Optimizing Photo-Encapsulation Viability of Heart Valve Cell Types in 3D Printable Composite Hydrogels.

Photocrosslinking hydrogel technologies are attractive for the biofabrication of cardiovascular soft tissues, but 3D printing success is dependent on multiple variables. In this study we systematically test variables associated with photocrosslinking hydrogels (photoinitiator type, photoinitiator concentration, and light intensity) for their effects on encapsulated cells in an extrusion 3D printable mixture of methacrylated gelatin/poly-ethylene glycol diacrylate/alginate (MEGEL/PEGDA3350/alginate). The fabrication conditions that produced desired hydrogel mechanical properties were compared against those that optimize aortic valve or mesenchymal stem cell viability. In the 3D hydrogel culture environment and fabrication setting studied, Irgacure can increase hydrogel stiffness with a lower proportional decrease in encapsulated cell viability compared to VA086. Human adipose derived mesenchymal stem cells (HADMSC) survived increasing photoinitiator concentrations in photo-encapsulation conditions better than aortic valve interstitial cells (HAVIC) and aortic valve sinus smooth muscle cells (HASSMC). Within the range of photo-encapsulation fabrication conditions tested with MEGEL/PEGDA/alginate (0.25-1.0% w/v VA086, 0.025-0.1% w/v Irgacure 2959, and 365 nm light intensity 2-136 mW/cm2), the highest viabilities achieved were 95, 93, and 93% live for HASSMC, HAVIC, and HADMSC respectively. These results identify parameter combinations that optimize cell viability during 3D printing for multiple cell types. These results also indicate that general oxidative stress is higher in photocrosslinking conditions that induce lower cell viability. However, suppressing this increase in intracellular oxidative stress did not improve cell viability, which suggests that other stress mechanisms also contribute.

Efficient Triplet-Triplet Annihilation-Based Upconversion for Nanoparticle Phototargeting.

High-efficiency upconverted light would be a desirable stimulus for triggered drug delivery. Here we present a general strategy to achieve photoreactions based on triplet-triplet annihilation upconversion (TTA-UC) and Förster resonance energy transfer (FRET). We designed PLA-PEG micellar nanoparticles containing in their cores hydrophobic photosensitizer and annihilator molecules which, when stimulated with green light, would undergo TTA-UC. The upconverted energy was then transferred by FRET to a hydrophobic photocleavable group (DEACM), also in the core. The DEACM was bonded to (and thus inactivated) the cell-binding peptide cyclo-(RGDfK), which was bound to the PLA-PEG chain. Cleavage of DEACM by FRET reactivated the PLA-PEG-bound peptide and allowed it to move from the particle core to the surface. TTA-UC followed by FRET allowed photocontrolled binding of cell adhesion with green light LED irradiation at low irradiance for short periods. These are attractive properties in phototriggered systems.

Preserved otolith organ function in caspase-3-deficient mice with impaired horizontal semicircular canal function.

Genetically engineered mice are valuable models for elucidation of auditory and vestibular pathology. Our goal was to establish a comprehensive vestibular function testing system in mice using: (1) horizontal angular vestibulo-ocular reflex (hVOR) to evaluate semicircular canal function and (2) otolith-ocular reflex (OOR) to evaluate otolith organ function and to validate the system by characterizing mice with vestibular dysfunction. We used pseudo off-vertical axis rotation to induce an otolith-only stimulus using a custom-made centrifuge. For the OOR, horizontal slow-phase eye velocity and vertical eye position were evaluated as a function of acceleration. Using this system, we characterized hVOR and OOR in the caspase-3 (Casp3) mutant mice. Casp3 (-/-) mice had severely impaired hVOR gain, while Casp3 (+/-) mice had an intermediate response compared to WT mice. Evaluation of OOR revealed that at low-to-mid frequencies and stimulus intensity, Casp3 mutants and WT mice had similar responses. At higher frequencies and stimulus intensity, the Casp3 mutants displayed mildly reduced otolith organ-related responses. These findings suggest that the Casp3 gene is important for the proper function of the semicircular canals but less important for the otolith organ function.

