ALPPS Offers a Better Chance of Complete Resection in Patients with Primarily Unresectable Liver Tumors Compared with Conventional-Staged Hepatectomies: Results of a Multicenter Analysis

Background

Portal vein occlusion to increase the size of the future liver remnant (FLR) is well established, using portal vein ligation (PVL) or embolization (PVE) followed by resection 4–8 weeks later. Associating liver partition with portal vein ligation for staged hepatectomy (ALPPS) combines PVL and complete parenchymal transection, followed by hepatectomy within 1–2 weeks. ALPPS has been recently introduced but remains controversial. We compare the ability of ALPPS versus PVE or PVL for complete tumor resection.

Methods

A retrospective review of all patients undergoing ALPPS or conventional staged hepatectomies using PVL or PVE at four high-volume HPB centres between 2003 and 2012 was performed. Patients with primary liver tumors and liver metastases were included. Primary endpoint was complete tumor resection. Secondary endpoints include 90-day mortality, complications, FLR increase, time to resection, and tumor recurrence.

Results

Forty-eight patients with ALPPS were compared with 83 patients with conventional-staged hepatectomies. Eighty-three percent (40/48 patients) of ALPPS patients achieved complete resection compared with 66 % (55/83 patients) in PVE/PVL (odds ratio 3.34, p = 0.027). Ninety-day mortality in ALPPS and PVE/PVL was 15 and 6 %, respectively (p = 0.2). Extrapolated growth rate was 11 times higher in ALPPS (34.8 cc/day; interquartile range (IQR) 26–49) compared with PVE/PVL (3 cc/day; IQR2-6; p = 0.001). Tumor recurrence at 1 year was 54 versus 52 % for ALPPS and PVE/PVL, respectively (p = 0.7).

Conclusions

This study provides evidence that ALPPS offers a better chance of complete resection in patients with primarily unresectable liver tumors at the cost of a high mortality. The technique is promising but should currently not be used outside of studies and registries.     

Antigen‐specific regulatory T cells can induce tolerance to immunogenic grafts without the need for chronic immunosuppression

Regulatory CD4⁺CD25⁺Foxp3⁺ T cells (Tregs) play an important role in the induction of allospecific tolerance. However tolerance in solid organ transplantation by mere transfer of Tregs has been difficult. Besides this the stability of the differentiation phenotype of Tregs has recently been questioned. We therefore aimed in generating large numbers of stable allospecific Tregs from naïve T cells by retroviral transduction with Foxp3. These were tested in an immunogenic skin transplantation model (C57BL/6→BALB/c). We established a system of transduction of mouse T cells with ecotropic retroviruses expressing Foxp3 and Thy1.1 as a surface marker to follow up transduced T cells. Alloantigen‐specific Tregs were generated by stimulating naïve recipient CD4⁺ T cells with irradiated donor splenocytes. CD25⁺ and/or CD69⁺ allospecific recipient CD4⁺ T cells were isolated and transduced with Foxp3. Alloantigen‐specific Foxp3 T cells (iTregs) showed high expression for the Treg markers Foxp3, CTLA4 and GITR. They could suppress a MLR in an alloantigen‐specific manner. Furthermore, they could be expanded up to 18 fold in vitro while maintaining their Treg phenotype and expression of lymph node homing markers like CCR7 and CD62L. iTregs prevented skin graft rejection without the need for chronic immunosuppression and recipients showed systemic allospecific allotolerance. Alloantigen‐specific Tregs were far more potent than polyspecific Tregs. Mechanisms of tolerance were graft specific homing, expansion and long‐term persistence of Tregs within the graft (>100 days, 90% of intragraft Tregs were alloantigen‐specific). In fact, tolerance could be transferred with re‐transplantation of the tolerant graft onto secondary recipients. Third party grafts were readily rejected demonstrating specificity of tolerance. Due to the Foxp3 transduction, iTregs did not lose their Treg phenotype. The results prove that large numbers of stable alloantigen‐specific Tregs can be generated from a polyclonal repertoire of naïve T cells. This is the first time that allotolerance was achieved in a non‐lymphopenic transplant model using skin grafts in an immunogenic strain combination. Therefore, antigen‐specific Tregs might have a huge therapeutic potential after solid organ transplantation.     

