Electroacupuncture improves peripheral neuropathy by up-regulating Sirt1/PGC-1α/TFAM pathway in type 2 diabetes rats with peripheral neuropathy. / 基于Sirt1/PGC-1α/TFAM通路探讨电针治疗2åž‹ç³–å°¿ç— å‘¨å›´ç¥žç»ç— å˜çš„æœºåˆ¶.

OBJECTIVES: To observe the effect of electroacupuncture (EA) on activation of silent information regulator 1 (Sirt1)/peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α)/mitochondrial transcription factor A (TFAM) pathway in type 2 diabetes (T2DM) rats with peripheral neuropathy (DPN) , so as to explore its possible mechanisms underlying improvement of DPN. METHODS: Thirty male SD rats were randomly divided into blank control group (n=8) and DPN model group (n=22) which were further divided into model group (n=8) and EA group (n=8) after successful modeling. The model of T2DM was established by high-fat diet and low-dose intraperitoneal injection of streptozocin (35 mg/kg). For rats of the EA group (anesthetized with isoflurane), EA stimulation (2 Hz/15 Hz, 2 mA) was applied to "Tianshu"(ST25) for 20 min, once daily, 6 times a week for 6 weeks. The blood glucose level, body weight, area under curve (AUC) of glucose tolerance test, and hind-paw mechanical pain threshold and thermal pain threshold were observed. The intra-epidermal nerve fiber density (IENFD) of the hind-foot pad was observed by immunofluorescence staining. The motor nerve conduction velocity (MNCV) of the sciatic nerve was measured by using electrophysiological method. H.E. staining was used to observe the histopathological changes of the sciatic nerve after modeling. Transmission electron microscopy (TEM) was used to observe the ultrastructural changes of the sciatic nerve. The protein expressions of energy-related Sirt1, PGC-1α and TFAM in the sciatic nerve was detected by Western blot. RESULTS: Compared with the blank control group, the model group had a higher blood glucose contents and AUC (P<0.001), a slower MNCV (P<0.01), and a decrease in the body weight and in the mechanical and thermal pain thresholds (P<0.001) and IENFD (P<0.001), and in the expression levels of Sirt1, PGC-1α and TFAM (P<0.05, P<0.01). In contrast to the model group, the EA group had a decrease in the blood glucose contents and AUC (P<0.05, P<0.01), and an increase in mechanical and thermal pain thresholds, MNCV, IENFD, and expression levels of Sirt1, PGC-1α and TFAM proteins (P<0.01, P<0.05). In addition, results of histopathological and ultrastructural changes of the sciatic nerve showed more fragmented and disordered distribution of axons on the transverse section, and extensive separation of myelin and axons, uneven myelin thickness, axonal degeneration and irregular shape in the model group, whereas in the EA group, the axons on the transverse section were relatively more dense and more complete, the myelin sheath of the sciatic nerve was relatively uniform, and the axonal shape was relatively regular with relatively milder lesions. CONCLUSIONS: EA up-regulates the expressions of Sirt1, PGC-1α, TFAM in T2DM rats with DPN, which may be associated with its functions in improving and repairing the injured peripheral nerves in rats with DPN.

Spinal Neuronal miR-124 Inhibits Microglial Activation and Contributes to Preventive Effect of Electroacupuncture on Chemotherapy-Induced Peripheral Neuropathy in Mice.

Chemotherapy-induced peripheral neuropathy (CIPN) is a persistent and irreversible side effect of antineoplastic agents. Patients with CIPN usually show chronic pain and sensory deficits with glove-and-stocking distribution. However, whether spinal neuronal microRNA (miR)-124 is involved in cisplatin-induced peripheral neuropathy remains to be studied. In this study, miR-124 was significantly reduced in the spinal dorsal horn in CIPN mice. Overexpression of neuronal miR-124 induced by injecting adeno-associated virus with neuron-specific promoter into the spinal cord of mice prevented the development of mechanical allodynia, sensory deficits, and the loss of intraepidermal nerve fibers induced by cisplatin. Meanwhile, cisplatin-induced M1 microglia activation and the release of proinflammatory cytokines were significantly inhibited by overexpression of neuronal miR-124. Furthermore, electroacupuncture (EA) treatment upregulated miR-124 expression in the spinal dorsal horn of CIPN mice. Interestingly, downregulation of spinal neuronal miR-124 significantly inhibited the regulatory effect of EA on CIPN and microglia activity as well as spinal neuroinflammation induced by cisplatin. These results demonstrate that spinal neuronal miR-124 is involved in the prevention and treatment of EA on cisplatin-induced peripheral neuropathy in mice. Our findings suggest that spinal neuronal miR-124 might be a potential target for EA effect, and we provide, to our knowledge, a new experimental basis for EA prevention of CIPN.

