Makoto Shono

Long-term survival after liver transplantation in patients with familial amyloid polyneuropathy

Objective: Familial amyloid polyneuropathy (FAP), which is a fatal disorder inherited in an autosomal dominant fashion, is characterized by systemic accumulation of polymerized transthyretin (TTR) in the peripheral nerves and systemic organs. Liver transplantation has become an accepted treatment of this disorder because it stops the major production of amyloidogenic TTR. However, improved survival of transplant patients compared with that of nontransplant patients has not been sufficiently demonstrated. This study investigated whether transplantation improved the long-term outcome of patients by comparing the survival of patients who had transplantations with that of patients who had not had transplantations. Methods: Eighty consecutive patients with FAP Val30Met who visited Kumamoto University Hospital between January 1990 and December 2010 were studied. The transplant group consisted of 37 patients who had a partial hepatic graft via living donor transplantation in Japan or who underwent liver transplantation in Sweden, Australia, or the United States. The nontransplant group consisted of 43 patients with FAP. Survival was evaluated by using Kaplan-Meier analysis, and the difference in survival was examined via the log-rank test. Results: The transplant group had prolonged survival (p < 0.001) compared with the nontransplant group. The estimated probability of survival at 10 years was 56.1% for the nontransplant group vs 100% for the transplant group. Conclusion: Liver transplantation should be considered as an effective treatment in clinical management of patients with FAP Val30Met. Classification of evidence: This study provides Class III evidence that liver transplantation prolongs survival in patients with FAP Val30Met.

Clinicopathological features of senile systemic amyloidosis: an ante- and post-mortem study

Senile systemic amyloidosis is a common age-related amyloidosis that involves accumulation of wild-type transthyretin, with cardiac dysfunction being a predominant result. The importance of obtaining an accurate diagnosis of senile systemic amyloidosis has been increasingly recognized, so that novel treatments are being developed. However, the clinicopathological features of senile systemic amyloidosis remain to be completely understood. Here, we evaluated cardiac specimens from 181 consecutive post-mortem cases older than 40 years, including 6 cases of senile systemic amyloidosis, and 5 cases of familial amyloidotic polyneuropathy, which is a hereditary systemic amyloidosis caused by mutant forms of transthyretin. Furthermore, we studied ante-mortem clinicopathological findings of 11 senile systemic amyloidosis cases, in which 9 cases underwent gastrointestinal tract biopsy and/or subcutaneous tissue biopsy, at Kumamoto University Hospital. Of the autopsied cases of elderly Japanese (older than 80 years), 12% had senile systemic amyloidosis, with the percentage increasing with age. The occurrence of senile systemic amyloidosis in elderly Japanese patients was lower than that in previous reports, which suggests that a genetic background and/or environmental factor(s) may have important roles in the occurrence of senile systemic amyloidosis. Transthyretin amyloid deposits in familial amyloidotic polyneuropathy cases developed mainly in the pericardium and the surrounding muscle fascicles, whereas in cases with senile systemic amyloidosis the transthyretin amyloid deposits had a patchy plaque-like shape and developed mainly inside the ventricular wall. Biopsies from senile systemic amyloidosis patients evidenced amyloid deposits in 44% (4/9) of gastrointestinal tract and subcutaneous tissue samples combined. As myocardial biopsy may be dangerous for elderly people, the use of a combination of gastrointestinal tract and subcutaneous tissue biopsies may make diagnosis of senile systemic amyloidosis easier.

Sorafenib-induced acute myocardial infarction due to coronary artery spasm

A 65-year-old man with advanced renal cell carcinoma was admitted due to continuing chest pain at rest. Two weeks before his admission, sorafenib had been started. He was diagnosed with non-ST-elevation myocardial infarction by laboratory data and electrocardiogram. Enhanced heart magnetic resonance imaging also showed subendocardial infarction. However, there was no stenosis in coronary arteries on angiography. Coronary artery spasm was induced by a provocative test. Cessation of sorafenib and administration of Ca-channel blocker and nitrates ameliorated his symptoms, but relapse occurred after resumption of sorafenib. Addition of oral nicorandil reduced his symptoms and maintained stable angina status. We report the first case of sorafenib-induced coronary artery spasm. Sorafenib is a multikinase inhibitor that targets signaling pathways necessary for cellular proliferation and survival. On the other hand, the Rho/ROCK pathway has an important role in the pathogenesis of coronary artery spasm. Our report may show an adverse effect on the Rho/ROCK pathway by sorafenib use.

