Non-canonical Hedgehog signaling mediates profibrotic hematopoiesis-stroma crosstalk in myeloproliferative neoplasms

The role of hematopoietic Hedgehog signaling in myeloproliferative neoplasms (MPNs) remains incompletely understood despite data suggesting that Hedgehog (Hh) pathway inhibitors have therapeutic activity in patients. We aim to systematically interrogate the role of canonical vs. non-canonical Hh signaling in MPNs. We show that Gli1 protein levels in patient peripheral blood mononuclear cells (PBMCs) mark fibrotic progression and that, in murine MPN models, absence of hematopoietic Gli1, but not Gli2 or Smo, significantly reduces MPN phenotype and fibrosis, indicating that GLI1 in the MPN clone can be activated in a non-canonical fashion. Additionally, we establish that hematopoietic Gli1 has a significant effect on stromal cells, mediated through a druggable MIF-CD74 axis. These data highlight the complex interplay between alterations in the MPN clone and activation of stromal cells and indicate that Gli1 represents a promising therapeutic target in MPNs, particularly that Hh signaling is dispensable for normal hematopoiesis.

MarrowCellDLD: a microfluidic method for label-free retrieval of fragile bone marrow-derived cells

Functional bone marrow studies have focused primarily on hematopoietic progenitors, leaving limited knowledge about other fragile populations, such as bone marrow adipocytes (BMAds) and megakaryocytes. The isolation of these cells is challenging due to rupture susceptibility and large size. We introduce here a label-free cytometry microsystem, MarrowCellDLD, based on deterministic lateral displacement. MarrowCellDLD enables the isolation of large, fragile BM-derived cells based on intrinsic size properties while preserving their viability and functionality. Bone marrow adipocytes, obtained from mouse and human stromal line differentiation, as well as megakaryocytes, from primary human CD34+ hematopoietic stem and progenitor cells, were used for validation. Precise micrometer-range separation cutoffs were adapted for each cell type. Cells were sorted directly in culture media, without pre-labeling steps, and with real-time imaging for quality control. At least 106 cells were retrieved intact per sorting round. Our method outperformed two FACS instruments in purity and yield, particularly for large cell size fractions. MarrowCellDLD represents a non-destructive sorting tool for large, fragile BM-derived cells, facilitating the separation of pure populations of BMAds and megakaryocytes to further investigate their physiological and pathological roles.

Urtica dioica Leaf Infusion Enhances the Sensitivity of Triple-Negative Breast Cancer Cells to Cisplatin Treatment

Urtica dioica (UD) has been widely used in traditional medicine due to its therapeutic benefits, including its anticancer effects. Natural compounds have a promising potential when used in combination with chemotherapeutic drugs. The present study explores the anticancer and anti-proliferative properties of UD tea in combination with cisplatin on MDA-MB-231 breast cancer cells in vitro. To elucidate the effect of this combination, a cell viability assay, Annexin V/PI dual staining, cell death ELISA, and Western blots were performed. The results showed that the combination of UD and cisplatin significantly decreased the proliferation of MDA-MB-231 cells in a dose- and time-dependent manner compared to each treatment alone. This was accompanied by an increase in two major hallmarks of apoptosis, the flipping of phosphatidylserine to the outer membrane leaflet and DNA fragmentation, as revealed by Annexin V/PI staining and cell death ELISA, respectively. DNA damage was also validated by the upregulation of the cleaved PARP protein as revealed by Western blot analysis. Finally, the increase in the Bax/Bcl-2 ratio further supported the apoptotic mechanism of death induced by this combination. Thus, a leaf infusion of Urtica dioica enhanced the sensitivity of an aggressive breast cancer cell line to cisplatin via the activation of apoptosis.

MarrowQuant 2.0: A Digital Pathology Workflow Assisting Bone Marrow Evaluation in Experimental and Clinical Hematology

