Novel readthrough agent suppresses nonsense mutations and restores functional type VII collagen and laminin 332 in epidermolysis bullosa.

Recessive dystrophic epidermolysis bullosa (RDEB) and junctional epidermolysis bullosa (JEB) are lethal blistering skin disorders resulting from mutations in genes coding for type VII collagen (COL7A1) and laminin 332 (LAMA3, LAMB3, or LAMC2), respectively. In RDEB, 25% of patients harbor nonsense mutations causing premature termination codons (PTCs). In JEB, a majority of mutations in LAMB3 are nonsense mutations (80%). ELX-02, an aminoglycoside analog, has demonstrated superior PTC readthrough activity and lower toxicity compared to gentamicin in various genetic disorders. This study investigated the ability of ELX-02 to suppress PTCs and promote the expression of C7 and laminin 332 in primary RDEB keratinocytes/fibroblasts and primary JEB keratinocytes harboring nonsense mutations. ELX-02 induced a dose-dependent production of C7 or laminin ß3 that surpassed the results achieved with gentamicin. ELX-02 reversed RDEB and JEB cellular hypermotility and improved poor cell-substratum adhesion in JEB cells. Importantly, ELX-02-induced C7 and laminin 332 localized to the dermal-epidermal junction. This is the first study demonstrating that ELX-02 can induce PTC readthrough and restore functional C7 and laminin 332 in RDEB and JEB caused by nonsense mutations. Therefore, ELX-02 may offer a novel and safe therapy for RDEB, JEB, and other inherited skin diseases caused by nonsense mutations.

Intravenous gentamicin therapy induces functional type VII collagen in patients with recessive dystrophic epidermolysis bullosa: an open-label clinical trial.

BACKGROUND: Recessive dystrophic epidermolysis bullosa (RDEB) is an incurable widespread blistering skin disorder caused by mutations in the gene encoding for type VII collagen (C7), the major component of anchoring fibrils. OBJECTIVES: To evaluate the efficacy and safety of intravenous (IV) gentamicin readthrough therapy in patients with RDEB harbouring nonsense mutations. The primary outcomes were increased expression of C7 in patients' skin and safety assessments (ototoxicity, nephrotoxicity, autoimmune response); secondary outcomes included measuring wound healing in target wounds and assessment by a validated Epidermolysis Bullosa Disease Activity and Scarring Index (EBDASI) scoring system. METHODS: An open-label pilot trial to assess two different IV gentamicin regimens between August 2018 and March 2020 with follow-up through to 180 days post-treatment was carried out. Three patients with RDEB with confirmed nonsense mutations in COL7A1 in either one or two alleles and decreased baseline expression of C7 at the dermal-epidermal junction (DEJ) of their skin participated in the study. Three patients received gentamicin 7.5 mg kg-1 daily for 14 days and two of the three patients further received 7.5 mg kg-1 IV gentamicin twice weekly for 12 weeks. Patients who had pre-existing auditory or renal impairment, were currently using ototoxic or nephrotoxic medications, or had allergies to aminoglycosides or sulfate compounds were excluded. RESULTS: After gentamicin treatment, skin biopsies from all three patients (age range 18-28 years) exhibited increased C7 in their DEJ. With both regimens, the new C7 persisted for at least 6 months post-treatment. At 1 and 3 months post-treatment, 100% of the monitored wounds exhibited > 85% closure. Both IV gentamicin infusion regimens decreased EBDASI total activity scores. Of the patients assessed with the EBDASI, all exhibited decreased total activity scores 3 months post-treatment. All three patients completed the study; no adverse effects or anti-C7 antibodies were detected. CONCLUSIONS: IV gentamicin induced the readthrough of nonsense mutations in patients with RDEB and restored functional C7 in their skin, enhanced wound healing and improved clinical parameters. IV gentamicin may be a safe, efficacious, low-cost and readily available treatment for this population of patients with RDEB.

