Effects of senescence and citral on neuronal vacuolar degeneration in rat pelvic ganglia

RIFM fragrance ingredient safety assessment, 3,7-dimethyl-3,6-octadienal, CAS registry number 55722-59-3

The existing information supports the use of this material as described in this safety assessment. 3,7-Dimethyl-3,6-octadienal was evaluated for genotoxicity, repeated dose toxicity, developmental and reproductive toxicity, local respiratory toxicity, phototoxicity/photoallergenicity, skin sensitization, and environmental safety. Data from read-across analog citral (CAS # 5392-40-5) show that 3,7-dimethyl-3,6-octadienal is not expected to be genotoxic and provided a calculated margin of exposure (MOE) >100 for the repeated dose toxicity and developmental and reproductive endpoints. Data from the read-across analog citronellal (CAS # 106-23-0) provided 3,7-dimethyl-3,6-octadienal a No Expected Sensitization Induction Level (NESIL) of 7000 μg/cm² for the skin sensitization endpoint. The phototoxicity/photoallergenicity endpoints were evaluated based on ultraviolet (UV) spectra; 3,7-dimethyl-3,6-octadienal is not expected to be phototoxic/photoallergenic. The local respiratory toxicity endpoint was evaluated using the threshold of toxicological concern (TTC) for a Cramer Class I material, and the exposure to 3,7-dimethyl-3,6-octadienal is below the TTC (1.4 mg/day). The environmental endpoints were evaluated; 3,7-dimethyl-3,6-octadienal was found not to be persistent, bioaccumulative, and toxic (PBT) as per the International Fragrance Association (IFRA) Environmental Standards, and its risk quotients, based on its current volume of use in Europe and North America (i.e., Predicted Environmental Concentration/Predicted No Effect Concentration [PEC/PNEC]), are <1.

Sonic hedgehog regulation of cavernous nerve regeneration and neurite formation in aged pelvic plexus

INTRODUCTION

Erectile dysfunction (ED) is a significant health concern that greatly impacts quality of life, and is common in men as they age, impacting 52% of men between the ages of 40 and 70. A significant underlying cause of ED development is injury to the cavernous nerve (CN), a peripheral nerve that innervates the penis. CN injury also occurs in up to 82% of prostatectomy patients. We recently showed that Sonic hedgehog (SHH) protein delivered by peptide amphiphile (PA) nanofiber hydrogel to the CN and penis of a prostatectomy model of CN injury, is neuroprotective, accelerates CN regeneration, improves erectile function ~60%, preserves penile smooth muscle 56% and suppresses collagen deposition 30%. This regenerative potential is substantial in an adult prostatectomy model (P120). However prostatectomy patients are typically older (61.5 ± 9.6 years) and our models should mimic patient conditions more effectively when considering translation. In this study we examine regenerative potential in an aged prostatectomy model (P200-329).

METHODS

The caudal portion of the pelvic ganglia (MPG) and CN were dissected from adult (n = 11), and aged (n = 13) Sprague Dawley rats, and were grown in organ culture 3 days. Uninjured and 2 day CN crushed MPG/CN were exposed to Affi-Gel beads containing SHH protein, PBS (control), or 5e1 SHH inhibitor. Neurites were quantified by counting the number of growth cones normalized by tissue perimeter (mm) and immunohistochemistry for SHH, patched1 (PTCH1), smoothened (SMO), GLI1-3, and GAP43 were performed.

RESULTS

SHH treatment increased neurites 3.5-fold, in uninjured adult, and 5.7-fold in aged rats. Two days after CN crush, SHH treatment increased neurites 1.8-fold in adult rats and 2.5-fold in aged rats. SHH inhibition inhibited neurite formation in uninjured MPG/CN but not in 2 day CN crushed MPG/CN. PTCH1 and SMO (SHH receptors), and SHH transcriptional activators/repressors, GLI1-3, were abundant in aged MPG/CN with unaltered localization. ROCK1 was induced with SHH treatment.