Genetic polymorphisms of SCN9A are associated with oxaliplatin-induced neuropathy.

BACKGROUND: Oxaliplatin is a chemotherapy agent active against digestive tumors. Peripheral neuropathy is one of the most important dose-limiting toxicity of this drug. It occurs in around 60-80% of the patients, and 15% of them develop severe neuropathy. The pathophysiology of oxaliplatin neurotoxicity remains unclear. SCN9A is a gene codifying for a subtype sodium channel (type IX, subunit α) and mutations in this gene are involved in neuropathic perception. In this study we investigated whether SCN9A genetic variants were associated with risk of neurotoxicity in patients diagnosed of cancer on treatment with oxaliplatin. METHODS: Blood samples from 94 patients diagnosed of digestive cancer that had received oxaliplatin in adjuvant or metastatic setting were obtained from three hospitals in Madrid. These patients were classified into two groups: "cases" developed oxaliplatin-induced grade 3-4 neuropathy (n = 48), and "controls" (n = 46) had no neuropathy or grade 1. The neuropathy was evaluated by an expert neurologist and included a clinical examination and classification according to validated neurological scales: National Cancer Institute Common Toxicity Criteria (NCI-CTC), Oxaliplatin-Specific Neurotoxicity Scale (OSNS) and Total Neuropathy score (TNS). Genotyping was performed for 3 SCN9A missense polymorphisms: rs6746030 (R1150W), rs74401238 (R1110Q) and rs41268673 (P610T), and associations between genotypes and neuropathy were evaluated. RESULTS: We found that SCN9A rs6746030 was associated with protection for severe neuropathy (OR = 0.39, 95% CI = 0.16-0.96; p = 0.041). Multivariate analysis adjusting for diabetes provided similar results (p = 0.036). No significant differences in neuropathy risk were detected for rs74401238 and rs41268673. CONCLUSION: SCN9A rs6746030 was associated with protection for severe oxaliplatin-induced peripheral neuropathy. The validation of this exploratory study is ongoing in an independent series.

[Mechanism of electroacupuncture on "Zusanli (ST 36)" for chemotherapy-induced peripheral neuropathy].

OBJECTIVE: To observe the effects and duration of electroacupuncture on the mechanical pain threshold induced by paclitaxel and explore its analgesic mechanism. METHODS: Sixty-four C57BL/6J male mice were randomly divided into 4 groups, a normal+sham EA group, a normal+EA group, a medicine+sham EA(Med+ sham EA) group, a medicine + EA (Med + EA) group, 16 cases in each group. The model of chemotherapy-induced peripheral neuropathy was established with paclitaxel intraperitoneal injection on the 1st, 3rd, 5th, 7th day in the Med + sham EA group and the Med + EA group. EA of 30 min was used on bilateral "Zusanli (ST 36)" on the 9th, 11th, 13th, 16th, 18th, 20th, 23rd, 25th, 27th, 30th day in the EA groups, 2 Hz/100 Hz and 1~ 1.5 mA. Acupuncture was applied on the same acupoint at the same times in the sham EA groups. Mechanical pain thresholds were tested by VonFrey before and after model establishment, namely on the 8th, 14th; 21st and, 28th day. The heart blood of 8 mice was drawn quickly to collect serum in every group on the 31st day, and the contents of tumor necrosis factor α (TNF-α), interleukin-1α (IL-1α), interleukin-1ß (IL-1ß) in proinflammatory cytokine were examined by ELISA. Mechanical pain thresholds were tested by VonFrey for the rest 8 mice of each group until there was no apparent difference in the two paclitaxel groups once a week,namely on the 35th, 42nd, 49th day. RESULTS: The pain thresholds of each group were not statistically different before model establishment (P > 0.05). After model establishment (on the 8th day), thresholds of the paclitaxel groups were lower than those of the normal groups (all P < 0.05). After EA, the mechanical pain thresholds of the Med + EA group were higher than those of the Med + sham EA group at all the time points, and there was statistical difference on the 14th, 21st and 28th day (all P < 0.05). The analgesic effect was lasting to the 49th day. The contents of TNF-α, IL-1α, IL-1ß of the Med + EA group were decreased than those of the Med+sham EA group in different degree, with statistical significance of IL-1α (P < 0.05). CONCLUSION: EA can effectively treat paclitaxel-induced peripheral neuropathy,and the analgesic mechanism is probably related to decreasing the proinflammatory cytokine.

