Sea Urchin Food Waste into Bioactives: Collagen and Polyhydroxynaphtoquinones from P. lividus and S. granularis

Approximately 75,000 tons of different sea urchin species are globally harvested for their edible gonads. Applying a circular economy approach, we have recently demonstrated that non-edible parts of the Mediterranean Sea urchin Paracentrotus lividus can be fully valorized into high-value products: antioxidant pigments (polyhydroxynaphthoquinones-PHNQs) and fibrillar collagen can be extracted to produce innovative biomaterials for biomedical applications. Can waste from other edible sea urchin species (e.g., Sphaerechinus granularis) be similarly valorised? A comparative study on PHNQs and collagen extraction was conducted. PHNQ extraction yields were compared, pigments were quantified and identified, and antioxidant activities were assessed (by ABTS assay) and correlated to specific PHNQ presence (i.e., spinochrome E). Similarly, collagen extraction yields were evaluated, and the resulting collagen-based biomaterials were compared in terms of their ultrastructure, degradation kinetics, and resistance to compression. Results showed a partially similar PHNQ profile in both species, with significantly higher yield in P. lividus, while S. granularis exhibited better antioxidant activity. P. lividus samples showed higher collagen extraction yield, but S. granularis scaffolds showed higher stability. In conclusion, waste from different species can be successfully valorised through PHNQ and collagen extraction, offering diverse applications in the biomedical field, according to specific technical requirements.

Recent Advances in the Development of Biomimetic Materials

In this review, we focused on recent efforts in the design and development of materials with biomimetic properties. Innovative methods promise to emulate cell microenvironments and tissue functions, but many aspects regarding cellular communication, motility, and responsiveness remain to be explained. We photographed the state-of-the-art advancements in biomimetics, and discussed the complexity of a "bottom-up" artificial construction of living systems, with particular highlights on hydrogels, collagen-based composites, surface modifications, and three-dimensional (3D) bioprinting applications. Fast-paced 3D printing and artificial intelligence, nevertheless, collide with reality: How difficult can it be to build reproducible biomimetic materials at a real scale in line with the complexity of living systems? Nowadays, science is in urgent need of bioengineering technologies for the practical use of bioinspired and biomimetics for medicine and clinics.

Mutable Collagenous Tissue Isolated from Echinoderms Leads to the Production of a Dermal Template That Is Biocompatible and Effective for Wound Healing in Rats

The mutable collagenous tissue (MCT) of echinoderms possesses biological peculiarities that facilitate native collagen extraction and employment for biomedical applications such as regenerative purposes for the treatment of skin wounds. Strategies for skin regeneration have been developed and dermal substitutes have been used to cover the lesion to facilitate cell proliferation, although very little is known about the application of novel matrix obtained from marine collagen. From food waste we isolated eco-friendly collagen, naturally enriched with glycosaminoglycans, to produce an innovative marine-derived biomaterial assembled as a novel bi-layered skin substitute (Marine Collagen Dermal Template or MCDT). The present work carried out a preliminary experimental in vivo comparative analysis between the MCDT and Integra, one of the most widely used dermal templates for wound management, in a rat model of full-thickness skin wounds. Clinical, histological, and molecular evaluations showed that the MCDT might be a valuable tool in promoting and supporting skin wound healing: it is biocompatible, as no adverse reactions were observed, along with stimulating angiogenesis and the deposition of mature collagen. Therefore, the two dermal templates used in this study displayed similar biocompatibility and outcome with focus on full-thickness skin wounds, although a peculiar cellular behavior involving the angiogenesis process was observed for the MCDT.

A Second Life for Seafood Waste: Therapeutical Promises of Polyhydroxynapthoquinones Extracted from Sea Urchin by-Products

Coping with a zero-waste, more sustainable economy represents the biggest challenge for food market nowadays. We have previously demonstrated that by applying smart multidisciplinary waste management strategies to purple sea urchin (Paracentrotus lividus) food waste, it is possible to obtain both a high biocompatible collagen to produce novel skin substitutes and potent antioxidant pigments, namely polyhydroxynapthoquinones (PHNQs). Herein, we have analyzed the biological activities of the PHNQs extract, composed of Spinochrome A and B, on human skin fibroblast cells to explore their future applicability in the treatment of non-healing skin wounds with the objective of overcoming the excessive oxidative stress that hinders wound tissue regeneration. Our results clearly demonstrate that the antioxidant activity of PHNQs is not restricted to their ability to scavenge reactive oxygen species; rather, it can be traced back to an upregulating effect on the expression of superoxide dismutase 1, one of the major components of the endogenous antioxidant enzymes defense system. In addition, the PHNQs extract, in combination with Antimycin A, displayed a synergistic pro-apoptotic effect, envisaging its possible employment against chemoresistance in cancer treatments. Overall, this study highlights the validity of a zero-waste approach in the seafood chain to obtain high-value products, which, in turn, may be exploited for different biomedical applications.