Bone marrow (BM) cellularity assessment is a crucial step in the evaluation of BM trephine biopsies for hematologic and nonhematologic disorders. Clinical assessment is based on a semiquantitative visual estimation of the hematopoietic and adipocytic components by hematopathologists, which does not provide quantitative information on other stromal compartments. In this study, we developed and validated MarrowQuant 2.0, an efficient, user-friendly digital hematopathology workflow integrated within QuPath software, which serves as BM quantifier for 5 mutually exclusive compartments (bone, hematopoietic, adipocytic, and interstitial/microvasculature areas and other) and derives the cellularity of human BM trephine biopsies. Instance segmentation of individual adipocytes is realized through the adaptation of the machine-learning-based algorithm StarDist. We calculated BM compartments and adipocyte size distributions of hematoxylin and eosin images obtained from 250 bone specimens, from control subjects and patients with acute myeloid leukemia or myelodysplastic syndrome, at diagnosis and follow-up, and measured the agreement of cellularity estimates by MarrowQuant 2.0 against visual scores from 4 hematopathologists. The algorithm was capable of robust BM compartment segmentation with an average mask accuracy of 86%, maximal for bone (99%), hematopoietic (92%), and adipocyte (98%) areas. MarrowQuant 2.0 cellularity score and hematopathologist estimations were highly correlated (R² = 0.92-0.98, intraclass correlation coefficient [ICC] = 0.98; interobserver ICC = 0.96). BM compartment segmentation quantitatively confirmed the reciprocity of the hematopoietic and adipocytic compartments. MarrowQuant 2.0 performance was additionally tested for cellularity assessment of specimens prospectively collected from clinical routine diagnosis. After special consideration for the choice of the cellularity equation in specimens with expanded stroma, performance was similar in this setting (R² = 0.86, n = 42). Thus, we conclude that these validation experiments establish MarrowQuant 2.0 as a reliable tool for BM cellularity assessment. We expect this workflow will serve as a clinical research tool to explore novel biomarkers related to BM stromal components and may contribute to further validation of future digitalized diagnostic hematopathology workstreams.

Next Generation Bone Marrow Adiposity Researchers: Report From the 1st BMAS Summer School 2021

The first International Summer School on Bone Marrow Adiposity was organized by members of Bone Marrow Adiposity Society and held virtually on September 6-8 2021. The goal of this meeting was to bring together young scientists interested in learning about bone marrow adipose tissue biology and pathology. Fifty-two researchers from different backgrounds and fields, ranging from bone physiopathology to adipose tissue biology and hematology, participated in the summer school. The meeting featured three keynote lectures on the fundamentals of bone marrow adiposity, three scientific workshops on technical considerations in studying bone marrow adiposity, and six motivational and career development lectures, spanning from scientific writing to academic career progression. Moreover, twenty-one participants presented their work in the form of posters. In this report we highlight key moments and lessons learned from the event.

The pro-apoptotic properties of a phytonutrient rich infusion of A. cherimola leaf extract on AML cells

Annonaceae family has broad uses in herbal medicine for treatment of several diseases, whether through seeds' or leaves' extracts. The present study investigates the antiproliferative and antitumor activity of Annona cherimola aqueous leaf (AAL) extract/infusion in acute myeloid leukemia (AML) cell lines in vitro. High-resolution LC-MS was first used to analyze the composition of the aqueous extract. Cell proliferation assay, Annexin V staining, cell cycle analysis, dual Annexin V/PI staining, cell death quantification by ELISA, ROS level detection and Western Blotting were then performed to elucidate the therapeutic effects of AAL extract. The results obtained revealed a potent antioxidant activity of AAL extract. Moreover, the extract exhibited dose- and time-dependent antiproliferative effects on AML cell lines by decreasing cell viability with an IC₅₀ of 5.03% (v/v) at 24 h of treatment of KG-1 cells. This decrease in viability was accompanied with a significant increase in apoptotic cell death with cell cycle arrest and flipping of the phosphatidylserine from the inner to the outer leaflet of the cell membrane. The respective overexpression and downregulation of proapoptotic proteins like cleaved caspase-8, cleaved PARP-1 and Bax and antiapoptotic proteins like Bcl-2 further validated the apoptotic pathway induced by AAL on AML cells. Finally, LC-MS revealed the presence of several compounds like fatty acids, terpenes, phenolics, cinnamic acids and flavonoids that could contribute to the antioxidant and anti-cancer effects of this herbal infusion. In addition to the generally known nutritional effects of the Annona cherimola fruit and leaves, the presented data validates the antioxidant and anti-cancerous effects of the leaf infusion on AML cell lines, proposing its potential therapeutic use against acute myeloid leukemia with future in vivo and clinical trials.

