Marcello Maestri

Combined use of intraoperative ultrasound and indocyanine green fluorescence imaging to detect liver metastases from colorectal cancer

OBJECTIVES Surgical excision is the standard strategy for managing liver metastases from colorectal carcinoma. The achievement of negative (R0) margins is a major determinant of disease-free survival in these patients. Current imaging techniques are of limited value in achieving this goal. A new approach to the intraoperative detection of colorectal liver metastatic tissue based on the emission of indocyanine green (ICG) fluorescence was evaluated. METHODS A total of 25 consecutive patients with liver metastases from primary colorectal cancers who were eligible for liver resection received a bolus of ICG (0.5 mg/kg body weight) 24 h before surgery. During surgery, ICG fluorescence, which accumulates around lesions as a result of defective biliary clearance, was detected with a near-infrared camera system, the Photodynamic Eye (PDE). Numbers of lesions detected by, respectively, PDE + ICG, intraoperative ultrasound (IOUS) and preoperative computed tomography (CT) were recorded. RESULTS The near-infrared camera plus ICG revealed a total of 77 metastatic liver nodules. Preoperative CT demonstrated 45 (58.4%) and IOUS showed 55 (71.4%). Preoperative CT and IOUS alone were inferior to the combined use of PDE + ICG and IOUS in the detection of lesions of ≤ 3 mm in size. CONCLUSIONS This experience suggests that PDE + ICG, combined with IOUS, may represent a safe and effective tool for ensuring the complete surgical eradication of liver metastases from colorectal cancer.

Allogenic platelet gel in the treatment of pressure sores: a pilot study

Although platelet gel is considered one of the most popular tools in the treatment of chronic ulcers, current consensus on its use is not unanimous. A prospective randomised trial was carried out at the Plastic Surgery Unit of the ‘Salvatore Maugeri’ Foundation Hospital of Pavia (Italy). The study involved 13 patients affected by spinal cord injury with 16 pressure sores over a period of 20 months. The ulcer was considered the experimental unit of the study irrespective of the number of ulcers per patient. Each consecutive ulcer was randomised to be treated either with allogenic platelet gel or with current best practice approach to chronic wounds dressing protocol. At the end of the treatment 15 ulcers out of 16 improved clinically. No statistically significant difference was demonstrated in volume reduction between the two groups, although a statistically significant difference could be demonstrated in the onset time of granulation tissue proliferation as in the wounds treated with platelet gel the healing process was triggered earlier. Our study suggests that platelet gel is mostly effective within the first 2 weeks of treatment while a prolonged treatment does not provide any significant advantage versus the current best practice approach to chronic wounds protocols.

Transarterial chemoembolization of hepatocellular carcinoma. Agents and drugs: an overview. Part 1

Introduction: Hepatocellular carcinoma (HCC) is one of the most common lethal malignancies. The prognosis is poor despite progress in early diagnosis. Transarterial chemoembolization (TACE) represents an important local therapy. More recently the embolic agent itself is used as a drug loaded carrier. An overview of the present situation in the field of TACE has been made, taking into account the materials constituting the embolizing agents and the way of controlled drug release. Areas covered: Clinical overview of TACE with attention to the present limits and problems of this technique; focus on the present situation of the materials (polymers) used for the preparation of the microparticulate systems to administer with attention to the new possible materials. Expert opinion: The use of TACE techniques is important in the treatment of HCCs. However, these techniques need to be improved, in particular taking into account the use of new materials for the preparation of embolizing agents able to control drug release.

Indocyanine green delivery systems for tumour detection and treatments.

Indocyanine green (ICG) is a cyanine compound that displays fluorescent properties in the near infrared region. This dye is employed for numerous indications but nowadays its major application field regards tumour diagnosis and treatments. Optical imaging by near infrared fluorescence provides news opportunities for oncologic surgery. The imaging of ICG can be useful for intraoperative identification of several solid tumours and metastases, and sentinel lymph node detection. In addition, ICG can be used as an agent for the destruction of malignant tissue, by virtue of the production of reactive oxygen species and/or induction of a hyperthermia effect under irradiation. Nevertheless, ICG shows several drawbacks, which limit its clinical application. Several formulative strategies have been studied to overcome these problems. The rationale of the development of ICG containing drug delivery systems is to enhance the in vivo stability and biodistribution profile of this dye, allowing tumour accumulation and resulting in better efficacy. In this review, ICG containing nano-sized carriers are classified based on their chemical composition and structure. In addition to nanosystems, different formulations including hydrogel, microsystems and others loaded with ICG will be illustrated. In particular, this report describes the preparation, in vitro characterization and in vivo application of ICG platforms for cancer imaging and treatment. The promising results of all systems confirm their clinical utility but further studies are required prior to evaluating the formulations in human trials.

