Targeted multicolor in vivo imaging over 1,000 nm enabled by nonamethine cyanines.

Recent progress has shown that using wavelengths between 1,000 and 2,000 nm, referred to as the shortwave-infrared or near-infrared (NIR)-II range, can enable high-resolution in vivo imaging at depths not possible with conventional optical wavelengths. However, few bioconjugatable probes of the type that have proven invaluable for multiplexed imaging in the visible and NIR range are available for imaging these wavelengths. Using rational design, we have generated persulfonated indocyanine dyes with absorbance maxima at 872 and 1,072 nm through catechol-ring and aryl-ring fusion, respectively, onto the nonamethine scaffold. Multiplexed two-color and three-color in vivo imaging using monoclonal antibody and dextran conjugates in several tumor models illustrate the benefits of concurrent labeling of the tumor and healthy surrounding tissue and lymphatics. These efforts are enabled by complementary advances in a custom-built NIR/shortwave-infrared imaging setup and software package for multicolor real-time imaging.

Method To Diversify Cyanine Chromophore Functionality Enables Improved Biomolecule Tracking and Intracellular Imaging.

Heptamethine indocyanines are invaluable probes for near-infrared (NIR) imaging. Despite broad use, there are only a few synthetic methods to assemble these molecules, and each has significant limitations. Here, we report the use of pyridinium benzoxazole (PyBox) salts as heptamethine indocyanine precursors. This method is high yielding, simple to implement, and provides access to previously unknown chromophore functionality. We applied this method to create molecules to address two outstanding objectives in NIR fluorescence imaging. First, we used an iterative approach to develop molecules for protein-targeted tumor imaging. When compared to common NIR fluorophores, the optimized probe increases the tumor specificity of monoclonal antibody (mAb) and nanobody conjugates. Second, we developed cyclizing heptamethine indocyanines with the goal of improving cellular uptake and fluorogenic properties. By modifying both the electrophilic and nucleophilic components, we demonstrate that the solvent sensitivity of the ring-open/ring-closed equilibrium can be modified over a wide range. We then show that a chloroalkane derivative of a compound with tuned cyclization properties undergoes particularly efficient no-wash live cell imaging using organelle-targeted HaloTag self-labeling proteins. Overall, the chemistry reported here broadens the scope of accessible chromophore functionality, and, in turn, enables the discovery of NIR probes with promising properties for advanced imaging applications.

Doubly Strapped Zwitterionic NIR-I and NIR-II Heptamethine Cyanine Dyes for Bioconjugation and Fluorescence Imaging.

Heptamethine cyanine dyes enable deep tissue fluorescence imaging in the near infrared (NIR) window. Small molecule conjugates of the benchmark dye ZW800-1 have been tested in humans. However, long-term imaging protocols using ZW800-1 conjugates are limited by their instability, primarily because the chemically labile C4'-O-aryl linker is susceptible to cleavage by biological nucleophiles. Here, we report a modular synthetic method that produces novel doubly strapped zwitterionic heptamethine cyanine dyes, including a structural analogue of ZW800-1, with greatly enhanced dye stability. NIR-I and NIR-II versions of these doubly strapped dyes can be conjugated to proteins, including monoclonal antibodies, without causing undesired fluorophore degradation or dye stacking on the protein surface. The fluorescent antibody conjugates show excellent tumor-targeting specificity in a xenograft mouse tumor model. The enhanced stability provided by doubly strapped molecular design will enable new classes of in vivo NIR fluorescence imaging experiments with possible translation to humans.

Cyanine Masking: A Strategy to Test Functional Group Effects on Antibody Conjugate Targeting.

