Radiolabeling, whole-body single photon emission computed tomography/computed tomography imaging, and pharmacokinetics of carbon nanohorns in mice

Minfang Zhang,1,2 Dhifaf A Jasim,1 Cécilia Ménard-Moyon,3 Antonio Nunes,1 Sumio Iijima,2 Alberto Bianco,3 Masako Yudasaka,2 Kostas Kostarelos1 1Nanomedicine Laboratory, Faculty of Medical and Human Sciences and National Graphene Institute, University of Manchester, Manchester, United Kingdom; 2Institute of Advanced Science and Industrial Technology (AIST), Tsukuba, Ibaraki, Japan; 3CNRS, Institute of Molecular and Cellular Biology, Laboratory of Immunopathology and Therapeutic Chemistry, Strasbourg, France Abstract: In this work, we report that the biodistribution and excretion of carbon nanohorns (CNHs) in mice are dependent on their size and functionalization. Small-sized CNHs (30–50 nm; S-CNHs) and large-sized CNHs (80–100 nm; L-CNHs) were chemically functionalized and radiolabeled with [111In]-diethylenetriaminepentaacetic acid and intravenously injected into mice. Their tissue distribution profiles at different time points were determined by single photon emission computed tomography/computed tomography. The results showed that the S-CNHs circulated longer in blood, while the L-CNHs accumulated faster in major organs like the liver and spleen. Small amounts of S-CNHs- and L-CNHs were excreted in urine within the first few hours postinjection, followed by excretion of smaller quantities within the next 48 hours in both urine and feces. The kinetics of excretion for S-CNHs were more rapid than for L-CNHs. Both S-CNH and L-CNH material accumulated mainly in the liver and spleen; however, S-CNH accumulation in the spleen was more prominent than in the liver. Keywords: biodistribution, excretion, functionalization, nano-carbon, nanomedicin

Lipidomic Analysis of the Outer Membrane Vesicles from Paired Polymyxin-Susceptible and -Resistant Klebsiella pneumoniae Clinical Isolates

Gram-negative bacteria produce outer membrane vesicles (OMVs) as delivery vehicles for nefarious bacterial cargo such as virulence factors, which are antibiotic resistance determinants. This study aimed to investigate the impact of polymyxin B treatment on the OMV lipidome from paired polymyxin-susceptible and -resistant Klebsiella pneumoniae isolates. K. pneumoniae ATCC 700721 was employed as a reference strain in addition to two clinical strains, K. pneumoniae FADDI-KP069 and K. pneumoniae BM3. Polymyxin B treatment of the polymyxin-susceptible strains resulted in a marked reduction in the glycerophospholipid, fatty acid, lysoglycerophosphate and sphingolipid content of their OMVs. Conversely, the polymyxin-resistant strains expressed OMVs richer in all of these lipid species, both intrinsically and increasingly under polymyxin treatment. The average diameter of the OMVs derived from the K. pneumoniae ATCC 700721 polymyxin-susceptible isolate, measured by dynamic light scattering measurements, was ~90.6 nm, whereas the average diameter of the OMVs isolated from the paired polymyxin-resistant isolate was ~141 nm. Polymyxin B treatment (2 mg/L) of the K. pneumoniae ATCC 700721 cells resulted in the production of OMVs with a larger average particle size in both the susceptible (average diameter ~124 nm) and resistant (average diameter ~154 nm) strains. In light of the above, we hypothesize that outer membrane remodelling associated with polymyxin resistance in K. pneumoniae may involve fortifying the membrane structure with increased glycerophospholipids, fatty acids, lysoglycerophosphates and sphingolipids. Putatively, these changes serve to make the outer membrane and OMVs more impervious to polymyxin attack

Selective brain entry of lipid nanoparticles in haemorrhagic stroke is linked to biphasic blood-brain barrier disruption

Haemorrhagic stroke represents a significant public health burden, yet our knowledge and ability to treat this type of stroke are lacking. Previously we showed that we can target ischaemic-stroke lesions by selective translocation of lipid nanoparticles through the site of blood-brain barrier (BBB) disruption. The data we presented in this study provide compelling evidence that haemorrhagic stroke in mice induces BBB injury that mimics key features of the human pathology and, more importantly, provides a gate for entry of lipid nanoparticles-based therapeutics selectively to the bleeding site. Methods: Haemorrhagic stroke was induced in mice by intra-striatal collagenase injection. lipid nanoparticles were injected intravenously at 3 h, 24 h & 48 h post-haemorrhagic stroke and accumulation in the brain studied using in-vivo optical imaging and histology. BBB integrity, brain water content and iron accumulation were characterised using dynamic contrast-enhanced MRI, quantitative T mapping, and gradient echo MRI. Results: Using in-vivo SPECT/CT imaging and optical imaging revealed biphasic lipid nanoparticles entry into the bleeding site, with an early phase of increased uptake at 3-24 h post-haemorrhagic stroke, followed by a second phase at 48-72 h. Lipid nanoparticles entry into the brain post-haemorrhage showed an identical entry pattern to the trans-BBB leakage rate (K trans [min -1 ]) of Gd-DOTA, a biomarker for BBB disruption, measured using dynamic contrast-enhanced MRI. Discussion: Our findings suggest that selective accumulation of liposomes into the lesion site is linked to a biphasic pattern of BBB hyper-permeability. This approach provides a unique opportunity to selectively and efficiently deliver therapeutic molecules across the BBB, an approach that has not been utilised for haemorrhagic stroke therapy and is not achievable using free small drug molecules

Treatment of sporadic port-wine stains: a retrospective review of 17 cases consecutively treated by pulsed sequential dual wavelength 595 and 1064 nm laser.

BACKGROUND Port-wine stains (PWS) are relatively common and often cause cosmetic and psychological concerns. The pulsed dye laser is currently the treatment of choice for PWS. OBJECTIVE To assess the effectiveness of the pulsed sequential dual wavelength 595 and 1064 nm laser as first-line treatment for PWS and to identify prognostic factors for treatment outcome in a retrospective series of 17 consecutive previously untreated patients. METHODS The response to treatment was evaluated 2 months after treatment utilizing comparative photographs and a standard physician global assessment (PGA) grading system. Furthermore, measurement of the normalized erythema index (NEI) reduction (ΔNEI%) was carried out using an image analysis system. The subjective improvement was assessed using a patient's satisfaction questionnaire. Multiple linear regression models were finally used to identify factors associated with ΔNEI% and patients' satisfaction. RESULTS Seventeen patients, with PWS, including 12 children were included. The average PGA assessment was 2.5 ± 1.3 corresponding to an amelioration of 50% with a high intraclass correlation coefficient among the experts. The before-after NEI showed a statistically significant mean reduction of 3.5 ± 2.6 units, corresponding to a relative reduction of 31%. Questionnaires showed that the satisfaction was very good with an average score of 6.1 points on a scale ranging from -10 to 10 points. Multiple regression analysis revealed that location in the frontotemporal area was associated with a significant reduction in ΔNEI% (38.4%; 95% CI 4.3, 72.6). Presence of PWS on the neck was associated with a lower patient satisfaction (-3.7 points; 95% CI -6.5, -0.9). There were no significant side-effects, except for transient discomfort and purpura. CONCLUSIONS Based on the results obtained in the largest reported series so far, the pulsed sequential dual wavelength 595 and 1064 nm laser represents an effective and safe first-line therapeutic option for the treatment of PWS