Arsenic Impairs Wound Healing Processes in Dermal Fibroblasts and Mice.

Inorganic arsenic (NaAsO2) is a naturally occurring metalloid found in water resources globally and in the United States at concentrations exceeding the U.S. Environmental Protection Agency Maximum Contamination Level of 10 ppb. While exposure to arsenic has been linked to cancer, cardiovascular disease, and skin lesions, the impact of arsenic exposure on wound healing is not fully understood. Cultured dermal fibroblasts exposed to NaAsO2 displayed reduced migration (scratch closure), proliferation, and viability with a lowest observable effect level (LOEL) of 10 µM NaAsO2 following 24 h exposure. An enrichment of Matrix Metalloproteinase 1 (MMP1) transcripts was observed at a LOEL of 1 µM NaAsO2 and 24 h exposure. In vivo, C57BL/6 mice were exposed to 10 µM NaAsO2 in their drinking water for eight weeks, then subjected to two full thickness dorsal wounds. Wounds were evaluated for closure after 6 days. Female mice displayed a significant reduction in wound closure and higher erythema levels, while males showed no effects. Gene expression analysis from skin excised from the wound site revealed significant enrichment in Arsenic 3-Methyltransferase (As3mt) and Estrogen Receptor 2 (Esr2) mRNA in the skin of female mice. These results indicate that arsenic at environmentally relevant concentrations may negatively impact wound healing processes in a sex-specific manner.

An acellular tissue engineered biomimetic wound healing device created using collagen and tropoelastin accelerates wound healing.

AIM: Tissue engineering has historically involved research combining scaffolds, cells, and active biomolecules to treat multiple pathologies. The current research seeks to determine if the wound healing cascade can be modulated using acellular scaffolds, engineered to create an acellular electrospun dermal biomimetic. METHODS: The dermal biomimetic has a similar architecture to the dermis, porosity and fiber diameter, as well as physiologically relevant ratios of the primary structural dermal proteins, collagen and tropoelastin. This biomimetic wound healing device (BMWHD) was implanted into a full thickness dermal wound murine model for six days. RESULTS: WHD-treated wounds had 30% greater re-epithelialization with a thicker epidermis, new elastin fibers in the wound bed, and healed architecture that matched unwounded extracellular matrix. CONCLUSIONS: Using these WHDs that closely match the native architecture and protein concentrations, accelerated the wound through the wound healing cascade and supports the hypothesis that structure alone can influence function when engineering acellular dermal biomimetic devices.

Environmentally Relevant Levels of Depleted Uranium Impacts Dermal Fibroblast Proliferation, Viability, Metabolic Activity, and Scratch Closure.

Uranium (U) is a heavy metal used in military and industrial settings, with a large portion being mined from the Southwest region of the United States. Uranium has uses in energy and military weaponry, but the mining process has released U into soil and surface waters that may pose threats to human and environmental health. The majority of literature regarding U's human health concern focuses on outcomes based on unintentional ingestion or inhalation, and limited data are available about its influence via cutaneous contact. Utilizing skin dermis cells, we evaluated U's topical chemotoxicity. Employing soluble depleted uranium (DU) in the form of uranyl nitrate (UN), we hypothesized that in vitro exposure of UN will have cytotoxic effects on primary dermal fibroblasts by affecting cell viability and metabolic activity and, further, may delay wound healing aspects via altering cell proliferation and migration. Using environmentally relevant levels of U found in water (0.1 µM to 100 µM [UN]; 23.8-23,800 ppb [U]), we quantified cellular mitosis and migration through growth curves and in vitro scratch assays. Cells were exposed from 24 h to 144 h for a time-course evaluation of UN chemical toxicity. The effects of UN were observed at concentrations above and below the Environmental Protection Agency threshold for safe exposure limits. UN exposure resulted in a dose-dependent decrease in the viable cell count; however, it produced an increase in metabolism when corrected for the viable cells present. Furthermore, cellular proliferation, population doubling, and percent closure was hindered at levels ≥10 µM UN. Therefore, inadvertent exposure may exacerbate pre-existing skin diseases in at-risk demographics, and additionally, it may substantially interfere in cutaneous tissue repair processes.