Nonbiodegradable Expanded Polytetrafluoroethylene-Covered Stent Implantation in Porcine Peripheral Arteries: Histologic Evaluation of Vascular Wall Response Compared with Uncoated Stents

AbstractPurpose: To test the vascular wall response to an expanded polytetrafluoroethylene-covered stent, compared with conventional stenting, up to 6 months after deployment in the vascular district of a swine model. Methods: Fourteen minipigs underwent implantation of expanded polytetrafluoroethylene-covered stents (CS) and bare stents (BS) in five peripheral arteries. Animals were killed at different time points (from 1 to 180 days). Histopathologic assessment by morphologic and morphometric analysis and by scanning electron microscopy (SEM) were used to assess the incorporation characteristics and re-endothelialization extent of the two types of stents. Results: A total of 70 stents (14 CS and 14 BS in the renal arteries; 28 CS in the iliac arteries, and 14 CS in the aorta) were implanted. Microscopic examination confirmed the absence of occlusive thrombi in both the CS and BS groups. Microthrombi were observed in 10 of 13 CS (77% of cases) and in four of four BS (100% of cases, p < 0.05). Inflammation was mild in 69% of segments in which a CS was implanted and in 74% of segments in which a BS was implanted (p= NS), while a severe inflammatory reaction was observed in 6% of CS segments and in 8% of BS segments (p= NS). No differences were detected at the long-term analysis between neointimal thickness in CS compared with BS segments (0.46 ± 0.18 mm vs 0.42 ± 0.26 mm at 90 days and 0.36 ± 0.08 mm vs 0.35 ± 0.04 mm at 180 days; p= NS, respectively). At SEM analysis, re-endothelization was evident 15 days after the implant in both CS and BS starting from the stent edges. Conclusion: CS implantation did not elicit a more severe thrombotic deposition compared with that of BS. A similar inflammatory reaction of the arterial wall was present in the two stent groups 3 and 6 months following the implant. In addition, CS implantation did not stimulate excessive neointimal formation when compared with BS.

Creation and implantation of acellular rat renal ECM-based scaffolds

Abstract Kidney transplantation is the only potentially curative treatment for patient facing end-stage renal disease, and it is now routinely used. Its use is mainly limited by the supply of transplantable donor organs, which far exceeds the demand. Regenerative medicine and tissue engineering offer promising means for overcoming this shortage. In the present study, we developed and validated a protocol for producing acellular rat renal scaffolds. Left kidneys were removed from 26 male Lewis rats (weights: 250–350 g) and decellularized by means of aortic anterograde perfusion with ionic and anionic detergents (Triton X-100 1% and SDS 1%, respectively). 19 scaffolds thus obtained (and contralateral native kidneys as controls) were deeply characterized in order to evaluate the decellularization quality, the preservation of extracellular matrix components and resultant micro-angioarchitecture structure. The other 7 were transplanted into 7 recipient rats that had undergone unilateral nephrectomy. Recipients were sacrificed on post-transplantation day 7 and the scaffolds subjected to histologic studies. The dual-detergent protocol showed, with only 5 h of perfusion per organ, to obtain thoroughly decellularized renal scaffolds consisting almost exclusively of extracellular matrix. Finally the macro- and the microarchitecture of the renal parenchyma were well preserved, and the grafts were implanted with ease. Seven days after transplant, the scaffolds were morphologically intact although all vascular structures were obstructed with thrombi. Production and implantation of acellular rat renal scaffolds is a suitable platform for further studies on regenerative medicine and tissue engineering.

Augmenter of liver regeneration enhances the success rate of fetal pancreas transplantation in rodents

BACKGROUND Treatment of fetal pancreas (FP) isografts with insulin-like growth factor-I greatly improves the rate of conversion to euglycemia in diabetic rats. Complete knowledge of other factors that may facilitate the engraftment and function of FP in vivo is still embryonic. Augmenter of liver regeneration (ALR) is a newly described polypeptide growth factor found in weanling rat livers. ALR has trophic effects on regenerating liver. We studied the effects of in situ administration of this agent on FP isografts in rats. METHODS Streptozotocin-diabetic Lewis rats (blood glucose > 300 mg/dl) received 16 FP isografts transplanted intramuscularly. ALR was delivered from day 1 through day 14, in doses of 40 or 400 ng/kg/d. Animals were followed for 3 months with serial weights and blood glucose monitoring. These animals were compared with those treated with vehicle alone. RESULTS Of the group treated with ALR at 40 ng/kg/day for 14 days, 89% (eight of nine) were euglycemic (P=0.0003). Of the group treated with ALR at 400 ng/kg/day for 14 days, 88% (seven of eight) were euglycemic (P=0.0007). Of the group treated with vehicle alone, none of the six were euglycemic. Euglycemia is defined here as glucose < 200 mg/dl for 3 days. Pathology of the intramuscular transplant site showed patches of islet tissue embedded in fat. These patches demonstrated insulin immunoreactivity. CONCLUSIONS Diabetes was reversed in a significantly greater proportion of FP + ALR-treated recipients than those animals treated with vehicle alone. Local delivery of growth factors may be used as an adjunct to FP transplantation to improve the rate of success. This in situ model may be useful to further evaluate other soluble factors.