Large-scale prospective pharmacogenomics study of oxaliplatin-induced neuropathy in colon cancer patients enrolled in the JFMC41-1001-C2 (JOIN Trial).

BACKGROUND: Peripheral sensory neuropathy (PSN) is a dose-limiting toxicity of oxaliplatin-based chemotherapy. Several genetic markers have been shown to predict oxaliplatin-induced PSN; however, results remain to be validated in a large-scale and prospective pharmacogenomics study. PATIENTS AND METHODS: Among 882 patients enrolled in the JFMC41-1001-C2 (JOIN trial), which was designed to investigate the tolerability of adjuvant-modified FOLFOX6 (mFOLFOX6) in Japanese Patients with stage II or III colon cancers undergoing curative resection, 465 patients were eligible for this pharmacogenomics analysis. Twelve single-nucleotide polymorphisms (SNPs) were selected based on published data. The effect of each genotype on time to PSN onset was evaluated in all patients (n = 465) using the Cox proportional hazard model. For the association analysis between severity of PSN and 12 SNP markers, 84 patients who failed to complete 12 cycles of mFOLFOX6 from grade 0/1 PSN group were excluded because the termination of the protocol treatment had been caused by reasons other than PSN. RESULTS: Comparison of grade 0/1 PSN with grade 2/3 PSN or grade 3 PSN showed no significant associations with any of the 12 SNP markers after adjustment for total dose of oxaliplatin. Time-to-onset analysis also failed to reveal any significant differences. CONCLUSIONS: Our large-scale and prospective pharmacogenomics study of Japanese patients receiving protocol treatment of adjuvant mFOLFOX6 could not verify a role for any of the 12 SNP markers reported as being significantly associated with PSN. Considering the OR observed in this study (range: 0.76-1.89), further evaluation of these 12 SNP markers in the context of L-OHP-induced PSN is unlikely to be clinically informative.

[Effect of Electroacupuncture Intervention on CaMK II-CREB Pathway in Spinal Cord in Rats with Spared Nerve Injury].

OBJECTIVE: To observe the effect of electroacupuncture (EA) stimulation of "Weizhong" (BL 40)-"Huantiao" (GB 30) on expression of phosphorylated calcium/calmodulin dependent protein kinase II (p-CaMK II) and cAMP response element binding protein (p-CREB) in the spinal cord in rats with spared nerve injury (SNI), so as to explore its mechanism underlying easing neuropathic pain. METHODS: Sixty SD rats were randomly divided into five groups: control (sham-operation) , model, EA, AP-5 (a NMDA receptor antagonist) and L-NAME (a non-selective nitric oxide synthase, NOS inhibitor) (n = 12 in each group). The neuropathic pain model was established by sectioning the right tibal nerve and common peroneal nerve. EA intervention (2 Hz, 1 mA, increasing 1 mA/10 min) was applied to "Weizhong" (BL 40) and "Huantiao" (GB 30) on the injured side for 30 min, once a day for 7 days. Rats of the AP-5 and L-NAME groups were treated by intragastric administration of AP-5 (0.7 mg · kg(-1) · d(-1)) and L-NAME (60 mg · kg(-1) · d(-1)) respectively from the 11 th day after operation, once daily for 7 days. The mechanical pain thresholds were measured before the SNI procedure (baseline) and at the 10th and 16th day after the procedure. The expression of p-CaMK II protein and p-CREB protein and gene of the spinal cord (L4-L6 segments) was determined by Western blot and fluorescence quantitative-polymerase chain reaction (PCR), separately. RESULTS: In comparison to the control group, the mechanical pain threshold was significantly decreased in the model group (P < 0.01). After EA intervention, the mechanical pain thresholds of the EA, AP-5 and L-NAME groups were obviously increased (P < 0.01, P < 0.05) on day 16 post SNI procedure. The expression levels of p-CaMK II and p-CREB proteins and CREB mRNA in the spinal cord were significantly higher in the model group than in the control group (P < 0.05). Compared with the model group, the expression levels of spinal p-CaMK II and p-CREB proteins and CREB mRNA were obviously down-regulated in the EA group (P < 0.05), but not in the AP-5 group and the L-NAME group (P > 0.055. CONCLUSION: EA intervention of BL 40-GB 30 may alleviate pain in neuropathic pain rats, which may be related to its effects in down-regulating spinal CaMK II-CREB pathway function.