Detection of SARS-CoV-2 and its S and N proteins using surface enhanced Raman spectroscopy.

The COVID-19 pandemic demonstrated the critical need for accurate and rapid testing for virus detection. This need has generated a high number of new testing methods aimed at replacing RT-PCR, which is the golden standard for testing. Most of the testing techniques are based on biochemistry methods and require chemicals that are often expensive and the supply might become scarce in a large crisis. In the present paper we suggest the use of methods based on physics that leverage novel nanomaterials. We demonstrate that using Surface Enhanced Raman Spectroscopy (SERS) of virion particles a very distinct spectroscopic signature of the SARS-CoV-2 virus can be obtained. We demonstrate that the spectra are mainly composed by signals from the spike (S) and nucleocapsid (N) proteins. It is believed that a clinical test using SERS can be developed. The test will be fast, inexpensive, and reliable. It is also clear that SERS can be used for analysis of structural changes on the S and N proteins. This will be an example of application of nanotechnology and properties of nanoparticles for health and social related matters.

Integration of choline geranate into electrospun protein scaffolds affords antimicrobial activity to biomaterials used for cutaneous wound healing.

Wound healing attempts to maintain homeostasis in the wound while minimizing the risk of infection to the tissue by foreign agents, such as opportunistic bacterial pathogens. Biofilms established by these pathogens are a common cause of chronic infections that slow the healing process. Preparation of skin wound healing devices comprised of electrospun proteins associated with skin have been shown to accelerate the healing process relative to conventional wound dressings. In this work, we have developed electrospinning methods to incorporate the antimicrobial ionic liquid/deep eutectic solvent choline geranate (CAGE) into these devices. Integration of CAGE into the dressing material was verified via 1 H nuclear magnetic resonance spectrometry, and the effect on the material property of the resultant devices were assessed using scanning electron microscopy. CAGE-containing devices demonstrate a concentration-dependent inactivation of exogenously applied solutions of both gram-positive and gram-negative pathogens (Enterococcus sp and Pseudomonas aeruginosa, respectively), but maintain their ability to serve as a compatible platform for proliferation of human dermal neonatal fibroblasts.

The Role of Platelet Homeostasis in a Novel Topical PRP Formulation.

BACKGROUND: Topical platelet-rich plasma (PRP) must demonstrate stability to insure biologic activity in aesthetic medicine. OBJECTIVE: The objective of this research was to evaluate the role of platelet homeostasis in a novel PRP topical cosmetic formulation to provide facial appearance improvement. METHODS: The stability of the topical PRP formulation was evaluated in vitro followed by clinical in vivo testing. The in vitro evaluation examined platelet stability and morphology over a 90-day period within the preservative cosmetic base utilizing ELISA and light microscopy (LM)/scanning electron microscopy (SEM). The in vivo clinical study enrolled 20 subjects in a 120-day double blind split face study to evaluate the effect of 5–7x concentrated PRP compared to 2–3x concentrated PRP on facial photoaging. Cosmetic effect was evaluated by the subject and the dermatologist investigator on a 5-point ordinal scale at baseline, week 8, and week 16. RESULTS: 90-day stability for the topical PRP formulation was verified via ELISA and LM/SEM. ELISA showed the PRP was more inactive than control conditions via analyte concentration curves (PDGF-AB, EGF, and P-Selectin). LM/SEM demonstrated the PRP had less aggregation/activation over time within the cosmetic base and that refrigeration is superior to room-temperature storage thus delaying full platelet degranulation. The in vivo clinical study demonstrated parity between 20ml and 60ml PRP in terms of clinical efficacy. CONCLUSION: Platelets remain viable for up to 90 days in a refrigerated cosmetic vehicle with demonstrated topical clinical PRP facial benefits. PRP kits of 20ml and 60ml volumes for topical PRP are equally efficacious. J Drugs Dermatol. 2020;19(12): doi:10.36849/JDD.2020.5495.

Improved Wound Closure Rates and Mechanical Properties Resembling Native Skin in Murine Diabetic Wounds Treated with a Tropoelastin and Collagen Wound Healing Device.

