[Protection of side-branch ostium by the jailed balloon technique validated by three-dimensional optical coherence tomography].

Objective: To evaluate the protective effect of jailed balloon technique on side branch (SB) ostium using three-dimensional optical coherence tomography(OCT). Methods: This is a retrospective study. Consecutive coronary disease patients with coronary artery bifurcation lesions who underwent percutaneous coronary intervention (PCI) and completed pre-and post-procedural OCT examinations at the Chinese People's Liberation Army General Hospital from September 2019 to March 2022 were enrolled. Patients were divided into the jailed balloon technique group and the unprotected group according to the options applied for the SB. The SB ostium area difference was calculated from OCT images (SB ostium area difference=post-PCI SB ostium area-pre-PCI SB ostium area). The SB ostium area differences were compared between the two groups and compared further in the subgroup of true bifurcation lesions and non-true bifurcation lesions. In the jailed balloon group, the SB ostium area difference was compared between the active jailed balloon technique and the conventional jailed balloon technique, between the jailed balloon>2.0 mm diameter and the jailed balloon≤2.0 mm diameter, and between the higher balloon pressure (>4 atm, 1 atm=101.325 kPa) and the lower balloon pressure (≤4 atm). Multivariate linear regression analysis was used to explore the correlation between the technical parameters of the jailed balloon technique and the SB protection effect. Results: A total of 176 patients with 236 bifurcation lesions were enrolled, aged (60.7±9.3) years, and there were 128 male patients (72.7%). There were 67 patients in the jailed balloon technique group with 71 bifurcation lesions and 123 patients in the unprotected group with 165 bifurcation lesions. Fourteen patients had 2 to 3 lesions, which were treated in different ways, so they appeared in the unprotected group and the jailed balloon technique group at the same time. The area difference in SB ostium was greater in the jailed balloon group than in the unprotected group (0.07 (-0.43, 1.05)mm2 vs.-0.33 (-0.83, 0.26)mm2, P<0.001), and the results were consistent in the true bifurcation lesion subgroup (0.29 (-0.35, 0.96)mm2 vs.-0.26 (-0.64, 0.29)mm2, P=0.004), while the difference between the two groups in the non-true bifurcation lesion subgroup was not statistically significant (P=0.136). In the jailed balloon technique group, the SB ostium area difference was greater in patients treated with the active jailed balloon technique than in those treated with the conventional jailed balloon technique ((0.43±1.36)mm2 vs. (-0.22±0.52)mm2, P=0.013). The difference in SB ostium area was greater in those using>2.0 mm diameter jailed balloons than in those using≤2.0 mm diameter jailed balloons (0.25 (-0.51, 1.31) mm2 vs.-0.01 (-0.45, 0.63) mm2, P=0.020), while SB ostium area difference was similar between those endowed with higher balloon pressure (>4 atm) compared to those with lower balloon pressure (≤4 atm) (P=0.731). Multivariate linear regression analysis showed that there was a positive correlation between jailed balloon diameter and SB ostium area difference (r=0.344, P=0.019). Conclusions: The jailed balloon technique significantly protects SB ostium, especially in patients with true bifurcation lesions. The active jailed balloon technique and larger diameter balloons may provide more protection to the SB.

[Five-year clinical outcomes of patients with in-stent chronic total occlusion undergoing percutaneous coronary intervention].