The selective anti-proliferative and pro-apoptotic effect of A. cherimola on MDA-MB-231 breast cancer cell line

Background

Herbal medicines have been a major target for numerous studies through the past years as an alternative treatment for cancer, mainly due to their minimal effects on normal healthy cells. Annona cherimola, popularly known as Cherimoya, is an edible natural fruit rich in phytochemical components and known to possess various biological activities. Previous studies have reported the anti-cancerous effect of A. cherimola ethanolic leaf extract (AELE) on leukemia. This study aims at studying the potential anti-cancer activity of this extract in vitro in two different breast cancer cell lines, namely MDA-MB-231 and MCF-7, in addition to investigating its toxicity on normal mesenchymal stem cells.

Methods

The anti-proliferative effect of AELE was evaluated via cell viability assay. Propidium iodide staining, Cell Death Detection ELISA and flow cytometry analysis of Annexin V binding were used to assess cell cycle progression, DNA fragmentation and apoptosis induction, respectively. Protein expression was determined via Western Blot analysis to decipher the underlying apoptotic molecular mechanism induced upon AELE treatment.

Results

The anti-proliferative effect of the extract was found to be selective on the triple-negative breast cancer cell line (MDA-MB-231) in a time- and dose-dependent manner with an IC₅₀ of 390.2 μg/mL at 48 h, with no cytotoxic effects on normal murine mesenchymal stem cells. The pro-apoptotic effect was confirmed by the increase in cellular and DNA fragmentation, flipping of the phosphatidylserine moiety to the outer leaflet, and the increase in Annexin V binding. The underlying molecular mechanism revealed the involvement of the mitochondrial pathway, as shown by alterations in mitochondrial permeability and the upregulation of cytochrome c expression.

Conclusion

All the data presented in our study suggest that AELE exhibits a selective anti-proliferative and pro-apoptotic effect on the chemo-resistant MDA-MB-231 breast cancer cells, providing evidence for the anti-tumor effects of A. cherimola.

MarrowQuant Across Aging and Aplasia: A Digital Pathology Workflow for Quantification of Bone Marrow Compartments in Histological Sections

The bone marrow (BM) exists heterogeneously as hematopoietic/red or adipocytic/yellow marrow depending on skeletal location, age, and physiological condition. Mouse models and patients undergoing radio/chemotherapy or suffering acute BM failure endure rapid adipocytic conversion of the marrow microenvironment, the so-called "red-to-yellow" transition. Following hematopoietic recovery, such as upon BM transplantation, a "yellow-to-red" transition occurs and functional hematopoiesis is restored. Gold Standards to estimate BM cellular composition are pathologists' assessment of hematopoietic cellularity in hematoxylin and eosin (H&E) stained histological sections as well as volumetric measurements of marrow adiposity with contrast-enhanced micro-computerized tomography (CE-μCT) upon osmium-tetroxide lipid staining. Due to user-dependent variables, reproducibility in longitudinal studies is a challenge for both methods. Here we report the development of a semi-automated image analysis plug-in, MarrowQuant, which employs the open-source software QuPath, to systematically quantify multiple bone components in H&E sections in an unbiased manner. MarrowQuant discerns and quantifies the areas occupied by bone, adipocyte ghosts, hematopoietic cells, and the interstitial/microvascular compartment. A separate feature, AdipoQuant, fragments adipocyte ghosts in H&E-stained sections of extramedullary adipose tissue to render adipocyte area and size distribution. Quantification of BM hematopoietic cellularity with MarrowQuant lies within the range of scoring by four independent pathologists, while quantification of the total adipocyte area in whole bone sections compares with volumetric measurements. Employing our tool, we were able to develop a standardized map of BM hematopoietic cellularity and adiposity in mid-sections of murine C57BL/6 bones in homeostatic conditions, including quantification of the highly predictable red-to-yellow transitions in the proximal section of the caudal tail and in the proximal-to-distal tibia. Additionally, we present a comparative skeletal map induced by lethal irradiation, with longitudinal quantification of the "red-to-yellow-to-red" transition over 2 months in C57BL/6 femurs and tibiae. We find that, following BM transplantation, BM adiposity inversely correlates with kinetics of hematopoietic recovery and that a proximal to distal gradient is conserved. Analysis of in vivo recovery through magnetic resonance imaging (MRI) reveals comparable kinetics. On human trephine biopsies MarrowQuant successfully recognizes the BM compartments, opening avenues for its application in experimental, or clinical contexts that require standardized human BM evaluation.