Chronic wounds in patients suffering from type II diabetes mellitus (DMII) where wounds remain open with a complicated pathophysiology, healing, and recovery process is a public health concern. Normal wound healing plays a critical role in wound closure, restoration of mechanical properties, and the biochemical characteristics of the remodeled tissue. Biological scaffolds provide a tissue substitute to help facilitate wound healing by mimicking the extracellular matrix (ECM) of the dermis. In the current study an electrospun biomimetic scaffold, wound healing device (WHD), containing tropoelastin (TE) and collagen was synthesized to mimic the biochemical and mechanical characteristics of healthy human skin. The WHD was compared to a commercially available porcine small intestinal submucosa (SIS) matrix that has been used in both partial and full-thickness wounds, Oasis® Wound Matrix. Using a diabetic murine model C57BKS.Cg-m+/+Leprdb/J mice (db/db) wound closure rates, histochemistry (CD31 and CD163), qPCR (GAPDH, TNF-α, NOS2, ARG1 and IL10), and mechanical testing of treated wound sites were evaluated. The WHD in a splinted, full thickness, diabetic murine wound healing model demonstrated skin organ regeneration, an enhanced rate of wound closure, decreased tissue inflammation, and a stronger and more durable remodeled tissue that more closely mimics native unwounded skin compared to the control device.

Pilot study: Autologous platelet-rich plasma used in a topical cream for facial rejuvenation.

BACKGROUND: Platelet rich plasma (PRP) is traditionally used as an injectable material for enhanced healing, hair growth, and facial rejuvenation. AIMS: This research examined the novel use of topical autologously sourced PRP added to a preservative cosmetic base and applied twice daily to the face following electroporation for 8 weeks. METHODS: 20 healthy female and male subjects 30-60 years of age were enrolled in this single-site, investigator blinded, vehicle controlled split-face study to evaluate the effect of a PRP-containing serum versus the serum alone on facial photoaging. RESULTS: 90 day stability for the PRP in a preservative serum was achieved with refrigeration at 4 degrees Celsius. Facial skin biopsy histologic findings included improved rete peg architecture. Immunohistochemical analysis showed upregulation for collagen type I with qPCR data demonstrating concomitant upregulation of mRNA for collagen after 8 weeks of topical PRP use. CONCLUSION: These pilot study findings may indicate value for topical PRP in facial rejuvenation.

In Vitro Scratch Assay to Demonstrate Effects of Arsenic on Skin Cell Migration.

Understanding the physiologic mechanisms of wound healing has been the focus of ongoing research for many years. This research directly translates into changes in clinical standards used for treating wounds and decreasing morbidity and mortality for patients. Wound healing is a complex process that requires strategic cell and tissue interaction and function. One of the many critically important functions of wound healing is individual and collective cellular migration. Upon injury, various cells from the blood, surrounding connective, and epithelial tissues rapidly migrate to the wound site by way of chemical and/or physical stimuli. This migration response can largely dictate the outcomes and success of a healing wound. Understanding this specific cellular function is important for translational medicine that can lead to improved wound healing outcomes. Here, we describe a protocol used to better understand cellular migration as it pertains to wound healing, and how changes to the cellular environment can significantly alter this process. In this example study, dermal fibroblasts were grown in media supplemented with fetal bovine serum (FBS) as monolayer cultures in tissue culture flasks. Cells were aseptically transferred into tissue culture treated 12-well plates and grown to 100% confluence. Upon reaching confluence, the cells in the monolayer were vertically scratched using a p200 pipet tip. Arsenic diluted in culture media supplemented with FBS was added to individual wells at environmentally relevant doses ranging 0.1-10 M. Images were captured every 4 hours (h) over a 24 h period using an inverted light microscope to observe cellular migration (wound closure). Images were individually analyzed using image analysis software, and percent wound closure was calculated. Results demonstrate that arsenic slows down wound healing. This technique provides a rapid and inexpensive first screen for evaluation of the effects of contaminants on wound healing.

Computationally Optimizing the Compliance of Multilayered Biomimetic Tissue Engineered Vascular Grafts.