Valorization of the Antioxidant Effect of Mantua PGI Pear By-Product Extracts: Preparation, Analysis and Biological Investigation

For improving the management of the production chain of PGI Mantua pears (which comprises many varieties, including Abate Fetel), applying the cardinal principles of circular economy and sustainability, the fruits with diseases or defects were recovered for producing dried rounds of pears from the Abate Fetel cultivar, a new product with high nutritional value that extends the remaining life. This process led to the production of secondary and residual by-products, which are mainly composed of the highest and lowest part of the fruits, comprising seeds, pulps, peels and petioles. Hence, this study was focused on the valorization of these secondary by-products of Abate Fetel pears through the production of pear extracts using traditional and "green" extraction methods that involve the use of supercritical CO₂ fluid extraction. The produced extracts, together with a reference solvent-derived extract, were analyzed by HPLC-ESI-MS, and in parallel, their direct and cellular antioxidant activity were assessed. Evidence has indicated that all the tested extracts reduced the H₂O₂-induced reactive oxygen species (ROS), lipid peroxidation and nitric oxide (NO) levels, respectively, in human intestinal Caco-2 cells. Hence, this study clearly suggests that extracts obtained from Mantuan PGI pear by-products may be used as valuable sources of bioactive upcycled phytocomplex for the development of dietary supplements and/or functional foods.

Synthesis and Characterization of Curcumin-Loaded Nanoparticles of Poly(Glycerol Sebacate): A Novel Highly Stable Anticancer System

The research for alternative administration methods for anticancer drugs, towards enhanced effectiveness and selectivity, represents a major challenge for the scientific community. In the last decade, polymeric nanostructured delivery systems represented a promising alternative to conventional drug administration since they ensure secure transport to the selected target, providing active compounds protection against elimination, while minimizing drug toxicity to non-target cells. In the present research, poly(glycerol sebacate), a biocompatible polymer, was synthesized and then nanostructured to allow curcumin encapsulation, a naturally occurring polyphenolic phytochemical isolated from the powdered rhizome of Curcuma longa L. Curcumin was selected as an anticancer agent in virtue of its strong chemotherapeutic activity against different cancer types combined with good cytocompatibility within healthy cells. Despite its strong and fascinating biological activity, its possible exploitation as a novel chemotherapeutic has been hampered by its low water solubility, which results in poor absorption and low bioavailability upon oral administration. Hence, its encapsulation within nanoparticles may overcome such issues. Nanoparticles obtained through nanoprecipitation, an easy and scalable technique, were characterized in terms of size and stability over time using dynamic light scattering and transmission electron microscopy, confirming their nanosized dimensions and spherical shape. Finally, biological investigation demonstrated an enhanced cytotoxic effect of curcumin-loaded PGS-NPs on human cervical cancer cells compared to free curcumin.

Mitigating long-term emissions of landfill aftercare: Preliminary results from experiments combining microbial electrochemical technologies and in situ aeration

Landfills still represent the main option for waste disposal in many parts of the world. Anyway, they often pose a significant pollution risk and contribute to potential environmental and human health impacts via gaseous and liquid (leachate) emission pathways if not properly managed. Some innovative technologies can help to reduce these emissions, such as in situ aeration and the application of microbial electrochemical technologies (METs). METs are an emerging field that open the possibility to control microbial reactions, enhancing electron flows from electron donors towards electron acceptors. To this end, several materials with different electrochemically-active properties are used, such as electrical conductivity, capacitance, surface electroactivity and charge. The present project named LA-LA-LAND (Landfill electron-Lapping for a LANDscape requalification) was aimed to apply METs to treat leachate-saturated zones in old landfills. A MET prototype was constructed using a granular anode (graphite) and a cylindrical air-cathode (electroactive biochar). The METs were integrated to three identical laboratory-scale landfill bioreactors coupled with the in situ aeration technique, while three control reactors run without MET. The maximum values of current and power density obtained were 0.015 A·m^-2 and 0.00035 W·m^-2. The influence of the MET system on the organic matter removal was evident in two reactors, where this technology was applied, with respect to the control ones: total organic carbon decreased on average 13%, while it reduced less than 5% in the control reactors. This preliminary experiment pointed out some critical aspects of MET configuration, such as the weakness of the cathode architecture, which was prone to be flooded by leachate, blocking the aeration flux.