Molecular network-based analysis of guizhi-shaoyao-zhimu decoction, a TCM herbal formula, for treatment of diabetic peripheral neuropathy.

AIM: Guizhi-shaoyao-zhimu decoction (GSZ), a traditional Chinese medicine (TCM) herbal formula, has been shown effective in the treatment of diabetic peripheral neuropathy (DPN). In this study, network analysis was performed to decipher the molecular mechanisms of GSZ in the treatment of DPN. METHODS: The chemical components of the 3 herbs forming GSZ, ie, Ramulus Cinnamomi (Guizhi), Paeonia lactiflora (Shaoyao) and Rhizoma Anemarrhenae (Zhimu), were searched in Chinese medicine dictionaries, and their target proteins were identified in PubChem. DPN genes were searched in PubMed gene databases. Ingenuity Pathway Analysis (IPA) was used to build the GSZ pharmacological network and DPN molecular network. The canonical pathways between the two networks were compared to decipher the molecular mechanisms of GSZ in the treatment of DPN. RESULTS: Sixty-one protein targets for Guizhi, 31 targets for Shaoyao, 47 targets for Zhimu, as well as 23 genes related to DPN were identified and uploaded to IPA. The primary functions of the DPN molecular network were inflammatory response, metabolic disease, cellular assembly and organization. As far as the pharmacological network functions were concerned, Guizhi target proteins were involved in neurological disease, inflammatory disease, cellular growth and proliferation, cell signaling, molecular transport, and nucleic acid metabolism, Shaoyao target proteins were related to neurological disease, inflammatory disease, and Zhimu target proteins focused on cell death and survival, cellular movement, immune cell trafficking, DNA replication, recombination and repair, and cell cycle. In the three-herb combination GSZ, several new network functions were revealed, including the inflammatory response, gene expression, connective tissue development and function, endocrine system disorders, and metabolic disease. The canonical pathway comparison showed that Shaoyao focused on IL-12 signaling and production in macrophages, and Zhimu focused on TNFR2 signaling, death receptor signaling, ILK signaling, IL-17A in gastric cells, IL-6 signaling, IL-8 signaling, the role of JAK1, JAK2, and TYK2 in interferon signaling, IL-9 signaling, HMGB1 signaling, NO production and ROS production in macrophages, whereas GSZ focused aryl hydrocarbon receptor signaling and apoptosis signaling in addition to those pathways induced by Guizhi, Shaoyao and Zhimu. CONCLUSION: Although each single herb can affect some DPN-related functions and pathways, GSZ exerts more effects on DPN-related functions and pathways. The effects of GSZ on aryl hydrocarbon receptor signaling and apoptosis signaling pathways may be the key components of its total molecular mechanisms.

Goshajinkigan, a traditional Japanese medicine, prevents oxaliplatin-induced acute peripheral neuropathy by suppressing functional alteration of TRP channels in rat.

The acute peripheral neuropathy induced by oxaliplatin treatment occurs very frequently and is aggravated by exposure to cold. Goshajinkigan (GJG), a traditional Japanese (kampo) medicine, was recently shown to be effective against oxaliplatin-induced acute neuropathy. However, because the effects of GJG and its mechanism in relation to those of its ingredients and its mechanism are not well understood, we examined the effects of GJG on acute neuropathy. Further, we investigated whether GJG affects the functions and gene expressions of transient receptor potential (TRP) channels using a rat model of oxaliplatin-induced neuropathy. Administration of oxaliplatin increased withdrawal responses from cold stimulation, and GJG or calcium gluconate/magnesium sulfate significantly inhibited the oxaliplatin-induced cold hypersensitivity. Application of menthol, a TRPA1/TRPM8 agonist, or allyl isothiocyanate (AITC), a selective TRPA1 agonist, to the hind paw of oxaliplatin-treated rats enhanced the nocifensive behaviors evoked by each agonist, whereas oxaliplatin had no significant effect on nocifensive behaviors evoked by capsaicin, a TRPV1 agonist. GJG treatment reduced menthol- or AITC-evoked withdrawal responses potentiated by oxaliplatin. Furthermore, GJG suppressed the increase of TRPA1 and TRPM8 mRNA expression induced by oxaliplatin in dorsal root ganglia. These findings suggest that GJG prevented oxaliplatin-induced acute peripheral neuropathy by suppressing functional alteration of TRP channels, especially TRPA1 and TRPM8.