Mitochondrial repair of 8-oxoguanine and changes with aging

Reactive oxygen species (ROS) are formed in all living organisms as a by-product of normal metabolism (endogenous sources) and as a consequence of exposure to environmental compounds (exogenous sources). Endogenous ROS are largely formed during oxidative phosphorylation in the mitochondria and, therefore, mitochondrial DNA (mtDNA) is at particularly high risk of ROS-induced damage. Mitochondria are essential for cell viability, and oxidative damage to mtDNA has been implicated as a causative factor in a wide variety of degenerative diseases, and in cancer and aging. One of the most common oxidative DNA lesions is 7,8-dihydro-8-oxoguanine (8-oxoG), which can introduce G/C to T/A transversions after DNA replication. Oxidative DNA base lesions, including 8-oxoG, are repaired primarily by the base excision repair (BER) pathway. While we know much about how this pathway functions in processing the nuclear DNA lesions, little is yet known about BER in mitochondria. We have used a number of different approaches to explore the mechanisms of DNA damage processing in the mtDNA. We have been able to demonstrate that mammalian mitochondria efficiently remove 8-oxoG from their genome, and that the efficiency of 8-oxoG incision increases with age in rats and mice. Yet 8-oxoG accumulates in mtDNA during aging. Changes in mitochondrial function with age have been observed in several organisms and accumulation of DNA lesions in mtDNA with age may be an underlying cause for numerous age-associated diseases including cancer.     

Evaluation of beneficial and adverse effects of glucocorticoids on a newly developed full-thickness skin model.

Glucocorticoids (GCs) are highly effective compounds widely used in the treatment of inflammatory diseases; however, they offer distinct adverse effects such as skin thinning in response to long-term topical treatment. Nevertheless it is difficult to deduce the safety of a newly synthesized compound from its structural formula. Efficient assay systems that measure beneficial and adverse effects are needed. In the present study the applicability of a three-dimensional full-thickness skin model (FTSM) is tested to display GC-induced effects regarding anti-inflammation and atrophy. It is shown that topical application of a commercial GC ointment suppresses the ultraviolet (UV)B induced induction of interleukin (IL)-6 and IL-8. Addition of purified betamethasone-17-valerate, prednicarbate and clobetasol-17-propionate to the culture medium for 14 days caused a reduction in the number of epidermal cell-layers corresponding to the atrophic risk found in vivo. Similarly, repeated topical application of five GC creams induced epidermal thinning. Evidence is given that the inhibitory effect on keratinocyte proliferation contributes to this effect. Furthermore, dermal thinning was monitored by measuring type I collagen synthesis; a decreased collagen synthesis similar to the in vivo situation is shown. The present study demonstrates the versatility of this FTSM in the validation of effectiveness and safety of GCs.     

Enhancing in vitro fertilization of mouse oocytes by partial zona pellucida digestion