Green Extraction Strategies for Sea Urchin Waste Valorization

Commonly known as “purple sea urchin,” Paracentrotus lividus occurs in the Mediterranean Sea and the eastern Atlantic Ocean. This species is a highly appreciated food resource and Italy is the main consumer among the European countries. Gonads are the edible part of the animal but they represent only a small fraction (10–30%) of the entire sea urchin mass, therefore, the majority ends up as waste. Recently, an innovative methodology was successfully developed to obtain high-value collagen from sea urchin by-products to be used for tissue engineering. However, tissues used for the collagen extraction are still a small portion of the sea urchin waste (<20%) and the remaining part, mainly the carbonate-rich test and spines, are discarded. Residual cell tissues, tests, and spines contain polyunsaturated fatty acids, carotenoids, and a class of small polyphenols, called polyhydroxynaphthoquinones (PHNQ). PHNQ, due to their polyhydroxylated quinonoid nature, show remarkable pharmacologic effects, and have high economic significance and widespread application in several cosmetic and pharmaceuticals applications. A green extraction strategy aimed to obtain compounds of interest from the wastes of sea urchins was developed. The core strategy was the supercritical CO₂ technique, characterized by low environmental impacts. Fatty acids and carotenoids were successfully and selectively extracted and identified depending on the physical parameters of the supercritical CO₂ extraction. Finally, the exhausted powder was extracted by solvent-based procedures to yield PHNQ. The presence of Spinochrome A and Spinochrome B was confirmed and extracts were characterized by a remarkably high antioxidant activity, measured through the 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay. Overall, the selective and successive extraction methods were validated for the valorization of waste from sea urchins, demonstrating the feasibility of the techniques targeting added-value compounds.

A new cyanine from oxidative coupling of chlorogenic acid with tryptophan: Assessment of the potential as red dye for food coloring

A red pigment was prepared by reaction of chlorogenic acid (CGA) with tryptophan (TRP) in air at pH 9 (37% w/w yield) and evaluated as food dye. The main component of pigment was formulated as an unusual benzochromeno[2,3-b]indole linked to a TRP unit, featuring a cyanine type chromophore (λ_max 542, 546 nm, 1% extinction coefficient of the sodium salt = 244 ± 2). The chromophore showed a minimal pH dependence and proved stable for at least 3 h at 90 °C, both at pH 3.6 or 7.0, whereas red wine anthocyanins showed a substantial (30%) and betanin a complete abatement after 1 h at the acidic pHs. An intense coloring of different food matrices was obtained with the pigment at 0.01 % w/w. No toxicity was observed up to 0.2 mg/mL on hepatic and colonic cell lines. These data make this dye a promising alternative for red coloring of food.

Bioactive Phenolic Compounds From Agri-Food Wastes: An Update on Green and Sustainable Extraction Methodologies

Phenolic compounds are broadly represented in plant kingdom, and their occurrence in easily accessible low-cost sources like wastes from agri-food processing have led in the last decade to an increase of interest in their recovery and further exploitation. Indeed, most of these compounds are endowed with beneficial properties to human health (e.g., in the prevention of cancer and cardiovascular diseases), that may be largely ascribed to their potent antioxidant and scavenging activity against reactive oxygen species generated in settings of oxidative stress and responsible for the onset of several inflammatory and degenerative diseases. Apart from their use as food supplements or as additives in functional foods, natural phenolic compounds have become increasingly attractive also from a technological point of view, due to their possible exploitation in materials science. Several extraction methodologies have been reported for the recovery of phenolic compounds from agri-food wastes mostly based on the use of organic solvents such as methanol, ethanol, or acetone. However, there is an increasing need for green and sustainable approaches leading to phenolic-rich extracts with low environmental impact. This review addresses the most promising and innovative methodologies for the recovery of functional phenolic compounds from waste materials that have appeared in the recent literature. In particular, extraction procedures based on the use of green technologies (supercritical fluid, microwaves, ultrasounds) as well as of green solvents such as deep eutectic solvents (DES) are surveyed.

Microbial recycling cells: First steps into a new type of microbial electrochemical technologies, aimed at recovering nutrients from wastewater

The aim of this work were to study terracotta-based porous air-water separators (4 mm thickness) in microbial recycling cells (MRCs) fed with cow manure (CM), swine manure (SM) and dairy wastewater (DW). Over 125 days, besides the removal of 60-90% of soluble-COD, considerable fractions of the main macronutrients (C, N, P, K, Fe, Mn, Ca, Mg) were removed from the wastewater and deposited on the terracotta separators as both inorganic salts and biomass deposits. Water evaporation at air-water interface as well as the high cathodic pH (10-12), induced by oxygen reduction to OH^-, were the predominant factors leading to precipitation. The separators were saturated of up to 10 g per kg of terracotta of the main macronutrients, with negligible concentrations of the main inorganic contaminants. These materials could be directly reused as nutrients-enriched solid conditioners for agricultural soils.