Recessive dystrophic epidermolysis bullosa (RDEB) is a rare and life-threatening inherited skin disease that causes widespread skin blisters that heal with scarring. RDEB affects around 1 in every 100,000 individuals globally. The condition is caused by a mutation in the gene coding for type VII collagen (C7), resulting in a deficiency of C7. C7 is a vital component of the skin as it is responsible for holding the skin's upper two layers together. To date, there are no approved systemic treatments that can cure RDEB. This study, from the United States, aimed to evaluate the effectiveness and safety of intravenous (medicine delivered directly into a patient's vein) gentamicin (an antibiotic) for people with RDEB who have nonsense mutations in their genes (a type of mutation that prevents the production of complete proteins by introducing an inappropriate 'stop signal'). We gave gentamicin to three patients with RDEB every day for 14 days, and two of the three patients further received intravenous gentamicin twice a week for 12 weeks. After gentamicin treatment, all three patients showed increased expression of C7. With both regimens, the new C7 stayed for at least 6 months after the treatment. At 1 and 3 months after treatment, 100% of the wounds being monitored in the patients had closed by more than 85%. All three patients completed the study, and no side-effects were experienced. In conclusion, intravenous gentamicin increased the production of C7 and improved wound healing and quality of life in patients with RDEB carrying nonsense mutations. Intravenous gentamicin may offer a safe, effective, low-cost and readily available therapy in patients with RDEB.

Why Are There So Few FDA-Approved Therapeutics for Wound Healing?

Since the only and the milestone FDA approval of becaplermin gel (RegranexTM, 0.01% human recombinant PDGF-BB) as a (diabetic) wound healing therapeutic more than 25 years ago, no new therapeutic (excluding physical therapies, devices, dressings, anti-microbial agents, or other preventive treatments) for any type of wound healing has advanced to clinical applications. During the same period of time, the FDA has approved additional 250 new drugs for various human tumors, which were famously described as "wounds that do not heal". Two similar pathological conditions have experienced such a dramatic difference in therapeutics. More surprisingly, few in the wound healing community seem to be alarmed by this mysterious deficit. As it is often said, "damaging is far easier than re-building". In contrast to the primary duty of a cancer drug to damage a single molecule of the signaling network, a wound healing drug must be able to re-build the multi-level damages in the wound. No known single molecule alone is capable of repairing multi-cell-type and multi-pathway damages all at once. We argue that the previous single molecule-based strategy for developing wound healing therapeutics is profoundly flawed in theory. The future success of effective wound healing therapeutics requires a fundamental change in the paradigm.

Incidence of injuries among lacrosse athletes: a systematic review and meta-analysis.

OBJECTIVES: The purpose of this systematic review was to determine the incidence of injuries among lacrosse athletes and the differences in rates of injury by location and gender. METHODS: The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines were implemented to conduct this systematic review.[1] The following variables were extracted from each of the included articles: location of injury, gender of patient, and incidence of injury among study population. The methodological quality of the included studies was assessed using mixed-methods appraisal tool (MMAT) version 2018.[2] Estimated rates were reported as pooled proportion with 95% CI. Rates of injury were calculated as a rate per 1000 athletic exposures (AEs), defined as an athlete participating in 1 practice or competition in which he or she was exposed to the possibility of athletic injury. RESULTS: This study found that the highest injury rate among lacrosse athletes was to the lower leg/ankle/foot with a rate of 0.66 injuries per 1000 AEs (95% CI, 0.51, 0.82). This injury pattern was also found to be the highest among both male and female lacrosse athletes. No statistical significance was detected when comparing rates of injury across gender, regardless of location. The injury pattern with the lowest rates of injury for female athletes being to the shoulder/clavicle and the neck for male athletes. CONCLUSION: The highest rate of injury among lacrosse athletes was to the lower leg/ankle/foot. As participation in lacrosse continues to rise, there is a greater need for understanding the rate of injury and injury characteristics for physicians and trainers to provide effective care to lacrosse athletes.

A Rapidly Enlarging Facial Abscess.

A woman in her late 70s with a history of immunoglobulin A monoclonal gammopathy of unknown significance presents with a tender, draining lesion of the central face. What is your diagnosis?

Molecular and Clinical Outcomes After Intravenous Gentamicin Treatment for Patients With Junctional Epidermolysis Bullosa Caused by Nonsense Variants.