Objective: To evaluate the safety and long-term clinical efficacy of percutaneous coronary intervention (PCI) in patients with in-stent chronic total occlusion (IS-CTO) lesions. Metheds: This is a retrospective analysis. Patients with IS-CTO who underwent PCI in Fuwai hospital from January 2010 to December 2013 were enrolled. A total of 212 patients who met the inclusion criteria were included in the IS-CTO group, 212 matched patients with primary CTO lesions were included in the de novo CTO group. The incidence of complications and the success rate of PCI were compared between the two groups. Successful PCI was defined as successfully implantation of stent(s) at target CTO lesions. The primary endpoint was defined as a composite event of cardiac death and myocardial infarction (MI). Secondary endpoints including PCI success, all-cause death, cardiac death, MI, target vessel related MI, revascularization, target vessel revascularization, heart failure for rehospitalization. The patients were followed up for 5 years after PCI. Results: A total of 424 cases were included. The mean age was (57.8±10.5) years, there were 364 males in this cohort. The left ventricular ejection fraction was significantly lower ((58.7±9.2)% vs. (61.0±7.7)%, P=0.01) and the SYNTAX scores was significantly higher (19.4±8.3 vs. 15.3±10.0, P<0.01) in IS-CTO group than that in de novo CTO group. The proportion of patients with target CTO lesions in left anterior descending artery was significantly higher (42.9% (50/212) vs. 23.6% (91/212), P<0.01) in IS-CTO group than that in de novo CTO group. The rate of successful PCI (71.7% (152/212) vs. 69.8% (148/212), P=0.70) and complication (40.6% (86/212) vs. 36.3% (77/212), P=0.37) was similar between the two groups. The incidence of primary endpoint at 5 years was significantly higher in IS-CTO group (10.8% (23/212) vs. 4.7% (10/212), P=0.02), which was driven by higher incidence of MI (9.0% (19/212) vs. 4.2% (9/212), P=0.05). There were a trend of higher secondary endpoints in IS-CTO group (all P>0.05). Conclusion: The safety and effectiveness of PCI are acceptable in patients with IS-CTO, but the risk of long-term cardiac death and MI is higher among patients with IS-CTO as compared to patients with primary CTO lesions.

[The safety and efficacy of Firesorb bioresorbable scaffold in first-in-man study for coronary artery disease: the four-year outcomes].

Objective: To evaluate the 4-year clinical outcomes of patients following Firesorb bioresorbable scaffold (BRS) implantation. Methods: The study reported the 4-year follow-up results of the FUTURE I study. FUTURE I was a prospective, single-center, open-label, first-in-man study which evaluated the feasibility, preliminary safety, and efficacy of Firesorb stent in the treatment of coronary artery stenosis. A total of 45 patients with single de novo lesions in native coronary arteries ,who hospitalized in Fuwai Hospital from January to March 2016 were enrolled. After successfully stent implantation these patients were randomized in a 2∶1 ratio into cohort 1 (n=30) or cohort 2 (n=15). The patients in cohort 1 underwent angiographic, IVUS or OCT examination at 6 months and 2 years; and cohort 2 underwent angiographic, IVUS or OCT at 1 and 3 years. All patients underwent clinical follow-up at 1, 6 months and 1 year and annually thereafter up to 5 years. The primary endpoint was target lesion failure (TLF, including cardiac death, target vessel myocardial infarction, and ischemia-driven target lesion revascularization). Secondary endpoints included patient-oriented composite endpoint (PoCE, defined as composite of all death, all miocardial infarction, or any revascularization). Results: A total of 45 patients were enrolled and implanted with Firesorb BRS, including 35 males (77.8%), and the age was (54.4±9.3) years. At 4 years, 10 patients in cohort 1 were reexamined by coronary angiography and OCT examination. Among them, 2 patients' stents were completely degraded and absorbed. Compared with the OCT images of the other 8 patients in cohort 2 at 3 years, the degree of stent degradation was increased, and no stent adherence was found. The 4-year clinical follow-up rate was 100%. In 4-year clinical following up, 2 patients suffered PoCE (4.4%): 1 patient underwent non-target vessel revascularization the day after index procedure and target vessel revascularization (Non-target lesion revascularization) at 2-year imaging follow-up; the other patient underwent target lesion revascularization during imaging follow-up at 4 years but not due to ischemic driven. There was no scaffold thrombosis or TLF events through 4 years. Conclusions: Four years after the implantation, complete degradation and absorption of the Firsorb stent are evidenced in some patients. Firesorb stent is feasible and effective in the treatment of patients with non-complex coronary lesions.

[Clinical features of patients with hypertrophic obstructive cardiomyopathy combining obstructive sleep apnea].