Green Corrosion Inhibitors from Natural Sources and Biomass Wastes

Over the past decade, green chemistry has been emphasizing the importance of protecting the environment and human health in an economically beneficial manner aiming at avoiding toxins and reducing wastes. The field of metallic materials degradation, generally faced by using toxic compounds, found a fertile research field in green chemistry. In fact, the use of inhibitors is a well-known strategy when metal corrosion needs to be prevented, controlled, or retarded. Green inhibitors are biodegradable, ecologically acceptable and renewable. Their valorization expands possible applications in industrial fields other than ‘waste to energy’ in the perspective of circular economy. Although lot of experimental work has been done and many research papers have been published, the topic of green inhibitors is still an open issue. The great interest in the field expanded the research, resulting in high numbers of tested molecules. However, the most frequently adopted approaches are conventional and, hence, not suitable to fully characterize the potential efficacy of inhibitors. All the mentioned aspects are the object of the present review and are meant as a constructive criticism to highlight the weak points of the green inhibitors field as to re-evaluate the literature and address the future research in the field that still lacks rationalization.

Assisting cultivation of photosynthetic microorganisms by microbial fuel cells to enhance nutrients recovery from wastewater

Spirulina was cultivated in cathodic compartments of photo-microbial fuel cells (P-MFC). Anodic compartments were fed with swine-farming wastewater, enriched with sodium acetate (2.34g_CODL^-1). Photosynthetic oxygen generation rates were sufficient to sustain cathodic oxygen reduction, significantly improving P-MFC electrochemical performances, as compared to water-cathode control experiments. Power densities (0.8-1Wm^-2) approached those of air-cathode MFCs, run as control. COD was efficiently removed and only negligible fractions leaked to the cathodic chamber. Spirulina growth rates were comparable to those of control (MFC-free) cultures, while pH was significantly (0.5-1unit) higher in P-MFCs, due to cathodic reactions. Alkaliphilic photosynthetic microorganisms like Spirulina might take advantage of these selective conditions. Electro-migration along with diffusion to the cathodic compartment concurred for the recovery of most nutrients. Only P and Mg were retained in the anodic chamber. A deeper look into electro-osmotic mechanisms should be addressed in future studies.

Tailored N-Containing Carbons as Catalyst Supports in Alcohol Oxidation

The introduction of N-containing functionalities in carbon-based materials is brought to stable and highly active metal-supported catalysts. However, up to now, the role of the amount and the nature of N-groups have not been completely clear. This study aims to clarify these aspects by preparing tailored N-containing carbons where different N-groups are introduced during the synthesis of the carbon material. These materials were used as the support for Pd nanoparticles. Testing these catalysts in alcohol oxidations and comparing the results with those obtained using Pd nanoparticles supported on different N-containing supports allowed us to obtain insight into the role of the different N-containing groups. In the cinnamyl alcohol oxidation, pyridine-like groups seem to favor both activity and selectivity toward cinnamaldehyde.

Intensive care of patients requiring open abdomen treatment: a case-series analysis

BACKGROUND

This retrospective overview examines the management of patients with temporary open abdomen (OA).

METHODS

The clinical characteristics and intensive care treatment of 34 consecutive patients with OA (1996-2012) were reviewed.

RESULTS

Average age was 61 years, SAPS II score 43, SOFA 8. Two patients had non-contaminated abdomen; 12 had intact gut (only 8 later during stay); 7 repaired gut (only later 4); 13 cutaneous stoma (later 14), and 2 entero-atmospheric fistula (later 8+1 entero-enteral). The median ICU stay was 48 [36-94] days. One quarter of the 2376 ICU-days were classified as severe sepsis/septic shock (antibiotics were given for two thirds of the stay); three quarters were with ventilation; in 95% of days sedatives were given (mainly enterally). Continuous cavity lavage was done in three quarters of days; in 3% of days patients were fasted whereas >20 kcal/kg was given for 74% of days; we fed the gut in 95% of fed-days, in half of them combined with parenteral nutrition. Complications are discussed; mortality was 32.4%, limited to the ICU stay.

CONCLUSION

The intensive care of patients with OA is challenging but can achieve better outcomes than expected. Continuous abdominal lavage improves the evacuation of contaminated fluid or debris and, coupled with antiseptics and low antibiotic pressure, reinforces the control of infection. The gut can be used for nutrition (even without gastrointestinal continuity), and long-term light sedation (mainly enteral) with minimal impact on perfusion, ventilation and gut motility.

Daily monitoring of biomarkers of sepsis in complicated long-term ICU-patients: can it support treatment decisions?

BACKGROUND

Diagnosis/grading of infection and the systemic response to infection may be difficult on admission to the intensive care unit, but it is even more complicated for severely ill patients with long intensive care stays. The ACCP-SCCM criteria are difficult to apply for such patients, and objective, validated biomarkers would be of great use in this setting.

METHODS

Long-term (>6 days) critically ill patients in the general ICU of University Hospital were prospectively enrolled in the study. All patients were assessed daily by the attending physician using the ACCP-SCCM classification. C-reactive protein (CRP, mg/dL), procalcitonin (PCT, ng/mL), and interleukin-6 (IL-6, pg/mL) of daily stored sera were measured after each patient's discharge. After discharge, an independent, overall clinical evaluation and an a posteriori ACCP-SCCM classification were chosen as the reference standard for all comparisons. The assessor was aware of the patient's clinical course but was blinded to levels of biomarkers.

