Systemic amyloidosis in transgenic mice carrying the human mutant transthyretin (Met 30) gene. Pathological and immunohistochemical similarity to human familial amyloidotic polyneuropathy, type I

To analyze the pathologic processes of amyloid deposition in type I familial amyloidotic polyneuropathy (FAP), mice were made transgenic by introducing the human mutant transthyretin (TTR) gene(MT-hMet 30). An inbred strain of mouse, C57 BL/6, was chosen. Transgenic mice were killed using ether anesthesia at 3-mo intervals up to 24 mo after birth. In these transgenic mice, amyloid deposition started in the gastrointestinal tract, cardiovascular system, and kidneys and extended to various other organs and tissues with advancing age. The pattern of amyloid deposition was similar to that observed in human autopsy cases of FAP, except for its absence in the choroid plexus and in the peripheral and autonomic nervous systems. We extracted the amyloid fibrils from kidneys of these mice with a human mutant TTR gene and analyzed them immunochemically and electronmicroscopically. Deposited amyloid was shown to be composed of human mutant TTR and mouse serum amyloid P component. Amyloid fibril from transgenic mice was morphologically and immunohistochemically similar to that of human FAP. The most striking pathologic feature of the transgenic mice was the absence of amyloid deposition in the peripheral and autonomic nervous tissues. Thus, other intrinsic factors may be involved in amyloid deposition in the nervous tissues of human FAP.

[Amyloidosis and hepatic amyloidosis]

The classification of amyloid and amyloidosis has undergone several revisions. The 1990 revision of the nomenclature at the 6th Internal Symposium on Amyloidosis in Oslo has been widely accepted and the basis for nomenclature and classification is the fibril protein making up the amyloid deposits. The liver is a major site of amyloid deposition in the disseminated form of the disease. Many studies have shown that the morphologic distribution of amyloid within the liver is not a reliable method for distinguishing AA from AL amyloidosis.

Secondary hypoplastic anemia in patients with familial amyloidotic polyneuropathy

The anemia of patients with familial amyloidotic polyneuropathy (FAP) was evaluated. Anemia was seen in 32 (91%) of the 35 FAP patients, more often with progression of the disease. The incidence of macrocytic hypochromic anemia was the most common type (40%). In 14 autopsied and 2 biopsied cases, no amyloid deposition was detected in the bone marrow. Thirteen (81%) of the 16 FAP patients showed hypoplastic bone marrow. Bone marrow aspiration of 2 patients revealed a decreased ratio of erythrocytic/myelocytic cells. The plasma levels of vitamin B12 and folate were within normal ranges. Neither oral nor intravenous administration of iron had any effect on the anemia of FAP patients. Intravenous erythropoietin elevated blood hemoglobin levels and blood pressure in 2 patients. Orthostatic hypotension, one of the most common symptoms of FAP, was unexpectedly improved. Secondary hypoplastic anemia is common in FAP, but treatment of anemia in this disease using erythropoietin is promising.

Effect of serum amyloid P component level on transthyretin-derived amyloid deposition in a transgenic mouse model of familial amyloidotic polyneuropathy

To elucidate the pathogenesis of amyloid deposition associated with familial amyloidotic polyneuropathy (FAP), we developed several transgenic mouse lines carrying the human mutant transthyretin (TTR) gene. We found that human TTR and mouse serum amyloid P component (SAP) are deposited as amyloid in tissues of these mouse lines. Because SAP is a major acute-phase reactant in mice, we asked whether repeated injections of Escherichia coli lipopolysaccharide (LPS) would enhance the amyloid deposition in one of these transgenic mouse lines. During the course of repeated LPS injections, serum levels of SAP in the transgenic mice remained between severalfold to about 50-fold higher than seen in the absence of stimulation. As no significant difference was detected in the onset, progression, and tissue distribution of TTR-derived amyloid (ATTR) deposition between the LPS-stimulated and unstimulated transgenic mice, the induction of SAP synthesis by acute inflammation probably does not affect the onset and extent of ATTR deposition.

Familial amyloidotic polyneuropathy: report of patients heterozygous for the transthyretin Gly42 gene

We studied 2 patients from a Japanese family with familial amyloidotic polyneuropathy (FAP). Their clinical features are similar to type 1 FAP, and the proband's rectal tissue contained amyloid that stained with antihuman transthyretin (TTR) antiserum. Direct DNA sequencing of the proband's TTR gene revealed a guanine-for-adenine substitution in the second base of codon 42, producing a glycine for glutamate substitution in the plasma protein.

