Effect of intra-vaginal electric stimulation on bladder compliance in stress urinary incontinence patients: the involvement of autonomic tone

ObjectiveIn addition to the well-established advantage that strengthened pelvic musculature increases urethral resistance in stress urinary incontinence (SUI) patients, intra-vaginal electrical stimulation (iVES) has been shown in preclinical studies to improve bladder capacity via the pudendal-hypogastric mechanism. This study investigated whether iVES also benefits bladder storage in SUI patients by focusing on compliance, a viscoelastic parameter critically defining the bladder’s storage function, in a clinical study. Moreover, the potential involvement of stimulation-induced neuromodulation in iVES-modified compliance was investigated by comparing the therapeutic outcomes of SUI patients treated with iVES to those who underwent a trans-obturator tape (TOT) implantation surgery, where a mid-urethral sling was implanted without electric stimulation.Patients and methodsUrodynamic and viscoelastic data were collected from 21 SUI patients treated with a regimen combining iVES and biofeedback-assisted pelvic floor muscle training (iVES-bPFMT; 20-min iVES and 20-min bPFMT sessions, twice per week, for 3 months). This regimen complied with ethical standards. Data from 21 SUI patients who received TOT implantation were retrospectively analyzed. Mean compliance (Cm), infused volume (Vinf), and threshold pressure (Pthr) from the pressure-flow/volume investigations were assessed.ResultsCompared with the pretreatment control, iVES-bPFMT consistently and significantly increased Cm (18/21; 85%, p = 0.017, N = 21) and Vinf (16/21; 76%, p = 0.046; N = 21) but decreased Pthr (16/21; 76%, p = 0.026, N = 21). In contrast, TOT implantation did not result in consistent or significant changes in Cm, Vinf, or Pthr (p = 0.744, p = 0.295, p = 0.651, respectively; all N = 21).ConclusionOur results provide viscoelastic and thermodynamic evidence supporting an additional benefit of iVES-bPFMT to bladder storage in SUI patients by modifying bladder compliance, possibly due to the potentiated hypogastric tone, which did not occur in TOT-treated SUI patients.Clinical trial registration:ClinicalTrials.gov, NCT02185235 and NCT05977231

Neuropathic Allodynia Involves Spinal Neurexin-1 beta-dependent Neuroligin-1/Postsynaptic Density-95/NR2B Cascade in Rats

Background: Neuroligin-1 (NL1) forms a complex with the presynaptic neurexin-1 beta (Nrx1b), regulating clustering of N-methyl-D-aspartate receptors with postsynaptic density-95 (PSD-95) to underlie learning-/memory-associated plasticity. Pain-related spinal neuroplasticity shares several common features with learning-/memory-associated plasticity. The authors thereby investigated the potential involvement of NL1-related mechanism in spinal nerve ligation (SNL)-associated allodynia. Methods: In 626 adult male Sprague-Dawley rats, the withdrawal threshold and NL1, PSD-95, phosphorylated NR2B (pNR2B) expressions, interactions, and locations in dorsal horn (L4 to L5) were compared between the sham operation and SNL groups. A recombinant Nrx1b Fc chimera (Nrx1b Fc, 10 mu g, 10 mu l, i.t., bolus), antisense small-interfering RNA targeting to NL1 (10 mu g, 10 mu l, i.t., daily for 4 days), or NR2B antagonist (Ro 25-6981; 1 mu M, 10 mu l, i.t., bolus) were administered to SNL animals to elucidate possible cascades involved. Results: SNL-induced allodynia failed to affect NL1 or PSD-95 expression. However, pNR2B expression (mean +/- SD from 13.1 +/- 2.87 to 23.1 +/- 2.52, n = 6) and coexpression of NL1-PSD-95, pNR2B-PSD-95, and NL1-total NR2B were enhanced by SNL (from 10.7 +/- 2.27 to 22.2 +/- 3.94, 11.5 +/- 2.15 to 23.8 +/- 3.32, and 8.9 +/- 1.83 to 14.9 +/- 2.27 at day 7, n = 6). Furthermore, neuron-localized pNR2B PSD-95-pNR2B double-labeled and NL1/PSD-95/pNR2B triple-labeled immunofluorescence in the ipsilateral dorsal horn was all prevented by Nrx1b Fc and NL1-targeted small-interfering RNA designed to block and prevent NL1 expression. Without affecting NL1-PSD-95 coupling, Ro 25-6981 decreased the SNL-induced PSD-95-pNR2B coprecipitation (from 18.7 +/- 1.80 to 14.7 +/- 2.36 at day 7, n = 6). Conclusion: SNL-induced allodynia, which is mediated by the spinal NL1/PSD-95/pNR2B cascade, can be prevented by blockade of transsynaptic Nrx1b-NL1 interactions

