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1.
JFMS Open Rep ; 10(1): 20551169231224534, 2024.
Article in English | MEDLINE | ID: mdl-38357272

ABSTRACT

Case series summary: A 1-year-old castrated male domestic shorthair cat was suspected with myasthenia gravis (MG) based on neurological examination, complete blood count (CBC), serum biochemistry, radiography and electrophysiological examination. In addition, a 9-year-old spayed female domestic shorthair cat was diagnosed with MG based on neurological examination, CBC, serum biochemistry, radiography, ultrasonography and increased acetylcholine receptor antibody titre. Positioning head tilt (PHT) was observed at the time of diagnosis in both cats. Relevance and novel information: Although the pathophysiology of PHT in cats is not fully understood, the mechanism for PHT in cats with MG may be similar to that of cats with hypokalaemic myopathy, supporting our hypothesis that muscle spindle dysfunction causes PHT.

2.
Front Vet Sci ; 10: 1264916, 2023.
Article in English | MEDLINE | ID: mdl-37941813

ABSTRACT

A 15-year-old spayed female domestic shorthaired cat was evaluated for chronic progressive paraparesis and proprioceptive ataxia. Neurological examination was consistent with a T3-L3 myelopathy. Plain thoracolumbar vertebral column radiographs and CT without intravenous contrast or myelography performed at another facility did not highlight any abnormalities. MRI of the thoracolumbar spinal cord identified an intraparenchymal space-occupying lesion extending from T10-T12. Surgery was performed to remove as much of the mass as possible, and to submit samples for histopathology. A dorsal laminectomy was performed over T9-T13. A midline myelotomy provided access to the mass, which was debrided with an intraoperative estimate of 80% removal. Histopathologic examination was consistent with a diagnosis of an astrocytoma. Post-operative treatment consisted of amoxicillin clavulanic acid, prednisolone, gabapentin, and additional analgesic medications in the direct post-operative period. Over the following 4 months, slow recovery of motor function was seen with continued physiotherapy. During the following 2 months, renal and cardiopulmonary disease were diagnosed and treated by other veterinarians. The cat was also reported to have lost voluntary movement in the pelvic limbs during this period, suggesting regression to paraplegia. Finally, 6 months post-surgery, the owner elected humane euthanasia. This is the second documentation of surgical treatment and outcome of an astrocytoma in the spinal cord of a cat.

3.
J Feline Med Surg ; 25(6): 1098612X231175761, 2023 06.
Article in English | MEDLINE | ID: mdl-37318332

ABSTRACT

CASE SERIES SUMMARY: Positioning head tilt (PHT) is a dynamic neurological sign in which the head tilts to the opposite side to which it is moving. This sign is triggered in response to head movement and is thought to be due to the lack of inhibition of vestibular nuclei by the cerebellar nodulus and uvula (NU). The occurrence of PHT in animals has been suggested to be an indicator of NU dysfunction. Here, we describe the acute onset of PHT in 14 cats. All the cats were diagnosed with hypokalaemic myopathy caused by a range of pathologies. The PHT resolved along with other signs related to myopathy, such as cervical flexion and generalised weakness, after electrolyte correction in all cats. RELEVANCE AND NOVEL INFORMATION: Hypokalaemic myopathy was the likely cause of PHT in the present feline cases.


Subject(s)
Cat Diseases , Muscular Diseases , Cats , Animals , Vestibular Nuclei/physiology , Muscular Diseases/veterinary , Cat Diseases/diagnosis
6.
Aliment Pharmacol Ther ; 55(4): 422-433, 2022 02.
Article in English | MEDLINE | ID: mdl-34812502

