Transthyretin cardiac amyloidosis in aortic stenosis: Prevalence,diagnostic challenges,and clinical implications

Transthyretin cardiac amyloidosis (ATTR-CA) is a challenging and underdiagnosed cause of heart failure. Advances in cardiac imaging have enabled noninvasive diagnosis of ATTR-CA, causing the recent upsurge in disease awareness and detection. ATTR-CA has been increasingly recognized in patients with degenerative aortic stenosis (AS). With the growing number of elderly patients undergoing aortic valve intervention, the identification of ATTR-CA in this group of patients is of high clinical importance. Timely and correct diagnosis is essential for amyloid-directed therapies, as well as deciding on the AS treatment strategy. This review provides a comprehensive overview of the recent studies investigating coexistence of these two entities. We present the data on the prevalence of ATTR-CA in AS and their prognostic associations. As the diagnosis of ATTR-CA may be challenging, special attention is paid to the diagnostic utility of different imaging modalities, namely, echocardiography, cardiovascular magnetic resonance, nuclear imaging, and distinctive imaging features, in patients with dual pathology. We also present a flowchart summarizing integrated imaging in patients with suspected ATTR-CA.     

RNA-Seq analysis in an avian model of maternal phenylketonuria

Cardiac malformations (CVMs) are a leading cause of infant morbidity and mortality. CVMs are particularly prevalent when the developing fetus is exposed to high levels of phenylalanine in-utero in mothers with Phenylketonuria. Yet, elucidating the underlying molecular mechanism leading to CVMs has proven difficult. In this study we used RNA-Seq to investigate an avian model of MPKU and establish differential gene expression (DEG) characteristics of the early developmental stages HH10, 12, and 14. In total, we identified 633 significantly differentially expressed genes across stages HH10, 12, and 14. As expected, functional annotation of significant DEGs identified associations seen in clinical phenotypes of MPKU including CVMs, congenital heart defects, craniofacial anomalies, central nervous system defects, and growth anomalies. Additionally, there was an overrepresentation of genes involved in cardiac muscle contraction, adrenergic signaling in cardiomyocytes, migration, proliferation, metabolism, and cell survival. Strikingly, we identified significant changes in expression with multiple genes involved in Retinoic Acid (RA) metabolism and downstream targets. Using qRTPCR, we validated these findings and identified a total of 42 genes within the RA pathway that are differentially expressed. Here, we report the first elucidation of the molecular mechanisms of cardiovascular malformations in MPKU conducted at early developmental timepoints. We provide evidence suggesting a link between PHE exposure and the alteration of RA pathway. These results are promising and offer novel findings associated with congenital heart defects in MPKU.     

血清多肽谱在胃癌早期诊断中的应用价值

目的 寻找早期胃癌相关的血清标志物,并评价其诊断价值.方法 利用质谱联合纳米磁珠技术对433例胃癌患者（其中包括65例ⅠA期患者）和120名健康人群的血清多肽谱进行研究,用Biomarker Wizard软件筛选差异峰.将所有研究对象分为测试组（204例胃癌患者和70名健康人）和验证组（229例胃癌患者和50名健康人）.进一步用SPSS 12.0中ROC曲线分析差异峰,评价其灵敏度和特异性 并分析差异峰在不同分期的胃癌患者中分布情况.结果 通过42例胃癌患者和42名性别年龄匹配的健康人群血清比较筛选出13个差异峰（均P＜0.01）.在测试组和验证组中ROC曲线面积都在0.8以上的有2745、2768、6629、3402、6436 m/z 5个差异峰,同时鉴定出6629 m/z差异峰为甲状腺素运载蛋白.测试组分析显示,当6629 m/z取24.58这个截点时,可获得较高的诊断敏感度和特异度.验证组分析显示,6629 m/z总体诊断敏感度和特异度分别为65.5%和92.0%,对于ⅠA胃癌患者,其诊断敏感度为59.4%.结论 6629 m/z差异峰（甲状腺素运载蛋白）对于早期胃癌具有较高的诊断价值,有助于胃癌的早期筛查.     

Genetic testing improves identification of transthyretin amyloid (ATTR) subtype in cardiac amyloidosis

Amyloidosis is a group of conditions characterized by the accumulation of amyloid deposits in various tissues. Among these disorders, ATTR amyloidosis occurs either with or without a TTR pathogenic variant. Treatment for amyloidosis depends on the subtype, which is often identified through a tissue biopsy followed by liquid chromatography tandem mass spectrometry (LC–MS/MS). Genetic testing may be done to confirm these results for patients with ATTR amyloidosis; however, the necessity of genetic testing after LC–MS/MS has not been evaluated. A retrospective review identified 153 patients diagnosed with biopsy-proven ATTR amyloidosis, and 56 of these patients underwent both genetic testing and LC–MS/MS. LC–MS/MS and proteomics correctly reported the mutant peptide and heterozygosity in 47/56 (84%) cases. It failed to identify two individuals who were homozygous for the ATTRV122I mutation and failed to detect the following mutations in six other individuals: ATTRA19D, ATTRF44L, ATTRT60A, ATTRI68L and ATTRV122I. Therefore, LC–MS/MS is not sufficient to rule out a pathogenic mutation in cases of ATTR amyloid, and genetic testing should be performed in most cases of ATTR amyloidosis. Correct recognition of hereditary ATTR amyloidosis is important for estimating prognosis, proper familial counselling and guiding use of therapies, such as liver transplantation.     