Conjugates of small molecules and antibodies are broadly employed diagnostic and therapeutic agents. Appending a small molecule to an antibody often significantly impacts the properties of the resulting conjugate. Here, we detail a systematic study investigating the effect of various functional groups on the properties of antibody-fluorophore conjugates. This was done through the preparation and analysis of a series of masked heptamethine cyanines (CyMasks)-bearing amides with varied functional groups. These were designed to exhibit a broad range of physical properties, and include hydrophobic (-NMe2), pegylated (NH-PEG-8 or NH-PEG-24), cationic (NH-(CH2)2NMe3+), anionic (NH-(CH2)2SO3-), and zwitterionic (N-(CH2)2NMe3+)-(CH2)3SO3-) variants. The CyMask series was appended to monoclonal antibodies (mAbs) and analyzed for the effects on tumor targeting, clearance, and non-specific organ uptake. Among the series, zwitterionic and pegylated dye conjugates had the highest tumor-to-background ratio (TBR) and a low liver-to-background ratio. By contrast, the cationic and zwitterionic probes had high tumor signal and high TBR, although the latter also exhibited an elevated liver-to-background ratio (LBR). Overall, these studies provide a strategy to test the functional group effects and suggest that zwitterionic substituents possess an optimal combination of high tumor signal, TBR, and low LBR. These results suggest an appealing strategy to mask hydrophobic payloads, with the potential to improve the properties of bioconjugates in vivo.

Targeted Fluorogenic Cyanine Carbamates Enable In Vivo Analysis of Antibody-Drug Conjugate Linker Chemistry.

Antibody-drug conjugates (ADCs) are a rapidly emerging therapeutic platform. The chemical linker between the antibody and the drug payload plays an essential role in the efficacy and tolerability of these agents. New methods that quantitatively assess the cleavage efficiency in complex tissue settings could provide valuable insights into the ADC design process. Here we report the development of a near-infrared (NIR) optical imaging approach that measures the site and extent of linker cleavage in mouse models. This approach is enabled by a superior variant of our recently devised cyanine carbamate (CyBam) platform. We identify a novel tertiary amine-containing norcyanine, the product of CyBam cleavage, that exhibits a dramatically increased cellular signal due to an improved cellular permeability and lysosomal accumulation. The resulting cyanine lysosome-targeting carbamates (CyLBams) are ∼50× brighter in cells, and we find this strategy is essential for high-contrast in vivo targeted imaging. Finally, we compare a panel of several common ADC linkers across two antibodies and tumor models. These studies indicate that cathepsin-cleavable linkers provide dramatically higher tumor activation relative to hindered or nonhindered disulfides, an observation that is only apparent with in vivo imaging. This strategy enables quantitative comparisons of cleavable linker chemistries in complex tissue settings with implications across the drug delivery landscape.

Multiphase Assembly of Small Molecule Microcrystalline Peptide Hydrogel Allows Immunomodulatory Combination Therapy for Long-Term Heart Transplant Survival.

Combination therapies that target multiple pathways involved in immune rejection of transplants hold promise for patients in need of restorative surgery. Herein, a noninteracting multiphase molecular assembly approach is developed to crystallize tofacitinib, a potent JAK1/3 inhibitor, within a shear-thinning self-assembled fibrillar peptide hydrogel network. The resulting microcrystalline tofacitinib hydrogel (MTH) can be syringe-injected directly to the grafting site during surgery to locally deliver the small molecule. The rate of drug delivered from MTH is largely controlled by the dissolution of the encapsulated microcrystals. A single application of MTH, in combination with systemically delivered CTLA4-Ig, a co-stimulation inhibitor, affords significant graft survival in mice receiving heterotopic heart transplants. Locoregional studies indicate that the local delivery of tofacitinib at the graft site enabled by MTH is required for the observed enhanced graft survival.

Application of a Scavenger Receptor A1-Targeted Polymeric Prodrug Platform for Lymphatic Drug Delivery in HIV.