The pro-apoptotic effect of a Terpene-rich Annona cherimola leaf extract on leukemic cell lines

BACKGROUND

The edible fruit Annona cherimola has previously shown many nutritional and medicinal properties. The current study evaluates the anti-cancer and anti-proliferative properties of Annona cherimola ethanolic leaf extract (AELE) on Acute Myeloid Leukemia (AML) cell lines cultured in vitro (Monomac-1 and KG-1).

METHODS

The anti-proliferative effect of A. cherimola ethanolic leaf extract was evaluated via cell viability assay. Its pro-apoptotic effect was assessed through Cell Death ELISA and dual Annexin V/PI staining. To further investigate the molecular mechanism by which the extract promoted apoptosis and inhibited the proliferation of the AML cells used, apoptotic protein expression was determined through western blots. Extract composition was elucidated by Gas Chromatography-Mass Spectrometry (GC-MS).

RESULTS

Our results showed that the treatment with A. cherimola ethanolic leaf extract exhibited an inhibitory effect on the proliferation of both cancer cell lines used in a dose- and time-dependent manner, with no toxic effects on normal mononuclear cells (MNCs) isolated from human bone marrow. This effect was mediated by DNA fragmentation and apoptosis, as revealed by Cell Death ELISA and dual Annexin V/PI staining. Western blot analysis revealed a Bax/Bcl2 dependent mechanism of apoptosis, as well as PARP cleavage, confirming the apoptotic results observed previously. These effects may be attributed to the presence of terpenes which constitute a large component of the leafy extract, as revealed via GC-MS.

CONCLUSION

All the data presented in our study show that the terpene-rich A. cherimola ethanolic leaf extract exhibits an anti-proliferative and pro-apoptotic effect on the AML cell lines used.

Semiautomatic macroencapsulation of fresh or cryopreserved porcine hepatocytes maintain their ability for treatment of acute liver failure

We have previously demonstrated that fresh or cryopreserved xenogeneic hepatocytes manually macroencapsulated in AN69 polymer and transplanted intraperitoneally in rats were able to improve the survival rate after 95% hepatectomy without immunosuppression. In addition, we developed a semiautomatic device where porcine hepatocytes were coextruded with AN69 hydrogel in order to macroencapsulate large amounts of cells. The purpose of the present study was to 1) test whether transplanted porcine hepatocytes macroencapsulated in this device remained functional as evaluated by their ability to prevent death from acute liver failure, and 2) compare the efficiency of cryopreserved or freshly isolated hepatocytes. Fresh or cryopreserved porcine hepatocytes were macroencapsulated in the semiautomatic device by coextrusion in AN69 polymer in 2-m minitubes containing 6 x 10(7) cells. Acute liver failure was induced in rats by two-step 95% hepatectomy. At the time of completion of liver resection, rats were either not transplanted with minitubes (control group I, n = 13), or were implanted with two minitubes containing culture medium (control group II, n = 11), hepatocytes killed by heat treatment (control group III, n = 10), coextruded fresh hepatocytes (group IV, n = 11), or coextruded cryopreserved hepatocytes (group V, n = 11), without immunosuppression. The survival rate at day 7 was between 0% and 31% in the three control groups. By contrast, coextruded fresh hepatocytes significantly improved the survival rate (group IV, 82%) as did cryopreserved cells (group V, 91% survival). In surviving rats, minitubes were explanted after 20 days; either fresh or cryopreserved hepatocytes appeared morphologically viable and their ultrastructure was preserved. Their detoxification capacities evaluated by the activity of the cyt P450 CYP3A4 were partly maintained. In conclusion, porcine hepatocytes macroencapsulated by coextrusion using a semiautomatic device and transplanted without immunosuppression were able to prevent death from acute liver failure in rats. Cryopreserved cells were as efficient as fresh hepatocytes.

Survival and differentiation of porcine hepatocytes encapsulated by semiautomatic device and allotransplanted in large number without immunosuppression

BACKGROUND/AIMS

The aim of this study was to evaluate the survival and functions of porcine hepatocytes transplanted in large quantities in the peritoneal cavity of allogeneic animals following semiautomatic encapsulation.

