Airway Epithelial Cell-Derived Colony Stimulating Factor-1 Promotes Allergen Sensitization.

Airway epithelial cells (AECs) secrete innate immune cytokines that regulate adaptive immune effector cells. In allergen-sensitized humans and mice, the airway and alveolar microenvironment is enriched with colony stimulating factor-1 (CSF1) in response to allergen exposure. In this study we found that AEC-derived CSF1 had a critical role in the production of allergen reactive-IgE production. Furthermore, spatiotemporally secreted CSF1 regulated the recruitment of alveolar dendritic cells (DCs) and enhanced the migration of conventional DC2s (cDC2s) to the draining lymph node in an interferon regulatory factor 4 (IRF4)-dependent manner. CSF1 selectively upregulated the expression of the chemokine receptor CCR7 on the CSF1R+ cDC2, but not the cDC1, population in response to allergen stimuli. Our data describe the functional specification of CSF1-dependent DC subsets that link the innate and adaptive immune responses in T helper 2 (Th2) cell-mediated allergic lung inflammation.

A small molecule redistributes iron in ferroportin-deficient mice and patient-derived primary macrophages.

Deficiencies of the transmembrane iron-transporting protein ferroportin (FPN1) cause the iron misdistribution that underlies ferroportin disease, anemia of inflammation, and several other human diseases and conditions. A small molecule natural product, hinokitiol, was recently shown to serve as a surrogate transmembrane iron transporter that can restore hemoglobinization in zebrafish deficient in other iron transporting proteins and can increase gut iron absorption in FPN1-deficient flatiron mice. However, whether hinokitiol can restore normal iron physiology in FPN1-deficient animals or primary cells from patients and the mechanisms underlying such targeted activities remain unknown. Here, we show that hinokitiol redistributes iron from the liver to red blood cells in flatiron mice, thereby increasing hemoglobin and hematocrit. Mechanistic studies confirm that hinokitiol functions as a surrogate transmembrane iron transporter to release iron trapped within liver macrophages, that hinokitiol-Fe complexes transfer iron to transferrin, and that the resulting transferrin-Fe complexes drive red blood cell maturation in a transferrin-receptor-dependent manner. We also show in FPN1-deficient primary macrophages derived from patients with ferroportin disease that hinokitiol moves labile iron from inside to outside cells and decreases intracellular ferritin levels. The mobilization of nonlabile iron is accompanied by reductions in intracellular ferritin, consistent with the activation of regulated ferritin proteolysis. These findings collectively provide foundational support for the translation of small molecule iron transporters into therapies for human diseases caused by iron misdistribution.

Nanotherapeutic kidney cell-specific targeting to ameliorate acute kidney injury.

Acute kidney injury (AKI) increases the risk of in-hospital death, adds to expense of care, and risk of early chronic kidney disease. AKI often follows an acute event such that timely treatment could ameliorate AKI and potentially reduce the risk of additional disease. Despite therapeutic success of dexamethasone in animal models, clinical trials have not demonstrated broad success. To improve the safety and efficacy of dexamethasone for AKI, we developed and characterized a novel, kidney-specific nanoparticle enabling specific within-kidney targeting to proximal tubular epithelial cells provided by the megalin ligand cilastatin. Cilastatin and dexamethasone were complexed to H-Dot nanoparticles, which were constructed from generally recognized as safe components. Cilastatin/Dexamethasone/H-Dot nanotherapeutics were found to be stable at plasma pH and demonstrated salutary release kinetics at urine pH. In vivo, they were specifically biodistributed to the kidney and bladder, with 75% recovery in the urine and with reduced systemic toxicity compared to native dexamethasone. Cilastatin complexation conferred proximal tubular epithelial cell specificity within the kidney in vivo and enabled dexamethasone delivery to the proximal tubular epithelial cell nucleus in vitro. The Cilastatin/Dexamethasone/H-Dot nanotherapeutic improved kidney function and reduced kidney cellular injury when administered to male C57BL/6 mice in two translational models of AKI (rhabdomyolysis and bilateral ischemia reperfusion). Thus, our design-based targeting and therapeutic loading of a kidney-specific nanoparticle resulted in preservation of the efficacy of dexamethasone, combined with reduced off-target disposition and toxic effects. Hence, our study illustrates a potential strategy to target AKI and other diseases of the kidney.

