Anti-HMGCR immune-mediated necrotizing myopathy: A case report / 北京大学学报(医学版)

The patient was a 55-year-old man who was admitted to hospital with "progressive myalgia and weakness for 4 months, and exacerbated for 1 month". Four months ago, he presented with persistent shoulder girdle myalgia and elevated creatine kinase (CK) at routine physical examination, which fluctuated from 1 271 to 2 963 U/L after discontinuation of statin treatment. Progressive myalgia and weakness worsened seriously to breath-holding and profuse sweating 1 month ago. The patient was post-operative for renal cancer, had previous diabetes mellitus and coronary artery disease medical history, had a stent implanted by percutaneous coronary intervention and was on long-term medication with aspirin, atorvastatin and metoprolol. Neurological examination showed pressure pain in the scapularis and pelvic girdle muscles, and V- grade muscle strength in the proximal extremities. Strongly positive of anti-HMGCR antibody was detected. Muscle magnetic resonance imaging (MRI) T2-weighted image and short time inversion recovery sequences (STIR) showed high signals in the right vastus lateralis and semimembranosus muscles. There was a small amount of myofibrillar degeneration and necrosis, CD4 positive inflammatory cells around the vessels and among myofibrils, MHC-Ⅰ infiltration, and multifocal lamellar deposition of C5b9 in non-necrotic myofibrils of the right quadriceps muscle pathological manifestation. According to the clinical manifestation, imageological change, increased CK, blood specific anti-HMGCR antibody and biopsy pathological immune-mediated evidence, the diagnosis of anti-HMGCR immune-mediated necrotizing myopathy was unequivocal. Methylprednisolone was administrated as 48 mg daily orally, and was reduced to medication discontinuation gradually. The patient's complaint of myalgia and breathlessness completely disappeared after 2 weeks, the weakness relief with no residual clinical symptoms 2 months later. Follow-up to date, there was no myalgia or weakness with slightly increasing CK rechecked. The case was a classical anti-HMGCR-IMNM without swallowing difficulties, joint symptoms, rash, lung symptoms, gastrointestinal symptoms, heart failure and Raynaud's phenomenon. The other clinical characters of the disease included CK as mean levels >10 times of upper limit of normal, active myogenic damage in electromyography, predominant edema and steatosis of gluteus and external rotator groups in T2WI and/or STIR at advanced disease phase except axial muscles. The symptoms may occasionally improve with discontinuation of statins, but glucocorticoids are usually required, and other treatments include a variety of immunosuppressive therapies such as methotrexate, rituximab and intravenous gammaglobulin.

Research progress of anti-3-hydroxy-3-methylglutaryl-coenzyme A reductase myopathy / 中华神经科杂志

Anti-3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) myopathy is one of the subtypes of immune-mediated necrotizing myopathy. Anti-HMGCR antibodies induce complement activation,subsequently resulting in myofiber necrosis,regeneration with autophagy abnormalities and mitochondrial changes. The age of onset is from children to adulthood. Some patients have a history of exposure to statins. Most patients are subacute onset. The patients with chronic progressive process, are more like muscular dystrophy. The main symptoms are proximal symmetrical weakness of limbs and usually accompanied with extra-muscle symptoms. The MRI showed muscle edema in all patients and fatty infiltrates in some patients. Myositis-specific auto-antibodies and muscle biopsies play key roles in diagnosis of HMGCR myopathy. Corticosteroids and immunosuppressants were first line therapy. Pediatric patients or patients with chronic course are usually refractory, and the efficacy of different combinations of immunosuppressants needs to be further investigated.

Study on effects and mechanism of Tibetan medicine Shanhu qishiwei pill in lowering blood lipid of hyperlipidemia model rats / 中国药房

OBJECTIVE To study the effects of Tibetan medi cine Shanhu qishiwei pill in lowering blood lipid of hyperlipidemia（HLP）model rats ，and to explore its mechanism primarily. METHODS According to their body weigh ，60 SD rats were randomly divide into normal group ，model group ，simvastatin group （positive control ，20 mg/kg）and Shanhu qishiwei pill low-dose，medium-dose and high-dose groups （50，100，200 mg/kg），with 10 rats in each group. Normal group was given conventional diet ，and other groups were given high-lipid diet to induce HLP model ，for consecutive 4 weeks. Administration groups were given relevant medicine intragastrically at the same time of modeling ；normal group and model group were given equal volume of normal saline intragastrically ，once a day ，for consecutive 4 weeks. After last administration ，the serum levels of TC ，TG， LDL-C and HDL-C were determined ；pathological changes of liver tissue were observed ；the protein expressions of AMPK ， p-AMPK，LKB1，and HMGCR in liver tissue were detected in each group. RESULTS Low-dose，medium-dose and high-dose of Shanhu qishiwei pill could significantly reduce the serum levels of TC ，TG and LDL-C and protein expression of HMGCR in liver tissue（P＜0.05），while significantly increased serum level of HDL-C ，phosphorylation level of AMPK ，protein expression of LKB 1 in liver tissue in HLP model rats （P＜0.05）；the pathological changes of liver tissue in HLP model rats were improved to different extents. CONCLUSIONS Shanhu qishiwei pill can reduce the blood lipid level of HLP model rats ，and its mechanism may be related to inhibiting the transmission of LKB 1/AMPK signal pathway and regulating lipid metabolism.

Human hydroxymethylglutaryl-coenzyme A reductase (HMGCR) and statin sensitivity.

While statins, hydroxymethylglutaryl-coenzyme A reductase (HMGCR) inhibitors, are clinically proven to reduce plasma cholesterol levels, a wide variation in inter-individual response to statin therapy has been observed. Pharmacogenetic studies have identified multiple loci that potentially contribute towards the statin response, including the HMGCR gene. To examine, if a statin-resistant, catalytically-active isoform of the human HMGCR could be generated, we have rationally altered the protein to include additional residues in the flap domain, which has a role in statin binding. Comparative enzyme assays with purified wild-type and mutant isoforms reveal the alteration imposes a slight (38%) decrease in the for the substrate, a near 2-fold increase in turnover number, and a 480% increase in the Ki for lovastatin. Thus, alterations in HMGCR could contribute towards the synergistic effects of multiple loci in the statin response.

Study of total flavonoid in Ligustrum Lucidum Ait on lipometabolism regulation of HepG2 cell / 国际中医中药杂志

Objective To study molecular target of total flavonoid in Ligustrum Lucidum Ait(TFL) on lipometabolism regulation of HepG2 cell.Methods Treatment doses of total flavonoid in Ligustrum Lucidum Ait were determined by MTT and LDH.The expression of lipoprotein lipase(LPL),3-hydroxy-3-methylglutary-coenzyme A redutasein(HMGCR)and peroxisome proliferator-actived receptorsα(PPARα)mRNA of HepG2 cell were determined by reversed transcription polymerase chain reaction(RT-PCR).Results Increased expression of LPL mRNA and PPARαmRNA with TFL(10-6～10-4g/ml)were found in HepG2 cells after treated with TFL(10-5g/ml),but decreased expression of HMGCR mRNA was found after treated with TFL(10-5,10-4 g/ml).Conclusion The potential mechanisms of total flavonoid in Ligustrum Lucidum Ait's hypolipidmic effects may be with its functions of regulating lipoprotein degradation through PPARα-LPL pathway,or regulating steroid biosynthesis by reducing HMGCR.