Objective: To investigate the clinical features of patients with hypertrophic obstructive cardiomyopathy (HOCM) combined with obstructive sleep apnea (OSA). Methods: From 2010 to 2018, a total of 299 patients who were diagnosed with hypertrophic cardiomyopathy and underwent sleep monitoring at Fuwai Hospital were retrospectively analyzed. General clinical features, data of echocardiography, and sleep breathing parameters were recorded. OSA was diagnosed by apnea-hypopnea index ≥ 5 events/hour. Clinical characteristics were compared between patients with and without OSA. Results: A total of 156 (52.2%) HOCM patients were diagnosed with OSA. Compared with patients without OSA, patients with OSA were older((54±10) years vs (45±14) years, P<0.001), had a higher body mass index ((27±3) kg/m(2) vs (25±3) kg/m(2), P<0.001), a higher prevalence of hypertension (54.4% (85/156) vs 21.0% (30/143), P<0.001), hyperlipidemia (37.2% (58/156) vs 13.3% (19/143), P<0.001) and smoking history (48.1% (75/156) vs 35.0% (50/143), P=0.022). Patients with OSA also had a higher incidence of New York Heart Association functional class Ⅱ or Ⅲ (P=0.017), atrial fibrillation (P=0.005), and higher levels of systolic and diastolic blood pressure, fast glucose and high-sensitive c-reactive protein (all P<0.001). Left ventricular end-diastolic diameter as well as ascending aorta diameter in patients with OSA were also greater than those without OSA (both P<0.001). Apnea-hypopnea index (AHI) value positively correlated with left ventricular end-diastolic diameter (r=0.346), ascending aorta diameter (r=0.357) and high-sensitive c-reactive protein (r=0.230) (all P<0.001). Conclusions: A high prevalence of OSA occurs in patients with HOCM. Severity of OSA correlates with cardiac remodeling and serum inflammatory factor level. As for HOCM patients, clinicians should actively monitor the sleep breathing parameters in order to recognize and treat potential OSA, thereby improving the prognosis of patients with HOCM.

[Impact of type 2 diabetes mellitus on the progression and revascularization of coronary non-target lesions in patients with coronary heart disease].

Objective: To investigate the impact of type 2 diabetes mellitus on progression and revascularization of coronary non-target lesions in patients with coronary heart disease. Methods: From January 2010 to September 2014, we retrospectively analyzed the clinical data of patients with coronary heart disease who underwent two consecutive coronary angiographies at Fuwai Hospital. At least one coronary non-target lesion was recorded at the first procedure in these patients. Patients were grouped according to the diagnose of type 2 diabetes mellitus. Demographic features, risk factors of coronary heart disease, laboratory results as well as characteristics of coronary non-target lesions were collected at baseline (first coronary angiography) and follow-up (second coronary angiography). Lesion progression was defined by quantitative coronary angiography analysis. Lesions revascularization was recorded. Multivariable Cox regression analysis was used to define the impacts of diabetes mellitus on progression and revascularization of non-target lesions. Subgroup analysis in diabetic and non-diabetic groups were further performed. Receiver operating characteristics curve was used to identify the predictive value of HbA1c. Results: A total of 1 255 patients were included, and 1 003(79.9%) were male, age was(58.0±9.7) years old. And 486 patients were diagnosed with type 2 diabetes mellitus. Follow-up time was (14.8±4.5) months. Compared with non-diabetic group, diabetic group were older with less male and had higher BMI index as well as higher prevalence of hypertension, dyslipidemia, prior myocardial infarction and prior percutaneous coronary intervention(all P<0.05). Diabetic patients also had higher level of white blood cells, erythrocyte sedimentation rate, C-reactive protein, endothelin and HbA1c at both baseline and follow-up compared with non-diabetic patients (all P<0.01). There was no significant difference on progression of non-target lesions (20.0%(97/486) vs. 18.5%(142/769), P=0.512), revascularization of non-target lesions (13.2%(64/486) vs. 15.9%(122/769), P=0.190) and non-target lesion related myocardial infarction(1.9%(9/486) vs. 1.3%(10/769), P=0.436) between diabetic and non-diabetic patients. Multivariable Cox regression analysis revealed that diabetes mellitus was not an independent predictor for progression and revascularization of non-target lesions (Both P>0.05). Subgroup analysis in diabetic patients showed that baseline HbA1c level(HR=1.160, 95%CI 1.009-1.333, P=0.037) was an independent predictor for non-target lesion progression. Cut-off value of HbA1c was 6.5% (Area Under Curve(AUC) 0.57, specificity 88.7%; sensitivity 24.2%, P=0.046) by receiver operating characteristics curve. Patients with HbA1c level above 6.5% had 2.8 times higher risk of lesion progression compared with patients with HbA1c level below 6.5% (HR=2.838, 95%CI 1.505-5.349, P=0.001). Compared with non-diabetic patients, diabetic patients with HbA1c below 6.5% also had lower risk of lesion progression (HR=0.469, 95%CI 0.252-0.872, P=0.012). ST-segment elevated myocardial infarction was an independent predictor for revascularization of non-target lesions in diabetic patients. Conclusion: Type 2 diabetes mellitus is not an independent predictor for progression and revascularization of coronary non-target lesions in patients with coronary heart disease. However, elevated HbA1c level is a risk factor for progression of non-target lesion in patients with type 2 diabetes mellitus.