ABSTRACT

BACKGROUND: After hepatitis C virus (HCV) elimination, patients should be followed up due to risk of hepatocellular carcinoma (HCC). Growth differentiation factor 15 (GDF15) is a cytokine induced by mitochondrial dysfunction or oxidative stress. Aim To evaluate the prognostic value of GDF15 for HCC occurrence after HCV elimination. METHODS: We measured GDF15 levels in stored serum from patients with chronic HCV infection without a history of HCC who had achieved sustained virological response with direct-acting antiviral agents (DAAs). The patients were randomly divided into derivation (n = 964) and validation (n = 642) cohorts. RESULTS: In the derivation cohort, serum GDF15 levels were higher in those with HCC occurrence after DAA treatment than in those without. Multivariate Cox proportional hazards analysis revealed baseline GDF15 (>1350 pg/mL, HR 2.54), AFP (>5 ng/mL, HR 2.00), and the FIB-4 index (>3.25, HR 2.69) to be independent risk factors for HCC. Scoring based on GDF15, AFP and the FIB-4 index stratified HCC occurrence risk. In the validation cohort, the cumulative HCC occurrence rate at 3 years was 0.64%, 3.27% and 15.3% in low-score (N = 171), medium-score (N = 300) and high-score (N = 166) groups, respectively. In the total cohort, scoring divided patients with a FIB-4 index ≤3.25, whose HCC occurrence rate was 2.0% at 3 years, into medium-score and low-score groups with HCC occurrence rates at 3 years of 3.76% and 0.24%, respectively. CONCLUSIONS: Serum GDF15 predicts de novo HCC occurrence. Scoring using GDF15, AFP, and the FIB-4 index can predict de novo HCC occurrence risk after HCV elimination.


Subject(s)
Carcinoma, Hepatocellular , Hepatitis C, Chronic , Hepatitis C , Liver Neoplasms , Antiviral Agents/therapeutic use , Carcinoma, Hepatocellular/diagnosis , Carcinoma, Hepatocellular/drug therapy , Carcinoma, Hepatocellular/etiology , Growth Differentiation Factor 15 , Hepacivirus , Hepatitis C/drug therapy , Hepatitis C, Chronic/complications , Hepatitis C, Chronic/drug therapy , Humans , Liver Neoplasms/diagnosis , Liver Neoplasms/drug therapy , Liver Neoplasms/etiology , Risk Factors , Sustained Virologic Response , alpha-Fetoproteins/analysis
7.
Front Vet Sci ; 8: 802668, 2021.
Article in English | MEDLINE | ID: mdl-34970622

ABSTRACT

Positioning head tilt is a neurological sign that has recently been described in dogs with congenital cerebellar malformations. This head tilt is triggered in response to head movement and is believed to be caused by a lack of inhibition of the vestibular nuclei by the cerebellar nodulus and ventral uvula (NU), as originally reported cases were dogs with NU hypoplasia. We hypothesized that other diseases, such as lysosomal storage diseases that cause degeneration in the whole brain, including NU, may cause NU dysfunction and positioning head tilt. Videos of the clinical signs of canine lysosomal storage disease were retrospectively evaluated. In addition, post-mortem NU specimens from each dog were histopathologically evaluated. Nine dogs were included, five with lysosomal storage disease, two Chihuahuas with neuronal ceroid lipofuscinosis (NCL), two Border Collies with NCL, one Shikoku Inu with NCL, two Toy Poodles with GM2 gangliosidosis, and two Shiba Inus with GM1 gangliosidosis. Twenty-eight videos recorded the clinical signs of the dogs. In these videos, positioning head tilt was observed in seven of nine dogs, two Chihuahuas with NCL, one Border Collie with NCL, one Shikoku Inu with NCL, one Toy Poodle with GM2 gangliosidosis, and two Shiba Inus with GM1 gangliosidosis. Neuronal degeneration and loss of NU were histopathologically confirmed in all diseases. As positioning head tilt had not been described until 2016, it may have been overlooked and may be a common clinical sign and pathophysiology in dogs with NU dysfunction.