Complement C1q essential for aeroallergen sensitization via CSF1R+ conventional dendritic cells type 2.

BACKGROUND: Dendritic cells (DCs) are heterogeneous, comprising multiple subsets with unique functional specifications. Our previous work has demonstrated that the specific conventional type 2 DC subset, CSF1R+cDC2s, plays a critical role in sensing aeroallergens. OBJECTIVE: It remains to be understood how CSF1R+cDC2s recognize inhaled allergens. We sought to elucidate the transcriptomic programs and receptor-ligand interactions essential for function of this subset in allergen sensitization. METHODS: We applied single-cell RNA sequencing to mouse lung DCs. Conventional DC-selective knockout mouse models were employed, and mice were subjected to inhaled allergen sensitization with multiple readouts of asthma pathology. Under the clinical arm of this work, human lung transcriptomic data were integrated with mouse data, and bronchoalveolar lavage (BAL) specimens were collected from subjects undergoing allergen provocation, with samples assayed for C1q. RESULTS: We found that C1q is selectively enriched in lung CSF1R+cDC2s, but not in other lung cDC2 or cDC1 subsets. Depletion of C1q in conventional DCs significantly attenuates allergen sensing and features of asthma. Additionally, we found that C1q binds directly to human dust mite allergen, and the C1q receptor CD91 (LRP1) is required for lung CSF1R+cDC2s to recognize the C1q-allergen complex and induce allergic lung inflammation. Lastly, C1q is enriched in human BAL samples following subsegmental allergen challenge, and human RNA sequencing data demonstrate close homology between lung IGSF21+DCs and mouse CSF1R+cDC2s. CONCLUSIONS: C1q is secreted from the CSF1R+cDC2 subset among conventional DCs. Our data indicate that the C1q-LRP1 axis represents a candidate for translational therapeutics in the prevention and suppression of allergic lung inflammation.

Dual near-infrared II laser modulates the cellular redox state of T cells and augments the efficacy of cancer immunotherapy.

Immunotherapy, including immune checkpoint inhibitors, has revolutionized cancer treatment, but only a minor fraction of patients shows durable responses. A new approach to overcome this limitation is yet to be identified. Recently, we have shown that photobiomodulation (PBM) with near-infrared (NIR) light in the NIR-II window reduces oxidative stress and supports the proliferation of CD8+ T cells, suggesting that PBM with NIR-II light could augment anti-cancer immunity. Here, we report a novel approach to support tumor-infiltrating CD8+ T cells upon PBM with NIR-II laser with high tissue penetration depth. Brief treatments of a murine model of breast cancer with dual 1064 and 1270 nm lasers reduced the expression of the programmed cell death protein 1 (PD-1) in CD8+ T cells in a syngeneic mouse model of breast cancer. The direct effect of the NIR-II laser treatment on T cells was confirmed by the enhanced tumor growth delay by the adoptive transfer of laser-treated CD8+ T cells ex vivo against a model tumor antigen. We further demonstrated that specific NIR-II laser parameters augmented the effect of the immune checkpoint inhibitor on tumor growth. PBM with NIR-II light augments the efficacy of cancer immunotherapy by supporting CD8+ T cells. Unlike the current immunotherapy with risks of undesirable drug-drug interactions and severe adverse events, the laser is safe and low-cost. It can be broadly combined with other therapy without modification to achieve clinical significance. In addition, our study established a path to develop a novel laser-based therapy to treat cancer effectively.

H-Dot Mediated Nanotherapeutics Mitigate Systemic Toxicity of Platinum-Based Anticancer Drugs.

Platinum-based anticancer agents have revolutionized oncological treatments globally. However, their therapeutic efficacy is often accompanied by systemic toxicity. Carboplatin, recognized for its relatively lower toxicity profile than cisplatin, still presents off-target toxicities, including dose-dependent cardiotoxicity, neurotoxicity, and myelosuppression. In this study, we demonstrate a delivery strategy of carboplatin to mitigate its off-target toxicity by leveraging the potential of zwitterionic nanocarrier, H-dot. The designed carboplatin/H-dot complex (Car/H-dot) exhibits rapid drug release kinetics and notable accumulation in proximity to tumor sites, indicative of amplified tumor targeting precision. Intriguingly, the Car/H-dot shows remarkable efficacy in eliminating tumors across insulinoma animal models. Encouragingly, concerns linked to carboplatin-induced cardiotoxicity are effectively alleviated by adopting the Car/H-dot nanotherapeutic approach. This pioneering investigation not only underscores the viability of H-dot as an organic nanocarrier for platinum drugs but also emphasizes its pivotal role in ameliorating associated toxicities. Thus, this study heralds a promising advancement in refining the therapeutic landscape of platinum-based chemotherapy.