[Efficacy of bare metal stent for treating focal coronary artery aneurysm complicating with severe stenosis in single coronary artery].

Objective: To investigate the efficacy of bare metal stent for treating focal coronary artery aneurysm complicating with severe stenosisin single coronary artery. Methods: This retrospective analysis was performed in 7 patients who were diagnosed as local coronary artery aneurysm complicating with severe stenosis(≥70%) in single coronary artery and treated with bare metal stent during the period from December 2012 to June 2015 in Fuwai Hospital. All 7 patients were male with age of (62±11) years old. During the interventional operation, the narrow parts were pre-expanded,and all patients received bare metal stents implantation to cover aneurysms.The clinical and imaging data of patients immediately post procedure and at postoperative follow-up were collected to evaluate the clinical efficacy. Results: There were 5 cases of left anterior descending aneurysms and 2 cases of right coronary artery aneurysms. The diameter of aneurysm was (5.21±1.28)mm, and the length was (13.71±3.88)mm. There was intracranial vortex in coronary arteriography immediately after intervention.Proximalstenosis of coronary artery aneurysm was disappeared,and the distal blood flow was TIMI class 3.There were no signs of aortic dissection and thrombus formation.During 6(6 16) months follow-up, the aneurysms were disappeared,and there were no major adverse cardiovascular events which including myocardial ischemia, acute myocardial infarction, revascularization,bleeding,and death for all patients. Conclusion: Initial experience shows that double-layer bare metal stents implantation for patients with localized coronary artery aneurysm complicating with severe stenosis in single vessel is safe and effective.

[Long-term outcome and related predictors of alcohol septal ablation for patients with hypertrophic obstructive cardiomyopathy].

Objective: To observe the long-term prognosis and related outcome predictors for hypertrophic obstructive cadiomyopathy (HOCM) patients underwent alcohol septal ablation (ASA). Methods: A total of 227 consecutive patients(age: (47.8±11.7) years) treated by ASA from September 2005 to December 2013 in our hospital were included and followed-up for 4.42 years(range: ( 1.17-9.93) years). Follow up rate is 97.4%(221/227). General information, medical history, data of ASA and complications during hospitalization were obtained through access to medical records of patients. The patients were followed up by telephone or outpatient visit. Results: During hospitalization period, one patient died due to retroperitoneal hemorrhage, two ventricular fibrillation events and two sustained ventricular tachycardia events occurred and all patients were successfully recovered after electrical cardioversion (defibrillation). Four cardiac tamponade events occurred, 35.7% (81/227) patients experienced temporary three degree atrioventricular block. Five delayed three degree atrioventricular block evens occurred. During follow up, the percent of NYHA Ⅲ/Ⅳclass was significantly reduced (10.1%(23/227)vs. 74.9%(170/227), P=0.000). The incidence of syncope and amaurosis fugax was also reduced(2.6% (6/227) vs. 39.2% (89/227), P=0.035). A total of six patients died (4 cardiac death), one patient complicating atrial fibrillation died of cerebral embolism, one patient died of rectal cancer. One cerebral hemorrhage occurred. Six patients developed-new onset atrial fibrillation. One patient received permanent pacemaker implantation. Eight patients received surgical myocardial resection. Three patients underwent repeated ASA. Survival free of all-cause mortality at 1, 5, 9 year was 100%, 96%, 96%, respectively. Survival free of cardiac death and NYHA Ⅲ/Ⅳclass at 1, 5, 9 year was 100%, 86%, 70%, respectively. Cox-regression analysis showed that residual left ventricular outflow tract gradient after ablation(HR=1.027, 95%CI 1.006-1.048, P=0.010), less volume of injected ethanol(HR=0.596, 95%CI 0.398-0.892, P=0.012), presence of temporary complete atrioventricular block (HR=0.332, 95%CI 0.124-0.886, P=0.028)were independent predictors of cardiac death and NYHA Ⅲ/Ⅳ. Conclusion: Our study results suggest that ASA could significantly improve symptoms and outcome in patients with HOCM. Residual left ventricular outflow tract gradient after ablation, less volume of injected ethanol, presence of temporary complete atrioventricular block during ASA are independent predictors of cardiac death and NYHA Ⅲ/Ⅳ.