8.
Vet Sci ; 8(10)2021 Oct 12.
Article in English | MEDLINE | ID: mdl-34679057

ABSTRACT

A two-year-and-eleven-month-old male Shikoku Inu was referred for evaluation of progressive gait abnormality that had begun three months prior. Neurological examination revealed ventral flexion of the neck, a wide-based stance in the hindlimb, wide excursions of the head from side to side, tremor in all four limbs, hypermetria in all four limbs, proprioceptive deficits in all four limbs, reduced patellar reflex in both hindlimbs, and postural vertical nystagmus. Later, behavioral and cognitive dysfunction, ataxia, and visual deficits slowly progressed. Magnetic resonance imaging revealed symmetrical progressive atrophy of the whole brain and cervical spinal cord. Bilateral retinal degeneration was observed, and both flush and flicker electroretinograms were bilaterally non-recordable at the age of five years and eight months, and the dog was euthanized. Histopathologically, faint-to-moderate deposition of light-brown pigments was frequently observed in the cytoplasm of neurons throughout the cerebrum, cerebellum, and nuclei of the brainstem. The pigments were positive for Luxol fast blue, periodic acid-Schiff, and Sudan black B, and exhibited autofluorescence. Electron microscopic examination revealed the accumulation of membranous material deposition in the neuronal cytoplasm. Small foci of pigment-containing macrophages were frequently observed around the capillary vessels. Based on these clinical and pathological findings, the animal was diagnosed with adult-onset neuronal ceroid lipofuscinosis.

9.
Aliment Pharmacol Ther ; 54(10): 1340-1349, 2021 11.
Article in English | MEDLINE | ID: mdl-34618934

ABSTRACT

BACKGROUND: Several factors associated with hepatocellular carcinoma (HCC) occurrence after sustained virological response (SVR) in patients with hepatitis C have been reported. However, few validation studies have been performed in the era of direct-acting anti-virals (DAAs). AIMS: To develop a prediction model for HCC occurrence after DAA-mediated SVR and validate its usefulness. METHODS: We analysed 2209 patients with SVR and without a history of HCC who initiated DAA treatment at 24 Japanese hospitals. These patients were divided into a training set (1473 patients) and a validation set (736 patients). RESULTS: In the training set, multivariate Cox proportional hazards analysis showed that the baseline BMI (≥25.0 kg/m2 , P = 0.024), baseline fibrosis-4 (FIB-4) index (≥3.25, P = 0.001), albumin level at SVR (<4.0 g/dL, P = 0.010) and alpha-foetoprotein level at SVR (≥5.0 ng/mL, P = 0.006) were significantly associated with HCC occurrence. We constructed a prediction model for HCC occurrence with these four factors (2 points were added for the FIB-4 index, and 1 point was added for each of the other three factors). Receiver operating characteristics curve analysis identified a score of 2 as the optimal cut-off value for the prediction model (divided into 0-1 and 2-5). In the validation set, the sensitivity and negative predictive value for HCC occurrence were 87.5% and 99.7%, respectively, at 2 years and 71.4% and 98.0%, respectively, at 3 years. CONCLUSION: A prediction model combining these four factors contributes to an efficient surveillance strategy for HCC occurrence after DAA-mediated SVR.


Subject(s)
Carcinoma, Hepatocellular , Hepatitis C, Chronic , Hepatitis C , Liver Neoplasms , Antiviral Agents/therapeutic use , Carcinoma, Hepatocellular/diagnosis , Carcinoma, Hepatocellular/epidemiology , Carcinoma, Hepatocellular/etiology , Hepatitis C/drug therapy , Hepatitis C, Chronic/complications , Hepatitis C, Chronic/drug therapy , Humans , Liver Cirrhosis/drug therapy , Liver Neoplasms/diagnosis , Liver Neoplasms/drug therapy , Liver Neoplasms/epidemiology , Sustained Virologic Response
10.
Anticancer Res ; 41(4): 2187-2192, 2021 Apr.
Article in English | MEDLINE | ID: mdl-33813432