Coronary artery bypass grafts used to treat coronary artery disease (CAD) often fail due to compliance mismatch. In this study, we have developed an experimental/computational approach to fabricate an acellular biomimetic hybrid tissue engineered vascular graft (TEVG) composed of alternating layers of electrospun porcine gelatin/polycaprolactone (PCL) and human tropoelastin/PCL blends with the goal of compliance-matching to rat abdominal aorta, while maintaining specific geometrical constraints. Polymeric blends at three different gelatin:PCL (G:PCL) and tropoelastin:PCL (T:PCL) ratios (80:20, 50:50, and 20:80) were mechanically characterized. The stress-strain data were used to develop predictive models, which were used as part of an optimization scheme that was implemented to determine the ratios of G:PCL and T:PCL and the thickness of the individual layers within a TEVG that would compliance match a target compliance value. The hypocompliant, isocompliant, and hypercompliant grafts had target compliance values of 0.000256, 0.000568, and 0.000880 mmHg-1, respectively. Experimental validation of the optimization demonstrated that the hypercompliant and isocompliant grafts were not statistically significant from their respective target compliance values (p-value = 0.37 and 0.89, respectively). The experimental compliance values of the hypocompliant graft were statistically significant than their target compliance value (p-value = 0.047). We have successfully demonstrated a design optimization scheme that can be used to fabricate multilayered and biomimetic vascular grafts with targeted geometry and compliance.

Estrogen Mitigates the Negative Effects of Arsenic Contamination in an In Vitro Wound Model.

Arsenic, a naturally occurring environmental contaminant, is harmful to humans at elevated concentrations. Increased levels of arsenic in the environment occur as a result of human activities and from natural geologically sourced leaching into ground and surface water. These sources pose an exposure risk above the USEPA standard to individuals whose food and water sources become contaminated. Arsenic exposure negatively impacts organ function and increases the risk for developing pathologies, including cancer. Some of the effects of arsenic on cancer translate to normal cell function in wound healing. To evaluate whether arsenic influences wound healing, an in vitro scratch assay was employed to study the effects of arsenic on cellular migration, which is a key component in the normal wound-healing process. In this study, skin cells were exposed to environmentally relevant concentrations of arsenic, and wound closure was evaluated. Results indicated that arsenic significantly decreased the rate of cellular migration in the scratch assay when compared with controls. In addition, estradiol, which has been shown to positively influence cellular and tissue processes involved in wound healing, reversed the slowing effects of arsenic on wound closure. These results suggest that arsenic contamination may inhibit, and estrogen may provide a therapeutic benefit for individuals with arsenic-contaminated wounds.

A Bench-Top In Vitro Wound Assay to Demonstrate the Effects of Platelet-Rich Plasma and Depleted Uranium on Dermal Fibroblast Migration.

Cellular migration assays are useful tools to investigate physiologic events on the bench top. Furthermore, this migration assay can be utilized to investigate wound healing therapeutics (those that encourage or accelerate wound closure) as well as deleterious agents (ones that mitigate or slow wound closure). The current study used an in vitro scratch assay to measure the effects of platelet-rich plasma (PRP) and depleted uranium (DU) in the form of uranyl acetate on cellular migration of human neonatal dermal fibroblasts in an in vitro simulation of wound healing. Data analyses included percent wound closure measured as the distance between cell margins, and rates of wound closure versus untreated controls. The highest doses of PRP (0.063, 0.125%) resulted in 50-65% wound closure after 4-8 hours relative to 38-44% in controls and the low-dose treatment group (0.031%). The high-dose treatments of PRP (0.125, 0.063%) reached 100% wound closure at 12 hours postwound versus 16 hours for controls and the low-dose treatment group (0.031%). Conversely, the higher doses of DU treatments (50 and 100 µM) resulted in <80% closure versus 100% closure in controls after 16 hours, with full closure observed at 20 hours. The highest dose of DU (1,000 µM) resulted in <20% closure versus 100% closure in controls after 16 hours. The use of the described scratch assay serves as a translatable bench-top model that has the potential to predict in vivo outcomes, and in many early studies can help to demonstrate proof-of-concept before moving into complex biological systems.