Modulation of Nerve Injury-induced HDAC4 Cytoplasmic Retention Contributes to Neuropathic Pain in Rats

Background: The histone deacetylases (HDACs) have been implicated in pain hypersensitivity. This study investigated the potential involvement of an HDAC4-related mechanism in the spinal nerve ligation (SNL)-induced nociceptive hypersensitivity. Methods: The left L5 to L6 spinal nerves of 627 adult male Sprague-Dawley rats were surgically ligated. The withdrawal threshold of hind paws and the abundances, cellular location, and interactions of proteins in the dorsal horn were assayed before and after surgery. The 14-3-3-targeting small-interfering RNA, a serum- and glucocorticoid-inducible kinase 1 (SGK1) antagonist, or an HDAC inhibitor was spinally injected to elucidate the role of 14-3-3, SGK1, and HDAC4. Results: Without affecting the HDAC4 level, SNL provoked SGK1 phosphorylation (mean SEM from 0.24 +/- 0.02 to 0.78 +/- 0.06 at day 7, n = 6), HDAC4 phosphorylation (from 0.38 +/- 0.03 to 0.72 +/- 0.06 at day 7, n = 6), 14-3-3 expression (from 0.53 +/- 0.09 to 0.88 +/- 0.09 at day 7, n = 6), cytoplasmic HDAC4 retention (from 1.18 +/- 0.16 to 1.92 +/- 0.11 at day 7, n = 6), and HDAC4-14-3-3 coupling (approximately 2.4-fold) in the ipsilateral dorsal horn in association with behavioral allodynia. Knockdown of spinal 14-3-3 expression prevented the SNL-provoked HDAC4 retention (from 1.89 +/- 0.15 to 1.32 +/- 0.08 at day 7, n = 6), HDAC4-14-3-3 coupling (approximately 0.6-fold above SNL 7D), and behavioral allodynia (from 0.16 +/- 0.3 to 6 +/- 1.78 at day 7, n = 7), but not SGK1 (from 0.78 +/- 0.06 to 0.71 +/- 0.04 at day 7, n = 6) or HDAC4 (from 0.75 +/- 0.15 to 0.68 +/- 0.11 at day 7, n = 6) phosphorylation. Conclusion: Neuropathic pain maintenance involves the spinal SGK1 activation-dependent HDAC4 phosphorylation and its subsequent association with 14-3-3 that promotes cytoplasmic HDAC4 retention in dorsal horn neurons

Fbxo3-Dependent Fbxl2 Ubiquitination Mediates Neuropathic Allodynia through the TRAF2/TNIK/GluR1 Cascade

Emerging evidence has indicated that the pathogenesis of neuropathic pain is mediated by spinal neural plasticity in the dorsal horn, which provides insight for analgesic therapy. Here, wereport that the abundance of tumor necrosis factor receptor-associated factor 2 and NcK-interacting kinase (TNIK), a kinase that is presumed to regulate neural plasticity, was specifically enhanced in ipsilateral dorsal horn neurons after spinal nerve ligation (SNL; left L5 and L6). Spinal TNIK-associated allodynia is mediated by downstream TNIK-GluR1 coupling and the subsequent phosphorylation-dependent trafficking of GluR1 toward the plasma membrane in dorsal horn neurons. Tumor necrosis factor receptor-associated factor 2 (TRAF2), which is regulated by spinal F-box protein 3 (Fbxo3)-dependent F-box and leucine-rich repeat protein 2 (Fbxl2) ubiquitination, contributes to SNL-induced allodynia by modifying TNIK/GluR1 phosphorylation-associated GluR1 trafficking. Although exhibiting no effect on Fbxo3/Fbxl2/TRAF2 signaling, focal knockdown of spinal TNIK expression prevented SNL-induced allodynia by attenuating TNIK/GluR1 phosphorylation-dependent subcellular GluR1 redistribution. In contrast, intrathecal administration of BC-1215 (N1, N2-Bis[[4-(2-pyridinyl)phenyl]methyl]-1,2-ethanediamine) (a novel Fbxo3 inhibitor) prevented SNL-induced Fbxl2 ubiquitination and subsequent TFAF2 de-ubiquitination to ameliorate behavioral allodynia via antagonizing TRAF2/TNIK/GluR1 signaling. By targeting spinal Fbxo3-dependent Fbxl2 ubiquitination and the subsequent TRAF2/TNIK/GluR1 cascade, spinal application of a TNF-alpha-neutralizing antibody ameliorated SNL-induced allodynia, and, conversely, intrathecal TNF-alpha injection into naive rats induced allodynia via a spinal Fbxo3/Fbxl2-dependent modification of the TRAF2/TNIK/GluR1 cascade. Together, our results suggest that spinal TNF-alpha contributes to the development of neuropathic pain by upregulating TRAF2/TNIK/GluR1 signaling via Fbxo3-dependent Fbxl2 ubiquitination and degradation. Thus, we propose a potential medical treatment strategy for neuropathic pain by targeting the F-box protein or TNIK