We have developed a macromolecular prodrug platform based on poly(l-lysine succinylated) (PLS) that targets scavenger receptor A1 (SR-A1), a receptor expressed by myeloid and endothelial cells. We demonstrate the selective uptake of PLS by murine macrophage, RAW 264.7 cells, which was eliminated upon cotreatment with the SR-A inhibitor polyinosinic acid (poly I). Further, we observed no uptake of PLS in an SR-A1-deficient RAW 264.7 cell line, even after 24 h incubation. In mice, PLS distributed to lymphatic organs following i.v. injection, as observed by ex vivo fluorescent imaging, and accumulated in lymph nodes following both i.v. and i.d. administrations, based on immunohistochemical analysis with high-resolution microscopy. As a proof-of-concept, the HIV antiviral emtricitabine (FTC) was conjugated to the polymer's succinyl groups via ester bonds, with a drug loading of 14.2% (wt/wt). The prodrug (PLS-FTC) demonstrated controlled release properties in vitro with a release half-life of 15 h in human plasma and 29 h in esterase-inhibited plasma, indicating that drug release occurs through both enzymatic and nonenzymatic mechanisms. Upon incubation of PLS-FTC with human peripheral blood mononuclear cells (PBMCs), the released drug was converted to the active metabolite FTC triphosphate. In a pharmacokinetic study in rats, the prodrug achieved ∼7-19-fold higher concentrations in lymphatic tissues compared to those in FTC control, supporting lymphatic-targeted drug delivery. We believe that the SR-A1-targeted macromolecular PLS prodrug platform has extraordinary potential for the treatment of infectious diseases.

Shoulder Instability in the Overhead Athlete.

Shoulder instability encompasses a spectrum of disease ranging from subluxation to dislocation, and is typically associated with collision athletes such as wrestlers and football players. Instability, however, also can be the result of repetitive microtrauma, as seen in overhead athletes (baseball, tennis, volleyball, swimming). The presentation of instability can be subtle, and difficult to diagnose in the absence of an acute traumatic event without the proper suspicion, physical examination, and diagnostic evaluation. Overhead athletes present the unique challenge of requiring the glenohumeral joint to exceed its physiologic limits during competition; therefore, injury in this population can be devastating. Additionally, athletes who experience instability, regardless of treatment, require rehabilitation (including periscapular strengthening) to maximize strength of the surrounding musculature. Specifically they will require coordinated throwing programs, and gradual return to play protocols dependent on their sport. This article reviews the specific physiology, diagnosis, and treatment of shoulder instability in this population.

Safety and efficacy of continuous femoral nerve catheter with single shot sciatic nerve block vs epidural catheter anesthesia for same-day bilateral total knee arthroplasty.

In a retrospective analysis, we evaluated the safety and efficacy of peripheral nerve blocks (PNB) compared to epidural anesthesia in 221 consecutive patients undergoing same-day bilateral total knee arthroplasty (TKA). Primary outcome measures included: hypotension requiring physician intervention, number of blood transfusions, perioperative hespan and crystalloid consumption, incidences of respiratory desaturation, pruritis, urinary retention, and nausea/vomiting. The incidences of hypotension, urinary retention, and pruritis were all higher in the epidural group, compared to PNB. Epidural patients also required more blood transfusions and greater volumes of hespan and crystalloid. PNB are safe and efficacious modality of analgesia for same day bilateral TKA and provide adequate pain relief with a significant decrease in postoperative complications compared to epidural anesthesia.

A dual-luciferase bioluminescence system for the assessment of cellular therapies.

Bioluminescence imaging is a well-established platform for evaluating engineered cell therapies in preclinical studies. However, despite the discovery of new luciferases and substrates, optimal combinations to simultaneously monitor two cell populations remain limited. This makes the functional assessment of cellular therapies cumbersome and expensive, especially in preclinical in vivo models. In this study, we explored the potential of using a green bioluminescence-emitting click beetle luciferase, CBG99, and a red bioluminescence-emitting firefly luciferase mutant, Akaluc, together to simultaneously monitor two cell populations. Using various chimeric antigen receptor T cells and tumor pairings, we demonstrate that these luciferases are suitable for real-time tracking of two cell types using 2D and 3D cultures in vitro and experimental models in vivo. Our data show the broad compatibility of this dual-luciferase (duo-luc) system with multiple bioluminescence detection equipment ranging from benchtop spectrophotometers to live animal imaging systems. Although this study focused on investigating complex CAR T cells and tumor cell interactions, this duo-luc system has potential utility for the simultaneous monitoring of any two cellular components-for example, to unravel the impact of a specific genetic variant on clonal dominance in a mixed population of tumor cells.