This work was undertaken in order to evaluate the effect of partial zona digestion on fertilization in vitro of mouse oocytes and assess zona surface changes induced by the procedure. Three hundred forty-six oocytes allocated for treatment were exposed to Ham's F-10 medium supplemented with 0.5% Pronase for either 3 min (188 oocytes) or 5 min (158 oocytes); 324 oocytes served as controls. Oocyte losses incurred as a result of the procedure were small (15 oocytes; 4.3%). Control and Pronase-treated oocytes were each divided into four subgroups and inseminated with 5 ×10 ⁵,5 ×10 ⁴,5 ×10 ³,or 5 ×10 ² sperm cells/ml. Fertilization was assessed 8 hr following insemination by the appearance of two pronuclei and development to the two- to four-cell stage the following day. The morphology of the zona pellucida following Pronase treatment was assessed by phase-contrast and scanning electron (SEM) microscopies performed immediately after treatment. Fertilization rate of control oocytes was 80% at a sperm concentration of 500,000/ml and gradually declined to ~30% at 500 cells/ml. In contrast, treated oocytes inseminated with 500 sperm cells/ml demonstrated a normal rate of fertilization. At this low sperm concentration the longer Pronase treatment was significantly (P < 0.05) more efficient in enhancing fertilization (69 and 88% for 3 and 5 min of Pronase treatment, respectively). Polyspermic fertilization was not observed in any of the subgroups. Phase-contrast microscopic examination of oocytes at the time of Pronase treatment showed an initial swelling of the zona pellucida for 30–60 sec with a time-dependent increase in its transparency. SEM demonstrated that the fine meshlike structure of the outer surface of zona pellucida digested away, leaving a smoother surface. These morphologic changes were not associated with a diminution in sperm binding or penetration. This work demonstrates that partial zona digestion, which causes uniform dissolution of the zona pellucida and reduction of its thickness, is simple and safe. The procedure significantly increased fertilization efficiency at very low sperm concentrations and could, by itself or in conjunction with other methodologies, improve the reproductive capacity of men producing sperm with a reduced penetrating ability.     

Differential involvement of hippocampal and amygdalar NMDA receptors in contextual and aversive aspects of inhibitory avoidance memory in rats

Adult male rats bilaterally implanted with guide canullae aimed either at the dorsal hippocampus (dHIP) or the basolateral nucleus of the amygdala (BLA) were trained in a step-down inhibitory avoidance task (IA) and tested for retention 24 h after training. Immediately after training, animals were given a bilateral infusion of the N-methyl-D-aspartate (NMDA) glutamate receptor antagonist D,L-2-amino-5-phosphonopentanoic acid (AP5) (5.0 microg) into the dHIP or the BLA. Both intrahippocampal and intraamygdala infusions of AP5 blocked IA retention. Preexposure to the training box, but not to a different environment 24 h prior to training prevented the impairing effect of intrahippocampal infusion of AP5 on retention. Preexposure did not affect the retention impairment induced by intraamygdala infusion of AP5. These data suggest that hippocampal NMDA receptors might be involved in the contextual and spatial aspects, while amygdalar NMDA receptors might be involved in the aversive aspects of memory for IA.     

Motor-evoked potential facilitation during progressive cortical suppression by propofol

We characterized the effects of various stimulation patterns on motor-evoked potentials (MEPs) elicited by repetitive transcranial magnetoelectric stimulation at different levels of cortical suppression by propofol. In 20 patients undergoing lumbar disk surgery, propofol target plasma concentrations (PTPCs) were increased incrementally by target plasma-level controlled infusion during the induction of anesthesia. MEPs were recorded from the muscles of the upper extremities after single, double, and quadruple magnetoelectric stimulation at 500, 200, and 100 Hz. The mean PTPC during loss of responsiveness to verbal instructions (CP50) was 3 microg/mL (CP(95), 5 microg/mL). At PTPCs <3 microg/mL, maximal MEP amplitudes were elicited by quadruple stimulation at 100 Hz. At PTPCs > or =3 microg/mL, four pulses at 200 Hz yielded peak MEP amplitudes. Therefore, quadruple magnetoelectric stimulation at 100 Hz yields peak myogenic responses in awake patients. With progressive cortical suppression resulting from PTPCs beyond 3 microg/mL, the most effective stimulation frequency shifts to 200 Hz. This may be explained by a differential dose-dependent action of propofol on GABAergic cortical interneurons, corresponding to the clinically observed state of vigilance. Recording of spinal cord evoked potentials will aid in further elucidation of the modulatory effects of general anesthesia on intracortical facilitation. IMPLICATIONS: We investigated the effect of different transcranial magnetoelectric stimulation paradigms on motor-evoked potentials during different levels of cortical suppression by propofol. The most effective stimulation frequency seems to change from 100 to 200 Hz during progressive propofol dose escalation, possibly because of specific interaction with cortical interneurons.