HSA-ZW800-PEG for Enhanced Optophysical Stability and Tumor Targeting.

Small molecule fluorophores often face challenges such as short blood half-life, limited physicochemical and optical stability, and poor pharmacokinetics. To overcome these limitations, we conjugated the zwitterionic near-infrared fluorophore ZW800-PEG to human serum albumin (HSA), creating HSA-ZW800-PEG. This conjugation notably improves chemical, physical, and optical stability under physiological conditions, addressing issues commonly encountered with small molecules in biological applications. Additionally, the high molecular weight and extinction coefficient of HSA-ZW800-PEG enhances biodistribution and tumor targeting through the enhanced permeability and retention effect. The unique distribution and elimination dynamics, along with the significantly extended blood half-life of HSA-ZW800-PEG, contribute to improved tumor targetability in both subcutaneous and orthotopic xenograft tumor-bearing animal models. This modification not only influences the pharmacokinetic profile, affecting retention time and clearance patterns, but also enhances bioavailability for targeting tissues. Our study guides further development and optimization of targeted imaging agents and drug-delivery systems.

Highly sensitive near-infrared SERS nanoprobes for in vivo imaging using gold-assembled silica nanoparticles with controllable nanogaps.

BACKGROUND: To take advantages, such as multiplex capacity, non-photobleaching property, and high sensitivity, of surface-enhanced Raman scattering (SERS)-based in vivo imaging, development of highly enhanced SERS nanoprobes in near-infrared (NIR) region is needed. A well-controlled morphology and biocompatibility are essential features of NIR SERS nanoprobes. Gold (Au)-assembled nanostructures with controllable nanogaps with highly enhanced SERS signals within multiple hotspots could be a breakthrough. RESULTS: Au-assembled silica (SiO2) nanoparticles (NPs) (SiO2@Au@Au NPs) as NIR SERS nanoprobes are synthesized using the seed-mediated growth method. SiO2@Au@Au NPs using six different sizes of Au NPs (SiO2@Au@Au50-SiO2@Au@Au500) were prepared by controlling the concentration of Au precursor in the growth step. The nanogaps between Au NPs on the SiO2 surface could be controlled from 4.16 to 0.98 nm by adjusting the concentration of Au precursor (hence increasing Au NP sizes), which resulted in the formation of effective SERS hotspots. SiO2@Au@Au500 NPs with a 0.98-nm gap showed a high SERS enhancement factor of approximately 3.8 × 106 under 785-nm photoexcitation. SiO2@Au@Au500 nanoprobes showed detectable in vivo SERS signals at a concentration of 16 µg/mL in animal tissue specimen at a depth of 7 mm. SiO2@Au@Au500 NPs with 14 different Raman label compounds exhibited distinct SERS signals upon subcutaneous injection into nude mice. CONCLUSIONS: SiO2@Au@Au NPs showed high potential for in vivo applications as multiplex nanoprobes with high SERS sensitivity in the NIR region.

Reversal of genetic brain iron accumulation by N,N'-bis(2-mercaptoethyl)isophthalamide, a lipophilic metal chelator, in mice.

N,N'-bis(2-mercaptoethyl)isophthalamide (NBMI) is a novel lipophilic metal chelator and antioxidant used in mercury poisoning. Recent studies have suggested that NBMI may also bind to other metals such as lead and iron. Since NBMI can enter the brain, we evaluated if NBMI removes excess iron from the iron-loaded brain and ameliorates iron-induced oxidative stress. First, NBMI exhibited preferential binding to ferrous (Fe2+) iron with a negligible binding affinity to ferric (Fe3+) iron, indicating a selective chelation of labile iron. Second, NBMI protected SH-SY5Y human neuroblastoma cells from the cytotoxic effects of high iron. NBMI also decreased cellular labile iron and lessened the production of iron-induced reactive oxygen species in these cells. Deferiprone (DFP), a commonly used oral iron chelator, failed to prevent iron-induced cytotoxicity or labile iron accumulation. Next, we validated the efficacy of NBMI in Hfe H67D mutant mice, a mouse model of brain iron accumulation (BIA). Oral gavage of NBMI for 6 weeks decreased iron accumulation in the brain as well as liver, whereas DFP showed iron chelation only in the liver, but not in the brain. Notably, depletion of brain copper and anemia were observed in BIA mice treated with DFP, but not with NBMI, suggesting a superior safety profile of NBMI over DFP for long-term use. Collectively, our study demonstrates that NBMI provides a neuroprotective effect against BIA and has therapeutic potential for neurodegenerative diseases associated with BIA.