Voltage-gated sodium channel polymorphisms play a pivotal role in the development of oxaliplatin-induced peripheral neurotoxicity: results from a prospective multicenter study.

BACKGROUND: The current prospective, multicenter study sought to identify single nucleotide polymorphisms of voltage-gated sodium channels (SCNAs) genes that might confer susceptibility to an increased incidence and severity of oxaliplatin-induced peripheral neuropathy (OXAIPN) in patients treated with either leucovorin, 5-fluorouracil, and oxaliplatin (FOLFOX) or oxaliplatin plus capecitabine (XELOX) for colorectal cancer (CRC). METHODS: A total of 200 patients with CRC were genotyped with real-time polymerase chain reaction using locked nucleic acid hydrolysis probes or allele-specific primers. All patients had received oxaliplatin-based chemotherapy, either in the adjuvant or metastatic setting. The incidence and severity of cumulative OXAIPN was graded using the clinical version of the Total Neuropathy Score and the neurosensory National Cancer Institute Common Toxicity Criteria (version 3.0). The incidence of acute OXAIPN was assessed using a descriptive questionnaire (yes/no response format) at each clinical evaluation. Acute OXAIPN was present in 169 of 200 patients (84.5%), whereas after treatment discontinuation, the cumulative/chronic form of neurotoxicity occurred in 145 of 200 patients (72.5%). RESULTS: In the logistic regression analysis adjusted for confounding factors, the overdominant model (CT vs CC + TT) of 2 single nucleotide polymorphisms (ie, SCN4A-rs2302237 and SCN10A-rs1263292) emerged as being significantly associated with an increased incidence of acute OXAIPN (rs2302237: odds ratio of 2.62 [95% confidence interval (95% CI), 1.15-6.00]; P = .019; and rs12632942: OR of 0.39 [95% CI, 0.17-0.88]; P = .023). However, only SCN4A-rs2302237 emerged as also being predictive of the clinical severity of acute OXAIPN (OR, 2.50 [95% CI, 1.35-4.63]; P = .0029) and the occurrence of cumulative/chronic OXAIPN (OR, 2.47 [95% CI, 1.04-5.85]; P = .037). CONCLUSIONS: The results of the current study provide evidence to support a causal relationship between SCNA polymorphisms and OXAIPN. However, further studies from independent groups are warranted to confirm these results.

KCNS1, but not GCH1, is associated with pain intensity in a black southern African population with HIV-associated sensory neuropathy: a genetic association study.

KCNS1 and GCH1 were investigated for their association with pain intensity in black Southern Africans with HIV-associated sensory neuropathy. Previously associated single nucleotide polymorphisms (SNPs) were supplemented with population-specific tagSNPs. No SNPs in KCNS1 were individually associated with pain intensity. However, several haplotypes of population-specific tagSNPs correlated with pain intensity on univariate analysis and after correcting for age, gender, and CD4 T-cell count. This suggests that the haplotypes incorporate the causative SNP(s). No SNPs or haplotypes in GCH1 were associated with pain intensity. The study shows the importance of conducting association analyses in different ethnic groups, using population-based marker selection.

Severe combined immunodeficiency resulting from mutations in MTHFD1.

Folate and vitamin B(12) metabolism are essential for de novo purine synthesis, and several defects in these pathways have been associated with immunodeficiency. Here we describe the occurrence of severe combined immunodeficiency (SCID) with megaloblastic anemia, leukopenia, atypical hemolytic uremic syndrome, and neurologic abnormalities in which hydroxocobalamin and folate therapy provided partial immune reconstitution. Whole exome sequencing identified compound heterozygous mutations in the MTHFD1 gene, which encodes a trifunctional protein essential for processing of single-carbon folate derivatives. We now report the immunologic details of this novel genetic cause of SCID and the response to targeted metabolic supplementation therapies. This finding expands the known metabolic causes of SCID and presents an important diagnostic consideration given the positive impact of therapy.

