In vivo molecular engineering of the urethra for treatment of stress incontinence using novel biomimetic proteoglycans.

Stress urinary incontinence (SUI), a serious condition which affects ~56% of postmenopausal women, is the involuntary leakage of urine through urethra during physical activity that causes an increase in abdominal pressure. SUI is associated with a decrease in compliance and volume of urethral tissue, likely due to a reduced proteoglycan: collagen ratio in the extracellular matrix and collagen disorganization. Here, we investigated the use of biomimetic proteoglycans (BPGs) to molecularly engineer urethral tissue of New Zealand White rabbits to examine biocompatibility in vivo. BPG concentrations of 50 mg/mL (n = 6, 1 week) and 200 mg/mL (n = 6, 1 week and n = 6, 6 weeks) dissolved in 1× phosphate-buffered saline (PBS) were injected transurethrally using a 9 French cystoscope, and were compared to PBS-injected controls (n = 3, 1 week) and non-injected controls (n = 2, 1 week). Urethral compression pressure measurements confirm BPG injections did not modify normal urethral pressure, as intended. Histological assessment demonstrated biological tolerance of BPGs in urethra and no inflammatory response was detected after 1 and 6 weeks compared to non-injected controls. Confocal imaging of fluorescently-labeled BPG injected urethral specimens demonstrated the integration of BPGs into the interstitial connective tissue and confirmed they were still present after 6 weeks. A general decrease of collagen density was exhibited near injection sites which may be due to increased hydration induced by BPGs. Injection of BPGs is a novel approach that demonstrates potential as molecular treatment for SUI and may be able to reverse some of the degenerative tissue changes of individuals affected by this condition. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: 00B: 000-000, 2019. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 2409-2418, 2019.

Biomimetic proteoglycans can molecularly engineer early osteoarthritic cartilage in vivo.

Biomimetic proteoglycans (BPGs) have the potential to treat osteoarthritis (OA) given that these molecules mimic the structure and properties of natural proteoglycans, which are significantly reduced in OA. We examined the effects of BPGs injected into the intra-articular space in an in vivo OA rabbit knee model and evaluated the effect on histological response, joint friction, and BPG distribution and retention. Rabbits underwent ACL transection to create an arthritic state after 5 weeks. OA rabbits were treated with BPGs or Euflexxa® (hyaluronic acid) intra-articular injections. Non-OA rabbits were injected similarly with BPGs; contralateral joints served as controls. The progression of OA and response to injections were evaluated using Mankin and gross grading systems indicating that mild OA was achieved in operated joints. The coefficient of friction (COF) of the intact knee joints were measured using a custom pendulum friction apparatus, showing that OA joints and OA + Euflexxa® joints demonstrated increased COF than non-operated controls, while BPG-injected non-OA and OA + BPGs were not significantly different from non-OA controls. Injected fluorescently labeled BPGs demonstrated that BPGs diffused into cartilage with localization in the pericellular region. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:403-411, 2019.

Animal models of herpes simplex virus immunity and pathogenesis.

Herpes simplex viruses are ubiquitous human pathogens represented by two distinct serotypes: herpes simplex virus (HSV) type 1 (HSV-1); and HSV type 2 (HSV-2). In the general population, adult seropositivity rates approach 90% for HSV-1 and 20-25% for HSV-2. These viruses cause significant morbidity, primarily as mucosal membrane lesions in the form of facial cold sores and genital ulcers, with much less common but more severe manifestations causing death from encephalitis. HSV infections in humans are difficult to study in many cases because many primary infections are asymptomatic. Moreover, the neurotropic properties of HSV make it much more difficult to study the immune mechanisms controlling reactivation of latent infection within the corresponding sensory ganglia and crossover into the central nervous system of infected humans. This is because samples from the nervous system can only be routinely obtained at the time of autopsy. Thus, animal models have been developed whose use has led to a better understanding of multiple aspects of HSV biology, molecular biology, pathogenesis, disease, and immunity. The course of HSV infection in a spectrum of animal models depends on important experimental parameters including animal species, age, and genotype; route of infection; and viral serotype, strain, and dose. This review summarizes the animal models most commonly used to study HSV pathogenesis and its establishment, maintenance, and reactivation from latency. It focuses particularly on the immune response to HSV during acute primary infection and the initial invasion of the ganglion with comparisons to the events governing maintenance of viral latency.

Exposure of laboratory animal care workers to airborne mouse and rat allergens.

Urine of rats and mice is the main source of allergenic proteins that can enter the respiratory tract of laboratory animal care workers. Little is known about the levels and determinants of these exposures in the United States. We investigated the relationship between activities in animal facilities and levels of personal exposure to allergen by collecting personal breathing zone dust samples from 7 caretakers during full workdays for 1 wk. Mice and rat urinary allergens in inhalable dust were quantified via immunoassay. The activities of the sampled workers were observed, and the methods of preventing exposure to allergens were recorded. Mouse urinary allergen was detected in 20 of 39 measurements, yielding a geometric mean of 0.8 ng/m(3) with a maximum of 24 ng/m(3). Washing and cleaning cages and the number of mice handled daily were the most important determinants of personal exposure to mouse urinary allergen, as identified by using multiple linear regressions that explained 51% of total variance. Personal exposures to mouse urinary allergen were associated with day-to-day variation of tasks rather than characteristics of workers. Where potential for personal exposure is the highest, protective measures (N95 masks and cage dumping stations) appeared to be used, as is appropriate. Rat urinary allergen was detected in 4 of 39 measurements; detectable concentrations were between 0.8 and 39 ng/m(3). Only persons who handled rats were exposed to rat urinary allergen. The current findings are valuable for establishing exposure levels against which comparisons of improvement or deterioration of personal exposures can be made.

Acute Paralysis Caused by Fibrocartilaginous Embolism in a Pigtail Macaque.

An adult female pigtail macaque was evaluated for acute flaccid rear limb paralysis with reduced patellar and anal reflexes. Despite supportive care, antibiotics, and corticosteroids, the monkey showed no improvement and was euthanized 7 days after the onset of clinical signs. Necropsy revealed a soft and swollen spinal cord within the L1 to L3 vertebrae. Microscopic examination of the spinal cord showed severe, diffuse ischemic necrosis, particularly of gray matter. Several small vessels within the spinal nerve root were partially to nearly totally occluded by material resembling fibrocartilage. To the best of our knowledge, this is the first reported case of fibrocartilaginous embolism in a nonhuman primate.