Neuroimaging Modalities in Alzheimer's Disease: Diagnosis and Clinical Features.

Alzheimer's disease (AD) is a neurodegenerative disease causing progressive cognitive decline until eventual death. AD affects millions of individuals worldwide in the absence of effective treatment options, and its clinical causes are still uncertain. The onset of dementia symptoms indicates severe neurodegeneration has already taken place. Therefore, AD diagnosis at an early stage is essential as it results in more effective therapy to slow its progression. The current clinical diagnosis of AD relies on mental examinations and brain imaging to determine whether patients meet diagnostic criteria, and biomedical research focuses on finding associated biomarkers by using neuroimaging techniques. Multiple clinical brain imaging modalities emerged as potential techniques to study AD, showing a range of capacity in their preciseness to identify the disease. This review presents the advantages and limitations of brain imaging modalities for AD diagnosis and discusses their clinical value.

Endogenous Stem Cell-Based In Situ Tissue Regeneration Using Electrostatically Interactive Hydrogel with a Newly Discovered Substance P Analog and VEGF-Mimicking Peptide.

The use of chemoattractants to promote endogenous stem cell-based in situ tissue regeneration has recently garnered much attention. This study is the first to assess the endogenous stem cell migration using a newly discovered substance P (SP) analog (SP1) by molecular dynamics simulations as an efficient chemoattractant. Further, a novel strategy based on electrostatic interaction using cationic chitosan (Ch) and anionic hyaluronic acid (HA) to prepare an SP1-loaded injectable C/H formulation without SP1 loss is developed. The formulation quickly forms an SP1-loaded C/H hydrogel in situ through in vivo injection. The newly discovered SP1 is found to possess human mesenchymal stromal cells (hMSCs) migration-inducing ability that is approximately two to three times higher than that of the existing SP. The designed VEGF-mimicking peptide (VP) chemically reacts with the hydrogel (C/H-VP) to sustain the release of VP, thus inducing vasculogenic differentiation of the hMSCs that migrate toward the C/H-VP hydrogel. Similarly, in animal experiments, SP1 attracts a large number of hMSCs toward the C/H-VP hydrogel, after which VP induces vasculogenic differentiation. Collectively, these findings indicate that SP1-loaded C/H-VP hydrogels are a promising strategy to facilitate endogenous stem cell-based in situ tissue regeneration.

ZW800-PEG: A Renal Clearable Zwitterionic Near-Infrared Fluorophore for Potential Clinical Translation.

Near-infrared (NIR) fluorescence imaging has advanced medical imaging and image-guided interventions during the past three decades. Despite tremendous advances in imaging devices, surprisingly only a few dyes are currently available in the clinic. Previous fluorophores, ZW800-1A and ZW800-1C, significantly improved the poor performance of the FDA-approved indocyanine green. However, ZW800-1A is not stable in serum and ZW800-1C induces severe stacking in aqueous media. To solve such dilemmas, ZW800-PEG was designed by introducing a flexible yet stable thiol PEG linker. ZW800-PEG shows high solubility in both aqueous and organic solvents, thus improving renal clearance with minimal binding to serum proteins during systemic circulation. The sulfide group on the meso position of the heptamethine core improves serum stability and physicochemical properties including the maximum emission wavelength shift to 800 nm, enabling the use of ZW800-PEG for image-guided interventions and augmenting photothermal therapy.

Mini-Platform for Off-On Near-Infrared Fluorescence Imaging Using Peptide-Targeting Ligands.

