Wide-Targeted Semi-Quantitative Analysis of Acidic Glycosphingolipids in Cell Lines and Urine to Develop Potential Screening Biomarkers for Renal Cell Carcinoma.

Glycosphingolipids (GSLs), mainly located in the cell membrane, play various roles in cancer cell function. GSLs have potential as renal cell carcinoma (RCC) biomarkers; however, their analysis in body fluids is challenging because of the complexity of numerous glycans and ceramides. Therefore, we applied wide-targeted lipidomics using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with selected reaction monitoring (SRM) based on theoretical mass to perform a comprehensive measurement of GSLs and evaluate their potency as urinary biomarkers. In semi-quantitative lipidomics, 240 SRM transitions were set based on the reported/speculated structures. We verified the feasibility of measuring GSLs in cells and medium and found that disialosyl globopentaosylceramide (DSGb5 (d18:1/16:0)) increased GSL in the ACHN medium. LC-MS/MS analysis of urine samples from clear cell RCC (ccRCC) patients and healthy controls showed a significant increase in the peak intensity of urinary DSGb5 (d18:1/16:0) in the ccRCC group compared with that in the control group. Receiver operating characteristic analysis indicated that urinary DSGb5 could serve as a sensitive and specific marker for RCC screening, with an AUC of 0.89. This study demonstrated the possibility of urinary screening using DSGb5 (d18:1/16:0). In conclusion, urinary DSGb5 (d18:1/16:0) was a potential biomarker for cancer screening, which could contribute to the treatment of RCC patients.

Durvalumab plus carboplatin-etoposide treatment in a patient with small-cell lung cancer on hemodialysis: a case report and literature review.

Little is known about the efficacy and safety of durvalumab plus carboplatin-etoposide treatment in patients with extensive-disease (ED) small-cell lung cancer (SCLC) on hemodialysis. Here, we present a case of a 67-year-old man with pleuroperitoneal communication on continuous ambulatory peritoneal dialysis who was diagnosed with ED-SCLC based on a cytological analysis of the peritoneal fluid. He was switched from peritoneal dialysis to hemodialysis and received durvalumab (1500 mg/body on day 1) plus carboplatin (area under the concentration-time curve = 5, 125 mg on day 1) and etoposide (50 mg/m2 on days 1 and 3) as first-line therapy. During the first cycle, grade 2 anemia, grade 3 neutropenia, and grade 3 upper gastrointestinal bleeding occurred; therefore, durvalumab and reduced doses of carboplatin and etoposide were administered. No other severe adverse events occurred, and a partial response was observed after four cycles. Our findings indicate that durvalumab plus carboplatin-etoposide treatment is safe and effective even in patients on hemodialysis.

Elucidation and Regulation of Tyrosine Kinase Inhibitor Resistance in Renal Cell Carcinoma Cells from the Perspective of Glutamine Metabolism.

Tyrosine kinase inhibitors (TKIs) play a crucial role in the treatment of advanced renal cell carcinoma (RCC). However, there is a lack of useful biomarkers for assessing treatment efficacy. Through urinary metabolite analysis, we identified the metabolites and pathways involved in TKI resistance and elucidated the mechanism of TKI resistance. To verify the involvement of the identified metabolites obtained from urine metabolite analysis, we established sunitinib-resistant RCC cells and elucidated the antitumor effects of controlling the identified metabolic pathways in sunitinib-resistant RCC cells. Through the analysis of VEGFR signaling, we aimed to explore the mechanisms underlying the antitumor effects of metabolic control. Glutamine metabolism has emerged as a significant pathway in urinary metabolite analyses. In vitro and in vivo studies have revealed the antitumor effects of sunitinib-resistant RCC cells via knockdown of glutamine transporters. Furthermore, this antitumor effect is mediated by the control of VEGFR signaling via PTEN. Our findings highlight the involvement of glutamine metabolism in the prognosis and sunitinib resistance in patients with advanced RCC. Additionally, the regulating glutamine metabolism resulted in antitumor effects through sunitinib re-sensitivity in sunitinib-resistant RCC. Our results are expected to contribute to the more effective utilization of TKIs with further improvements in prognosis through current drug therapies.

Rapidly progressive interstitial lung disease with positive anti-MDA5 antibody as an immune-related complication of nivolumab: A case report.

