The role of atorvastatin in collateral circulation formation induced by encephaloduroarteriosynangiosis: a prospective trial.

OBJECTIVE: This prospective study was designed to confirm the role of atorvastatin in collateral circulation formation induced by encephaloduroarteriosynangiosis (EDAS) in patients with moyamoya disease (MMD). METHODS: Patients who were diagnosed with MMD at the Department of Neurosurgery in the Fifth Medical Center of Chinese PLA General Hospital, Beijing, China, between June 2017 and May 2018 were included. Blood samples were obtained from an antecubital vein and were analyzed using flow cytometry. Endothelial progenitor cells (EPCs) were defined as CD34brCD133+CD45dimKDR+. All patients included in the study underwent EDAS. Patients voluntarily chose whether to undergo atorvastatin treatment after EDAS. The correlation between atorvastatin and good postoperative collateral circulation was evaluated. RESULTS: A total of 106 patients with MMD were included in this study. Fifty-three patients (50%) received atorvastatin treatment. The baseline characteristics did not display statistically significant differences between the atorvastatin-treated and non-atorvastatin groups. Seventy-eight (42.9%) of the 182 hemispheres investigated postoperatively were classified as grade A collateral circulation, 47 (25.8%) as grade B, and 57 (31.3%) as grade C. Multivariate analysis revealed that only atorvastatin was significantly correlated with good collateral circulation after EDAS (p = 0.041). CONCLUSIONS: The results of this prospective clinical trial have indicated that atorvastatin administered at 20 mg daily is safe and effective for the formation of postoperative collateral induced by EDAS.

Endothelial Progenitor Cells Induce Angiogenesis: a Potential Mechanism Underlying Neovascularization in Encephaloduroarteriosynangiosis.

Encephaloduroarteriosynangiosis (EDAS) is one of the most commonly used indirect vascular reconstruction methods. EDAS aids in the formation of collateral vessels from the extracranial to the intracranial circulation in patients with moyamoya disease (MMD). However, the underlying mechanism of collateral vessel formation is not well understood. Endothelial progenitor cells (EPCs) differentiate to form the vascular endothelial cells and play a very important role in angiogenesis. We designed this prospective clinical trial to investigate the presence of EPCs in patients with MMD and to explore the neovascularization mechanism mediated by the EPCs in EDAS. The patients who were diagnosed with MMD were recruited between February 5, 2017, and January 7, 2018. The blood samples were obtained from an antecubital vein and were analyzed using flow cytometry. EPCs were defined as CD34brCD133+CD45dimKDR+. All the patients enrolled in the study underwent EDAS. Cerebral arteriography was performed 6 months post-EDAS to assess the efficacy of synangiosis. The correlation between EPC count and good collateral circulation was evaluated. Among the 116 patients with MMD enrolled in this study, 73 were women and 43 were men. The average age of the patients was 33.8 ± 15.2 years. The EPC count of the patients with MMD was 0.071% ± 0.050% (expressed as percentage of the peripheral blood mononuclear cells). The EPC count in the good postoperative collateral circulation group was significantly higher (0.085% ± 0.054%) than that in the poor collateral circulation group (0.048% ± 0.034%) (P = 0.000). The age, modified Suzuki-Mugikura grade, and EPC count were significantly correlated with the good collateral circulation post-EDAS in the multivariate analysis (P = 0.018, P = 0.007, and P = 0.003, respectively). The formation of collateral vessels by EDAS is primarily driven by angiogenesis. The EPC count may be the most critical factor for collateral circulation. The therapeutic effect of EDAS is more likely to benefit younger or severe ischemic patients with MMD.

Contribution of Spinal PKCγ Expression to Short- and Long-lasting Pain Behaviors in Formalin-induced Inflamed Mice.

BACKGROUND: Over-expression of spinal protein kinase Cγ(PKCγ) contributes to the induction of persistent bilateral hyperalgesia following inflammatory injury, yet the role of spinal PKCγ in short- and long-lasting pain behavior is poorly understood. OBJECTIVE: This study aimed to characterize the contribution of spinal PKCγ to spontaneous pain and long-lasting bilateral hyperalgesia in formalin-induced inflamed mice using pharmacological inhibition. STUDY DESIGN: Laboratory animal study. SETTING: The study was performed in the Department of Human Anatomy and K.K. Leung Brain Research Centre, Preclinical School of Medicine, the Fourth Military Medical University (Xi'an, China) and the Department of Anesthesiology, Fuzhou General Hospital (Fuzhou, China). METHODS: Male mice were unilaterally intraplantarly injected with formalin to induce inflammatory pain. Spontaneous pain behaviors, including flinches and lickings, were recorded by off-line video during the first hour post-injection and counted. Using von Frey tests, long-lasting bilateral mechanical paw withdrawal thresholds were determined before injection and at indicated time points thereafter. Temporal expression of spinal PKCγ was observed by immunohistochemical staining. For pharmacological inhibition, mice were treated daily with intrathecal Tat carrier or selective PKCγ inhibitor KIG31-1, from 1 hour prior to 10 days after formalin injection. Spontaneous pain behaviors and long-lasting bilateral mechanical hyperalgesia were assessed. Spinal PKCγ expression was also observed by using immunohistochemical staining and western blot. RESULTS: The number of PKCγ-immunoreactive (ir) spinal neurons was significantly higher at 10 days, but not 2 hours, after formalin intraplantar injection, and accompanied by long-lasting bilateral hyperalgesia. Furthermore, long-lasting bilateral hyperalgesia could be reversed by pharmacological inhibition of over-expressed spinal PKCγ; however, pretreating with intrathecal KIG31-1 showed no antinociceptive effects on short-term spontaneous pain behaviors. LIMITATIONS: All results were obtained from the mice and no PKCγ inhibitors were available through clinical practice. Therefore, it remains difficult to draw definitive connections between animal research and human application. CONCLUSION: Our findings suggest that spinal PKCγ plays a predominant role in long-lasting bilateral hyperalgesia, but not in the spontaneous pain behaviors induced by formalin. KEY WORDS: Formalin, spontaneous pain, mechanical hyperalgesia, protein kinase C gamma, KIG31-1, mice.