Here, we propose a zwitterionic near-infrared (NIR) fluorophore-tryptophan (Trp) conjugate with a cleavable linker as a minimal-sized versatile platform (MP) for the preparation of peptide ligand-based off-on type molecular probes. The zwitterionic NIR fluorophore in MP undergoes fluorescence quenching via a photoinduced electron transfer mechanism when in close proximity to tryptophan, and nonspecific binding with serum proteins is minimized by the zwitterionicity of the fluorophore. The linker can be cleaved inside cancer cells in response to tumor-associated stimuli. As a proof-of-concept experiment, ATTO655 was covalently linked with Trp via a diarginine linker to form an MP. A cyclic peptide consisting of Arg-Gly-Asp-d-Phe-Lys (cRGD) was used as a cancer-targeting ligand and was conjugated to the MP to form cRGD-MP. The NIR fluorescence of cRGD-MP could be selectively turned on inside the target cancer cells, thereby enabling specific fluorescence imaging of integrin αvß3-overexpressing cancer cells in vitro and in vivo.

Role of Albumin in Accumulation and Persistence of Tumor-Seeking Cyanine Dyes.

Some heptamethine cyanine dyes accumulate in solid tumors in vivo and persist there for several days. The reasons why they accumulate and persist in tumors were incompletely defined, but explanations based on uptake into cancer cells via organic anion transporting polypeptides (OATPs) have been widely discussed. All cyanine-based "tumor-seeking dyes" have a chloride centrally placed on the heptamethine bridge (a "meso-chloride"). We were intrigued and perplexed by the correlation between this particular functional group and tumor uptake, so the following study was designed. It features four dyes (1-Cl, 1-Ph, 5-Cl, and 5-Ph) with complementary properties. Dye 1-Cl is otherwise known as MHI-148, and 1-Ph is a close analog wherein the meso-chloride has been replaced by a phenyl group. Data presented here shows that both 1-Cl and 1-Ph form noncovalent adducts with albumin, but only 1-Cl can form a covalent one. Both dyes 5-Cl and 5-Ph have a methylene (CH2) unit replaced by a dimethylammonium functionality (N+Me2). Data presented here shows that both these dyes 5 do not form tight noncovalent adducts with albumin, and only 5-Cl can form a covalent one (though much more slowly than 1-Cl). In tissue culture experiments, uptake of dyes 1 is more impacted by the albumin in the media than by the pan-OATP uptake inhibitor (BSP) that has been used to connect uptake of tumor-seeking dyes in vivo with the OATPs. Uptake of 1-Cl in media containing fluorescein-labeled albumin gave a high degree of colocalization of intracellular fluorescence. No evidence was found for the involvement of OATPs in uptake of the dyes into cells in media containing albumin. In an in vivo tumor model, only the two dyes that can form albumin adducts (1-Cl and 5-Cl) gave intratumor fluorescence that persisted long enough to be clearly discerned over the background (∼4 h); this fluorescence was still observed at 48 h. Tumors could be imaged with a higher contrast if 5-Cl is used instead of 1-Cl, because 5-Cl is cleared more rapidly from healthy tissues. Overall, the evidence is consistent with in vitro and in vivo results and indicates that the two dyes in the test series that accumulate in tumors and persist there (1-Cl and 5-Cl, true tumor-seeking dyes) do so as covalent albumin adducts trapped in tumor tissue via uptake by some cancer cells and via the enhanced permeability and retention (EPR) effect.

Colony-stimulating factor 1 and its receptor are new potential therapeutic targets for allergic asthma.

BACKGROUND: A new approach targeting aeroallergen sensing in the early events of mucosal immunity could have greater benefit. The CSF1-CSF1R pathway has a critical role in trafficking allergens to regional lymph nodes through activating dendritic cells. Intervention in this pathway could prevent allergen sensitization and subsequent Th2 allergic inflammation. OBJECTIVE: To examine the therapeutic effectiveness of CSF1 and CSF1R inhibition for blocking the dendritic cell function of sensing aeroallergens. METHODS: We adopted a model of chronic asthma induced by a panel of three naturally occurring allergens and novel delivery system of CSF1R inhibitor encapsulated nanoprobe. RESULTS: Selective depletion of CSF1 in airway epithelial cells abolished the production of allergen-reactive IgE, resulting in prevention of new asthma development as well as reversal of established allergic lung inflammation. CDPL-GW nanoprobe containing GW2580, a selective CSF1R inhibitor, showed favorable pharmacokinetics for inhalational treatment and intranasal insufflation delivery of CDPL-GW nanoprobe ameliorated asthma pathologies including allergen-specific serum IgE production, allergic lung and airway inflammation and airway hyper-responsiveness (AHR) with minimal pulmonary adverse reaction. CONCLUSION: The inhibition of the CSF1-CSF1R signaling pathway effectively suppresses sensitization to aeroallergens and consequent allergic lung inflammation in a murine model of chronic asthma. CSF1R inhibition is a promising new target for the treatment of allergic asthma.