Transmission of circulating cell-free AA amyloid oligomers in exosomes vectors via a prion-like mechanism

Recent studies clearly demonstrated that several types of pathogenic amyloid proteins acted as agents that could transmit amyloidosis by means of a prion-like mechanism. Systemic AA amyloidosis is one of the most severe complications of chronic inflammatory disorders, particularly rheumatoid arthritis. It is well known that, similar to an infectious prion protein, amyloid-enhancing factor (AEF) acts as a transmissible agent in AA amyloidosis. However, how AEF transmits AA amyloidosis in vivo remained to be fully elucidated. In the present study, we focused on finding cell-free forms of AEF and its carriers in circulation by using the murine transfer model of AA amyloidosis. We first determined that circulating cell-free AEF existed in blood and plasma in mice with systemic AA amyloidosis. Second, we established that plasma exosomes containing AA amyloid oligomers derived from serum amyloid A had AEF activity and could transmit systemic AA amyloidosis via a prion-like mechanism. These novel findings should provide insights into the transmission mechanism of systemic amyloidoses.

East Asian Variant of Aldehyde Dehydrogenase 2 Is Associated With Coronary Spastic Angina Possible Roles of Reactive Aldehydes and Implications of Alcohol Flushing Syndrome

Background— Coronary spastic angina (CSA) is a common disease among East Asians, including Japanese. The prevalence of alcohol flushing syndrome associated with deficient activity of the variant aldehyde dehydrogenase 2 ( ALDH2*2 ) genotype is prevalent among East Asians. We examined whether CSA is associated with the ALDH2*2 genotype in Japanese. Methods and Results— The study subjects consisted of 202 patients in whom intracoronary injection of acetylcholine was performed by angiography on suspicion of CSA (119 men and 83 women; mean age, 66.2±11.4 years). They were divided into CSA (112 patients) and control groups (90 patients). ALDH2 genotyping was performed by the direct application of the TaqMan polymerase chain reaction system on dried whole blood. Clinical and laboratory data were examined using conventional methods. The frequencies of male sex, ALDH2*2 genotype carriers, alcohol flushing syndrome, tobacco smoking, and the plasma level of uric acid were higher ( P <0.001, P <0.001, P <0.001, P <0.001, and P =0.007, respectively) and the plasma high-density lipoprotein cholesterol levels were lower ( P <0.001) in the CSA group than in the control group. The multivariable logistic regression analysis revealed that ALDH2*2 genotype and smoking were significantly associated with CSA ( P <0.001 and P =0.024, respectively). Conclusions— East Asian variant ALDH2*2 genotypes and, hence, deficient ALDH2 activity were associated with CSA in Japanese. These data support further investigation of treatment targeting aldehydes for CSA. # CLINICAL PERSPECTIVE {#article-title-47}Background— Coronary spastic angina (CSA) is a common disease among East Asians, including Japanese. The prevalence of alcohol flushing syndrome associated with deficient activity of the variant aldehyde dehydrogenase 2 (ALDH2*2) genotype is prevalent among East Asians. We examined whether CSA is associated with the ALDH2*2 genotype in Japanese. Methods and Results— The study subjects consisted of 202 patients in whom intracoronary injection of acetylcholine was performed by angiography on suspicion of CSA (119 men and 83 women; mean age, 66.2±11.4 years). They were divided into CSA (112 patients) and control groups (90 patients). ALDH2 genotyping was performed by the direct application of the TaqMan polymerase chain reaction system on dried whole blood. Clinical and laboratory data were examined using conventional methods. The frequencies of male sex, ALDH2*2 genotype carriers, alcohol flushing syndrome, tobacco smoking, and the plasma level of uric acid were higher (P<0.001, P<0.001, P<0.001, P<0.001, and P=0.007, respectively) and the plasma high-density lipoprotein cholesterol levels were lower (P<0.001) in the CSA group than in the control group. The multivariable logistic regression analysis revealed that ALDH2*2 genotype and smoking were significantly associated with CSA (P<0.001 and P=0.024, respectively). Conclusions— East Asian variant ALDH2*2 genotypes and, hence, deficient ALDH2 activity were associated with CSA in Japanese. These data support further investigation of treatment targeting aldehydes for CSA.

The endothelial nitric oxide synthase gene -786T/C polymorphism is a predictive factor for reattacks of coronary spasm.

