Murine Orchiectomy and Ovariectomy to Reduce Sex Hormone Production

Sex hormone signaling plays a critical role in multiple organ systems as well as in the progression of various diseases, including neurodegenerative disease. The manipulation of sex hormone levels in the murine model system allows for the study of their impact on organs/tissues and within disease progression. Orchiectomy - the surgical removal of the testes - and ovariectomy - the surgical removal of the ovaries - provide a method to deplete the endogenous sex hormones so that the precise hormone levels can be provided through drug or other delivery methods. Here, we provide rapid and minimally invasive methods for both orchiectomy and ovariectomy in the murine model system for the reduction of sex hormones. This protocol details the surgical preparation and excision of the testes through the scrotal sac, and excision of the ovaries via two incisions in the right and left lateral dorsum.

Kasai portoenterostomy delays: Is a HIDA scan worth the wait?

BACKGROUND

Biliary Atresia (BA), an obstructive cholangiopathy, is the most common cause of end-stage liver disease and liver transplantation in children. Timely differentiation of BA from other causes of neonatal jaundice remains a challenge, yet is critical to improving outcomes.

METHODS

Clinical characteristics including demographics, age at jaundice presentation, age at hepatobiliary scintigraphy, age at surgery, severity of liver fibrosis, and native-liver survival were reviewed in infants with hyperbilirubinemia and suspected BA for this single center retrospective cohort study. We investigated the accuracy of hepatobiliary scintigraphy as well as elapsed time from jaundice presentation to diagnostic intervention.

RESULTS

BA was suspected in 234 infants. BA was identified in 17% of infants with hepatobiliary scintigraphy and 72% of infants who underwent operative exploration without hepatobiliary scintigraphy. Elapsed time from jaundice presentation to Kasai Portoenterostomy (KPE) for BA patients was 2.1x longer if hepatobiliary scintigraphy was obtained (p = 0.084). The mean age at KPE for this cohort was 66.8 days (n = 54), with a significantly higher mean age at KPE (75.2 days) for infants who were later listed or underwent liver transplantation (p = 0.038). Histologically, the lowest liver fibrosis scores were seen in infants undergoing KPE <30 days old and worsened significantly with increased age (p < 0.001).

CONCLUSION

Hepatobiliary scintigraphy compared to operative exploration for the diagnostic evaluation of infants with suspected BA introduces significant time delays to KPE but enables avoidance of surgery in some infants. The temporal pattern of worsening cholestatic liver injury from BA with each day of increased age highlights the importance of intervening as early as possible for the best prognosis.

TYPE OF STUDY

Retrospective study, Level of evidence: III.

Long-term progression of retinal degeneration in a preclinical model of CLN7 Batten disease as a baseline for testing clinical therapeutics

BACKGROUND

Batten disease is characterized by cognitive and motor impairment, retinal degeneration, and seizures leading to premature death. Recent studies have shown efficacy for a gene therapy approach for CLN7 Batten disease. This gene therapy approach is promising to treat cognitive and motor impairment, but is not likely to delay vision loss. Additionally, the natural progression of retinal degeneration in CLN7 Batten disease patients is not well-known.

METHODS

We performed visual examinations on five patients with CLN7 Batten disease and found that patients were far progressed in degeneration within their first five years of life. To better understand the disease progression, we characterized the retina of a preclinical mouse model of CLN7 Batten disease, through the age at which mice present with paralysis and premature death.

FINDINGS

We found that this preclinical model shows signs of photoreceptor to bipolar synaptic defects early, and displays rod-cone dystrophy with late loss of bipolar cells. This vision loss could be followed not only via histology, but using clinical live imaging similar to that used in human patients.

INTERPRETATION

Natural history studies of rare paediatric neurodegenerative conditions are complicated by the rapid degeneration and limited availability of patients. Characterization of degeneration in the preclinical model allows for future experiments to better understand the mechanisms underlying the retinal disease progression in order to find therapeutics to treat patients, as well as to evaluate these therapeutic options for future human clinical trials.

FUNDING

Van Sickle Family Foundation Inc., NIHP30EY030413, Morton Fichtenbaum Charitable Trust and 5T32GM131945-03.

Differential effects of obstructive sleep apnea on the corneal subbasal nerve plexus and retinal nerve fiber layer

Purpose

Obstructive sleep apnea (OSA) is an established independent risk factor for peripheral neuropathy. Macro and microvascular changes have been documented in OSA, including high levels of potent vasoconstrictors. In diabetes, vasoconstriction has been identified as an underlying risk factor for corneal neuropathy. This study sought to establish a potential relationship between OSA and corneal nerve morphology and sensitivity, and to determine whether changes in corneal nerves may be reflective of OSA severity.

Design

Single center cross-sectional study.

Methods

Sixty-seven patients were stratified into two groups: those with OSA and healthy controls. Groups were matched for age, sex, race, smoking, and dry eye status. Outcome measures included serologies, a dilated fundus exam, dry eye testing, anthropometric parameters, corneal sensitivity, subbasal nerve plexus morphology, retinal nerve fiber layer (RNFL) thickness, and the use of questionnaires to assess symptoms of dry eye disease, risk of OSA, and continuous positive airway pressure (CPAP) compliance.

Results

No significant differences were observed in corneal nerve morphology, sensitivity, or the number of dendritic cells. In the OSA test group, RNFL thinning was noted in the superior and inferior regions of the optic disc and peripapillary region. A greater proportion of participants in the OSA group required a subsequent evaluation for glaucoma than in the control. In those with OSA, an increase in the apnea hypopnea index was associated with an increase in optic nerve cupping.

Conclusions

OSA does not exert a robust effect on corneal nerves. OSA is however, associated with thinning of the RNFL. Participants with glaucomatous optic nerve changes and risk factors for OSA should be examined as uncontrolled OSA may exacerbate glaucoma progression.