A Hybrid Speller Design Using Eye Tracking and SSVEP Brain-Computer Interface.

Steady-state visual evoked potentials (SSVEPs) have been extensively utilized to develop brain-computer interfaces (BCIs) due to the advantages of robustness, large number of commands, high classification accuracies, and information transfer rates (ITRs). However, the use of several simultaneous flickering stimuli often causes high levels of user discomfort, tiredness, annoyingness, and fatigue. Here we propose to design a stimuli-responsive hybrid speller by using electroencephalography (EEG) and video-based eye-tracking to increase user comfortability levels when presented with large numbers of simultaneously flickering stimuli. Interestingly, a canonical correlation analysis (CCA)-based framework was useful to identify target frequency with a 1 s duration of flickering signal. Our proposed BCI-speller uses only six frequencies to classify forty-eight targets, thus achieve greatly increased ITR, whereas basic SSVEP BCI-spellers use an equal number of frequencies to the number of targets. Using this speller, we obtained an average classification accuracy of 90.35 ± 3.597% with an average ITR of 184.06 ± 12.761 bits per minute in a cued-spelling task and an ITR of 190.73 ± 17.849 bits per minute in a free-spelling task. Consequently, our proposed speller is superior to the other spellers in terms of targets classified, classification accuracy, and ITR, while producing less fatigue, annoyingness, tiredness and discomfort. Together, our proposed hybrid eye tracking and SSVEP BCI-based system will ultimately enable a truly high-speed communication channel.

A novel pilot animal model for the surgical prevention of lymphedema: the power of optical imaging.

BACKGROUND: Breast cancer-related lymphedema affects more than 400,000 survivors in the United States. In 2009, lymphatic microsurgical preventive healing approach (LYMPHA) was first described as a surgical technique to prevent lymphedema by bypassing divided arm lymphatics into adjacent veins at the time of an axillary lymph node dissection. We describe the first animal model of LYMPHA. METHODS: In Yorkshire pigs, each distal hind limb lymphatic system was cannulated and injected with a different fluorophore (human serum albumin-conjugated indocyanine green or Evans Blue). Fluorescence-assisted resection and exploration imaging system was used to map the respective lymphangiosomes to the groin. Baseline lymphatic clearance of each hind limb lymphangiosome was obtained by measuring the fluorescence of each dye from centrally obtained blood samples. A lymphadenectomy versus lymphadenectomy with LYMPHA was then performed. The injections were then repeated to obtain clearance rates that were compared against baseline values. RESULTS: Human serum albumin-conjugated indocyanine green and Evans Blue allowed for precise lymphatic mapping of each respective hind limb using fluorescence-assisted resection and exploration imaging. Lymphatic clearance from the distal hind limb dropped 68% when comparing baseline clearance versus after a groin lymphadenectomy. In comparison, lymphatic clearance dropped only 21% when comparing baseline clearance versus a lymphadenectomy with LYMPHA. CONCLUSIONS: We describe the first animal model for LYMPHA, which will enable future studies to further evaluate the efficacy and potential limitations of this technique. Of equal importance, we demonstrate the power of optical imaging to provide real-time lymphatic clearance rates for each hind limb.

Multivalent Mannose-Decorated NIR Nanoprobes for Targeting Pan Lymph Nodes.

Lymphadenectomy is a prerequisite for most malignancies to define the precise staging of cancer, as well as resect the possible metastases completely. While it improves prognosis, lymphadenectomy often causes postoperative edema or bleeding because of unclear surgical margins. In this study, we synthesized near-infrared (NIR) fluorescent nanoprobes with conjugating various mannose moieties on the surface to target macrophages in the lymph node. Armed with these NIR nanoprobes, we demonstrated the feasibility of intraoperative pan lymph nodes (PLN) mapping and real-time optical imaging under the NIR fluorescence imaging system. We found that even single mannose-conjugated ZW800-1 showed specific uptake in lymph nodes within 4 h, and multiple mannose-employed polyrotaxanes highlighted PLN efficiently with low background signals in major organs. This technology can help surgeons perform lymphadenectomy with ease and safety by identifying all regional lymph nodes proficiently after a single intravenous injection of NIR nanoprobes.