RESULTS

We studied clinical variables and biomarkers of 26 patients over a total of 592 patient days. The day-by-day ACCP-SCCM classification of the attending physician overestimated the severity of the inflammatory response to infection. The diagnostic discriminative ability of severe-sepsis/septic-shock for PCT was high (ROC area 0.952 [0.931-0.973]) and had a best threshold value of 1.58 (83.7% sensitivity, 94.6 % specificity). IL-6 had better discriminative ability than CRP, but both were worse than PCT.

CONCLUSION

PCT > 0.43 ng/mL could add to the clinical propensity for sepsis vs. SIRS not related to infection. Values higher than 1.58 ng/mL may support the bedside clinical diagnosis of severe-sepsis. PCT between 0.5 and 1.0 suggest tight daily monitoring of clinical conditions and re-evaluation of PCT.

Feasibility of localized immunosuppression: 1. Exploratory studies with glucocorticoids in a biohybrid device designed for cell transplantation

Emerging biotechnologies, such as the use of biohybrid devices for cellular therapies, are showing increasing therapeutic promise for the treatment of various diseases, including type 1 diabetes mellitus. The functionality of such devices could be greatly enhanced if successful localized immunosuppression regimens could be established, since they would eliminate the many otherwise unavoidable side effects of currently used systemic immunosuppressive therapies. The existence of local immune privilege at some specialized tissues, such as the eye, CNS, or pregnant uterus, supports the feasibility of localized immunomodulation, and such an approach is particularly well-suited for cell transplant therapies where all transplanted tissue is localized within a device. Following the success of syngeneic transplantation in a subcutaneous prevascularized device as a bioartificial pancreas in a rodent model, we now report the first results of exploratory in vivo islet allograft studies in rats using locally delivered glucocorticoids (dexamethasone phosphate and the soft steroid loteprednol etabonate). Following in vitro assessments, in silico drug distribution models were used to establish tentative therapeutic dose ranges. Sustained local delivery was achieved via implantable osmotic mini-pumps through a central sprinkler, as well as with a sustained-delivery formulation for loteprednol etabonate using poly(D,L-lactic) acid (PLA) microspheres. Doses delivered locally were approximately hundred-fold smaller than those typically used in systemic treatments. While several solubility, stability, and implantation problems still remain to be addressed, both compounds showed promise in their ability to prolong graft survival after tapering of systemic immunosuppression, compared to control groups.

Effects of systemic immunosuppression on islet engraftment and function into a subcutaneous biocompatible device

The aim of this study was to explore the effect of sirolimus (Sir) and tacrolimus (Tac) on islets implanted into a subcutaneous (SC), prevascularized device in syngeneic rats. Animals received a 40-day treatment with Tac and Sir (alone or in combination) starting either on day 0 or 40 days after islet transplantation. Controls received no treatment. A 40-day washout period was performed after immunosuppression (IS). Glycemia and intravenous glucose tolerance tests (IVGTT) were assessed at follow-up. In the control group, 75% of recipients achieved stable normoglycemia after islet transplantation, while none reversed diabetes with any IS regimen started on day 0. Graft dysfunction was irreversible after IS withdrawal. Glucose clearance (IVGTT) was significantly impaired among Tac-treated compared with control groups (P < .05 with IS; P < .01 after washout). Among animals with established grafts, islet dysfunction which occurred under IS treatment persisted after washout in animals treated with Tac and Sir plus Tac. When compared with controls, glucose clearance was significantly impaired in the Tac and Tac plus Sir groups before and after IS (P < .01, Tac; P < 0.01, Tac plus Sir). Sir and Tac showed profound deleterious effects on islet cell engraftment and function, which may hinder the success of implantation into biohybrid devices. Nondiabetogenic IS protocols must be developed for clinical application of islet transplantation into biohybrid devices.

Soft corticosteroids for local immunosuppression: exploring the possibility for the use of loteprednol etabonate for islet transplantation

Transplantation of pancreatic islets into subcutaneous, neovascularized devices is one of the possibilities explored as part of our search for a cure of diabetes. We have recently reported that syngeneic transplantation in a subcutaneous prevascularized device can restore euglycemia and sustain long-term function in rats and that explanted grafts showed preserved islets and intense vascular networks. Because all of the transplanted tissue is localized within the device, if such a bioartificial pancreas approach is used, localized immunosuppression might provide sufficient protection against rejection to achieve long-term function, while also avoiding the serious systemic side effects and the susceptibility for opportunistic infections that are commonly associated with systemic immunosuppressive therapies as only much smaller and localized doses are needed. Soft steroids are obvious candidates because soft drugs are specifically designed to produce targeted local activity, but no systemic side effects due to prompt metabolic (preferably extrahepatic, e.g., hydrolytic) inactivation. However, local concentrations that are effective for immunosuppression, but non-toxic to insulin-producing beta-cells have to be found, and nontrivial difficulties related to long-term local deliverability have to be addressed. Here, we report preliminary results obtained using in vitro studies with human islets used to establish a tentative therapeutic concentration range together with fully scaled three-dimensional finite element method (FEM)-based Comsol multiphysics computational models that were used to explore various possibilities to achieve and maintain these concentration levels within the device.