Polymorphic markers associated with severe oxaliplatin-induced, chronic peripheral neuropathy in colon cancer patients.

BACKGROUND: To identify potential genetic markers for severe oxaliplatin-induced chronic peripheral neuropathy (OXCPN), the authors performed a genome-wide association analysis of patients with colon cancer who received oxaliplatin-based chemotherapy. METHODS: This was a prospective study in which DNA was purified in peripheral blood from patients with colon cancer who received oxaliplatin. The primary endpoint was the development of severe (grade 2 lasting for >7 days or grade 3) OXCPN. For the discovery set, genotyping was done for 96 patients who received adjuvant fluorouracil and oxaliplatin using the a genome-wide human single-nucleotide polymorphism (SNP) array. An association between polymorphisms and severe OXCPN was investigated. At the same time, 247 patients who received oxaliplatin-based, first-line chemotherapy for advanced disease were enrolled as a validation set. RESULTS: Among the 32 genotyped candidate SNPs selected from the discovery set, 9 SNPs in 8 genes (tachykinin, precursor 1[TAC1]; forkhead box C1 [FOXC1]; integrin, alpha 1 [ITGA1]; acylphosphatase 2, muscle type [ACYP2]; deleted in lymphocytic leukemia, 7 [DLEU7]; B-cell translocation gene 4 [BTG4]; calcium/calmodulin-dependent protein kinase II inhibitor 1 [CAMK2N1]; and phenylalanyl-tRNA synthase 2 [FARS2]) had nominal replication (P < .05). The most significant association was observed at reference SNP number (rs)10486003 in TAC1 (P = 4.84 × 10(-7)) in combined data from 2 sets. Five SNPs (rs10486003, rs2338, rs830884, rs843748, and rs797519) were significant in a multiple regression analysis (P < .05). Overall prediction accuracy calculated by the regression model was 72.8% (95% confidence interval, 65.8%-79.9%) in the model development and 75.9% (95% confidence interval, 66.9%-84.9%) in the model evaluation. CONCLUSIONS: The current results indicated that a genome-wide pharmacogenomic approach is useful for identifying novel polymorphism predictors of severe OXCPN that may be used in personalized chemotherapy.

Auditory cortical N100 in pre- and post-synaptic auditory neuropathy to frequency or intensity changes of continuous tones.

OBJECTIVES: Auditory cortical N100s were examined in ten auditory neuropathy (AN) subjects as objective measures of impaired hearing. METHODS: Latencies and amplitudes of N100 in AN to increases of frequency (4-50%) or intensity (4-8 dB) of low (250 Hz) or high (4000 Hz) frequency tones were compared with results from normal-hearing controls. The sites of auditory nerve dysfunction were pre-synaptic (n=3) due to otoferlin mutations causing temperature sensitive deafness, post-synaptic (n=4) affecting other cranial and/or peripheral neuropathies, and undefined (n=3). RESULTS: AN consistently had N100s only to the largest changes of frequency or intensity whereas controls consistently had N100s to all but the smallest frequency and intensity changes. N100 latency in AN was significantly delayed compared to controls, more so for 250 than for 4000 Hz and more so for changes of intensity compared to frequency. N100 amplitudes to frequency change were significantly reduced in ANs compared to controls, except for pre-synaptic AN in whom amplitudes were greater than controls. N100 latency to frequency change of 250 but not of 4000 Hz was significantly related to speech perception scores. CONCLUSIONS: As a group, AN subjects' N100 potentials were abnormally delayed and smaller, particularly for low frequency. The extent of these abnormalities differed between pre- and post-synaptic forms of the disorder. SIGNIFICANCE: Abnormalities of auditory cortical N100 in AN reflect disorders of both temporal processing (low frequency) and neural adaptation (high frequency). Auditory N100 latency to the low frequency provides an objective measure of the degree of impaired speech perception in AN.

Two novel HADHB gene mutations in a Korean patient with mitochondrial trifunctional protein deficiency.