Insulin-like growth factor-I ameliorates delayed kidney graft function and the acute nephrotoxic effects of cyclosporine.

BACKGROUND Delayed graft function (DGF) is a relatively common complication after cadaveric renal transplantation. The adverse effect of DGF on long-term graft survival has lead to intensive efforts to reduce ischemic graft injury. In this study we examined the effects of a new protective treatment based on insulin growth factor (IGF)-I. We evaluated the impact of the treatment on renal recovery and on the nephrotoxicity that is a common side effect of mainstream immunosuppressants. Because therapy with IGF-I or the analog des(1-3)IGF-I is effective in treating experimental ischemic renal failure, these peptides may be useful as perspective clinical treatments. METHODS We have addressed three areas relating to the potential use of IGF-I and its analog des(1-3)IGF-I. First, because of the immunogenic properties of IGF-I, we assessed the effect of des(1-3)IGF-I on the rejection of skin allografts in Lewis rats. Next we determined whether treatment with des(1-3)IGF-I influences the early function of transplanted kidneys in a model of DGF induced by a combination of warm and cold ischemia. Finally we tested whether IGF-I protects against acute cyclosporine nephrotoxicity. RESULTS Des(1-3)IGF-I did not accelerate the rejection of the skin grafts (P=0.57). The administration of this peptide in a model of syngenic renal transplant improved the early function of the graft. Postoperative values of creatinine and blood urea nitrogen were significantly better (P<0.05) in treated animals. IGF-I also ameliorated the nephrotoxicity of cyclosporine, with better values of creatinine and blood urea nitrogen (P<0.05). CONCLUSIONS In evaluating this study it should be recognized that the animal models studied, although widely used, differ from the human condition. However, IGF-I and des(1-3)IGF-I exhibit properties that strongly suggest their value in preventing clinical DGF, and they deserve further studies.

Development of thermosensitive chitosan/glicerophospate injectable in situ gelling solutions for potential application in intraoperative fluorescence imaging and local therapy of hepatocellular carcinoma: a preliminary study

Objectives: Thermosensitive chitosan/glycerophosphate (C/GP) solutions exhibiting sol–gel transition around body temperature were prepared to develop a class of injectable hydrogel platforms for the imaging and loco-regional treatment of hepatocellular carcinoma (HCC). Indocyanine green (ICG) was loaded in the thermosensitive solutions in order to assess their potential for the detection of tumor nodules by fluorescence. Methods: The gel formation of these formulations as well as their gelling time, injectability, compactness and resistance of gel structure, gelling temperature, storage conditions, biodegradability, and in vitro dye release behavior were investigated. Ex vivo studies were carried out for preliminary evaluation using an isolated bovine liver. Results: Gel strengths and gelation rates increased with the cross-link density between C and GP. These behaviors are more evident for C/GP solutions, which displayed a gel-like precipitation at 4°C. Furthermore, formulations with the lowest cross-link density between C and GP exhibited the best injectability due to a lower resistance to flow. The loading of the dye did not influence the gelation rate. ICG was not released from the hydrogels because of a strong electrostatic interaction between C and ICG. Ex vivo preliminary studies revealed that these injectable formulations remain in correspondence of the injected site. Conclusions: The developed ICG-loaded hydrogels have the potential for intraoperative fluorescence imaging and local therapy of HCC as embolic agents. They form in situ compact gels and have a good potential for filling vessels and/or body cavities.

Effect of Hyperbarism on Radiofrequency Ablation Outcome

OBJECTIVE Our objective was to investigate whether increases in atmospheric or local tissue pressure would affect the outcome of radiofrequency ablation procedures and the size of the created thermal lesions. MATERIALS AND METHODS Thermal lesions were produced in specimens of explanted bovine liver inside a hyperbaric chamber at 101 (atmospheric), 141, 202, 273, and 364 kPa using radiofrequency power settings of 20, 30, 40, and 50 W. In subsequent in vivo experiments, thermal lesions were produced in the livers of anesthetized pigs with or without occlusion of the hepatic vein draining the ablation site. RESULTS At each radiofrequency power setting, progressive increases in applied pressure were paralleled by decreases in minimum impedance and increases in maximum tissue temperatures at the electrode tip (reflecting tissue-fluid boiling points), delivery time, total energy delivered, and thermal lesion volumes. Similar increases were observed in radiofrequency ablation procedures performed in vivo under occlusion of the vein draining the ablation site. CONCLUSION By elevating the tissue-fluid boiling point, increased pressure delays the desiccation of tissue in contact with the radiofrequency electrode tip and the related sharp increase in impedance. The result is prolonged delivery of larger amounts of radiofrequency energy and larger thermal lesions.