ABSTRACT

BACKGROUND/AIM: The present study aimed to examine the therapeutic efficacy of ramucirumab compared with that of sorafenib as subsequent systemic therapy for patients with hepatocellular carcinoma (HCC) and serum α-fetoprotein (AFP) levels ≥400 ng/ml. PATIENTS AND METHODS: In our prospectively registered, real-world cohort, 13 and 11 patients treated with ramucirumab or sorafenib, respectively, were analyzed. Progression-free survival (PFS) was primarily compared between the ramucirumab and sorafenib groups. RESULTS: The PFS was significantly longer in the ramucirumab group than in the sorafenib group (median, 2.7 vs. 0.9 months, respectively; p=0.005). There were no significant differences in the objective response rates or the disease control rates between the ramucirumab and sorafenib groups (9.1% and 54.5% vs. 0.0% and 22.2%, respectively). CONCLUSION: Subsequent systemic therapy with ramucirumab showed a better ability to control tumor progression than sorafenib in HCC patients with serum AFP levels ≥400 ng/ml.


Subject(s)
Antibodies, Monoclonal, Humanized/therapeutic use , Carcinoma, Hepatocellular/drug therapy , Liver Neoplasms/drug therapy , Sorafenib/therapeutic use , Aged , Aged, 80 and over , Carcinoma, Hepatocellular/blood , Carcinoma, Hepatocellular/mortality , Carcinoma, Hepatocellular/pathology , Chemotherapy, Adjuvant/methods , Cohort Studies , Disease Progression , Female , Humans , Japan/epidemiology , Liver Neoplasms/blood , Liver Neoplasms/pathology , Male , Middle Aged , Progression-Free Survival , Survival Rate , Treatment Outcome , alpha-Fetoproteins/metabolism , Ramucirumab
12.
Hepatol Res ; 51(5): 517-527, 2021 May.
Article in English | MEDLINE | ID: mdl-33507588

ABSTRACT

AIM: The aim of the present study was to investigate the clinical course in hepatitis C virus (HCV)-positive patients with decompensated liver cirrhosis after direct-acting antivirals (DAAs) have been used for HCV infection. METHODS: This multicenter study prospectively analyzed a registered cohort composed of 73 HCV-positive patients with decompensated cirrhosis who attended our 11 institutions between January 2018 and July 2018. Prognoses, including changes in the liver reserve, hepatocellular carcinoma (HCC), decompensation events, and survival, were analyzed up to July 2020, as was the initiation of DAA treatment. RESULTS: Sixty-four (87.7%) and nine (12.3%) patients had Child-Pugh class (C-P) B and C at baseline, respectively. Within 2 years after enrollment, 17 patients (23.3%) received treatment with DAAs, and 31 patients (42.5%) developed uncontrolled HCC, switched to palliative care, or died. Patients who received DAA treatment were significantly younger and had significantly higher alanine aminotransferase levels and lower platelet counts than the patients who did not receive DAA treatment. The rates of overall survival, cumulative HCC occurrence, and cumulative hospitalization for any hepatic decompensation event at 2 years were 64.8%, 13.1%, and 65.6%, respectively. Overall survival was significantly shorter and the HCC occurrence and hospitalization rates were significantly higher in C-P C patients than in C-P B patients. CONCLUSIONS: Among HCV-positive patients with decompensated cirrhosis, approximately one-fourth received DAA treatment, but more than 40% of the patients lost the opportunity for treatment with DAAs.