IMPORTANCE: Junctional epidermolysis bullosa (JEB) is an incurable blistering skin disorder with high infant mortality often caused by nonsense variants in the genes that encode laminin 332. OBJECTIVE: To evaluate the safety and outcomes following intravenous gentamicin readthrough therapy and subsequent laminin 332 expression in patients with JEB. DESIGN, SETTING, AND PARTICIPANTS: This open-label, pilot nonrandomized clinical trial assessed 1 course of low- or high-dose intravenous gentamicin, including follow-up at 30 and 90 days after treatment. Five pediatric patients with JEB (2 with intermediate JEB and 3 with severe JEB) and confirmed nonsense variants in LAMA3 or LAMB3 in 1 or 2 alleles and decreased expression of laminin 332 at the dermal-epidermal junction of their skin participated in the study, which was performed at a single institution in collaboration with physicians and home infusion services near the patients from April 1, 2019, to February 28, 2021, with follow-up until May 31, 2021. INTERVENTIONS: Three patients received gentamicin at 7.5 mg/kg daily for 14 days, and 2 patients received gentamicin at 10 mg/kg daily for 24 days. MAIN OUTCOMES AND MEASURES: Primary outcomes were change in expression of laminin 332 in patients' skin and assessments for safety (ototoxic effects, nephrotoxic effects, and autoimmune response). Secondary outcomes included wound healing in monitored wounds and Epidermolysis Bullosa Disease Activity and Scarring Index (EBDASI) score. RESULTS: After gentamicin treatment, all 5 patients (age range, 3 months to 10 years, 4 [80%] female) exhibited increased laminin 332 in the dermal-epidermal junction. By 1 month, 7 of 9 wounds in patients receiving low-dose intravenous gentamicin and all wounds in patients receiving high-dose intravenous gentamicin exhibited at least 50% wound closure. By 3 months, 8 of 9 wounds in patients receiving low-dose gentamicin and all wounds in patients receiving high-dose intravenous gentamicin exhibited greater than 85% closure. All 3 patients who were evaluated with EBDASI showed a decrease in total activity scores that met minimal clinically important differences 1 month after treatment. All 5 patients completed the study, and no ototoxic effects, nephrotoxic effects, or anti-laminin 332 antibodies were detected. CONCLUSIONS AND RELEVANCE: In this nonrandomized clinical trial, intravenous gentamicin therapy was associated with induced readthrough of nonsense variants in patients with JEB, restored functional laminin 332 in their skin, and wound closure during the 3-month study period. Although long-term safety and efficacy requires further evaluation, a single cycle of intravenous gentamicin may be a safe and readily available therapy in the short term for this population of patients with JEB. TRIAL REGISTRATION: ClinicalTrials.gov Identifiers: NCT03526159 and NCT04140786.

Aged Mice Demonstrate Greater Muscle Degeneration of Chronically Injured Rotator Cuff.

Massive tears of the rotator cuff (RC) are often associated with progressive and irreversible muscle degeneration due to fibrosis, fatty infiltration, and muscle atrophy. RC tears are common in individuals older than 60 years and the repair of these tears is amongst the most prevalent of orthopedic procedures. However, most current models of this injury are established in young animals, which may not accurately recapitulate the clinical condition. In this study, we used a murine model of massive RC tears to evaluate age-related muscle degeneration following chronic injury. The expression of the fibro-adipogenic genes encoding collagen type III and leptin was higher in aged RC compared with matched injured young tissue at 2 weeks post-injury, and development of fibrosis was accelerated in aged mice within 5 days post-injury. Furthermore, the synthesis of collagens type I and III and fat tissue accumulation were significantly higher in injured RCs of aged mice. Similar frequency of fibro-adipogenic PDGFRß+ PDGFRα+ progenitor cells was measured in non-injured RC of aged and young mice, but PDGFRß+ PDGFRα+ cells contributed to significantly larger fibrotic lesions in aged RCs within 2 weeks post-injury, implying a more robust fibrotic environment in the aged injured muscle. Altogether, these findings demonstrate age-dependent differences in RC response to chronic injury with a more profound fibro-adipogenic change in aged muscles. Clinically, cell therapies for muscular pathologies should not only consider the cell type being transplanted but also the recipient milieu into which these cells are seeded. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:320-328, 2020.