Allograft reconstruction for digital nerve loss.

PURPOSE: To investigate the outcomes of digital nerve repairs using processed nerve allograft for defects measuring 30 mm or less. METHODS: Seventeen patients with 21 digital nerve lacerations in the hand underwent reconstruction with processed nerve allograft. Outcome data for 14 patients with 18 digital nerve lacerations were available for analysis. Postoperative outcome data were recorded at a minimum of 12 months and an average of 15 months. The average nerve gap measured 11 mm (range, 5-30 mm). Outcome measures included postoperative sensory examination as assessed by Semmes-Weinstein monofilaments and static and moving 2-point discrimination. Pain was graded using a visual analog scale throughout the recovery period. In addition, patients completed the Quick Disabilities of the Arm, Shoulder, and Hand survey before and after surgery. RESULTS: Using Taras outcome criteria, 7 of 18 (39%) digits had excellent results, 8 of 18 (44%) had good results, 3 of 18 (17%) digits had fair results, and none had poor results. At final follow-up, Semmes-Weinstein monofilament testing results ranged from 0.08 g to 279 g. Quick Disabilities of the Arm, Shoulder, and Hand scores recorded at the patient's first postoperative visit averaged 45 (range, 2-80), and final scores averaged 26 (range, 2-43). There were no signs of infection, extrusion, or graft reaction. CONCLUSIONS: The data suggest that processed nerve allograft provides a safe and effective alternative for the reconstruction of peripheral digital nerve deficits measuring up to 30 mm.

Restorative dentistry clinical decision-making for hypodontia: retained primary molars.

Primary molar teeth that are retained beyond their exfoliation pose a clinical decision-making challenge for dental teams. The retention of these teeth may be due to absence of a permanent successor. As a result, careful planning is required to determine if retention or extraction is necessary. This article aims to discuss the prevalence of retained primary molars, assessment and treatment planning considerations, from both orthodontic and restorative perspectives.

Cross-neutralizing protection of vaginal and oral mucosa from HPV challenge by vaccination in a mouse model.

The species and tissue specificities of HPV (human papillomavirus) for human infection and disease complicates the process of prophylactic vaccine development in animal models. HPV pseudoviruses (PsV) that carry only a reporter plasmid have been utilized in vivo to demonstrate cell internalization in mouse mucosal epithelium. The current study sought to expand the application of this HPV PsV challenge model with both oral and vaginal inoculation and to demonstrate its utility for testing vaccine-mediated dual-site immune protection against several HPV PsV types. We observed that passive transfer of sera from mice vaccinated with the novel experimental HPV prophylactic vaccine RG1-VLPs (virus-like particles) conferred HPV16-neutralizing as well as cross-neutralizing Abs against HPV39 in naïve recipient mice. Moreover, active vaccination with RG1-VLPs also conferred protection to challenge with either HPV16 or HPV39 PsVs at both vaginal and oral sites of mucosal inoculation. These data support the use of the HPV PsV challenge model as suitable for testing against diverse HPV types at two sites of challenge (vaginal vault and oral cavity) associated with the origin of the most common HPV-associated cancers, cervical cancer and oropharyngeal cancer.

Engineering CD276/B7-H3-targeted antibody-drug conjugates with enhanced cancer-eradicating capability.