Micro-RNA-128 (miRNA-128) down-regulation in glioblastoma targets ARP5 (ANGPTL6), Bmi-1 and E2F-3a, key regulators of brain cell proliferation.

High density micro-RNA (miRNA) arrays, fluorescent-reporter miRNA assay and Northern miRNA dot-blot analysis show that a brain-enriched miRNA-128 is significantly down-regulated in glioblastoma multiforme (GBM) and in GBM cell lines when compared to age-matched controls. The down-regulation of miRNA-128 was found to inversely correlate with WHO tumor grade. Three bioinformatics-verified miRNA-128 targets, angiopoietin-related growth factor protein 5 (ARP5; ANGPTL6), a transcription suppressor that promotes stem cell renewal and inhibits the expression of known tumor suppressor genes involved in senescence and differentiation, Bmi-1, and a transcription factor critical for the control of cell-cycle progression, E2F-3a, were found to be up-regulated. Addition of exogenous miRNA-128 to CRL-1690 and CRL-2610 GBM cell lines (a) restored 'homeostatic' ARP5 (ANGPTL6), Bmi-1 and E2F-3a expression, and (b) significantly decreased the proliferation of CRL-1690 and CRL-2610 cell lines. Our data suggests that down-regulation of miRNA-128 may contribute to glioma and GBM, in part, by coordinately up-regulating ARP5 (ANGPTL6), Bmi-1 and E2F-3a, resulting in the proliferation of undifferentiated GBM cells.

Prognostic Factors for Survival in Node-Negative Gastric Cancer Patients Who Underwent Curative Resection.

BACKGROUND AND AIM: Lymph node involvement is the strongest prognostic factor for patients with gastric cancer; patients with node-negative gastric cancer present with better survival. However, some patients develop recurrent gastric cancer. The aim of this study was to review the clinicopathological characteristics and factors for prognosis in patients with node-negative gastric cancer who underwent curative resection. METHODS: Between January 2004 and December 2015, the clinicopathological characteristics of 302 patients with node-negative gastric cancer who underwent curative gastrectomy in our hospital were retrospectively analyzed. RESULTS: The 1-, 3-, and 5-year overall survival rates for patients with node-negative gastric cancer were 80.0%, 69.0%, and 63.0%, respectively. Univariate analysis showed that tumor size, histologic type, and depth of invasion had significant effects on survival (p < 0.05). Multivariate analysis showed that tumor size (hazard ratio: 1.83%, 95.0% confidence interval: 1.13-2.96, p = 0.014), histologic type (hazard ratio: 1.57%, 95.0% confidence interval: 1.01-2.44, p = 0.042), and depth of invasion (hazard ratio: 1.38%, 95.0% confidence interval: 1.14-1.67, p = 0.001) were independent prognostic factors. CONCLUSION: Tumor size, histologic type, and depth of invasion are important prognostic factors in patients with node-negative gastric cancer. These parameters should be considered to stratify patients for therapy and follow-up strategies.

Effects of spinal cord stimulation on touch-evoked allodynia involve GABAergic mechanisms. An experimental study in the mononeuropathic rat.