Culture medium modulates proinflammatory conditions of human pancreatic islets before transplantation

A portion of transplanted islets is lost during engraftment as a result of stressful events, involving hypoxia and production of proinflammatory molecules by islets. Two of these molecules (monocyte chemoattractant protein-1, CCL2/MCP-1 and tissue factor, TF) are directly correlated with reduced graft function. We evaluated which factors reduce islet proinflammatory conditions. In particular the effects of different culture media supplemented with proteins or antioxidant agents on CCL2/MCP-1 and TF human islet release were evaluated. We observed that human islets after culture in final wash culture medium (FW) significantly decreased CCL2/MCP-1 release and TF production compared with CMRL and M199. These effects were independent from the type of protein added to the media (human serum, human albumin, fetal calf serum). Glutathione in FW further decreased CCL2/MCP-1 in a dose-dependent manner. Culture conditions can modulate the proinflammatory state of islets, and could be used in clinical islet transplantation to reduce inflammation during engraftment.

Islet isolation for allotransplantation: variables associated with successful islet yield and graft function

AIMS/HYPOTHESIS

Efficient islet isolation is an important prerequisite for successful clinical islet transplantation. Although progressively improved, islet yield and quality are, however, unpredictable and variable and require standardisation.

METHODS

Since 1989 we have processed 437 pancreases using the automated method. The donor characteristics, pancreas procurement, and digestion and purification procedures including a wide enzyme characterisation of these pancreases were analysed and correlated with islet yield and transplant outcome.

RESULTS

By univariate analysis, islet yield was significantly associated with donor age (r=0.16; p=0.0009), BMI (r=0.19; p=0.0004), good pancreas condition (p=0.0031) and weight (r=0.15; p=0.0056), total collagenase activity (r=0.22; p=0.0001), adjusted collagenase activity/mg (r=0.18; p=0.0002), collagenase activity/solution volume (r=0.18; p=0.0002) and neutral protease activity/solution volume (r=0.14; p=0.0029). A statistically significant contribution to the variability of islet yield in a multivariate analysis performed on donor variables was found for donor BMI (p=0.0008). In a multivariate analysis performed on pancreas variables a contribution was found for pancreas weight (p=0.0064), and for a multivariate analysis performed on digestion variables we found a contribution for digestion time (p=0.0048) and total collagenase activity (p=0.0001). Twenty-four patients with type 1 diabetes received single islet preparations from single donors. In these patients, multivariate analyses showed that the reduction in insulin requirement was significantly associated with morphological aspects of islets (p=0.0010) and that 1-month C-peptide values were associated with islet purity (p=0.0071).

CONCLUSIONS/INTERPRETATION

These data provide baseline donor, digestion and purification selection criteria for islet isolation using the automated method and indicate that the morphological aspect may be a clinically relevant measure of islets on which the decision for transplant can be based.

In vitro modulation of monocyte chemoattractant protein-1 release in human pancreatic islets

Islet transplantation is a new approach to treat type 1 diabetic patients. Despite its great potential and progressively increasing success rate, islet engraftment still represents an unsolved problem. Only part of the transplanted beta-cell mass survives after infusion due to hypoxia and inflammatory reactions, principally mediated by macrophages. We have demonstrated that human islets release monocyte chemoattractant protein-1 (MCP-1), one of the most powerful macrophage chemokines, which may impair the fate of a transplant. In this study we have attempted to modulate in vitro MCP-1 release by human islets. Human islets isolated using the automated method were cultured in CMRL or M199 standard culture media alone or supplemented with (1) two intracellular kinase inhibitors (10 micromol/L RO8220, a protein kinase C inhibitor, and rcAMP 20 micromol/L, a protein kinase A inhibitor) or (2) two antioxidant and cell-protective agents (vitamin E, vitamin B); or (3) immunosuppressive drugs (0.001 to 10 ng/mL cyclosporine, 0.1 to 100 ng/mL rapamycin, 0.1 to 10 ng/mL tacrolimus, 0.001 to 10 ng/mL mycophenolate acid). We observed that the only culture condition that significantly decreased MCP-1 in human islets were CMRL (31 +/- 12 in CMRL vs 539 +/- 184 pg/mL, in M199, P <.05) or cyclosporine (514 +/- 83 pg/mL in control islet vs 307 +/- 13, 231 +/- 44, 192 +/- 4, 242 +/- 113, 169 +/- 15 pg/mL in islet plus cyclosporine ranging from 0.001 to 10 ng/mL, respectively, P >.05). The capacity of in vitro factors to decrease human islet MCP-1 release suggests strategies to increase the success of islet transplantation.

