Strengthening the skin with topical delivery of keratinocyte growth factor-1 using a novel DNA plasmid.

Fragile skin, susceptible to decubitus ulcers and incidental trauma, is a problem particularly for the elderly and for those with spinal cord injury. Here, we present a simple approach to strengthen the skin by the topical delivery of keratinocyte growth factor-1 (KGF-1) DNA. In initial feasibility studies with the novel minimalized, antibiotic-free DNA expression vector, NTC8385-VA1, the reporter genes luciferase and enhanced green fluorescent protein were delivered. Transfection was documented when luciferase expression significantly increased after transfection. Microscopic imaging of enhanced green fluorescent protein-transfected skin showed green fluorescence in hair follicles, hair shafts, and dermal and superficial epithelial cells. With KGF-1 transfection, KGF-1 mRNA level and protein production were documented with quantitative reverse transcriptase-polymerase chain reaction and immunohistochemistry, respectively. Epithelial thickness of the transfected skin in the KGF group was significantly increased compared with the control vector group (26 ± 2 versus 16 ± 4 µm) at 48 hours (P = 0.045). Dermal thickness tended to be increased in the KGF group (255 ± 36 versus 162 ± 16 µm) at 120 hours (P = 0.057). Biomechanical assessment showed that the KGF-1-treated skin was significantly stronger than control vector-transfected skin. These findings indicate that topically delivered KGF-1 DNA plasmid can increase epithelial thickness and strength, demonstrating the potential of this approach to restore compromised skin.

Current insight in the localized insulin-derived amyloidosis (LIDA): clinico-pathological characteristics and differential diagnosis.

BACKGROUND: In diabetic patients, subcutaneous insulin injection may cause several types of injection site-related lesions, such as lipoatrophy, insulin-induced cutaneous lipohypertrophy (IICL), allergic reaction, and iatrogenic localized insulin-derived amyloidosis (LIDA). Among these complications, both IICL and LIDA present as tumor-like and slow growing lesions; and they may be confused with one another. The clinical implication and management of IICL and LIDA are different. LIDA causes poor blood glycemic controls due to inadequate absorption of the insulin. Thus, accurate diagnosis of the lesion is critical in diabetic patients. REVIEW OF LITERATURE: LIDA is an extremely rare complication and often overlooked, it is managed by a surgical intervention. Whereas, IICL is a common side effect and can be managed by a non-surgical approach. Furthermore, in long-standing diabetics, patients may develop hypertrophic cardiomyopathy, proteinuria, peripheral, and autonomic neuropathy; these symptoms can be mistaken for a systemic amyloidosis. It is also necessary to distinguish LIDA from the systemic amyloidosis, which requires a more aggressive systemic therapy. LIDA should also be distinguished from primary cutaneous amyloidosis, with high risk of progression to a systemic amyloidosis. In this effort we reviewed 25 published manuscripts, including case reports and case series studies. We also summarized the literature and discussed differential diagnosis, including the approach to diagnose LIDA. CONCLUSION: The identification of amyloid material and immunoreactivity with anti-insulin antibodies are key diagnostic features of LIDA. Although several clinical and animal studies were made in recent years, the lesion is still under-diagnosed and underreported. The clinical suspicion and knowledge of the lesion play a crucial role for the accurate diagnosis of LIDA. Surgical excision of the lesion can dramatically decrease insulin requirement and improve glycemic control.

Cellular GFP Toxicity and Immunogenicity: Potential Confounders in in Vivo Cell Tracking Experiments.

Green Fluorescent protein (GFP), used as a cellular tag, provides researchers with a valuable method of measuring gene expression and cell tracking. However, there is evidence to suggest that the immunogenicity and cytotoxicity of GFP potentially confounds the interpretation of in vivo experimental data. Studies have shown that GFP expression can deteriorate over time as GFP tagged cells are prone to death. Therefore, the cells that were originally marked with GFP do not survive and cannot be accurately traced over time. This review will present current evidence for the immunogenicity and cytotoxicity of GFP in in vivo studies by characterizing these responses.

Knockout of Angiotensin AT2 receptors accelerates healing but impairs quality.

Wounds are among the most common, painful, debilitating and costly conditions in older adults. Disruption of the angiotensin type 1 receptors (AT1R), has been associated with impaired wound healing, suggesting a critical role for AT1R in this repair process. Biological functions of angiotensin type 2 receptors (AT2R) are less studied. We investigated effects of genetically disrupting AT2R on rate and quality of wound healing. Our results suggest that AT2R effects on rate of wound closure depends on the phase of wound healing. We observed delayed healing during early phase of wound healing (inflammation). An accelerated healing rate was seen during later stages (proliferation and remodeling). By day 12, fifty percent of AT2R(-/-) mice had complete wound closure as compared to none in either C57/BL6 or AT1R(-/-) mice. There was a significant increase in AT1R, TGFß1 and TGFß2 expression during the proliferative and remodeling phases in AT2R(-/-) mice. Despite the accelerated closure rate, AT2R(-/-) mice had more fragile healed skin. Our results suggest that in the absence of AT2R, wound healing rate is accelerated, but yielded worse skin quality. Elucidating the contribution of both of the angiotensin receptors may help fine tune future intervention aimed at wound repair in older individuals.