There is much evidence that tactile allodynia in rat models of mononeuropathy produced by sciatic nerve constriction is linked to disturbance of spinal GABAergic functions. Spinal cord stimulation (SCS) applied to such animals via chronically implanted electrodes may in some of the animals induce a significant increase of the withdrawal threshold in response to innocuous mechanical stimulation with von Frey filaments applied to the paw of the nerve ligated leg. The present study was performed in mononeuropathic animals with definite signs of tactile allodynia, which did not respond to SCS, GABA and the GABAB-agonist baclofen were administered intrathecally, in doses per se insufficient to influence the withdrawal thresholds, together with the previously ineffective SCS. This combination resulted in a marked and long-lasting increase of the thresholds. The GABAA-agonist muscimol given together with SCS also produced a similar, but less prominent threshold increase. The GABAB-antagonist 5-aminovaleric acid (5-AVA) produced a transient suppression of the threshold increase induced by SCS together with either GABA or baclofen. In contrast, the GABAA-antagonist bicuculline had no apparent inhibitory effect on the threshold augmentation produced by SCS combined with GABA or baclofen. It is concluded that SCS may operate by upgrading the spinal GABAergic systems and that its potential for producing pain relief is dependent upon the availability of responsive GABA-containing inhibitory interneurons. Moreover, it seems that the effects of SCS are more linked to the GABAB-than to the GABAA-receptor system.

Spinal cord stimulation attenuates augmented dorsal horn release of excitatory amino acids in mononeuropathy via a GABAergic mechanism.

Neuropathic pain may be effectively relieved by electric stimulation of the spinal cord (SCS). However, the underlying mechanisms for the ensuing pain relief are poorly understood. In a rat model of neuropathy displaying hypersensitivity to innocuous tactile stimuli, (allodynia), we have earlier demonstrated that SCS may normalise withdrawal response thresholds. In the present study, using microdialysis, it is shown that SCS induces a decreased release of the dorsal horn excitatory amino acids (EAA), glutamate and aspartate, concomitant with an increase of the GABA release. Local perfusion with a GABA(B)-receptor antagonist in the dorsal horn transiently abolishes the SCS-induced suppression of the EAA release. Thus, the effect of SCS on neuropathic pain and allodynia may be due to an activation of local GABAergic mechanisms inhibiting the EAA release which is chronically elevated in such conditions.

Regulation of galanin and neuropeptide Y in dorsal root ganglia and dorsal horn in rat mononeuropathic models: possible relation to tactile hypersensitivity.

The expression of galanin and neuropeptide Y in rat lumbar 5 (L5) dorsal root ganglia and dorsal horn (L4-5) was studied after four types of peripheral nerve injury using immunohistochemistry and in situ hybridization. The possible correlation between these two peptides and tactile allodynia-like behaviour was analysed as well. The models employed were the Gazelius (photochemical lesion) and Seltzer and Bennett (constriction lesions) models, as well as complete sciatic nerve transection (axotomy). Two weeks after surgery, the Gazelius model rats more frequently displayed a greater tactile allodynia than the rats from the Seltzer and Bennett models. Tactile allodynia was not observed in any of the axotomized rats. A marked increase in the number of galanin-immunoreactive and galanin messenger RNA-positive neuron profiles was observed in ipsilateral dorsal root ganglia in all types of models. The increase in allodynic rats (Gazelius, Seltzer and Bennett models) was less pronounced than that after axotomy. In addition, in the Bennett model the number of galanin-immunoreactive neurons was significantly lower in allodynic rats as compared to non-allodynic rats, and the same tendency, but less obvious was found in the Seltzer model. Furthermore, an increase in galanin-immunoreactive fibres was found in the superficial laminae of the ipsilateral dorsal horn in all lesion models, especially in lamina II. A dramatic increase in the number of neuropeptide Y and neuropeptide Y messenger RNA-positive neuron profiles was also found in the ipsilateral dorsal root ganglia in all models, but no significant difference was found in peptide levels between allodynic and non-allodynic rats in any of the models. The present results suggest that the levels of endogenous galanin may play a role in whether or not allodynia develops in the Bennett model.