CONCLUSIONS

Reintroduction of SHH protein in an aged prostatectomy model is even more effective in promoting neurite formation/CN regeneration than in the adult. The first 48 h after CN injury are a critical window when growth factors are released, that impact later neurite formation. These studies are significant because most prostatectomy patients are not young and healthy, as with adult rats, so the aged prostatectomy model will more accurately simulate ED patient response. Understanding how neurite formation changes with age is critical for clinical translation of SHH PA to prostatectomy patients.

Differences in innervated neurons of the internal anal sphincter based on age and sex: A histological study

AIM

Previous studies have shown sex and age differences in anal sphincter function, but few morphological studies have focused on the quality and quantity of the nerves that control the sphincter muscles. The present study aimed to determine whether there are morphological and quantitative sex and age differences in the nerves in the conjoined longitudinal muscle.

METHODS

This was a single-center, retrospective study using surgical specimens from 44 patients who underwent abdominoperineal resection between 2003 and 2012. Hematoxylin-eosin- and S-100-stained peripheral nerves (nerve fibers and ganglion cells) in the conjoined longitudinal muscle beneath the dentate line were observed microscopically. A qualitative examination assessed the degeneration score, which was based on the presence or absence of karyopyknosis, vacuolar degeneration, acidophilic degeneration of the cytoplasm, denucleation and adventitial neuronal changes. For quantitative examinations, each neuronal and muscular area was traced to calculate the neuronal area ratio in S-100-immunostained photomicrographs at the observation site.

RESULTS

Women had a significantly lower quantity of nerves than men. Older individuals (aged ≥80 years) had a significantly lower quantity of nerves than younger individuals. Furthermore, older individuals tended to show greater morphological changes that appeared to be a result of degeneration.

CONCLUSIONS

The present findings suggest that anal hypofunction in women and older individuals might result from differences in the quantity and quality of the neurons controlling the anal sphincter muscle. Geriatr Gerontol Int 2018; 18: 495-500.

Morphological changes in peri-prostatic sympathetic ganglion cells in aging males

A significant part of morbidity in elderly male patients involves the pelvic organs and their autonomic neural regulation. The aim of the current study was to report the histopathological changes in the peri-prostatic ganglia in elderly males. The sympathetic ganglia from 36 prostatectomy specimens, 26 due to carcinoma of the prostate and 10 prostates from total cystectomies for transitional cell carcinoma, were examined. The age range was 54-88 years. A total of 5,075 ganglion cells were counted in all the specimens. Pathological changes were identified in 1,696 neuron cells as follows: Neuronophagia in 746 neuron cells, neuron cell vacuolization (330 cells), satellite cells vacuolization (423 cells), cell pyknosis (148 cells) and nageotte nodules (49 cells). A number of these changes increased with age. All the changes were more marked in the peri-prostatic ganglion cells of patients with prostatic adenocarcinoma compared with those with benign prostate hyperplasia, which may be due to local environmental changes associated with the presence of malignancy.

Neurogenic mechanisms in bladder and bowel ageing

The prevalence of both urinary and faecal incontinence, and also chronic constipation, increases with ageing and these conditions have a major impact on the quality of life of the elderly. Management of bladder and bowel dysfunction in the elderly is currently far from ideal and also carries a significant financial burden. Understanding how these changes occur is thus a major priority in biogerontology. The functions of the bladder and terminal bowel are regulated by complex neuronal networks. In particular neurons of the spinal cord and peripheral ganglia play a key role in regulating micturition and defaecation reflexes as well as promoting continence. In this review we discuss the evidence for ageing-induced neuronal dysfunction that might predispose to neurogenic forms of incontinence in the elderly.