Mitochondrial trifunctional protein (MTP) is a heterocomplex composed of 4 alpha-subunits containing LCEH (long-chain 2,3-enoyl-CoA hydratase) and LCHAD (long-chain 3-hydroxyacyl CoA dehydrogenase) activity, and 4 beta-subunits that harbor LCKT (long-chain 3-ketoacyl-CoA thiolase) activity. MTP deficiency is an autosomal recessive disorder that causes a clinical spectrum of diseases ranging from severe infantile cardiomyopathy to mild chronic progressive polyneuropathy. Here, we report the case of a Korean male newborn who presented with severe lactic acidosis, seizures, and heart failure. A newborn screening test and plasma acylcarnitine profile analysis by tandem mass spectrometry showed an increase of 3-hydroxy species: 3-OH-palmitoylcarnitine, 0.44 nmol/ml (reference range, RR <0.07); 3-OH-linoleylcarnitine, 0.31 nmol/ml (RR <0.06); and 3-OH-oleylcarnitine, 0.51 nmol/ml (RR <0.04). These findings suggested either long-chain 3-hydroxyacyl-coA dehydrogenase deficiency or complete MTP deficiency. By molecular analysis of the HADHB gene, the patient was found to be a compound heterozygote for c.358dupT (p.A120CfsX8) and c.1364T>G (p.V455G) mutations. These 2 mutations of the HADHB gene were novel and inherited. Although the patient was treated by reduction of glucose administration and supplementation of a medium-chain triglyceride-based diet with L-carnitine, he died 2 mo after birth due to advanced cardiac failure.

Spectrum of magnetic resonance imaging findings in a family with giant axonal neuropathy confirmed by genetic studies.

Giant axonal neuropathy (GAN) is a disorder that affects both the peripheral and central nervous system with clinical and genetic heterogeneity. We describe the spectrum of magnetic resonance imaging (MRI), MR-spectroscopy (MRS), and diffusion changes in two siblings from India. In addition to the described MRI findings two unreported findings, hyperintensity signals of both the globus pallidus on T1-weighted images and involvement of bilateral thalamus, were observed. MRS showed elevated choline peaks and reduced N-acetylaspartate peaks as well as presence of lactate peaks. Diffusion weighted images showed restricted diffusion.

Vesicular glutamate transporter VGLUT2 expression levels control quantal size and neuropathic pain.

Uptake of L-glutamate into synaptic vesicles is mediated by vesicular glutamate transporters (VGLUTs). Three transporters (VGLUT1-VGLUT3) are expressed in the mammalian CNS, with partial overlapping expression patterns, and VGLUT2 is the most abundantly expressed paralog in the thalamus, midbrain, and brainstem. Previous studies have shown that VGLUT1 is necessary for glutamatergic transmission in the hippocampus, but the role of VGLUT2 in excitatory transmission is unexplored in glutamatergic neurons and in vivo. We examined the electrophysiological and behavioral consequences of loss of either one or both alleles of VGLUT2. We show that targeted deletion of VGLUT2 in mice causes perinatal lethality and a 95% reduction in evoked glutamatergic responses in thalamic neurons, although hippocampal synapses function normally. Behavioral analysis of heterozygous VGLUT2 mice showed unchanged motor function, learning and memory, acute nociception, and inflammatory pain, but acquisition of neuropathic pain, maintenance of conditioned taste aversion, and defensive marble burying were all impaired. Reduction or loss of VGLUT2 in heterozygous and homozygous VGLUT2 knock-outs led to a graded reduction in the amplitude of the postsynaptic response to single-vesicle fusion in thalamic neurons, indicating that the vesicular VGLUT content is critically important for quantal size and demonstrating that VGLUT2-mediated reduction of excitatory drive affects specific forms of sensory processing.

Role of astrocytic S100beta in behavioral hypersensitivity in rodent models of neuropathic pain.