The Analgesic Effects of Celecoxib on the Formalin-induced Short- and Long-term Inflammatory Pain.

The non-steroidal anti-inflammatory drug celecoxib has long been used for reducing pain, in spite of moderate gastrointestinal side effects. In previous studies, it has been shown that celecoxib can inhibit formalin-induced spontaneous pain and secondary hyperalgesia. Injecting formalin into a rodent's hind paw not only induces acute pain behaviors, but also produces long-lasting hyperalgesia. Whether celecoxib can also have long-lasting effects is still unknown. Our results show that pretreatment with an intraperitoneal injection of celecoxib at one hour before formalin injection induced inhibition on the spontaneous flinch and licking behaviors in the second phase but not the first phase. Meanwhile, FOS expressions were also reduced with celecoxib pretreatment. Consecutive administration of celecoxib also protects the hind paw from hypoalgesia and relieves formalin-induced, long-lasting hyperalgesia in the ipsilateral hind paw. These analgesic effects may be related to suppression of the activation of neurons and astrocytes indicated by FOS and GFAP expressions. Based on the above findings, celecoxib demonstrated analgesic effects not only on acute spontaneous pain behavior but also on long-lasting hyperalgesia induced by formalin injection. The inhibition of neurons and astrocytes by celecoxib may be possible reasons for its analgesia.

Different analgesic effects of intrathecal endomorphin-2 on thermal hyperalgesia and evoked inflammatory pain in ovariectomized rats.

Hormone replacement remains one of the common therapies for menopause-related pain but is associated with risk of orofacial or back pain. Spinal endomorphin-2 (EM-2) is involved in varied pain and its release is steroid-dependent, but whether increasing spinal EM-2 can inhibit thermal hyperalgesia and inflammatory pain in ovariectomized (OVX) female rats, an animal model mimicking menopause, is not clear, nor is the potential involvement of spinal mu-opioid receptor (MOR). In the current study, we revealed that the temporal decrease of spinal EM-2 is accompanied with OVX-induced thermal hyperalgesia that was dose-dependently attenuated by intrathecal (IT) delivery of EM-2. The subcutaneous injection of formalin-induced inflammatory pain in OVX rats was exacerbated and IT delivery of EM-2 dose-dependently inhibited the inflammatory pain. However, the ED50 for IT delivery of EM-2 on thermal hyperalgesia is smaller than that on inflammatory pain in OVX rats, suggesting different contributions of the EM-2 system to these 2 pain modalities in OVX rats. IT pretreatment with MOR antagonist, beta-funaltrexamine (ß-FNA), attenuated IT EM-2 analgesia on both thermal hyperalgesia and inflammatory pain in OVX rats. Furthermore, IT delivery of EM-2 did not affect the animals' locomotion or anxiety status. Our findings suggested that IT EM-2 might be a safer analgesia strategy than hormone replacement therapy in reducing risk of orofacial or back pain. However, a long-lasting form of EM-2 with less tolerance is needed to induce sustained analgesia.

Off-line analysis of single-unit neuronal discharge in the globus pallidus region in Parkinson's disease.

BACKGROUND: The accuracy of microelectrode-guided localization can make the operation safe and effective, but only experienced neurosurgeons are capable of performing this operation. A good index to identify neuronal discharges between globus pallidus interna and globus pallidus externa is needed. The aim of this research was to establish a good and practical electrophysiologic index to distinguish neuronal discharge in the interior globus pallidus from neuronal discharge in the exterior globus pallidus region of the brain in Parkinson's disease. The effect of neurons having an atypical discharge on successful surgical localization was also quantitatively evaluated. METHODS: The study included 30 patients with primary Parkinson's disease who underwent pallidotomy between September 2000 and October 2002. During each pallidotomy, the neuronal discharges in the pallidum and its vicinity were recorded. The recorded spikes were used to calculate the frequency, burst index, pause index, and pause ratio of the single-unit discharge. The interior and exterior globus pallidus regions were compared in terms of frequency, burst index, pause index, and pause ratio. The sensitivity, specificity, false-negative ratio, false-positive ratio, and accuracy of those indices were then evaluated. RESULTS: The values of frequency, burst index, pause index, and pause ratio in the interior globus pallidus were (96 +/- 43) Hz, 2.31 +/- 1.81, 0.05 +/- 0.05, and 0.27 +/- 0.28, respectively, and in the exterior globus pallidus were (59 +/- 27) Hz, 0.88 +/- 0.63, 0.20 +/- 0.14, and 1.54 +/- 1.17, respectively. Use of the four indices to distinguish the two neuron types produced a sensitivity of 0.84, 0.78, 0.77, and 0.93 with a specificity of 0.64, 0.79, 0.88, and 0.87, respectively. The false-positive ratio was 0.36, 0.21, 0.12, and 0.13 and the false-negative ratio was 0.16, 0.22, 0.23, and 0.07 while the accuracy was 0.72, 0.79, 0.80, and 0.90, respectively. CONCLUSIONS: Pause ratio is a relatively reliable index to distinguish neuronal discharges between the interior and exterior globus pallidus regions in Parkinson's disease. The effect of neurons with atypical discharge on the successful surgical localization would be reduced to 10% when the pause ratio is used as the index.