Photochemically induced ischaemic lesion of the rat sciatic nerve. A novel method providing high incidence of mononeuropathy.

The incidence of behavioural signs of mononeuropathy in rats subjected to chronic constriction injury (CCI) of the sciatic nerve is unpredictable and often low. In the present study, an ischaemic lesion of the rat sciatic nerve was induced photochemically using a low power laser. In these rats tactile allodynia developed with a considerably greater incidence (95%) than in control rats subjected to CCI (45%). The allodynia lasted longer and was more prominent. Responses to thermal stimulation did not markedly differ between the two groups. The ischaemic lesions displayed marked degeneration, particularly of large myelinated fibres. The results suggest that laser irradiation of a peripheral nerve inducing a local photochemical reaction followed by Wallerian degeneration may be a convenient and reproducible experimental method of producing signs of peripheral mononeuropathy.

Effect of spinal cord stimulation on tactile hypersensitivity in mononeuropathic rats is potentiated by simultaneous GABA(B) and adenosine receptor activation.

In rats with abnormally low withdrawal thresholds ('allodynia') in one hindpaw induced by a photochemical sciatic lesion, an intrathecal catheter was inserted to the lumber enlargement and an epidural electrode was implanted at T11. I.t. administration of GABA(B) or adenosine A1 receptor agonists (baclofen, R(-)-N6-(2-phenylisopropyl)adenosine (R-PIA)) suppressed allodynia in a dose-dependent fashion. When the two agonists were given together, each in an ineffective dose, there was a normalization of the thresholds. Rats, in which spinal cord stimulation (SCS) could not suppress the allodynia (non-responders), were transformed into SCS-responders by injection of baclofen and R-PIA in low, ineffective doses, combined with SCS. In SCS responding rats, combination of a selective GABA(B) and an adenosine A1 receptor antagonist (CGP 55845, CPT) in low, ineffective doses abolished the SCS-induced threshold normalization. These results indicate that GABAergic and adenosine-dependent mechanisms are involved in the SCS effect and further suggest a strategy for enhancing the therapeutic efficacy of SCS.

Adenosine receptor activation suppresses tactile hypersensitivity and potentiates spinal cord stimulation in mononeuropathic rats.

The aim of the present study was to investigate the intrathecal (i.t.) action of a selective A1-adenosine receptor agonist, R-phenylisopropyl adenosine (R-PIA), on tactile withdrawal thresholds in a rat model of mononeuropathy produced by sciatic chronic constriction injury (CCI). An additional aim was to examine whether adenosine receptor activation is involved in the effects of spinal cord stimulation (SCS), which activates low-threshold fibers and suppresses touch-evoked pain both in patients and in experimental animals with neuropathy. Animals presenting hindlimb withdrawal to von Frey filaments with a bending force of < 7.5 g on the lesioned side (compared to > or = 35 g in the normal limb), were considered as having tactile hypersensitivity ("allodynia'). R-PIA (1-10 nmol i.t.) induced a dose-dependent suppression of the tactile allodynia without producing impairment of motor function. The effect of R-PIA (3 nmol i.t.), a clearly submaximal dose, was abolished by concomitant treatment with the selective A1-adenosine receptor antagonist cyclopentylxanthine (10 nmol i.t.). In animals where SCS failed to influence tactile allodynia, concomitant i.t. administration of R-PIA (3 nmol) and SCS induced a clear-cut and long-lasting suppression of the hypersensitivity to tactile stimulation. In conclusion, adenosine receptor stimulation antagonizes tactile hypersensitivity in a CCI model of mononeuropathy and potentiates the action of spinal cord stimulation.

Release of gamma-aminobutyric acid in the dorsal horn and suppression of tactile allodynia by spinal cord stimulation in mononeuropathic rats.