Modulation of Nerve Injury-induced HDAC4 Cytoplasmic Retention Contributes to Neuropathic Pain in Rats

Background: The histone deacetylases (HDACs) have been implicated in pain hypersensitivity. This study investigated the potential involvement of an HDAC4-related mechanism in the spinal nerve ligation (SNL)-induced nociceptive hypersensitivity. Methods: The left L5 to L6 spinal nerves of 627 adult male Sprague-Dawley rats were surgically ligated. The withdrawal threshold of hind paws and the abundances, cellular location, and interactions of proteins in the dorsal horn were assayed before and after surgery. The 14-3-3-targeting small-interfering RNA, a serum- and glucocorticoid-inducible kinase 1 (SGK1) antagonist, or an HDAC inhibitor was spinally injected to elucidate the role of 14-3-3, SGK1, and HDAC4. Results: Without affecting the HDAC4 level, SNL provoked SGK1 phosphorylation (mean SEM from 0.24 +/- 0.02 to 0.78 +/- 0.06 at day 7, n = 6), HDAC4 phosphorylation (from 0.38 +/- 0.03 to 0.72 +/- 0.06 at day 7, n = 6), 14-3-3 expression (from 0.53 +/- 0.09 to 0.88 +/- 0.09 at day 7, n = 6), cytoplasmic HDAC4 retention (from 1.18 +/- 0.16 to 1.92 +/- 0.11 at day 7, n = 6), and HDAC4-14-3-3 coupling (approximately 2.4-fold) in the ipsilateral dorsal horn in association with behavioral allodynia. Knockdown of spinal 14-3-3 expression prevented the SNL-provoked HDAC4 retention (from 1.89 +/- 0.15 to 1.32 +/- 0.08 at day 7, n = 6), HDAC4-14-3-3 coupling (approximately 0.6-fold above SNL 7D), and behavioral allodynia (from 0.16 +/- 0.3 to 6 +/- 1.78 at day 7, n = 7), but not SGK1 (from 0.78 +/- 0.06 to 0.71 +/- 0.04 at day 7, n = 6) or HDAC4 (from 0.75 +/- 0.15 to 0.68 +/- 0.11 at day 7, n = 6) phosphorylation. Conclusion: Neuropathic pain maintenance involves the spinal SGK1 activation-dependent HDAC4 phosphorylation and its subsequent association with 14-3-3 that promotes cytoplasmic HDAC4 retention in dorsal horn neurons

高低頻電針刺激合骨穴引發大鼠差異性之交感神經系統活性

To address the effect of electroacupuncture (Ea) on autonomic nerve activity, the responses of rhythmic micturition contraction (RMC), urine excretion (UE), blood pressure (BP), renal sympathetic nerve activity (RNA ) and pelvic parasympathetic nerve activity (PNA) to Ea were investigated in urethane-anesthetized rats. The acupoint Hoku (Li-4) was tested with two different stimulation frequencies (2 Hz and 20 Hz). Elongation of the RMC cycle and an increase in UE associated with the elevation of BP and RNA was elicited during Ea at Hoku. However, the pressor response induced by low frequency Ea (LFEa) was different from that by high frequency Ea ( HFEa), i.e. a tonic effect was elicited by LFEa, while a phasic one was induced by HFEa . These results imply that: (1) Ea at Hoku may selectively activate the sympathetic, but not the parasympathetic nervous system, (2) Ea at Hoku with a different stimulation frequency may elicit a distinct mechanism to activate the sympathetic nervous system and (3) Ea at Hoku may ameliorate the hyperactive bladder in clinical therapy