Hereditary and acquired amyloid neuropathies

Amyloid neuropathies occur in a context of hereditary (FAP) or acquired amyloidosis. They present usually as severe and progressive polyneuropathy and carry a poor prognosis. Most FAP are associated with endoneurial deposits of variant transthyretin (TTR) with substitution of one aminoacid and are secondary to a point mutation of the TTR gene. Portugal is the main endemic area of TTR-FAP, secondary to point mutation of exon 2. However, around the world, 50 other TTR gene mutations have been recently reported, each one in few families. Genetic studies are useful for diagnosis of FAP in patients with a positive family history and for identification of the cause of seemingly sporadic cases. TTR gene analysis is also useful for genetic counselling including antenatal diagnosis in variants with early onset. Gelsolin-FAP are the second variety and present as a benign cranial and sensory polyneuropathy and affect essentially Finnish patients. Acquired amyloid neuropathy concerns only immunoglobulin light chain amyloidosis (AL) and are frequently associated with renal manifestations and monoclonal protein in serum or urine. Specific treatment of amyloid polyneuropathy varies with the variety of amyloidosis including liver transplantation in TTR-FAP, at the onset of the disease or chemotherapy for immunoglobulin light chain amyloidosis. Received: 8 March 2001 / Accepted: 12 March 2001     

Phenotypic heterogeneity in a family with FAP due to a TTR Leu58Arg mutation: a clinicopathologic study

A family with familial amyloid polyneuropathy (FAP) due to a transthyretin (TTR) Leu58Arg mutation was investigated clinicopathologically. The proband presented with sensorimotor-autonomic polyneuropathy and autopsy demonstrated massive amyloid deposition in the peripheral nerves and heart. However, the mother was characterized by carpal tunnel syndrome and ocular vitreous opacities. Thus, there was considerable phenotypic heterogeneity among family members despite the identical TTR genotype.     

Epidemiology of familial amyloid polyneuropathy in Japan: Identification of a novel endemic focus

BACKGROUND: Familial amyloid polyneuropathy (FAP) is distributed worldwide with several endemic foci including two major foci in Japan. OBJECTIVE: To elucidate a nationwide epidemiology of FAP in Japan. DESIGN, SETTING, AND PATIENTS: (i) We analyzed the data of FAP patients registered by the Ministry of Health, Labour, and Welfare, Japan, during 2003-2005. (ii) As Ishikawa prefecture was found to be a novel endemic focus, we examined 27 FAP patients in Ishikawa to characterize their clinical and genetic features in comparison with other endemic foci. RESULTS: (i) The prevalence of familial amyloidosis in Japan was estimated to be 0.87-1.1 per 1,000,000 persons. Nagano prefecture had the highest prevalence (11-15.5), followed by Kumamoto (10.1-10.3), and then Ishikawa (3.5-4.2). (ii) All the FAP patients in Ishikawa had transthyretin (TTR) type FAP; all the families had a TTR Val30Met mutation except one family with a Leu58Arg mutation. FAP with Val30Met mutation in Ishikawa was characterized by late onset, high penetrance, and moderate autonomic dysfunction. CONCLUSIONS: Ishikawa prefecture is the third endemic focus of FAP in Japan. FAP with TTR Val30Met mutation in Japan can be classified to (i) early-onset and endemic (Nagano and Kumamoto), (ii) late-onset and endemic (Ishikawa), and (iii) late-onset and non-endemic types.     

一个遗传性玻璃体淀粉样变性家系TTR基因的突变检测

目的 对1个遗传性玻璃体淀粉样变性家系进行致病基因分析.方法 采集该家系4个成员(包括临床确诊患者3例,无症状者1例)的外周静脉血,提取基因组DNA.PCR方法扩增TTR基因的4个外显子,产物直接测序进行基因突变检测,同时选择150名无亲缘关系的正常对照.结果 该家系的4例受检者中均检测到TTR基因第3外显子第103位密码子发生了G＞C(Gly103Arg)杂合突变,而150名正常对照中未发现相同的突变.结论 TTR基因Gly103Arg杂合突变可能与该家系遗传性玻璃体淀粉样变性的发病有关.     

Ultrastructural immunolabelling of amyloid fibrils in acquired and hereditary amyloid neuropathies

Both acquired and familial amyloid neuropathies carry a poor prognosis. In addition, amyloid is sometimes difficult to visualise in nerve biopsy specimens, and the pathogenesis of nerve lesions is still a matter of controversy. In order to learn more on the subject, we studied nerve specimens from seven patients with proven amyloid neuropathy by ultrastructural immunocytochemistry in order to better understand their pathogeny and to evaluate the reliability of the method for detection of amyloid antigens in the endoneurium. An indirect immunolabelling technique using protein A-gold complex (pA-g) was applied. Polyclonal antisera against human IgG, IgM, lambda and kappa light chains and prealbumin were assayed. Amyloid fibrils were labelled in six of seven cases: in four cases with anti-transthyretin (TTR) antibodies and in two with anti-lambda light chain antibodies. The type of immunolabelling correlated with the biochemical type of the amyloidosis as defined by TTR gene analysis and serum immunoelectrophoresis. The amyloid fibrils and gold labelling were always located in the endoneurial space. No intracellular deposit or labelling was found. The immunolabelling was highly specific, gold particles being detected only near to amyloid fibrils with no background gold labelling. Ultrastructural immunolabelling with pA-g could be used for detection of amyloid in progressive axonal neuropathy of unknown origin, with important therapeutic implications.