OBJECTIVE: The aim of the present study is to monitor the extracellular gamma-aminobutyric acid (GABA) levels in the lumbar dorsal horn of allodynic rats, which respond to spinal cord stimulation (SCS) with a normalization of the tactile withdrawal threshold. In addition, we monitored the GABA levels in nonresponding and sham-stimulated rats. METHODS: Partial constriction injury of the sciatic nerve was performed, and a permanent electrode for SCS was inserted into the spinal canal. The response to SCS was assessed with von Frey hairs in awake animals. Later, microdialysis was performed in the dorsal horn of the spinal cord under halothane anesthesia. The concentration of GABA in the microdialysate was assessed by high-performance liquid chromatography. RESULTS: Extracellular GABA levels in rats with sciatic nerve lesions and allodynia (2.3 +/- 0.5 nmol/L) were significantly lower (P < 0.001) than in control rats with intact sciatic nerves (8.1 +/- 1.0 nmol/L), whereas only slightly decreased GABA levels (5.7 +/- 1.1 nmol/L) were detected in nonallodynic rats with sciatic nerve lesions. In the allodynic rats, which respond to SCS by a normalization of the tactile withdrawal threshold, significantly (P < 0.001) increased GABA levels (6.7 +/- 2.3 nmol/L) were detected after SCS. In contrast, neither the allodynic rats, which did not respond to SCS, nor the sham-stimulated allodynic rats displayed increased GABA levels in response to stimulation. CONCLUSION: Our results indicate that the development of allodynia, a common symptom in neuropathic pain states, may be linked to a decreased spinal release of GABA. We suggest that an SCS-induced release of GABA could be important for the suppression of allodynia observed in rats after SCS. Similar mechanisms could also be involved in the SCS-induced alleviation of pain in patients with peripheral neuropathy.

Spinal cord stimulation improves survival in ischemic skin flaps: an experimental study of the possible mediation by calcitonin gene-related peptide.

Currently, spinal cord stimulation is used to treat ischemia and ischemic pain, with the best results observed in vasospastic cases. It was earlier demonstrated that spinal cord stimulation may attenuate experimentally induced vasospasm in an island flap in the rat. The present study was designed to investigate whether preemptive spinal cord stimulation could increase long-term flap survival and to explore the neurohumoral mediation of the effect. A total of 56 rats were implanted with chronic spinal cord stimulation systems. Three days later, a groin flap based on the superficial epigastric vessels was harvested, and the single feeding artery was occluded by a detachable microvascular clip. After 12 hours, the clip was removed. Flap survival was evaluated after 7 days. Immediately before flap surgery, two groups of animals received 30 minutes of stimulation using current clinical parameters and with stimulation amplitudes of 70 (n = 10) or 90 percent (n = 8) of that evoking muscular contractions. The outcomes in these groups were compared with those in two control groups (n = 20; n = 10). In one group, an additional calcitonin gene-receptor peptide (CGRP) antagonist was intravenously injected before stimulation (n = 8). In the control groups without stimulation, virtually all flaps necrotized. In treated groups, flap survival was 60 percent at the lower intensity and almost 90 percent at the higher one. The administration of a CGRP antagonist before treatment reduced its efficacy to below 40 percent survival. The differences between the untreated and treated groups were significant. The decrease in survival after CGRP-receptor block was significant in one of two tests. Preemptive spinal cord stimulation increases survival of skin flaps with critical ischemia. The effects are dependent on the stimulation intensity and are possibly mediated by the release of CGRP in the periphery.

Increased expression of miRNA-146a in Alzheimer's disease transgenic mouse models.

A mouse and human brain-enriched micro-RNA-146a (miRNA-146a) is known to be important in modulating the innate immune response and inflammatory signaling in certain immunological and brain cell types. In this study we examined miRNA-146a levels in early-, moderate- and late-stage Alzheimer's disease (AD) neocortex and hippocampus, in several human primary brain and retinal cell lines, and in 5 different transgenic mouse models of AD including Tg2576, TgCRND8, PSAPP, 3xTg-AD and 5xFAD. Inducible expression of miRNA-146a was found to be significantly up-regulated in a primary co-culture of human neuronal-glial (HNG) cells stressed using interleukin1-beta (IL-1ß), and this up-regulation was quenched using specific NF-кB inhibitors including curcumin. Expression of miRNA-146a correlated with senile plaque density and synaptic pathology in Tg2576 and in 5xFAD transgenic mouse models used in the study of this common neurodegenerative disorder.