Clinically amyopathic dermatomyositis (CADM) with a positive anti-MDA5 antibody titer is often associated with lethal rapidly progressive interstitial lung disease (RP-ILD). Despite the widespread use of immune checkpoint inhibitors (ICIs) in practice, there is no report of CADM with positive anti-MDA5 antibodies as their immune-related complication. We present a case of malignant mesothelioma who developed RP-ILD accompanied by distinct skin manifestations following the administration of nivolumab. Postmortem assessment of stored samples revealed a pre-existing positive titer of anti-MDA5 antibody, further augmented following ICI use, suggesting the possible value of serum screening for better risk stratification of this lethal complication.

Anaphylaxis and Severe Disseminated Intravascular Coagulation Due to Remdesivir.

A 69-year-old woman suffering with multiple myeloma developed coronavirus disease 2019 (COVID-19). Shortly after administration of remdesivir, she presented with symptoms of facial flushing, wheezing, and hypoxemia. Subsequently, thrombocytopenia and hypofibrinogenemia rapidly manifested, leading to a diagnosis of enhanced fibrinolytic-type disseminated intravascular coagulopathy (DIC). This clinical presentation was considered an immediate hypersensitivity reaction with associated coagulation abnormalities induced by remdesivir. Although remdesivir is generally considered safe and efficacious in the treatment of COVID-19, physicians should remain vigilant regarding the potential for severe adverse events associated with this medication.

Predictive model for recurrence of renal cell carcinoma by comparing pre- and postoperative urinary metabolite concentrations.

To improve treatment outcomes in real practice, useful biomarkers are desired when predicting postoperative recurrence for renal cell carcinoma (RCC). We collected data from patients who underwent definitive surgery for RCC and for benign urological tumor at our department between November 2016 and December 2019. We evaluated the differences in pre- and postoperative urinary metabolites with our precise quantitative method and identified predictive factors for RCC recurrence. Additionally, to clarify the significance of metabolites, we measured the intracellular metabolite concentration of three RCC cell lines. Among the 56 patients with RCC, nine had a recurrence (16.0%). When comparing 27 patients with T1a RCC and 10 with benign tumor, a significant difference was observed between pre- and postoperative concentrations among 10 urinary metabolites. In these 10 metabolites, multiple logistic regression analysis identified five metabolites (lactic acid, glycine, 2-hydroxyglutarate, succinic acid, and kynurenic acid) as factors to build our recurrence prediction model. The values of area under the receiver operating characteristic curve, sensitivity, and specificity in this predictive model were 0.894%, 88.9%, and 88.0%, respectively. When stratified into low and high risk groups of recurrence based on this model, we found a significant drop of recurrence-free survival rates among the high risk group. In in vitro studies, intracellular metabolite concentrations of metastatic tumor cell lines were much higher than those of primary tumor cell lines. By using our quantitative evaluation of urinary metabolites, we could predict postoperative recurrence with high sensitivity and specificity. Urinary metabolites could be noninvasive biomarkers to improve patient outcome.

Metabolomic Analysis to Elucidate Mechanisms of Sunitinib Resistance in Renal Cell Carcinoma.

Metabolomics analysis possibly identifies new therapeutic targets in treatment resistance by measuring changes in metabolites accompanying cancer progression. We previously conducted a global metabolomics (G-Met) study of renal cell carcinoma (RCC) and identified metabolites that may be involved in sunitinib resistance in RCC. Here, we aimed to elucidate possible mechanisms of sunitinib resistance in RCC through intracellular metabolites. We established sunitinib-resistant and control RCC cell lines from tumor tissues of RCC cell (786-O)-injected mice. We also quantified characteristic metabolites identified in our G-Met study to compare intracellular metabolism between the two cell lines using liquid chromatography-mass spectrometry. The established sunitinib-resistant RCC cell line demonstrated significantly desuppressed protein kinase B (Akt) and mesenchymal-to-epithelial transition (MET) phosphorylation compared with the control RCC cell line under sunitinib exposure. Among identified metabolites, glutamine, glutamic acid, and α-KG (involved in glutamine uptake into the tricarboxylic acid (TCA) cycle for energy metabolism); fructose 6-phosphate, D-sedoheptulose 7-phosphate, and glucose 1-phosphate (involved in increased glycolysis and its intermediate metabolites); and glutathione and myoinositol (antioxidant effects) were significantly increased in the sunitinib-resistant RCC cell line. Particularly, glutamine transporter (SLC1A5) expression was significantly increased in sunitinib-resistant RCC cells compared with control cells. In this study, we demonstrated energy metabolism with glutamine uptake and glycolysis upregulation, as well as antioxidant activity, was also associated with sunitinib resistance in RCC cells.