Vitamin D deficiency in mycosis fungoides and Sézary syndrome patients is similar to other cancer patients.

BACKGROUND: The purpose of this study was to determine the prevalence of vitamin D deficiency in CTCL patients and whether supplementation corrects vitamin D deficiency or treatment outcome. PATIENTS AND METHODS: Three hundred eleven CTCL patients including 27/311 (8.7%) with Sézary syndrome (SS), 169 cancer controls, and 69 normal controls from the M.D. Anderson clinics had 25(OH)D3 levels determined and categorized as deficient (< 20 ng/mL),insufficient (20-29 ng/mL), or sufficient (≥ 30 ng/mL). Clinical response was determined according to a change in percent body surface area involvement. RESULTS: Low 25(OH)D3 (< 30 ng/mL) levels were present in 76.9% of mycosis fungoides/SS patients, 75.2% of cancer controls, and 66.7% of healthy controls (P » .05, .07) and in 30% to 39% of historical normal controls. Correction of deficiency was successful in 35% or 55 of 156 patients who were given dealer's choice of either vitamin D2 at 50,000 IU orally (p.o.) biweekly or D3 1000 IU p.o. daily. Correction of vitamin D levels was noted in 27 of 100 (27%) patients given D3 and 28 of 56 (50%) given D2. Responses to standard CTCL therapy was similar among patients with corrected and persistently low levels (P » .51). CONCLUSION: To our knowledge,this is the first study of vitamin D status in CTCL patients. Vitamin D deficiency was present in CTCL and other cancer patients compared with normal and historical controls. Correction of vitamin D deficiency and type of vitamin D supplementation used did not affect the overall clinical disease response.

Hyaluronic acid-human blood hydrogels for stem cell transplantation.

Tissue engineering-based approaches have the potential to improve stem cell engraftment by increasing cell delivery to the myocardium. Our objective was to develop and characterize a naturally-derived, autologous, biodegradable hydrogel in order to improve acute stem cell retention in the myocardium. HA-blood hydrogels (HA-BL) were synthesized by mixing in a 1:1(v/v) ratio, lysed whole blood and hyaluronic acid (HA), whose carboxyl groups were functionalized with N-hydroxysuccinimide (NHS) to yield HA succinimidyl succinate (HA-NHS). We performed physical characterization and measured survival/proliferation of cardiosphere-derived cells (CDCs) encapsulated in the hydrogels. Hydrogels were injected intra-myocardially or applied epicardially in rats. NHS-activated carboxyl groups in HA react with primary amines present in blood and myocardium to form amide bonds, resulting in a 3D hydrogel bound to tissue. HA-blood hydrogels had a gelation time of 58±12 s, swelling ratio of 10±0.5, compressive and elastic modulus of 14±3 and 1.75±0.6 kPa respectively. These hydrogels were not degraded at 4 wks by hydrolysis alone. CDC encapsulation promoted their survival and proliferation. Intra-myocardial injection of CDCs encapsulated in these hydrogels greatly increased acute myocardial retention (p=0.001). Epicardial application of HA-blood hydrogels improved left ventricular ejection fraction following myocardial infarction (p=0.01). HA-blood hydrogels are highly adhesive, biodegradable, promote CDC survival and increase cardiac function following epicardial application after myocardial infarction.

Anaphylactoid reaction after retrograde pyelography despite preoperative steroid preparation.

A 19-year-old woman with a known allergy to iodinated contrast presented with intermittent, gross hematuria of 2 years' duration. The patient was scheduled to undergo cystoscopy with bilateral retrograde pyelography, because this is considered a safe alternative to intravenous pyelography or computed tomography. Because of her contrast allergy, the patient completed a 13-hour steroid preparation before the procedure. However, within minutes of extubation, she developed an anaphylactoid reaction and, despite appropriate management, required reintubation and subsequent transfer to the intensive care unit. The patient was subsequently extubated 8 hours later and recovered completely.