Engineered nanoparticles offer the chance to improve drug transport and delivery through biological barriers, exploiting the possibility to leave the blood circulation and traverse the endothelial vascular bed, blood–brain barrier (BBB) included, to reach their target. It is known that nanoparticles gather molecules on their surface upon contact with biological fluids, forming the “protein corona”, which can affect their fate and therapeutic/diagnostic performance, yet no information on the corona’s evolution across the barrier has been gathered so far. Using a cellular model of the BBB and gold nanoparticles, we show that the composition of the corona undergoes dramatic quantitative and qualitative molecular modifications during passage from the “blood” to the “brain” side, while it is stable once beyond the BBB. Thus, we demonstrate that the nanoparticle corona dynamically and drastically evolves upon crossing the BBB and that its initial composition is not predictive of nanoparticle fate and performance once beyond the barrier at the target organ.

OBJECTIVE—The aim of this study was to evaluate whether long-term administration of l-arginine acting through a normalization of NO/cyclic-guanosine-3′,5′-cyclic monophosphate (cGMP) pathway was able to ameliorate peripheral and hepatic insulin sensitivity in 12 lean type 2 diabetic patients. RESEARCH DESIGN AND METHODS—A double-blind study was performed for 3 months. In the first month, patients were treated with their usual diet. Then they were randomly allocated into two groups. In group 1, patients were treated with diet plus placebo (orally three times per day) for 2 months. In group 2 patients were treated for 1 month with diet plus placebo (orally, three times per day) and then for 1 month with diet plus l-arginine (3 g three times per day). At the end of the first and the second month of therapy, patients underwent a euglycemic-hyperinsulinemic clamp combined with [6,6-²H₂]glucose infusion. A total of 10 normal subjects underwent the same test as control subjects. RESULTS—In group 1, no changes in basal cGMP levels, systolic blood pressure, forearm blood flow, glucose disposal, and endogenous glucose production were observed throughout. In group 2, l-arginine normalized basal cGMP levels and significantly increased forearm blood flow by 36% and glucose disposal during the clamp by 34%, whereas it decreased systolic blood pressure and endogenous glucose production by 14 and 29%, respectively. However, compared with normal subjects, l-arginine treatment was not able to completely overcome the defect in glucose disposal. CONCLUSIONS—l-Arginine treatment significantly improves but does not completely normalize peripheral and hepatic insulin sensitivity in type 2 diabetic patients.

Renal cell carcinoma (RCC) accounts for about 3% of all human malignancies and its incidence is increasing. There are no standard biomarkers currently used in the clinical management of patients with renal cell carcinoma. A promising strategy for new biomarker detection is comparative proteomics of urinary exosomes (UE), nanovesicles released by every epithelial cell facing the urinary space, enriched in renal proteins and excluding high-abundance plasmatic proteins, such as albumin. Aim of the work is to establish the protein profile of exosomes isolated from urines of RCC patient compared with control subjects. We enrolled 29 clear cell RCC patients and 23 control healthy subjects (CTRL), age and sex-matched, for urine collection and vesicle isolation by differential centrifugation. Such vesicles were morphologically and biochemically characterized and proved to share exosome properties. Proteomic analysis, performed on 9 urinary exosome (UE) pooled samples by gel based digestion followed by LC-MS/MS, led to the identification of 261 proteins from CTRL subject UE and 186 from RCC patient UE, and demonstrated that most of the identified proteins are membrane associated or cytoplasmic. Moreover, about a half of identified proteins are not shared between RCC and control UE. Starting from these observations, and from the literature, we selected a panel of 10 proteins, whose UE differential content was subjected to immunoblotting validation. Results show for the first time that RCC UE protein content is substantially and reproducibly different from control UE, and that these differences may provide clues for new RCC biomarker discovery.

Eur J Clin Invest 2012; 42 (9): 1027–1036 While large numbers of proteomic biomarkers have been described, they are generally not implemented in medical practice. We have investigated the reasons for this shortcoming, focusing on hurdles downstream of biomarker verification, and describe major obstacles and possible solutions to ease valid biomarker implementation. Some of the problems lie in suboptimal biomarker discovery and validation, especially lack of validated platforms with well‐described performance characteristics to support biomarker qualification. These issues have been acknowledged and are being addressed, raising the hope that valid biomarkers may start accumulating in the foreseeable future. However, successful biomarker discovery and qualification alone does not suffice for successful implementation. Additional challenges include, among others, limited access to appropriate specimens and insufficient funding, the need to validate new biomarker utility in interventional trials, and large communication gaps between the parties involved in implementation. To address this problem, we propose an implementation roadmap. The implementation effort needs to involve a wide variety of stakeholders (clinicians, statisticians, health economists, and representatives of patient groups, health insurance, pharmaceutical companies, biobanks, and regulatory agencies). Knowledgeable panels with adequate representation of all these stakeholders may facilitate biomarker evaluation and guide implementation for the specific context of use. This approach may avoid unwarranted delays or failure to implement potentially useful biomarkers, and may expedite meaningful contributions of the biomarker community to healthcare.