Validating whole slide digital morphometric analysis as a microscopy tool.

Whole slide imaging (WSI) can be used to quantify multiple responses within tissue sections during histological analysis. Feature Analysis on Consecutive Tissue Sections (FACTS®) allows the investigator to perform digital morphometric analysis (DMA) within specified regions of interest (ROI) across multiple serial sections at faster rates when compared with manual morphometry methods. Using FACTS® in conjunction with WSI is a powerful analysis tool, which allows DMA to target specific ROI across multiple tissue sections stained for different biomarkers. DMA may serve as an appropriate alternative to classic, manual, histologic morphometric measures, which have historically relied on the selection of high-powered fields of views and manual scoring (e.g., a gold standard). In the current study, existing preserved samples were used to determine if DMA would provide similar results to manual counting methods. Rodent hearts (n=14, left ventricles) were stained with Masson's trichrome, and reacted for cluster of differentiation 68 (CD-68). This study found no statistical significant difference between a classic, manual method and the use of digital algorithms to perform the similar counts (p=0.38). DMA offers researchers the ability to accurately evaluate morphological characteristics in a reproducible fashion without investigator bias and with higher throughput.

TGFß2 differentially modulates smooth muscle cell proliferation and migration in electrospun gelatin-fibrinogen constructs.

A main goal of tissue engineering is the development of scaffolds that replace, restore and improve injured tissue. These scaffolds have to mimic natural tissue, constituted by an extracellular matrix (ECM) support, cells attached to the ECM, and signaling molecules such as growth factors that regulate cell function. In this study we created electrospun flat sheet scaffolds using different compositions of gelatin and fibrinogen. Smooth muscle cells (SMCs) were seeded on the scaffolds, and proliferation and infiltration were evaluated. Additionally, different concentrations of Transforming Growth Factor-beta2 (TGFß2) were added to the medium with the aim of elucidating its effect on cell proliferation, migration and collagen production. Our results demonstrated that a scaffold with a composition of 80% gelatin-20% fibrinogen is suitable for tissue engineering applications since it promotes cell growth and migration. The addition of TGFß2 at low concentrations (≤ 1 ng/ml) to the culture medium resulted in an increase in SMC proliferation and scaffold infiltration, and in the reduction of collagen production. In contrast, TGFß2 at concentrations >1 ng/ml inhibited cell proliferation and migration while stimulating collagen production. According to our results TGFß2 concentration has a differential effect on SMC function and thus can be used as a biochemical modulator that can be beneficial for tissue engineering applications.

Electrospun Tropoelastin for Delivery of Therapeutic Adipose-Derived Stem Cells to Full-Thickness Dermal Wounds.

Objective: To evaluate the physiological effects of electrospun tropoelastin scaffolds as therapeutic adipose-derived stem cell (ADSC) delivery vehicles for the treatment of full-thickness dermal wounds. Approach: Using the process of electrospinning, several prototype microfiber scaffolds were created with tropoelastin. Initial testing of scaffold biocompatibility was performed in vitro through ADSC culture, followed by scanning electron microscopy (SEM) for assessment of ADSC attachment, morphology, and new extracellular matrix (ECM) deposition. The wound healing effects of ADSC-seeded scaffolds were then evaluated in a murine dermal excisional wound model. Results: For the in vitro study, SEM revealed exceptional biocompatibility of electrospun tropoelastin for ADSCs. In the wound-healing study, ADSC-treated groups demonstrated significantly enhanced wound closure and epithelial thickness compared to controls. Innovation: This is the first report on the use of tropoelastin-based biomaterials as delivery vehicles for therapeutic ADSCs. Conclusion: We have demonstrated that tropoelastin-based ADSC delivery vehicles significantly accelerate wound healing compared to controls that represent the current clinical standard of care. Furthermore, the unique mechanical and biochemical characteristics of tropoelastin may favor its use over other biological or synthetic scaffolds for the treatment of certain pathologies due to its unique intrinsic mechanical properties.

An electrically coupled tissue-engineered cardiomyocyte scaffold improves cardiac function in rats with chronic heart failure.