Objective We previously found a -786T/C polymorphism in the 5′-flanking region of the endothelial nitric oxide synthase (eNOS) gene and reported that this polymorphism is strongly associated with coronary spasm. In this study, we examined whether the polymorphism is a prognostic marker in coronary spasm patients. Methods and results We examined the clinical courses of 201 consecutive patients with coronary spasm who were admitted to our institution: 146 patients with the -786T/T genotype; 50 patients with the -786C/T genotype; and five patients with the -786C/C genotype. The mean follow-up period was 76±60 months. All the patients took calcium channel blockers and/or nitrate during the follow-up period. In this study, no patients died due to a cardiac event. About 25 patients were readmitted owing to cardiovascular disease. Out of these 25 patients, 23 patients were readmitted owing to a reattack of coronary spasm. The -786C allele was significantly associated with readmission due to coronary spasm (P=0.0072, odds ratio: 3.37 in the dominant effect). Kaplan–Meier analysis revealed that the occurrence of readmission was significantly higher in the patients with the -786C allele than in the patients without the -786C allele (P=0.0079). Further, multiple logistic regression analysis revealed that the -786T/C polymorphism was an independent predictor for readmission due to reattack of coronary spasm (P=0.006; relative risk=3.590). Conclusions The eNOS -786C allele is an independent risk factor for readmission due to a recurrent attack of coronary spasm in patients with coronary spasm, even if the patients have taken calcium channel blockers and/or nitrate.

Novel function of transthyretin in pancreatic alpha cells

Although transthyretin (TTR) is expressed in pancreatic alpha (glucagon) cells in the islets of Langerhans, the function of TTR in pancreatic alpha cells remains unknown. In this study, by using TTR knockout (TTR KO) mice, we determined the novel role of TTR in glucose homeostasis. We demonstrated that TTR KO mice evidenced impaired recovery of blood glucose and glucagon levels. Lack of TTR induced significantly lower levels of glucagon in the islets of Langerhans. These results suggest that TTR expressed in pancreatic alpha cells may play important roles in glucose homeostasis via regulating the expression of glucagon.

Cyclodextrin, a novel therapeutic tool for suppressing amyloidogenic transthyretin misfolding in transthyretin-related amyloidosis

TTR (transthyretin), a β-sheet-rich protein, is the precursor protein of familial amyloidotic polyneuropathy and senile systemic amyloidosis. Although it has been widely accepted that protein misfolding of the monomeric form of TTR is a rate-limiting step for amyloid formation, no effective therapy targeting this misfolding step is available. In the present study, we focused on CyDs (cyclodextrins), cyclic oligosaccharides composed of glucose units, and reported the inhibitory effect of CyDs on TTR amyloid formation. Of various branched β-CyDs, GUG-β-CyD [6-O-α-(4-O-α-D-glucuronyl)-D-glucosyl-β-CyD] showed potent inhibition of TTR amyloid formation. Far-UV CD spectra analysis showed that GUG-β-CyD reduced the conformational change of TTR in the process of amyloid formation. In addition, tryptophan fluorescence and 1H-NMR spectroscopy analyses indicated that GUG-β-CyD stabilized the TTR conformation via interaction with the hydrophobic amino acids of TTR, especially tryptophan. Moreover, GUG-β-CyD exerted its inhibitory effect by reducing TTR deposition in transgenic rats possessing a human variant TTR gene in vivo. Collectively, these results indicate that GUG-β-CyD may inhibit TTR misfolding by stabilizing its conformation, which, in turn, suppresses TTR amyloid formation.

Spinal multifocal amyloidosis derived from wild-type transthyretin

Abstract Spinal amyloidosis can occur as a part of systemic amyloidosis or as localized amyloidomas. However, the exact pathogenesis of the spinal amyloidosis remains to be fully understood. Transthyretin (TTR) is an amyloidogenic protein causing two kinds of amyloid diseases. One is senile systemic amyloidosis (SSA), which is caused by wild-type (WT) TTR and primarily affects cardiac functions. The other type is familial amyloidosis, which is mainly induced by mutated TTR. We report here the first case of multifocal spinal TTR amyloidosis derived from WT TTR with radiculomyelopathy and destructive spondylosis. The data and clinical manifestations suggest that the patient may develop SSA. Clinical manifestations of TTR-related amyloidosis may vary more than we previously thought. In spinal amyloidosis, WT TTR is one of the candidate precursor proteins for the disease.

Antibody therapy for familial amyloidotic polyneuropathy

Although it is believed that altered conformations exposing cryptic regions are intermediary and critical steps in the mechanism of transthyretin (TTR) amyloid formation, no effective therapy targeting this step is available. In this study, to establish the antibody therapy for familial amyloidotic polyneuropathy (FAP), we generated a monoclonal anti-TTR antibody, which specifically reacts with surface epitopes of TTR (MAb ATTR) and evaluated its binding affinity and specificity for TTR amyloid fibrils. MAb ATTR showed specific binding affinity for TTR amyloid fibrils, but not for native form of TTR. Moreover, MAb ATTR indeed showed the high consistency with Congo red positive areas in tissue specimens from FAP ATTR V30M patients, indicating that MAb ATTR showed binding affinity and specificity for TTR amyloid fibrils in vitro and in vivo. MAb ATTR may have a potential to suppress TTR amyloid deposition and become a candidate for the antibody therapy for FAP.