CD276/B7-H3 represents a promising target for cancer therapy based on widespread overexpression in both cancer cells and tumor-associated stroma. In previous preclinical studies, CD276 antibody-drug conjugates (ADCs) exploiting a talirine-type pyrrolobenzodiazepine (PBD) payload showed potent activity against various solid tumors but with a narrow therapeutic index and dosing regimen higher than that tolerated in clinical trials using other antibody-talirine conjugates. Here, we describe the development of a modified talirine PBD-based fully human CD276 ADC, called m276-SL-PBD, that is cross-species (human/mouse) reactive and can eradicate large 500-1,000-mm3 triple-negative breast cancer xenografts at doses 10- to 40-fold lower than the maximum tolerated dose. By combining CD276 targeting with judicious genetic and chemical ADC engineering, improved ADC purification, and payload sensitivity screening, these studies demonstrate that the therapeutic index of ADCs can be substantially increased, providing an advanced ADC development platform for potent and selective targeting of multiple solid tumor types.

Growth factor dependency in mammary organoids regulates ductal morphogenesis during organ regeneration.

Signaling pathways play an important role in cell fate determination in stem cells and regulate a plethora of developmental programs, the dysregulation of which can lead to human diseases. Growth factors (GFs) regulating these signaling pathways therefore play a major role in the plasticity of adult stem cells and modulate cellular differentiation and tissue repair outcomes. We consider murine mammary organoid generation from self-organizing adult stem cells as a tool to understand the role of GFs in organ development and tissue regeneration. The astounding capacity of mammary organoids to regenerate a gland in vivo after transplantation makes it a convenient model to study organ regeneration. We show organoids grown in suspension with minimal concentration of Matrigel and in the presence of a cocktail of GFs regulating EGF and FGF signaling can recapitulate key epithelial layers of adult mammary gland. We establish a toolkit utilizing in vivo whole animal imaging and ultrasound imaging combined with ex vivo approaches including tissue clearing and confocal imaging to study organ regeneration and ductal morphogenesis. Although the organoid structures were severely impaired in vitro when cultured in the presence of individual GFs, ex vivo imaging revealed ductal branching after transplantation albeit with significantly reduced number of terminal end buds. We anticipate these imaging modalities will open novel avenues to study mammary gland morphogenesis in vivo and can be beneficial for monitoring mammary tumor progression in pre-clinical and clinical settings.

Modified norcyanines enable ratiometric pH imaging beyond 1000 nm.

Activatable fluorophores with emission beyond 1000 nm have the potential to enable high contrast imaging in complex in vivo settings. However, there are few scaffolds that can be applied to this challenge. Here we detail the synthesis and evaluation of benzo[c,d]indole-substituted norcyanines that enable pH responsive fluorescence imaging in the long wavelength (>1150 nm) range. A key component of our molecular design is the installation of a hydrophilic substituted quaternary amine in the central dihydropyridine ring system. A compound with a C4'-phenyl substituent, but not the C4'-protio homologue, exhibits absorbance maxima of 740 nm and 1130 nm in basic and acidic media, respectively, with evidence of J-aggregate-like properties. These two distinct absorbances enabled ratiometric imaging of probe internalization in a tumor model. Overall, these studies provide a new class of activatable long-wavelength responsive fluorophores with promising photophysical properties.

Antibacterial Gel Coatings Inspired by the Cryptic Function of a Mussel Byssal Peptide.

Although the adhesive and cohesive nature of mussel byssal proteins have long served to inspire the design of materials embodying these properties, their characteristic amino acid compositions suggest that they might also serve to inspire an unrelated material function not yet associated with this class of protein. Herein, it is demonstrated that a peptide derived from mussel foot protein-5, a key protein in mussel adhesion, displays antibacterial properties, a yet unreported activity. This cryptic function serves as inspiration for the design of a new class of peptide-based antibacterial adhesive hydrogels prepared via self-assembly, which are active against drug-resistant Gram-positive bacteria. The gels exert two mechanisms of action, surface-contact membrane disruption and oxidative killing affected by material-produced H2 O2 . Detailed studies relating amino acid composition and sequence to material mechanical adhesion/cohesion and antibacterial activity affords the MIKA2 adhesive gel, a material with a superior activity that is shown to inhibit colonization of titanium implants in mice.

