Efficacy of different spinal nerve roots for neuromodulation of micturition reflex in rats

Glutamine's protection against brain damage in septic rats via increased protein oxygen-N-acetylglucosamine modification

OBJECTIVE

This study aimed to observe the effect of glutamine (Gln) on brain damage in septic rats and explore its possible mechanism.

METHODS

Ninety-three Sprague-Dawley rats were randomly divided into five groups: sham operation group, sepsis group, Gln-treated group, quercetin/Gln-treated group, and alloxan/Gln-treated group. The rats in each group were continuously monitored for mean arterial pressure (MAP) and heart rate changes for 16 h. Neuroreflex scores were measured 24 h after surgery. The water content of the brain tissue was measured. Plasma neuron enolase and cysteine protease-3 were measured using the ELISA. The expression levels of heat shock protein 70 (HSP70) and oxygen-N-acetylglucosamine (O-GlcNAc) were determined by western blot analysis. Finally, the brain tissue was observed via hematoxylin and eosin staining.

RESULTS

The brain tissue water content, plasma neuron enolase content, brain tissue cysteine protease-3 content, and nerve reflex score were significantly lower in the Gln-treated group than in the sepsis group (P < 0.05). At the same time, the pathological brain tissue damage in the Gln-treated group was also significantly reduced. It is worth noting that the expression of HSP70 and the protein O-GlcNAc modification levels in the Gln-treated group were significantly elevated than the levels in the sepsis group (P < 0.05), and reversed by pretreatment with the HSP and O-GlcNAc inhibitors quercetion and alloxan.

CONCLUSIONS

Gln can attenuate brain damage in rats with sepsis, which may be associated with increased protein O-GlcNAc modification.

Sacral nerve stimulation for refractory OAB and idiopathic urinary retention: Can phenotyping improve the outcome for patients: ICI-RS 2019?

AIMS

Sacral nerve stimulation (SNS) is widely used to treat refractory idiopathic overactive bladder (OAB) and idiopathic urinary retention. However, clinical outcomes are variable and understanding predictive factors for success or side-effects would enable personalization of therapy and optimization of outcomes. At the International Consultation on Incontinence-Research Society meeting 2019, a Think Tank was convened to discuss how advances in the basic science study of SNS may be translatable into clinical practice to improve outcomes of patients undergoing SNS treatment.

METHODS

We conducted a literature review and expert consensus meeting focusing on current methods of phenotyping patients and specifically, how advances in basic science research of the mechanism of action of SNS can be translated into clinical practice to improve patient selection for therapy.

RESULTS

The terms "Idiopathic OAB" and "idiopathic urinary retention" encompass several underlying pathophysiological phenotypes. Commonly, phenotyping is based on clinical and urodynamic factors. Animal studies have demonstrated that high-frequency stimulation can produce rapid onset, reversible conduction block in peripheral nerves. Altering stimulation parameters may potentially enable personalization of therapy depending upon the clinical indication in the future. Similarly, advances in conditional and closed-loop stimulation may offer greater efficacy for certain patients. Phenotyping based on psychological comorbidity requires further study to potentially optimize patient selection for therapy.

CONCLUSIONS

Idiopathic OAB and idiopathic urinary retention are heterogenous conditions with multiple potential underlying phenotypes. Tailoring stimulation parameters to the needs of each individual according to phenotype could optimize outcomes. Assessing psychological comorbidity may improve patient selection. Areas for further research are proposed.

Suppression of Urinary Voiding "on Demand" by High-Frequency Stimulation of the S1 Sacral Nerve Root in Anesthetized Rats

OBJECTIVES

High-frequency (kHz) stimulation of preganglionic pelvic nerve afferents can inhibit voiding in both anesthetized and conscious rats. The afferents travel via the S1 sacral nerve root, which is easier to access than the distal pelvic nerve fibers within the abdominal cavity. We therefore investigated whether voiding could be inhibited by high-frequency stimulation at S1 and how this compared to distal pelvic nerve stimulation.

METHODS

Urethane-anesthetized rats were instrumented to record bladder pressure and abdominal wall electromyogram and to stimulate the distal preganglionic pelvic nerve bundle and S1 sacral root. Saline was infused continuously into the bladder to evoke repeated voiding. Stimulation was initiated within 1-2 sec of the onset of the steep rise in bladder pressure signaling an imminent void.

RESULTS

In six rats, stimulation of the distal pelvic nerve bundle (1-3 kHz sinusoidal waveform 1 mA, 60 sec) supressed the occurrence of an imminent void. Voiding resumed within 70 ± 13.0 sec (mean ± SEM) of stopping stimulation. Stimulation (using the same parameters) of the S1 root at the level of the sacral foramen suppressed voiding for the entire stimulation period in three rats and deferred voiding for 35-56 sec (mean 44.0 ± 3.2 sec) in the remaining three. Stimulation at either site when the bladder was approximately half full, as estimated from previous intervoid intervals, had no effect on voiding.

CONCLUSIONS

This preliminary study provides proof-of-concept for the sacral root as an accessible target for high-frequency stimulation that may be developed as an "on demand" neuromodulation paradigm to suppress unwanted urinary voids.

CONFLICT OF INTEREST

The authors reported no conflict of interest.