Expression of Ganglioside Disialosyl Globopentaosyl Ceramide in Prostate Biopsy Specimens as a Predictive Marker for Recurrence after Radical Prostatectomy.

Carbohydrate antigens are associated with carcinogenesis, cancer invasion, and metastasis and their expression reflect biological activities of various cancers. We previously reported that expression of disialosyl globopentaosyl ceramide (DSGb5), one of carbohydrate antigens, in radical prostatectomy specimens independently predicted biochemical recurrence (i.e., elevating serum prostate specific antigen without recurrent lesions in the image) after radical prostatectomy. However, it is important to evaluate the prognosis at the diagnosis. In this study we investigated DSGb5 expression in prostate biopsy specimens to develop a novel biomarker for providing appropriate management. Between 2005 and 2011, patients who underwent both prostate biopsy and radical prostatectomy in our institution were included. The median follow-up period was 88 months. DSGb5 expression was assessed by immunohistochemical staining and defined 116 patients as high DSGb5 expression (42 patients) or low DSGb5 expression (74 patients). High DSGb5 expression was significantly associated with lymphovascular invasion in radical prostatectomy specimens on both univariate and multivariable analyses (p = 0.028, 0.027). On multivariable analysis, Gleason Score in prostatectomy specimen, positive resection margin, and DSGb5 expression in the biopsy specimen were independently associated with biochemical recurrence-free survival following radical prostatectomy (p = 0.004, 0.008, 0.024). When targeting only patients with negative resection margin, DSGb5 expression was significantly associated with biochemical recurrence-free survival on both univariate and multivariable analyses (p = 0.006, 0.007). DSGb5 expression in prostate biopsy specimens is predictive of lymphovascular invasion and biochemical recurrence-free survival following radical prostatectomy. DSGb5 is a potential biomarker for preoperatively predicting oncological outcomes of prostate cancer.

A Biliary Mucinous Cystic Neoplasm with Intrahepatic and Lymph Node Metastases.

A 51-year-old woman who presented with a large cystic liver tumor with mural nodules in the lateral segment developed Trousseau's syndrome. A mural nodule directly invaded her liver parenchyma. Metastatic nodules were detected in the right lobe and portal/paraaortic lymph nodes. The pathological findings showed mucin-producing adenocarcinoma cells to have invaded the fibrous stroma forming a micropapillary cluster. She developed obstructive jaundice due to tumor progression and subsequently died of hepatic failure. Invasive biliary mucinous cystic neoplasm (MCN) is a rare form of a malignant tumor with a relatively favorable prognosis. This is a very rare case biliary MCN with invasive carcinoma that showed intrahepatic and lymph node metastases.

Accurate quantification of urinary metabolites for predictive models manifest clinicopathology of renal cell carcinoma.

Using surgically resected tissue, we identified characteristic metabolites related to the diagnosis and malignant status of clear cell renal cell carcinoma (ccRCC). Specifically, we quantified these metabolites in urine samples to evaluate their potential as clinically useful noninvasive biomarkers of ccRCC. Between January 2016 and August 2018, we collected urine samples from 87 patients who had pathologically diagnosed ccRCC and from 60 controls who were patients with benign urological conditions. Metabolite concentrations in urine samples were investigated using liquid chromatography-mass spectrometry with an internal standard and adjustment based on urinary creatinine levels. We analyzed the association between metabolite concentration and predictability of diagnosis and of malignant status by multiple logistic regression and receiver operating characteristic (ROC) curves to establish ccRCC predictive models. Of the 47 metabolites identified in our previous study, we quantified 33 metabolites in the urine samples. Multiple logistic regression analysis revealed 5 metabolites (l-glutamic acid, lactate, d-sedoheptulose 7-phosphate, 2-hydroxyglutarate, and myoinositol) for a diagnostic predictive model and 4 metabolites (l-kynurenine, l-glutamine, fructose 6-phosphate, and butyrylcarnitine) for a predictive model for clinical stage III/IV. The sensitivity and specificity of the diagnostic predictive model were 93.1% and 95.0%, respectively, yielding an area under the ROC curve (AUC) of 0.966. The sensitivity and specificity of the predictive model for clinical stage were 88.5% and 75.4%, respectively, with an AUC of 0.837. In conclusion, quantitative analysis of urinary metabolites yielded predictive models for diagnosis and malignant status of ccRCC. Urinary metabolites have the potential to be clinically useful noninvasive biomarkers of ccRCC to improve patient outcomes.