Ulnar Collateral Ligament Reconstruction in Adolescents: A Systematic Review.

BACKGROUND: Ulnar collateral ligament (UCL) reconstruction is an established surgical technique to restore UCL deficiency, especially in the overhead throwing athlete. Over the past decade, the number of patients requiring UCL reconstruction has increased significantly, particularly in the adolescent patient population. Return-to-play rates after UCL reconstruction reported in the literature have ranged from 33% to 92%, and a recent systematic review noted a return-to-play rate of 89.40% in all high school athletes. PURPOSE: To evaluate the outcomes, particularly return-to-play rates and subjective outcome scores, of UCL reconstruction of the elbow in adolescent throwing athletes. STUDY DESIGN: Systematic review. METHODS: A systematic review of the literature was conducted via the electronic databases Embase, PubMed, and Cochrane. Studies that reported on outcomes, particularly return-to-play rates, in adolescent throwing athletes met the inclusion criteria and were included in our analysis. Studies that did not report on adolescent throwing athletes and studies that reported on adolescent throwing athletes but did not specify the return-to-play outcomes for these athletes were excluded from our analysis. RESULTS: Nine studies met the inclusion criteria and were included in this review. There were 404 baseball players and 10 javelin throwers included in our analysis. A total of 349 of the 414 patients (84.30%) were successfully able to return to play at the same level of competition or higher. Successful rates of return to prior performance ranged from 66.67% to 91.49% in our analysis. Javelin throwers had a mean 80.00% rate of return to prior performance, while baseball players had a mean return-to-play rate of 84.40%. Complications were evaluated for 8 (88.9%) studies and 283 (68.4%) patients. There were 11 (3.9%) reported complications and 5 (1.8%) reoperations. CONCLUSION: The findings of this systematic review revealed that adolescent patients are generally able to return to their preinjury level of performance or higher with limited complications. Further investigation is necessary to determine long-term outcomes for return to play after UCL reconstruction of the elbow in adolescent throwing athletes.

Snapping Hamstring Tendons Case Report: Tenotomy and Tendon Transposition.

CASE: A 14-year-old girl with a hypermobility syndrome presented with bilateral snapping semimembranosus (SM) and semitendinosus (ST) tendons. After failure of conservative treatment, she was treated with tenotomy of SM and later tendon transposition of her ST to her gracilis. CONCLUSIONS: Surgical treatment of snapping hamstring tendons has historically consisted of the release of the tendon insertions (tenotomy) or tendon harvest. This new surgical technique describes an alternative technique for definitive management with tenotomy and tendon transposition where the snapping ST is transposed to the gracilis tendon to maintain hamstring muscle length, strength, and function.

Surface-fill hydrogel attenuates the oncogenic signature of complex anatomical surface cancer in a single application.

Tumours growing in a sheet-like manner on the surface of organs and tissues with complex topologies represent a difficult-to-treat clinical scenario. Their complete surgical resection is difficult due to the complicated anatomy of the diseased tissue. Residual cancer often responds poorly to systemic therapy and locoregional treatment is hindered by the limited accessibility to microscopic tumour foci. Here we engineered a peptide-based surface-fill hydrogel (SFH) that can be syringe- or spray-delivered to surface cancers during surgery or used as a primary therapy. Once applied, SFH can shape change in response to alterations in tissue morphology that may occur during surgery. Implanted SFH releases nanoparticles composed of microRNA and intrinsically disordered peptides that enter cancer cells attenuating their oncogenic signature. With a single application, SFH shows efficacy in four preclinical models of mesothelioma, demonstrating the therapeutic impact of the local application of tumour-specific microRNA, which might change the treatment paradigm for mesothelioma and possibly other surface cancers.