METHODS

Isolated porcine hepatocytes and a polymer solution composed of AN69 were coextruded through a double lumen spinneret. Minitubes containing hepatocytes were transplanted in the peritoneal cavity of 12 pigs (4 x 10(9) cells/animal) in the absence of immunosuppressive therapy. Seven, 15, and 21 days after transplantation, minitubes was collected and processed for analyses. The morphology was examined under light and electron microscopy. Albumin synthesis was assessed by semi-quantitative reverse transcription-polymerase chain reaction. Cytochrome P450 3A (CYP3A) gene expression was analyzed by Western blot and by testosterone 6-beta-hydroxylation assay.

RESULTS

The device allowed to encapsulate 55 x 10(6) hepatocytes/min. Hepatocytes exhibited normal structural and ultrastructural features up to day 21. Albumin gene expression decreased progressively between days 0 and 21. The amount of CYP3A protein and 6-beta-hydroxylase activity were approximately 2-fold lower at days 7 and 15 than in freshly encapsulated hepatocytes, and further decreased thereafter.

CONCLUSIONS

The preservation of hepatocyte functions during 1-2 weeks is encouraging for potential short-term use of such bioartificial liver in future clinical application.

Survival and functions of encapsulated porcine hepatocytes after allotransplantation or xenotransplantation without immunosuppression

BACKGROUND

This study evaluated the survival and functions of encapsulated porcine hepatocytes after intraperitoneal allotransplantation and xenotransplantation without immunosuppression.

METHODS

Isolated porcine hepatocytes were encapsulated in AN 69 polymer capsules (45.10(6)/capsule) and transplanted intraperitoneally in 12 rats and 12 pigs. Fifteen, 30, and 60 days after transplantation, capsules were removed and the viability and morphology of explanted hepatocytes were examined under light and electronic microscopy. The potential to produce albumin was assessed by evaluating the level of albumin messenger RNA, using semiquantitative reverse transcription-polymerase chain reaction. 6beta-Hydroxylase activity was measured by high-performance liquid chromatography. In addition, cytochrome P450 3A proteins were detected by Western blot only in allogeneic hepatocytes.

RESULTS

Similar results were observed after allotransplantation and xenotransplantation. Histologic studies showed that hepatocytes were well-preserved and arranged in cords for up to 30 days. The expression of porcine albumin gene was maintained up to 15 days. 6beta-Hydroxylase activity was 2.5-fold lower at day 15 than in freshly encapsulated hepatocytes, which were not transplanted. In allogeneic hepatocytes, the expression of CYP 3A protein was detected up to 60 days after transplantation.

CONCLUSIONS

Encapsulated porcine hepatocytes remain viable and functional for at least 15 days after allotransplantation and xenotransplantation without immunosuppression. The demonstration of maintained hepatic functions in transplanted porcine hepatocytes up to 15 days is a first step toward application in the treatment of acute liver failure.

Transplanted cryopreserved encapsulated porcine hepatocytes are as effective as fresh hepatocytes in preventing death from acute liver failure in rats

BACKGROUND

An implantable bioartificial liver (BAL) using xenogeneic isolated hepatocytes may be an alternative method to orthotopic liver transplantation for treatment of acute liver failure. The purpose of this study was to demonstrate that not only fresh but also cryopreserved porcine hepatocytes could be used in a BAL to prevent death after the onset of acute liver failure in rats.

METHODS

Acute liver failure was induced by two-stage 95% hepatectomy. At the time of completion of liver resection, 100 rats were assigned to undergo or not undergo transplantation into the peritoneum of 4 meters of hollow fibers filled with 60 million either fresh or cryopreserved porcine hepatocytes, or syngeneic hepatocytes, or culture medium, or of 60 million nonencapsulated cryopreserved porcine hepatocytes without immunosuppressive therapy. Survival rates at 7 days were compared between the different groups.

RESULTS

In the control groups of hepatectomized animals not receiving encapsulated hepatocytes, 69-79% of the rats died from acute liver failure. The mortality rate was reduced to 15% (2 of 13) in rats receiving fresh porcine hepatocytes (P<0.01), 25% (4 of 16) in rats transplanted with either cryopreserved or syngeneic hepatocytes (P<0.05). Survival rates were maintained when hollow fibers were explanted > or =4 days after hepatectomy. In surviving rats, the weight of the remnant native liver increased with time and returned to the initial weight after 1 month.

CONCLUSIONS

The implantable BAL using xenogeneic porcine hepatocytes was able in preventing death from acute liver failure without immunosuppressive therapy. Encapsulated cryopreserved hepatocytes were as effective as fresh hepatocytes.