S100beta is a calcium-binding peptide produced mainly by astrocytes that exerts paracrine and autocrine effects on neurons and glia. We have previously shown that S100beta is markedly elevated at the mRNA level in the spinal cord following peripheral inflammation, intraplantar administration of complete Freund's adjuvant in the rat. The purpose of the present study was to further investigate the role of astrocytic S100beta in mediating behavioral hypersensitivity in rodent models of persistent pain. First, we assessed the lumbar spinal cord expression of S100beta at the mRNA and protein level using real-time RT-PCR, Western blot and immunohistochemistry analysis following L5 spinal nerve transection in rats, a rodent model of neuropathic pain. Second, we assessed behavioral hypersensitivity (mechanical allodynia) in wild type and genetically modified mice lacking or overexpressing S100beta following L5 spinal nerve transection. Third, we assessed the expression level of S100beta protein in the CD1 wild type mice after nerve injury. We report that lumbar spinal S100beta mRNA steadily increased from days 4-28 after nerve injury. S100beta protein in the lumbar spinal cord was significantly increased in both rats and mice at day 14 following nerve injury as compared with sham control groups. S100beta genetically deficient mice displayed significantly increased tactile thresholds (reduced response to non-noxious stimuli) after nerve injury as compared with the wild type group. S100beta overexpressing mice displayed significantly decreased tactile threshold responses (enhanced response to non-noxious stimuli). Together, these results from both series of experiments using a peripheral nerve injury model in two different species implicate the involvement of glial-derived S100beta in the pathophysiology of neuropathic pain.

Increased sensitivity to acute and persistent pain in neuron-specific endothelin-1 knockout mice.

Endothelin-1 (ET-1) exists in endothelial cells as well as a variety of other cell types. The presence of ET-1 and its receptors in neurons suggests its possible role as a neurotransmitter and/or neuromodulator. Studies utilizing exogenous ET-1 have suggested that ET-1 affects pain transmission. This study was designed to examine the possible role(s) of neuronal ET-1 in pain processing. We produced neuron-specific ET-1 knockout mice using the Cre/loxP system with a synapsin I promoter and examined the effects produced by the lack of neuronal ET-1 on pain behavior using common pain models and a model of stress-induced analgesia. In acute nociceptive pain models, paw withdrawal thresholds to radiant heat and mechanical stimuli applied with von Frey hairs were significantly lower in the knockout mice compared with control. This indicated that the absence of neuronal ET-1 leads to greater sensitivity to acute nociceptive stimuli. After inflammation was produced by intraplantar injection of carrageenan, there was a significantly greater degree of thermal hyperalgesia and mechanical allodynia in the knockout mice even after the difference in baseline values was compensated. Furthermore, in a neuropathic pain model produced by spinal nerve ligation, there was also a greater degree of mechanical allodynia in the knockout mice. Finally, in a swim-stress model, the magnitude of stress-induced analgesia was less in the knockout mice, indicating the involvement of neuronal ET-1 in stress-induced analgesia. The results suggest that there is a basal release of ET-1 from neurons that affect baseline pain thresholds as well as an additional release during persistent pain states that acts to suppress the pain. The involvement of neuronal ET-1 in stress-induced analgesia further suggests its role in endogenous pain inhibitory systems. To confirm that ET-1 is released in persistent pain states and to determine which part of the CNS is involved, we measured the concentrations of ET-1 before and after inducing peripheral inflammation in different parts of the CNS involved in endogenous pain inhibitory systems in normal mice. We found that ET-1 was increased in the hypothalamus while no significant increase was observed in the midbrain, medulla and spinal cord. The results of the present study suggest that neuronal ET-1 is involved in endogenous pain inhibitory control likely via pathways through the hypothalamus.

Transgenic and knock-out mice: models of neurological disease.

Besides providing useful model systems for basic science, studies based on modification of the mammalian germ line are changing our understanding of pathogenetic principles. In this article, we review the most popular techniques for generating specific germ line mutations in vivo and discuss the impact of various transgenic models on the study of neurodegenerative diseases. The "gain of function" approach, i.e., ectopic expression of exogenous genes in neural structures, has deepened our understanding of neurodegeneration resulting from infection with papova viruses, picorna viruses, and human retroviruses. Further, inappropriate expression of mutated cellular molecules in the nervous system of transgenic mice is proving very useful for studying conditions whose pathogenesis is controversial, such as Alzheimer's disease and motor neuron diseases. As a complementary approach, ablation of entire cell lineages by tissue-specific expression of toxins has been useful in defining the role of specific cellular compartments. Modeling of recessive genetic diseases, such as Lesch-Nyhan syndrome, was helped by the development of techniques for targeted gene deletion (colloquially termed "gene knock-out"). Introduction of subtle homozygous mutations in the mouse genome was made possible by the latter approach. Such "loss of function" mutants have been used for clarifying the role of molecules thought to be involved in development and structural maintenance of the nervous system, such as the receptors for nerve growth factor and the P0 protein of peripheral myelin. In addition, these models are showing their assets also in the study of enigmatic diseases such as spongiform encephalopathies.