Identification of in vitro parameters predictive of graft function: a study in an animal model of islet transplantation

The quality of human islets is one of the factors decisive for the success of human islet transplantation. Several parameters have been proposed to characterize islet quality, but none of them has been able to predict the fate of a transplant. The aim of our study was to correlate a panel of in vitro parameters for islet viability with their in vivo function after transplantation in nude mice. Islets were obtained after enzymatic digestion of a human pancreas; they were purified from exocrine tissue using a continuous-density gradient. Two aliquots of islets (1000 and 2000 islets) were transplanted under the kidney capsule of diabetic nude mice. The animals were followed for 1 month with repeated measurements of blood glucose and body weight. One month after transplantation, mice were killed and their graft harvested for histologic analysis. In parallel we studied in vitro islet viability with propidium iodide and fura-2, their insulin content, their purity, and their insulin response to glucose upon static incubation. Ten islet preparations were transplanted: 3 out of 10 preparations did not restore normoglycemia; 4 out of 10 normalized glycemia only in mice receiving 2000 islets, and 3 out of 10 fully restore normoglycemia in all mice. The purity of preparations (R(2) = 0.63 and 0.85, respectively, with 1000 and 2000 islets) and the insulin content (R(2) = 0.75 with 2000 IE) correlated with transplant success. These data show that purity of islet preparations and their insulin content should be useful parameters for the selection of islet preparations for transplant purposes.

Non-invasive mechanical ventilation in patients with acute cardiogenic pulmonary edema

AIM

To evaluate the use of noninvasive mechanical ventilation (NIMV) in patients with acute cardiogenic pulmonary edema.

METHODS

DESIGN

prospective study.

SETTING

Emergency Department at a University hospital.

PATIENTS

84 patients with acute respiratory distress due to pulmonary edema. Interven-tions: NIMV, using a pressure support mode and positive end-expiratory pressure (PEEP). A "weaning test" to evaluate clinical stability.

MEASUREMENTS

heart rate, arterial blood pressure, respiratory rate, arterial blood gases, electrocardiogram and incidence of myocardial infarction before and after NIMV. Mortality and duration of hospital stay were also considered.

RESULTS

A total of 84 patients received NIMV with 14+/-3.6 cm H2O pressure support over PEEP of 8.3+/-2.1 cm H2O and FiO2 1. At the end of the study period, 16 patients (19%) were considered "non responders" and required invasive ventilation; 62 patients (74%) were considered "responders" and subsequently transferred to the medical ward. The hospital mortality was 14% and 25% in the "responder" and "non responder" groups, respectively; the length of stay was 15.7+/-10.1 days in the "responder" group vs 16+/-10.6 days in the "non responder" group. We never found new episodes of myocardial infarction related to NIMV. The only significant difference between "responder" and "non responder" patients was arterial blood pressure.

CONCLUSIONS

We hypothesize that "non responder" patients, characterized by blood pressure values lower than "responders", are less "cardiocompetent" and thus unable to cope with the increased work of breathing. NIMV avoided Intensive Care Unit admission for 74% of the observed patients.

Islet allotransplantation in type 1 diabetic patients

Islet transplantation was proposed more than 10 years ago as treatment for normalising glucose homeostasis in type 1 diabetic patients. Since the beginning it has aroused great interest among diabetic patients being an easy procedure, burdened by minor complications: islet transplantation in fact consists on a transhepatic percutaneous injection under local anaesthesia. The initial clinical outcomes not came up to expectations, being low the insulin independence rate and the long term graft function in recipients. Recently, thanks to the introduction of new immunosuppression strategies, clinical data greatly improved: insulin independence was reached in all recipients and maintained in more than 70% of them 2 years from the transplant. The need of an immunosuppression therapy limits the indication of islet transplantation to diabetic patients already immunosuppressed for a previous organ transplant or to patients with brittle diabetes, that is not controlled also with the new strategies of insulin treatment, with a poor quality of life and an increased rate of diabetic complications. Other problems are represented by the progressive decrease of graft function during long term follow up, and by the low number of organ donors that limits the number of transplantation feasible per year.

Cerebral CO2 vasoreactivity evaluation by transcranial Doppler ultrasound technique: a standardized methodology

OBJECTIVE

In normal subjects cerebral CO2 vasoreactivity is measured during spontaneous hyperventilation, breathholding, or adding CO2 to inspiratory gases. The correlation between CO2 and cerebral blood flow may, however, be invalidated by the effects of a modified respiratory pattern on venous return, sympathovagal balance, and cathecolamine release. Moreover, the duration of the test, usually not considered, may play an important role. This may justify the scattering of values found in literature. We evaluated a new standardized method for overcoming these confounding factors.