Semiautomatic macroencapsulation of large numbers of porcine hepatocytes by coextrusion with a solution of AN69 polymer

We have previously demonstrated that allogenic and xenogenic hepatocytes macroencapsulated manually in AN-69 polymer and transplanted intra-peritoneally in rats remained viable for several weeks. However, this manual technique is inadequate to encapsulate several billions of hepatocytes which would be required to correct hepatic failure in big animals or humans. In the present study, we developed an original semiautomatic device in which isolated pig hepatocytes and the polymer solution containing 6% poly(acrylonitrile-sodium methallylsulfonate), 91% dimethylsulfoxide and 3% 0.9% NaCl solution were coextruded through a double-lumen spinneret. The extruded minitube (inner diameter: 1.8 mm, wall thickness: 0.07-0.1 mm) containing the encapsulated hepatocytes fell and coiled up in a 0.9% NaCl solution at 4 degrees C and was cut down in 4 m units containing about 120 million hepatocytes. This process allowed to encapsulate 50 million hepatocytes by minute with a preserved immediate cell viability (92 +/- 5%). To test prolonged cell viability after coextrusion, the minitubes were implanted intraperitoneally in rats. Three and seven days after implantation, they were explanted and analyzed. Cells were viable and well-preserved. Therefore, the semiautomatic device appears able to efficiently macroencapsulate in a limited time several billions of porcine hepatocytes which remain viable after transplantation in xenogenic conditions.

[Viability and differentiation of human hepatocytes immunoprotected by macroencapsulation and transplanted in rats]

OBJECTIVES

To determine the viability and differentiation of human hepatocytes immunoprotected by encapsulation and transplanted in rats without immunosuppression.

METHODS

Freshly isolated human hepatocytes were encapsulated in hollow fibers and transplanted in the peritoneal cavity of immunocompetent rats. The fibers were explanted for analysis at D3, D7 and D14 following transplantation. Morphological features under light and electron microscopy and gene expression were compared to those of non-transplanted encapsulated hepatocytes (D0). Human cytochrome P450 3A and albumin mRNAs were quantified by Northern blot. Cytochrome P450 3A proteins were detected by Western blot and cytochrome P450 3A enzyme activity was assessed by measuring the formation of 6beta-hydroxytestosterone by high performance liquid chromatography.

RESULTS

Transplanted hepatocytes were more than 60 % viable and exhibited morphological criteria of hepatocytic differentiation up to D7. Albumin and cytochrome P450 3A transcripts were also detected up to D14. At D3 and D7, albumin mRNA levels were of 30 %, compared to control D0 hepatocytes, while cytochrome P450 3A5 and cytochrome P450 3A4 mRNA levels were 65 % and 0 %, respectively. Cytochrome P450 3A immunoreactivity was detected by Western blot up to D14 and 6beta-hydroxylase activity was 17 % at D3 compared to D0, supporting with disappearance of cytochrome P450 3A4 mRNA.

CONCLUSIONS

Human hepatocytes remain viable for a short period, following encapsulation and intraperitoneal transplantation in rat. Other experimental conditions need to be tested to prevent or delay a decrease in hepatocyte specific gene expression.

Results of coloanal anastomosis for rectal cancer

It is now accepted that, in the absence of direct invasion of the anal sphincter, cancers of the middle and lower rectum can be successfully treated with sphincter-preserving surgery. Conservation of the sphincter mechanism should never compromise the oncologic outcome of surgery and the method of neorectum construction must provide acceptable function for patients. This review describes the results of coloanal anastomosis following rectal excision. The oncological and functional results of both straight coloanal and colonic-J-pouch anal anastomosis are presented in detail. The authors discuss recent evidence supporting the functional superiority of colonic-J-pouch reconstruction after rectal excision.

A reversible model of acute hepatic failure by temporary hepatic ischemia in the pig

BACKGROUND

To evaluate new therapies for human fulminant hepatic failure, a suitable large animal model is needed. The purpose of this study was to develop a reversible surgical model of acute hepatic liver failure by transient ischemia in pigs.

MATERIALS AND METHODS

Under general anesthesia, an end-to-side portacaval shunt was performed in 17 pigs and tape was laid around the hepatoduodenal ligament. Two days after construction of the functional portacaval shunt, 13 ambulant pigs underwent transient total liver ischemia by tightening of the tape around the hepatoduodenal ligament for 5.5 h. During ischemia, 10% glucose was continuously infused intravenously to prevent hypoglycemia.