BACKGROUND: Varying strategies are currently being evaluated to develop tissue-engineered constructs for the treatment of ischemic heart disease. This study examines an angiogenic and biodegradable cardiac construct seeded with neonatal cardiomyocytes for the treatment of chronic heart failure (CHF). METHODS: We evaluated a neonatal cardiomyocyte (NCM)-seeded 3-dimensional fibroblast construct (3DFC) in vitro for the presence of functional gap junctions and the potential of the NCM-3DFC to restore left ventricular (LV) function in an in vivo rat model of CHF at 3 weeks after permanent left coronary artery ligation. RESULTS: The NCM-3DFC demonstrated extensive cell-to-cell connectivity after dye injection. At 5 days in culture, the patch contracted spontaneously in a rhythmic and directional fashion at 43 ± 3 beats/min, with a mean displacement of 1.3 ± 0.3 mm and contraction velocity of 0.8 ± 0.2 mm/sec. The seeded patch could be electrically paced at nearly physiologic rates (270 ± 30 beats/min) while maintaining coordinated, directional contractions. Three weeks after implantation, the NCM-3DFC improved LV function by increasing (p < 0.05) ejection fraction 26%, cardiac index 33%, dP/dt(+) 25%, dP/dt(-) 23%, and peak developed pressure 30%, while decreasing (p < 0.05) LV end diastolic pressure 38% and the time constant of relaxation (Tau) 16%. At 18 weeks after implantation, the NCM-3DFC improved LV function by increasing (p < 0.05) ejection fraction 54%, mean arterial pressure 20%, dP/dt(+) 16%, dP/dt(-) 34%, and peak developed pressure 39%. CONCLUSIONS: This study demonstrates that a multicellular, electromechanically organized cardiomyocyte scaffold, constructed in vitro by seeding NCM onto 3DFC, can improve LV function long-term when implanted in rats with CHF.

Topically delivered dissolved oxygen reduces inflammation and positively influences structural proteins in healthy intact human skin.

BACKGROUND: As oxygen is essential for wound healing and there is limited diffusion across the stratum corneum into the epidermis, we wanted to evaluate whether the topical delivery of a total dissolved oxygen in dressing form on intact human subject skin would improve clinical and histologic skin functioning. AIMS: Fifty normal, healthy subjects completed a pilot clinical evaluation to assess the efficacy and tolerability of a dissolved oxygen dressing (OxygeneSys™-Continuous) to improve the health and appearance of intact skin. METHODS: Clinical analysis was performed on 50 subjects; histological and gene expression analysis was performed on 12 of the 50 subjects to assess the effect of the dissolved oxygen dressing. RESULTS: Clinical data demonstrate that the dressing is well tolerated, and several measures of skin health and integrity showed improvements compared with a control dressing site. Skin hydration measurements showed a statistically significant increase in skin hydration at 0-4, 4-8, and 0-8 weeks (P < 0.05 at each time point). The blinded clinical investigator's grading of desquamation, roughness, and skin texture show significant decreases from baseline to the 8-week time point (P < 0.05). The dressings were removed prior to the blinded clinical investigator's grading. These data were supported by the histological and gene expression studies, which showed a general reduction in inflammatory response markers and transcription products (IL-6, IL-8, TNF-alpha, MMP-1, and MMP-12), while facilitating a general increase in structural skin proteins (collagen I, elastin, and filaggrin). Additionally, p53 signals from biopsy samples support the clinical investigator's observations of no safety concerns. CONCLUSION: The data from this study demonstrate that the dressing has no deleterious effects and stimulates beneficial effects on intact, nonwounded skin.

Hair regrowth following a Wnt- and follistatin containing treatment: safety and efficacy in a first-in-man phase 1 clinical trial.