Value of global metabolomics in association with diagnosis and clinicopathological factors of renal cell carcinoma.

Renal cell carcinoma (RCC) is a malignant tumor that currently lacks clinically useful biomarkers indicative of early diagnosis or disease status. RCC has commonly been diagnosed based on imaging results. Metabolomics offers a potential technology for discovering biomarkers and therapeutic targets by comprehensive screening of metabolites from patients with various cancers. We aimed to identify metabolites associated with early diagnosis and clinicopathological factors in RCC using global metabolomics (G-Met). Tumor and nontumor tissues were sampled from 20 cases of surgically resected clear cell RCC. G-Met was performed by liquid chromatography mass spectrometry and important metabolites specific to RCC were analyzed by multivariate statistical analysis for cancer diagnostic ability based on area under the curve (AUC) and clinicopathological factors (tumor volume, pathological T stage, Fuhrman grade, presence of coagulation necrosis and distant metastasis). We identified 58 metabolites showing significantly increased levels in tumor tissues, 34 of which showed potential early diagnostic ability (AUC >0.8), but 24 did not discriminate between tumor and nontumor tissues (AUC ≤0.8). We recognized 6 pathways from 9 metabolites with AUC >0.8 and 7 pathways from 10 metabolites with AUC ≤0.8 about malignant status. Clinicopathological factors involving malignant status correlated significantly with metabolites showing AUC ≤0.8 (p = 0.0279). The tricarboxylic acid cycle (TCA) cycle, TCA cycle intermediates, nucleotide sugar pathway and inositol pathway were characteristic pathways for the malignant status of RCC. In conclusion, our study found that metabolites and their pathways allowed discrimination between early diagnosis and malignant status in RCC according to our G-Met protocol.

Penile blood pressure is useful to identify candidates for tadalafil treatment in patients with lower urinary tract symptoms.

OBJECTIVES: To determine whether penile blood pressure (PBP) can be used to identify patients who can benefit from tadalafil treatment, the correlation between PBP at baseline and changes in lower urinary tract symptoms (LUTS) induced by tadalafil treatment was studied prospectively. PATIENTS AND METHODS: Patients with BPH who were poor responders to α1 -blockers and took tadalafil instead of an α1 -blocker were registered between 2014 and 2016. The patients were divided into two groups (low- and high-PBP groups) using the median baseline PBP of 110 mmHg as the threshold. The changes in the International Prostate Symptom Score (IPSS) between before and at 4 and 12 weeks after tadalafil treatment were compared between the low- and high-PBP groups. Multivariate analysis was performed to identify parameters associated with IPSS improvement with tadalafil treatment. RESULTS: In all, 51 patients were investigated. The IPSS in the low-PBP group decreased immediately after the start of treatment, and there was significant improvement in the IPSS from baseline at 4 and 12 weeks after the start of treatment, whilst the IPSS in the high-PBP group did not show significant changes. On multivariate analysis, PBP at baseline, anticholinergic drug use, and IPSS at baseline were significant predictors of a good IPSS response to tadalafil treatment. CONCLUSIONS: This study demonstrated that PBP could reliably identify patients with BPH who could benefit from tadalafil treatment. Patients with low PBP could be better responders to tadalafil.

Infliximab-Induced Tubulointerstitial Nephritis with Image Findings of Striated Nephrogram in Crohn's Disease.