RESULTS

Ten animals (77%) died with hepatic coma after a mean duration of 22.5 +/- 1.9 h. The 3 remaining animals survived more than 5 days and were sacrificed. In dying animals, encephalopathy was observed 14 +/- 1.7 h after the onset of ischemia. During ischemia, similar progressive decrease of fibrinogen, platelets, prothrombin time, and factors V and VII activities was observed in dying and surviving animals. Just before death, mean prothrombin and factors V and VII activities were respectively 22 +/- 2, 21 +/- 4.4, and 24 +/- 5%. At 22 h, plasma ammonia and lactate levels were respectively 705 +/- 93 micromol/L and 10.5 +/- 0.4 mmol/L in dying animals and 249 +/- 75 micromol/L and 2.9 +/- 0.1 mmol/L in surviving animals (P < 0.01). Estimation of the percentage liver cells necrosed was 74 +/- 4.7% in the survivors and 86 +/- 5.5% in animals who died of hepatic coma (NS).

CONCLUSIONS

This model is reproducible and reversible and should allow the quantitative evaluation of new technologies, such as bioartificial liver, for the support of hepatic failure in humans.

Anastomic dehiscence and severe peritonitis

Fifteen years of experience in the management of postoperative complications following GI surgery are reviewed. In the surgical ICU of the Hôpital Saint Antoine, Paris, France, a referral center for these conditions, 385 cases of postoperative peritonitis and 500 cases of enterocutaneous fistulas were observed from 1980 to 1995. Original techniques of management are described in surgical treatment: temporary stomas, intubation irrigation of leaks situated on the upper GI tract, primary closure of the abdominal wall without tension. New methods of intensive care of intestinal conditions have also been designed: control and/or obturation of complex enterocutaneous fistulas, reinfusion of chyme into the distal small bowel and continuous enteral nutrition. In accordance with their experience in this field, the authors review the most controversial points of surgical technique and intensive care.

[Intraperitoneal transplantation of isolated hepatocytes of the pig: the implantable bioartificial liver]

The general aim is to prepare a bioartificial liver to treat acute hepatic failure using allo- and xenogeneic hepatocytes, immunoprotected by macroencapsulation and transplanted into the peritoneal cavity. The goal of this study was to prepare a large amount of isolated porcine hepatocytes, to encapsulate them within biocompatible membranes for transplant in allo- and xenogeneic combinations and to examine the viability and functionality of the cells 6 weeks later. Hepatocyte isolation was performed in 12 kg pigs (n = 15) by dissociation of the liver with collagenase D (1 g) without oxygenation. Encapsulation of the hepatocyte suspension (10(7)/mL) was performed in hydrogel membranes AN69; hollow fibers (2 m x 0.8 mm) and flaskes (1.8 cm), and transplanted to Yucatan pigs (n = 4) and Lewis rats (n = 12). Six weeks later, they were removed to study the cell viability by histological examination, and the production of albumin by immunonephelometry. The rate of isolated hepatocytes was 38 +/- 5 x 10(9)/mL by liver of pig and the mean viability was 93 +/- 2%. Six weeks after transplantation, hepatocytes were viable, organized in lobules, and showed conserved albumin production. The same results were observed for allogenic and xenogeneic combinations. In conclusion, this method of liver dissociation allowed for preparation of a large amount of isolated hepatocytes from a single pig liver, theoretically sufficient to treat a patient with acute liver failure. Hydrogel membranes were well tolerated and allowed immunoprotection without immunosuppression. Transplanted hepatocytes remained functional. This work is an important step in progress toward clinical application.

[Metastatic implants after laparoscopic cholecystectomy in unsuspected gallbladder cancer. A case report and review of the literature]

A gallbladder carcinoma, diagnosed preoperatively, is a counter-indication for laparoscopic cholecystectomy. When this cancer is not diagnosed and laparoscopic surgery is undertaken, neoplastic dissemination may occur along the trocars pathways which renders the prognosis even worse. The most probable explanation of the dissemination is a seeding of sloughed cancerous cells onto abdominal wall during exsuflation. The authors report the case of a 36-year-old woman with an adenocarcinoma of the gallbladder discovered after laparoscopic cholecystectomy and who has had rapid intra-abdominal and parietal metastases.