procedure.

Hypertrophy of the non-embolized liver after chemotherapy

BACKGROUND

Neoadjuvant chemotherapy (NC(+)) and portal vein embolization (PVE) enables curative resection in more patients with colorectal-liver metastases (CRLM). However, after NC(+), structural alterations have been reported with the risk of post-operative hepatic failure. We undertook to determine if NC(+) toxicity limits future remnant liver (FRL) hypertrophy after PVE.

METHODS

PVE was performed in 20 patients, 13 (65%) of whom previously received a mean FOLFIRI (5-fluorouracil + leucovorin + irinotecan) regimen (NC(+)) of 6.6 cycles. The seven remaining patients served as the control group without NC (NC(-)).

RESULTS

CRLM were bilateral in 69% (NC(+)) and 57% (NC(-)), and synchronous in 84% (NC(+)) and 14% (NC(-)). The FRL hypertrophy rate was 54.1% (NC(+)) and 43.7% (NC(-)) (P= 0.3). CRLM were unresectable in four of our 20 patients, i.e. group NC(+): one insufficient FRL hypertrophy and one severe steatosis; and group NC(-): two tumoral progressions. In both groups, the operative parameters were comparable except for pedicular clamping: 8 (NC(+)) and 36 min (NC(-)), respectively (P < 0.05). Also, the surgical outcome rate and hospital stay were comparable. No significant pathological difference was observed between the two groups. No mortality occurred in either group.

CONCLUSION

In view of our limited experience, we conclude that hypertrophy of the non-embolized liver (FRL) is not altered after FOLFIRI-based NC.

Experimental obstructive cholestasis: the wound-like inflammatory liver response

Obstructive cholestasis causes hepatic cirrhosis and portal hypertension. The pathophysiological mechanisms involved in the development of liver disease are multiple and linked. We propose grouping these mechanisms according to the three phenotypes mainly expressed in the interstitial space in order to integrate them.Experimental extrahepatic cholestasis is the model most frequently used to study obstructive cholestasis. The early liver interstitial alterations described in these experimental models would produce an ischemia/reperfusion phenotype with oxidative and nitrosative stress. Then, the hyperexpression of a leukocytic phenotype, in which Kupffer cells and neutrophils participate, would induce enzymatic stress. And finally, an angiogenic phenotype, responsible for peribiliary plexus development with sinusoidal arterialization, occurs. In addition, an intense cholangiocyte proliferation, which acquires neuroendocrine abilities, stands out. This histopathological finding is also associated with fibrosis.It is proposed that the sequence of these inflammatory phenotypes, perhaps with a trophic meaning, ultimately produces a benign tumoral biliary process - although it poses severe hepatocytic insufficiency. Moreover, the persistence of this benign tumor disease would induce a higher degree of dedifferentiation and autonomy and, therefore, its malign degeneration.

The ultrastructural research of liver in experimental obstructive jaundice and effect of honey

BACKGROUND

To examine the effects of honey on oxidative stress and apoptosis in experimental obstructive jaundice model.

METHOD

Thirty rats were divided into 3 groups: group I, sham-operated; group II, ligation and division of the common bile duct (BDL); group III, BDL followed by oral supplementation of honey 10 g/kg/d. Liver samples were examined under light microscope and transmission electron microscope. Hepatocyte apoptosis was quantitated using the terminal deoxy-nucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) assay. Plasma and blood malondialdehyde (MDA) and glutation activities were measured for determining the oxidative stress.

RESULTS

The liver levels of MDA and GSH were significantly different between the honey and BDL groups (P = .006 and .001, respectively). However, there was no significant difference between the plasma MDA and GSH levels of these groups (P > .05). In group III, significant reductions in the size of enlarged hepatocytes and the edema were demonstrated. The dilatation of the bile canaliculi dramatically turned to original dimention. By TUNEL assay, it was shown that administration of honey decreased the number of apoptotic cells.

CONCLUSIONS

In the present study, we found that honey diminished the negative effects of BDL on the hepatic ultrastructure. We conclude that this effect might be due to its antioxidant and anti-inflammatory activities.

Portal vein embolization in preparation for major hepatic resection: evolution of a new standard of care

Portal vein (PV) embolization (PVE) is gaining acceptance in the preoperative management of patients selected for major hepatic resection. PVE redirects portal blood flow to the intended liver remnant to induce hypertrophy of the nondiseased portion of the liver and thereby reduce complications and shorten hospital stays after resection. This article reviews the rationale and existing literature on PVE, including the mechanisms of liver regeneration, the pathophysiology of PVE, the imaging techniques used to measure liver volumes and estimate functional hepatic reserve, and the technical aspects of PVE, including approaches and embolic agents used. In addition, the indications and contraindications for performing PVE in patients with and without chronic liver disease and the multidisciplinary approach required for the treatment of these complex cases are emphasized.

Dying a thousand deaths: redundant pathways from different organelles to apoptosis and necrosis

Cell death is an essential event in normal life and development, as well as in the pathophysiological processes that lead to disease. Although the literature on cell death has grown enormously in size and complexity, a pattern has emerged that each of several distinct organelles (plasma membrane, mitochondrion, nucleus, endoplasmic reticulum, lysosome) gives rise to signals that induce cell death. Most often these signals converge on mitochondria to initiate a common pathway to either caspase-dependent apoptosis or ATP depletion-dependent necrosis. This brief overview emphasizes the multiple and often redundant pathways between different organelles that lead ultimately to a cell's demise.