13.
Hepatol Res ; 50(9): 1091-1100, 2020 Sep.
Article in English | MEDLINE | ID: mdl-32559342

ABSTRACT

AIM: Preserved liver function may be an important factor affecting therapeutic efficacy in hepatocellular carcinoma patients treated with lenvatinib, but not all patients can be treated while preserving liver function. This study evaluated the therapeutic efficacy of lenvatinib in patients with poor liver function with and without portal hypertension. METHODS: This prospectively registered multicenter study analyzed 93 patients treated with lenvatinib. Progression-free survival was compared between patients with and without advanced portal hypertension according to baseline liver function. Advanced portal hypertension was defined as having both splenomegaly and any portosystemic collaterals. RESULTS: A total of 37 patients (40.7%) had advanced portal hypertension. Progression-free survival did not differ between patients with and without advanced portal hypertension in the entire cohort (median 7.6 vs. 4.1 months, respectively; P = 0.148), but was significantly longer in patients with advanced portal hypertension than in those without advanced portal hypertension in the albumin-bilirubin grade 2 or 3 group (median 7.6 vs. 2.1 months, respectively; P = 0.016). In a multivariate analysis, the presence of advanced portal hypertension was identified as the only significant predictor associated with prolonged progression-free survival in the albumin-bilirubin grade 2 or 3 group. CONCLUSIONS: Advanced portal hypertension was associated with the therapeutic efficacy of lenvatinib in controlling the progression of hepatocellular carcinoma in patients with poor liver function.

14.
PLoS One ; 15(6): e0234811, 2020.
Article in English | MEDLINE | ID: mdl-32544182

ABSTRACT

BACKGROUND: L31 and Y93 in the NS5A region of the hepatitis C virus (HCV) are the most important substitution positions associated with resistance to direct-acting antiviral (DAA) treatment. METHODS: We analyzed the frequency of NS5A L31M/V and Y93/H in NS5A inhibitor-naive HCV genotype 1 patients who received asunaprevir plus daclatasvir combination treatment using a conventional sequencing method and a deep sequencing method that can distinguish a single substitution at either position and a double substitution at both positions with a 0.1% detection threshold. RESULTS: The frequency of substitutions at both sites using the conventional method was very low, with 1 in 14 non-responders and 0 in 42 randomly selected responder patients. On the other hand, for the deep sequencing method, cases with double substitutions in the tandem sequence were detected in 8/14 non-responders and 1/42 responders (p<0.0001). For the conventional method, substitutions were detected at any position in 6/14 non-responders and 2/42 responders (p = 0.0019), with a clear difference between the two groups. The difference was also clear with the deep sequencing method, with 11/14 non-responders and 8/42 responders. Interestingly, for the deep sequencing method, the single substitution of L31 was found in 6/14 non-responders and 7/42 responders, whereas single substitutions of Y93 or double substitutions were found in 7/14 vs. 1/42 and 8/14 vs. 1/42 patients, respectively. CONCLUSIONS: NS5A L31 and Y93 substitutions were detected in tandem by the deep sequencing methods in several genotype 1 patients, who may be more resistant to DAA treatment containing an NS5A inhibitor.


Subject(s)
Antiviral Agents/therapeutic use , Hepacivirus/genetics , Hepatitis C/drug therapy , Imidazoles/therapeutic use , Isoquinolines/therapeutic use , Sulfonamides/therapeutic use , Viral Nonstructural Proteins/genetics , Aged , Carbamates , Case-Control Studies , Drug Resistance, Viral/genetics , Drug Therapy, Combination , Female , Genotype , Hepacivirus/isolation & purification , Hepatitis C/virology , Humans , Male , Mutation , Pyrrolidines , Sustained Virologic Response , Treatment Failure , Valine/analogs & derivatives
15.
Hepatol Res ; 50(3): 313-320, 2020 Mar.
Article in English | MEDLINE | ID: mdl-31747479

ABSTRACT

AIM: Several studies have recently reported that hepatocellular carcinoma (HCC) occurrence does not differ between hepatitis C virus patients receiving interferon (IFN)-based and IFN-free treatments considering the patients' backgrounds. However, liver fibrosis was not directly considered in these studies. METHODS: In total, 3972 patients without a history of HCC who started IFN-based or IFN-free treatment between August 2002 and April 2017 at 30 Japanese hospitals and achieved a sustained virologic response were included. Propensity score matching considering liver histology was performed. RESULTS: The median age and percentage of patients with advanced liver fibrosis (F3/4) were 58 years and 11.4% in the IFN-based group, and 68 years and 18.9% in the IFN-free group, respectively. The HCC occurrence rates at 1 year and 2 years were 0.4% and 1.1% in the IFN-based group, and 1.6% and 4.1% in the IFN-free group, respectively, and HCC occurrence in the IFN-free group was significantly higher than that in the IFN-based group (P < 0.001). The characteristics of the HCC occurrence patterns did not differ between the two groups. After propensity score matching, among 764 patients, the HCC occurrence rates at 1 year and 2 years were 0.5% and 1.9% in the IFN-based group and 1.1% and 3.0% in the IFN-free group, respectively, and no significant difference was observed between the two groups (P = 0.489). CONCLUSIONS: HCC occurrence in sustained virologic response patients does not differ between IFN-based and IFN-free treatment considering liver fibrosis stage. The degree of its progress at diagnosis does not differ between the two groups.