Tubulointerstitial nephritis is primary injury to renal tubules and interstititum which could be resulting in decreased renal function. The acute and chronic forms are most often due to allergic drug reactions or to infections. Tubulointerstitial nephritis in Crohn's disease has rarely been reported. Imaging findings of a striated nephrogram on enhanced computed tomography (CT) could represent the clinical state of tubulointerstitial nephritis. This is the first report of tubulointerstitial nephritis caused by infliximab, monoclonal antibody against human tumor necrosis factor-α, showing striated nephrograms in Crohn's disease. The case of a 28-year-old man treated with infliximab for Crohn's disease is described. Infliximab was added to his maintenance therapy, and bowel symptoms were stable. The patient presented with a 2-month history of fever and an elevated C-reactive protein after infliximab administration for 4.5 years. Contrast-enhanced CT showed striated nephrograms in both kidneys. Urinalysis showed no abnormal findings. The pathological diagnosis on CT-guided percutaneous renal needle biopsy was drug-induced tubulointerstitial nephritis because of eosinophilic infiltration with neutrophils mainly in the tubulointerstitial areas. The imaging findings of striated nephrogram are important for the diagnosis of tubulointerstitial nephritis. Tubulointerstitial nephritis could be caused by drug-induced inflammation or direct extension of Crohn's disease as an extra-interstitial manifestation. The treatment strategies for these two diseases are contradictory to each other and inappropriate treatment could worsen the renal function. Needle biopsy is therefore indispensable for differential diagnosis.

L-Lysine Attenuates Hepatic Steatosis in Senescence-Accelerated Mouse Prone 8 Mice.

Non-alcoholic hepatic steatosis is a phenotype of metabolic syndrome, and aging is a risk factor for this condition. Senescence-accelerated mouse prone 8 (SAMP8) is a murine model for studying aging-associated disorders. We here investigated the effect of dietary supplementation with L-lysine (Lys) on non-alcoholic hepatic steatosis in SAMP8 mice. Triglyceride (TG) and cholesterol (Chol) accumulated in the livers of SAMP8 mice fed a standard diet at 36 wk of age. However, intake of a Lys-rich diet for 2 mo prevented the accumulation of TG and Chol in the liver. Plasma alanine aminotransferase activity, an index of liver injury, was decreased by Lys. The mRNA expression levels of peroxisome proliferator-activated receptor gamma coactivator 1-α and carnitine palmitoyltransferase 1a, which regulate ß-oxidation, were increased in the livers of SAMP8 mice fed the Lys-rich diet. Taken together, our study suggests dietary intake of Lys prevents hepatic steatosis by stimulating ß-oxidation in SAMP8 mice.

[CORRESPONDENCE OF POLYMICROBIAL BACTERIURIA IN THE UNCOMPLICATED URINARY TRACT INFECTION OF THE PREMENOPAUSAL WOMAN].

(Objectives) We report the clinical features about polymicrobial bacteria detection cases in the uncomplicated urinary tract infection of the premenopausal woman from the voided midstream urine culture. (Methods) We retrospectively reviewed the premenopausal woman from 18-49 years patients visited Sendai City Hospital from April, 2006 to December, 2014, diagnosed uncomplicated cystitis or uncomplicated pyelonephritis. We analyzed for 375 specimens from the voided midstream urine culture. (Results) Among 375 specimens, the urine culture-positive for uropathogens were 211 specimens. The monomicrobial bacterial were detected in 184 specimens (87.2%) and polymicrobial bacterial specimens were 27 specimens (12.8%). The most combination group was the caused bacteria and periurethral microorganisms in 20 specimens (74.1%). Then 6 periurethral microorganisms specimens (22.2%), the caused bacteria were only 1 specimen was overlapped (3.7%). The case of urinary tract infections recurrence or revealed voiding dysfunction that need periodic treatment were more prevalent in the polymicrobial than the monomicrobial group (22.2% vs 9.8%, p=0.043). (Conclusions) When polymicrobial bacteria were detected in uncomplicated urinary tract infection in premenopausal woman, it was confirmed that there were the most combinations of caused bacteria and periurethral microorganisms. In these cases, treatment intended for only the caused bacteria. A risk of the infection recurrence and voiding dysfunction were statistically significant higher rate in the polymicrobial bacteria detection cases, and it might be necessary to consider that search to complicated urinary tract infection.

Pure Stage I Seminoma with an Elevated hCG of 25,265 mIU/ml: A Case Report.

We report a histologically pure stage 1 seminoma with an elevated human chorionic gonadotropin (hCG). A 38 year-old man was referred for the evaluation of the left testicular swelling. He showed an elevated serum hCG level of 25,265 mIU/ml with normal a fetoprotein and lactate dehydrogenase. Imaging showed heterogeneous tumor without any metastatic lesions. We conducted 4 courses of chemotherapy before detecting hCG nadir. The final pathological report showed pure seminoma with syncytiotrophoblastic cells but no choriocarcinoma components. The patient remains disease free until present time. The case raised several questions regarding diagnosis and treatment strategy for bulky testicular seminoma.