Determination of renal function and injury using near-infrared fluorimetry in experimental cardiorenal syndrome.

Cardiorenal syndrome type 1 causes acute kidney injury but is poorly understood; animal models and diagnostic aids are lacking. Robust noninvasive measurements of glomerular filtration rate are required for injury models and clinical use. Several have been described but are untested in translational models and suffer from biologic interference. We developed a mouse model of cardiorenal syndrome and tested the novel near-infrared fluorophore ZW800-1 to assess renal and cardiac function. We performed murine cardiac arrest and cardiopulmonary resuscitation followed by transthoracic echocardiography, 2 and 24 h later. Transcutaneous fluorescence of ZW800-1 bolus dispersion and clearance was assessed with whole animal imaging and compared with glomerular filtration rate (GFR; inulin clearance), tubular cell death (using unbiased stereology), and serum creatinine. Correlation, Bland-Altman, and polar analyses were used to compare GFR with ZW800-1 clearance. Cardiac arrest and cardiopulmonary resuscitation caused reversible cardiac failure, halving fractional shortening of the left ventricle (n = 12, P = 0.03). Acute kidney injury resulted with near-zero GFR and sixfold increase in serum creatinine 24 h later (n = 16, P < 0.01). ZW800-1 biodistribution and clearance were exclusively renal. ZW800-1 t1/2 and clearance correlated with GFR (r = 0.92, n = 31, P < 0.0001). ZW800-1 fluorescence was reduced in cardiac arrest, and cardiopulmonary resuscitation-treated mice compared with sham animals 810 s after injection (P < 0.01) and bolus time-dispersion curves demonstrated that ZW800-1 fluorescence dispersion correlated with left ventricular function (r = 0.74, P < 0.01). Cardiac arrest and cardiopulmonary resuscitation lead to experimental cardiorenal syndrome type 1. ZW800-1, a small near-infrared fluorophore being developed for clinical intraoperative imaging, is favorable for evaluating cardiac and renal function noninvasively.

Tissue-Specific Near-Infrared Fluorescence Imaging.

Near-infrared (NIR) fluorescence light has been widely utilized in clinical imaging by providing surgeons highly specific images of target tissue. The "NIR window" from 650 to 900 nm is especially useful due to several special features such as minimal autofluorescence and absorption of biomolecules in tissue, as well as low light scattering. Compared with visible wavelengths, NIR fluorescence light is invisible, thus allowing highly sensitivity real-time image guidance in human surgery without changing the surgical field. The benefit of using NIR fluorescence light as a clinical imaging technology can be attributed to its molecular fluorescence as an exogenous contrast agent. Indeed, whole body preoperative imaging of single-photon emission computed tomography (SPECT) and positron emission tomography (PET) remains important in diagnostic utility, but they lack the efficacy of innocuous and targeted NIR fluorophores to simultaneously facilitate the real-time delineation of diseased tissue while preserving vital tissues. Admittedly, NIR imaging technology has been slow to enter clinical use mostly due to the late-coming development of truly breakthrough contrast agents for use with current imaging systems. Therefore, clearly defining the physical margins of tumorous tissue remains of paramount importance in bioimaging and targeted therapy. An equally noteworthy yet less researched goal is the ability to outline healthy vital tissues that should be carefully navigated without transection during the intraoperative surgery. Both of these paths require optimizing a gauntlet of design considerations to obtain not only an effective imaging agent in the NIR window but also high molecular brightness, water solubility, biocompatibility, and tissue-specific targetability. The imaging community recognizes three strategic approaches which include (1) passive targeting via the EPR effect, (2) active targeting using the innate overall biodistribution of known molecules, and (3) activatable targeting through an internal stimulus, which turns on fluorescence from an off state. Recent advances in nanomedicine and bioimaging offer much needed promise toward fulfilling these stringent requirements as we develop a successful catalog of targeted contrast agents for illuminating both tumors and vital tissues in the same surgical space by employing spectrally distinct fluorophores in real time. These tissue-specific contrast agents can be versatile arsenals to physicians for real-time intraoperative navigation as well as image-guided targeted therapy. There is a versatile library of tissue-specific fluorophores available in the literature, with many discussed herein, which offers clinicians an array of possibilities that will undoubtedly improve intraoperative success and long-term postoperation prognosis.