DESIGN

Experimental.

PARTICIPANTS

Twenty-one healthy volunteers.

METHODS

Subjects were connected through a mouthpiece to a mechanical ventilator set in the intermittent positive pressure ventilation mode. The ventilator was fed by two 40-1 tanks, one of which contained 5% CO2. The inspiratory CO2 concentration was varied at fixed time intervals from 0% to 5% without modifying ventilator settings. End-tidal CO2 was measured at the mouthpiece. Mean blood velocity (V(m)) and pulsatility index (PI) in the middle cerebral artery were measured by means of transcranial Doppler ultrasound.

RESULTS

The test was easily applicable and well tolerated. No hemodynamic alterations were observed during the tests. The correlation between CO2 and V(m) was always linear and highly significant (R2 > 0.8, p < 0.0001). A low intersubject variability was observed. No difference was found between the two hemispheres, nor between the sexes.

CONCLUSIONS

The strict standardization of the technique, avoiding hemodynamic interference, may explain the low intersubject variability. The value of this technique in ventilated neurosurgical patients is still speculative, but it might allow the collecting of valuable data together with a reduction in exposure to CO2, and hence cerebral blood flow modifications.

[Respiratory failure caused by myopathy in severe sepsis]

OBJECTIVE

To describe a generalized myopathic disorder occurred in the convalescence phase of illness of a critically ill patient.

SETTING

Neurological Intensive Care Unit.

PATIENT

A 43-year-old man with acute leukoencephalopathy and severe sepsis complicated by sustained and prolonged cardiovascular, respiratory and renal failure. After 15 days of complete respiratory autonomy, the patient presented an acute ventilatory failure associated with generalized muscle weakness. Neither a relapse of sepsis nor neurological worsening were detected.

MEASUREMENTS AND RESULTS

Electromyogram resulted in normal conduction velocity in both motor and sensitive nervous fibers. Muscular biopsy showed marked fiber size variability with several hypotrophic fibers type II fiber grouping, several areas of degeneration-necrosis with macrophage invasion, dishomogeneous oxidative enzymatic activity, no increase in glycogen or lipid content.

CONCLUSIONS

These results excluded critical illness polyneuropathy and all the other known myopathies. Prolonged period of sepsis with multiple organ failure can result in a direct generalized myopathy. This possibility should be kept in mind while treating long term critically ill survivors.

[Energy metabolism and metabolite flow from muscle tissue during TPN of trauma patients]

AIM

We evaluated muscle-visceral interorgan flux of substrates in 8 critically ill patients in the flow phase after injury.

SETTING

This study was conducted on critically ill patients admitted in ICU.

PATIENTS

8 patients were studied immediately after injury.

RESULTS

We measured leg flux for oxygen, amino acids, glucose, lactate pyruvate, keton bodies, free fatty acids (FFA), free and total carnitine, and whole body oxygen consumption, nitrogen (N) balance and 3-methyl hystidine (3MEH) excretion during fasting and the second day of metabolic treatment (10.7 +/- 0.06 g x N x m-2 e 1035.5 +/- 3.9 kcal x m-2 x die). During fast the leg shows a net release of N, pyruvate, FFA and free carnitine while glucose, lactate and keton bodies fluxes are not different from zero. The energy balance of the leg is markedly negative (substrate for 79 kcal x m-2 burned for leg energy requirement and 347 kcal x m-2 released as a such). Assuming the body muscle tissue 4.5 times the leg tissue and knowing whole body energy balance, we were able to assess that the non muscular (visceral) part of the body resulted in a consistently positive energy balance. The metabolic treatment is able to match the energy expenditure and the substrate efflux of the leg (and the whole body muscle tissue). In fact the efflux of amino acids and FFA is reduced pyruvate blunted while glucose is remarkably taken up (the uptake of the whole muscle tissue accounted for 72% of the daily load). At the same time, the treatment blunts leg free carnitine and reduces body 3MEH output. Moreover, the caloric balance of the non muscular part of the body remains positive even if the qualiquantitative uptake of substrates is different from fasting.

CONCLUSION

Substrates for energy requirements of visceral tissue came from muscular tissue. The metabolic treatment is able to modulate this process.

Staged lengthening in the prevention of dwarfism in achondroplastic children: a preliminary report

We present our experience, since 1983, in lower-limb lengthening for the treatment of achondroplasic dwarfism. We stress the importance of our method, staged lengthening, which includes two separate operations on the tibia, at the ages of 5 and 10, and two on the femurs, at the ages of 6 and 12. This method allows an overall increase in height varying from 30 to 35 cm and has the advantage of minimizing complications, since children tolerate the lengthening-related problems far better. In 9 years 28 children have undergone limb lengthening, and six of these patients have now completed the first three stages, obtaining a total increase in length from 18 to 23 cm. We discuss the staged lengthening program, pointing out advantages and disadvantages of the method.