Antagonists of retinoic acid and BMP4 affect fetal mouse osteogenesis and odontoblast differentiation

Retinoic acid and bone morphogenetic protein (BMP4) are endogenous factors indispensable for the physiological development of vertebrates. The proximate aim of the present study was to investigate whether the natural compound citral (a retinoic acid synthesis inhibitor) and a monoclonal, anti-BMP4 antibody, administered to pregnant mice affect in the fetuses cranial osteogenesis and odontoblast differentiation. The present investigation was motivated by the fact that, retinoic acid inhibitors and BMP4 neutralizers may frequently contact human tissues (both intentional and unintentional, and/or unconsciously) inducing unanticipated effects. Our ultimate goal is the prevention of side effects and, future clinical implementation of the results. To this end, pregnant, white mice (balb-c Mus musculus) were intra-abdominally injected with either citral or anti-BMP4 antibody at the 9th gestational day. Newborns were processed within 5h, postnatal. Results were evaluated (a) macroscopically, (b) stereoscopically, following histochemical double staining of cartilage and osseous tissues and, (c) microscopically after (c(1)) histological staining of paraffin sections, and, (c(2)) immunohistochemical detection of apoptosis. Data indicate that in vivo administration of citral (biomimicking hypovitaminosis A) caused restriction/retardation of cranial chondrogenesis and osteogenesis. Apoptosis was not detected in teeth tissues. In vivo administration of anti-BMP4 antibody resulted in a transitory interference with the normal course of odontoblast differentiation and the production of pre-dentin, whereas, delay in the ossification also included the alveoli. Animals inspected in adulthood displayed a fairly normal phenotype. It is concluded that those two substances, under their concentrations experienced, are quite safe for the public.

Structural and functional investigations of the murine cavernosal nerve: a model system for serial spatio-temporal study of autonomic neuropathy

OBJECTIVE

To illustrate the ultrastructural fibre composition of the rat cavernosal nerve at serial levels, from its origin in the main pelvic ganglion to its termination in the corpus cavernosum of the distal penile shaft, and to develop a technique that permits repeated electrophysiological recording from the fibres that form the cavernosal nerve distinct from the axons of the dorsal nerve of the penis (DNP).

MATERIALS AND METHODS

For the light microscope and ultrastructural studies, Sprague-Dawley rats were anaesthetized and the pelvic organs and lower limbs were perfused with glutaraldehyde through the distal aorta. Tissue samples were embedded in epoxy resin and prepared for light and electron microscopy. Frozen tissue was used for the immunohistochemical studies and sections were stained with rabbit anti-nitric oxide synthetase 1 (NOS1). For the electrophysiology, anaesthetized rats were used in sterile conditions. Nerve conduction velocity for the cavernosal nerve was assessed from a point 2 mm below the main (major) pelvic ganglion after stimulating the nerve at the crus penis; multi-unit averaging techniques were used to enhance the recording of slow-conduction activity. Recordings from the DNP were obtained over the proximal shaft after stimulation at the base of the penis.

RESULTS

Step-serial sections of the cavernosal nerve revealed numerous ganglion cells in the initial segments and gradually fewer myelinated fibres at distal levels. At the point of crural entry, the nerve contained almost exclusively unmyelinated axons. As it descended the penile shaft, the nerve separated into small fascicles containing only one to four axons at the level of the distal shaft. In the corpus cavernosum, vesicle-filled presynaptic axon preterminals were close to smooth muscle fibres, but did not seem to be in direct contact. Immunohistochemical evaluation of NOS1 activity showed intense staining of the fibres of the DNP and most of the neurones in the main pelvic ganglion. There was also scattered NOS1 activity in the nerve bundles of the corpus cavernosum. Electrophysiology identified activity in C fibres on the cavernosal nerve and in Aalpha-Adelta fibres in the DNP.

CONCLUSION

These results show that it is possible to perform integrated cavernosal pressure monitoring and ultrastructural and electrophysiological studies in this model. These yielded accurate data about the erectile status of the penis, and the state of unmyelinated and myelinated fibres in the DNP and cavernosal nerves of the same animal. This study provides a useful template for future studies of experimental diabetic autonomic neuropathy.