16.
Hepatol Res ; 49(8): 853-859, 2019 Aug.
Article in English | MEDLINE | ID: mdl-31009550

ABSTRACT

AIM: Sofosbuvir (SOF) and ribavirin (RBV) combination therapy has improved the sustained virologic response (SVR) rate and shortened the treatment duration for patients with chronic hepatitis C virus (HCV) genotype 2 infection. Ribavirin-induced hemolytic anemia is one of the most troublesome side-effects of SOF/RBV therapy; however, factors associated with this condition have not been fully elucidated. We aimed to identify a safer way to complete treatment with SOF/RBV therapy by examining factors related to RBV-induced hemolytic anemia and identifying patients who did not develop anemia. METHODS: Two hundred and one patients with genotype 2 chronic hepatitis C treated with SOF/RBV therapy were studied. Significant factors associated with the decline in hemoglobin (Hb) levels from the baseline were analyzed. RESULTS: The SVR rate was 96.5% (194 out of 201 patients) based on intent-to-treat analysis. In multivariate analysis, inosine triphosphatase (ITPA) gene variation (P < 0.0001) and estimated glomerular filtration rate (eGFR) (0.001) were significantly associated with a decrease in Hb levels less than 2 g/dL. All patients were divided into four groups by ITPA and eGFR at baseline, and we identified patients with ITPA CA/AA and eGFR >75 as a group that did not develop anemia. CONCLUSIONS: The results presented here suggest that patients with ITPA CA/AA and eGFR >75 had no reduction in Hb levels during the treatment with SOF/RBV in HCV genotype 2-infected patients. Adding RBV to direct-acting antiviral therapy might not be problematic in certain patients, at least in terms of the occurrence of anemia.

17.
Hepatol Res ; 49(5): 570-578, 2019 May.
Article in English | MEDLINE | ID: mdl-30623521

ABSTRACT

AIM: In patients with chronic hepatitis C, hepatocellular carcinoma (HCC) occurs at a certain frequency, even if a sustained virologic response (SVR) is achieved by antiviral treatment. Old age, liver fibrosis, and high post-treatment α-fetoprotein (AFP) level are typical risk factors of post-SVR HCC. We examined whether the frequencies and factors of HCC in patients with an SVR achieved from interferon treatment changed. Methods Among patients prospectively registered for pegylated interferon and ribavirin treatment, 2021 with an SVR without HCC development during the treatment period were followed up. The mean observation period was 49.5 ± 26.2 months. RESULTS: The multivariable Cox regression analysis showed that older age, diabetes mellitus, advanced liver disease, and higher post-treatment AFP level were the independent risk factors throughout the observation period. The annual occurrence rate of HCC was 0.74% in the third year, 0.54% in the fourth year, and 0.40% in the fifth year; it gradually decreased from the third year. Because the time course hazards for HCC changed at 48 months, we separately analyzed its risk factors before and after this change point. The multivariable Cox regression analysis showed that the four above-mentioned factors were significantly related to HCC development within 4 years. Conversely, the univariable Cox regression analysis only identified diabetes mellitus as a significant factor for HCC development after 4 years. CONCLUSION: The frequency of HCC in hepatitis C patients who achieved an SVR from interferon treatment decreased during the observation period, and its risk factors changed between the early and late periods.