Research has shown the importance of follistatin, Wnt 7a, and wound healing growth factors on the stimulation of bulge cells and inter-follicular stem cells to induce hair growth. We have studied the effects of a bioengineered, non-recombinant, human cell-derived formulation, termed Hair Stimulating Complex (HSC), containing these factors to assess its hair growth activity in male pattern baldness. HSC showed in vitro Wnt activity and contained follistatin, KGF, and VEGF. The clinical study was a double-blind, placebo-controlled, randomized single site trial and was designed to evaluate safety of the HSC product and assess efficacy in stimulating hair growth. All 26 subjects tolerated the single, intradermal injection of HSC procedures well, and no signs of an adverse reaction were reported. Histopathological evaluation of the treatment site biopsies taken at 22 and 52 weeks post-treatment revealed no abnormal morphology, hamartomas, or other pathological responses. Trichoscan image analysis of HSC-treated sites at 12 and 52 weeks showed significant improvements in hair growth over the placebo. At the initial 12-week evaluation period, HSC-treated sites demonstrated an increase in hair shaft thickness (6.3%±2.5% vs. -0.63%±2.1%; P=0.046), thickness density (12.8%±4.5% vs. -0.2%±2.9%; P=0.028), and terminal hair density (20.6±4.9% vs. 4.4±4.9%; P=0.029). At one year, a statistically significant increase in total hair count (P=0.032) continued to be seen. These results demonstrate that a single intradermal administration of HSC improved hair growth in subjects with androgenetic alopecia and is a clinical substantiation of previous preclinical research with Wnts, follistatin, and other growth factors associated with wound healing and regeneration.

Three-dimensional fibroblast cultures stimulate improved ventricular performance in chronically ischemic canine hearts.

The current study's purpose was to evaluate the safety and biological effect of a scaffold-based three-dimensional human dermal fibroblast culture (3DFC, also known as Anginera™) to treat chronically ischemic canine hearts. It was hypothesized that treatment with 3DFC would be safe and significantly improve ventricular performance and wall motion. In this study, chronic myocardial ischemia was induced in 40 animals through the surgical placement of an ameroid constrictor. Approximately 30 days after ameroid placement, animals were randomized into four test groups: (1) sham treatment, (2) one unit of acellular 3DFC, (3) one unit of viable 3DFC, and (4) three units of viable 3DFC. Animals were necropsied 30 or 90 days after treatment. Evaluation of the safety endpoint demonstrated the safety of 3DFC at all dosing levels and at both time points. Additionally, parameters of cardiac output, left ventricular ejection fraction, left ventricular end systolic volume index, and systolic wall thickening support the conclusions that 3DFC stimulates a positive biologic effect on ischemic canine hearts. Further, these data support the conclusion that treatment with viable 3DFC improves ventricular performance and ventricular wall motion in chronically ischemic canine hearts 30 days after treatment.

Antibody to granulocyte macrophage colony-stimulating factor reduces the number of activated tissue macrophages and improves left ventricular function after myocardial infarction in a rat coronary artery ligation model.

Granulocyte macrophage colony-stimulating factor (GM-CSF) promotes infarct expansion and inappropriate collagen synthesis in a myocardial infarction (MI). This study was designed to determine if treatment with anti-GM-CSF will inhibit macrophage migration, preserve function, and limit left ventricular (LV) remodeling in the rat coronary artery ligation model. Treatment with a monoclonal antibody to GM-CSF (5 mg/kg) was initiated 24 hours before coronary artery ligation and continued every 3 days for 3 weeks. Left coronary arteries of rats were ligated, animals were recovered, and cardiac function was evaluated 3 weeks postligation. Tissue samples were processed for histochemistry. Anti-GM-CSF treatment increased LV ejection fraction (37 ± 3% vs 47 ± 5%) and decreased LV end systolic diameter (0.75 ± 0.12 vs 0.59 ± 0.05 cm) with no changes in LV systolic pressure (109 ± 4 vs 104 ± 5 mm Hg), LV end diastolic pressure (22 ± 4 vs 21 ± 2 mm Hg), LV end diastolic diameter (0.96 ± 0.04 vs 0.92 ± 0.05 cm), or the time constant of LV relaxation tau (25.4 ± +2.4 vs 22.7 ± 1.4 milliseconds) (P < 0.05). Significantly lower numbers of tissue macrophages and significant reductions in infarct size were found in the myocardium of antibody-treated animals (81 ± 21.24 vs 195 ± 31.7 positive cells per 0.105 mm, compared with controls. These findings suggest that inhibition of macrophage migration may be beneficial in the treatment of heart failure after MI.