Dietary L-Lysine Suppresses Autophagic Proteolysis and Stimulates Akt/mTOR Signaling in the Skeletal Muscle of Rats Fed a Low-Protein Diet.

Amino acids, especially L-leucine, regulate protein turnover in skeletal muscle and have attracted attention as a means of increasing muscle mass in people suffering from malnutrition, aging (sarcopenia), or a bedridden state. We previously showed that oral administration of L-lysine (Lys) by gavage suppressed proteolysis in skeletal muscles of fasted rats. However, the intake of Lys in the absence of other dietary components is unlikely in a non-experimental setting, and other dietary components may interfere with the suppressive effect of Lys on proteolysis. We supplemented Lys to a 10% casein diet and investigated the effect of Lys on proteolysis and autophagy, a major proteolytic system, in the skeletal muscle of rats. The rate of proteolysis was evaluated from 3-methylhisitidine (MeHis) released from isolated muscles, in plasma, and excreted in urine. Supplementing lysine with the 10% casein diet decreased the rate of proteolysis induced by intake of a low-protein diet. The upregulated autophagy activity [light chain 3 (LC3)-II/total LC3] caused by a low-protein diet was reduced, and the Akt/mTOR signaling pathway was activated by Lys. Importantly, continuous feeding of a Lys-rich 10% casein diet for 15 days increased the masses of the soleus and gastrocnemius muscles. Taken together, supplementation of Lys to a low-protein diet suppresses autophagic proteolysis through the Akt/mTOR signaling pathway, and continuous feeding of a Lys-rich diet may increase skeletal muscle mass.

Attenuation of autophagic-proteolysis in C2C12 cells by saccharopine.

Muscle wasting impairs physical function and leads people to a bedridden state. We previously demonstrated that lysine (Lys) suppresses autophagic-proteolysis through the Akt pathway. However, the effect of metabolites of Lys on proteolysis is unclear. In this study, we investigated the effect of saccharopine (Sac), a metabolite of Lys, on proteolysis in C2C12 cells. When C2C12 myotubes were incubated in serum-free medium containing Sac, the rate of proteolysis, which was evaluated by 3-methylhistidine released from C2C12 myotubes, and autophagy activity, which was assessed by amount of light chain 3-II, were suppressed. Sac stimulated Akt and mammalian target of rapamycin signaling, which was evaluated from eIF4E-binding protein 1 phosphorylation. The suppressive effects of Sac on proteolysis and autophagy were completely abolished by an Akt inhibitor. Therefore, we concluded that Sac suppresses autophagic-proteolysis through Akt as with Lys.

Lysine suppresses myofibrillar protein degradation by regulating the autophagic-lysosomal system through phosphorylation of Akt in C2C12 cells.

The prevention of muscle wasting is important for maintaining quality of life, since loss of muscle mass can lead to a bedridden state and decreased resistance to diseases. The prevention of muscle wasting requires an increase in protein synthesis and a decrease in protein degradation in skeletal muscle. We previously showed that lysine (Lys) markedly suppressed myofibrillar protein degradation by inhibiting the autophagic-lysosomal system via the mammalian target of rapamycin (mTOR) and other signal molecules in C2C12 cells. In this study, we investigated the involvement of Akt and adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK), two regulators of autophagy, on the suppressive effects of Lys on myofibrillar protein degradation in C2C12 cells. Lys induced the phosphorylation of Akt, but the suppressive effects of Lys on myofibrillar protein degradation and autophagy were completely abolished in the presence of Akt1/2 kinase inhibitor (Akti). Lys suppressed the phosphorylation of AMPK, but this effect was also abolished by Akti. On the other hand, AMPK activation by 5-aminoimidazole-4-carboxamide-1-ß-D-ribonucleoside (AICAR) did not affect either Akt activity or the autophagic-lysosomal system in C2C12 cells treated with Lys. These results indicate that regulation of AMPK activity is not essential for the regulation of autophagy by Lys. Taken together, our results show that Lys suppresses myofibrillar protein degradation by the autophagic-lysosomal system through the phosphorylation of Akt in C2C12 cells.