18.
Hepatol Commun ; 2(8): 884-892, 2018 Aug.
Article in English | MEDLINE | ID: mdl-30094400

ABSTRACT

Combination treatment of ledipasvir and sofosbuvir (LDV/SOF) is first-line treatment for patients with chronic hepatitis C genotype 1 in the United States, Europe, and Japan. However, the influence of LDV/SOF on the cardiovascular system is poorly characterized. A total of 470 chronic hepatitis C patients who started LDV/SOF treatment between September 2015 and February 2016 at nine hospitals in Japan were prospectively enrolled in this study. Corrected QT (QTc) prolongation was defined as a QTc interval ≥450 milliseconds. The sustained virologic response rate was 96.0% (451/470), and the discontinuance rate due to adverse effects was 0.9% (4/470). Among 395 patients whose electrocardiogram was evaluated over time and compared with baseline, the QTc interval was significantly prolonged during treatment and returned to baseline levels 12 weeks after the end of treatment. Twenty-four of 376 patients with baseline QTc intervals <450 milliseconds experienced on-treatment QTc prolongation. Higher aspartate aminotransferase-to-platelet ratio index scores (≥0.76; odds ratio, 4.375; P = 0.005) and longer QTc intervals (≥416 milliseconds; odds ratio, 4.823; P = 0.003) at baseline were significantly associated with on-treatment QTc prolongation on multivariate analysis. Patients with cirrhosis showed significantly longer QTc intervals than those without cirrhosis during treatment but not at baseline, and they developed on-treatment QTc prolongation at a higher rate than patients without cirrhosis. No cardiovascular events occurred, except for 1 patient who developed paroxysmal supraventricular tachycardia. Conclusion: Newly developed QTc prolongation was observed in 6.4% of Japanese patients during treatment and was associated with more advanced fibrosis. (Hepatology Communications 2018; 00:000-000).

20.
Sci Rep ; 7: 41660, 2017 01 30.
Article in English | MEDLINE | ID: mdl-28134353

ABSTRACT

Resistance-associated substitutions (RASs) in hepatitis C virus (HCV) appear upon failure of treatment with direct-acting antivirals (DAAs). However, their origin has not been clarified in detail. Among 11 HCV genotype 1b patients who experienced virologic failure with asunaprevir (ASV)/daclatasvir (DCV), 10 had major NS5A L31M/V-Y93H variants after treatment. L31M/V-Y93H variants were detected as a minor clone before therapy in 6 patients and were the most closely related to the post-treatment variants by phylogenetic tree analysis in 4 patients. Next, to consider the involvement of a trace amount of pre-existing variants below the detection limit, we analysed human hepatocyte chimeric mice infected with DAA-naïve patient serum. L31V-Y93H variants emerged after treatment with ledipasvir (LDV)/GS-558093 (nucleotide NS5B inhibitor) and decreased under the detection limit, but these variants were dissimilar to the L31V-Y93H variants reappearing after ASV/DCV re-treatment. Finally, to develop an infection derived from a single HCV clone, we intrahepatically injected full-genome HCV RNA (engineered based on the wild-type genotype 1b sequence) into chimeric mice. A new Y93H mutation actually occurred in this model after LDV monotherapy failure. In conclusion, post-treatment RASs appear by 2 mechanisms: the selection of pre-existing substitutions among quasispecies and the generation of novel mutations during therapy.


Subject(s)
Drug Resistance, Viral/genetics , Hepacivirus/genetics , Mutation , Animals , Anti-Retroviral Agents/pharmacology , Carbamates , Evolution, Molecular , Hepacivirus/classification , Hepacivirus/drug effects , Hepatitis C/drug therapy , Hepatitis C/virology , Humans , Imidazoles/pharmacology , Imidazoles/therapeutic use , Isoquinolines/pharmacology , Isoquinolines/therapeutic use , Mice , Phylogeny , Pyrrolidines , Selection, Genetic , Sulfonamides/pharmacology , Sulfonamides/therapeutic use , Valine/analogs & derivatives
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