A novel transthyretin mutation associated with familial amyloidotic polyneuropathy

We characterized the mutation associated with familial amyloidotic polyneuropathy in a Japanese patient. Sequence analysis of polymerase chain reaction-amplified exons of the transthyretin gene revealed a novel point mutation resulting in a substitution of arginine for glycine at position 47. The mutation was confirmed using allele-specific olgonucleotide hybridization procedures. This most likely represents a de novo mutation since neither parent carries the mutant allele.

Disturbed metabolism of glucose and related hormones in familial amyloidotic polyneuropathy: hypersensitivities of the autonomic nervous system and therapeutic prevention

Regulation of glucose metabolism was evaluated by oral glucose tolerance test (OGTT) in patients with familial amyloidotic polyneuropathy (FAP). Upon oral administration of a loading dose of glucose, plasma levels of glucose, insulin and glucagon changed abnormally in all FAP patients tested. Although plasma levels of glucose and insulin in the fasted patients were within normal ranges, 33% of FAP patients showed hypoglycemia after transient hyperinsulinemia during the examination. Furthermore, another three patients showed transient hypoglycemia during their daily life. Thus, perturbed glucose metabolism should be taken into account for treating patients with FAP. The salivary glands as well as the lacrimal glands showed transient hypersecretion after chewing a gum. Histochemical analysis at autopsy revealed significant amyloid deposition in the stroma, nerves and vessels of the pancreas, but not in Langerhans islets. Similar appearance was recognized in the salivary glands. These results suggest that denervation supersensitivity might occur not only in the exocrine glands but also in the endocrine gland.

Familial amyloidotic polyneuropathy type 1 in Kumamoto, Japan: a clinicopathologic, histochemical, immunohistochemical, and ultrastructural study

Seventeen autopsy and five biopsy cases of familial amyloidotic polyneuropathy were examined clinicopathologically, histochemically, immunohistochemically, and ultrastructurally. In the autopsy cases, amyloid deposits were predominant in the peripheral nerve tissues, autonomic nervous system, choroid plexus, cardiovascular system, and kidneys. Amyloid involvements in the anterior and posterior roots of the spinal cord, spinal ganglia, thyroid, and gastrointestinal tract were also frequent. In the cardiac conduction system, amyloid deposition was prominent in the sinoatrial node and in limbs of the intraventricular bundle. In the sural nerve biopsy, besides amyloid deposits, degenerative changes of nerve fibers and Schwann cells were detected ultrastructurally, and the morphometric analysis showed a marked reduction in the number of myelinated fibers which correlated with the clinical stage. Amyloid deposits were resistant to pretreatment with potassium permanganate in Congo red staining, and transthyretin was confirmed immunohistochemically as a major component of amyloid deposits, along with the presence of serum amyloid P-component. Besides the amyloid deposits, transthyretin was proven in the liver cells, epithelial cells of the choroid plexus, and pancreatic islet A cells, suggesting that the transthyretin produced by these cells is secreted, transferred into tissues, and deposited in situ as the major component of amyloid in this disorder.

Systemic amyloidosis in transgenic mice carrying the human mutant transthyretin (Met30) gene. Pathologic similarity to human familial amyloidotic polyneuropathy, type I

To analyze the pathologic processes of amyloid deposition in type I familial amyloidotic polyneuropathy (FAP), mice were made transgenic by introducing the human mutant transthyretin (TTR) gene. In these transgenic mice, amyloid deposition started in the gastrointestinal tract, cardiovascular system, and kidneys 6 months after birth and extended to various other organs and tissues with advancing age. At age 24 months, the pattern of amyloid deposition was similar to that observed in human autopsy cases of FAP, except for its absence in the choroid plexus and in the peripheral and autonomic nervous systems. Amyloid deposition was shown to be composed of human mutant TTR and, in addition, mouse serum amyloid P component. These results clearly indicate that human variant TTR produced in transgenic mice deposits is a major component of amyloid fibrils in various organs and tissues. Thus this animal model is useful for analyzing how amyloid deposition initiates and proceeds in FAP.

Role of serum amyloid P component for systemic amyloidosis in transgenic mice carrying human mutant transthyretin gene

The role of serum amyloid P component (SAP) for systemic amyloidosis in a transgenic mouse model for an autosomal dominant disease, familial amyloidotic polyneuropathy (FAP), was examined. For this purpose, two lines of transgenic mouse were produced by introducing the human mutant transthyretin (TTR) gene and the human SAP gene, respectively. Two lines of transgenic mice were mated to produce double transgenic mice carrying both human mutant TTR gene and human SAP gene. The serum concentration of human SAP in these transgenic mice was about 42 micrograms/ml and was about equal to that in human control serum. In case of single transgenic mice carrying human mutant TTR gene, amyloid deposition starts at around 6 months of age, and the amount of amyloid deposition increases gradually with age. Amyloid deposition is observed in many tissues including heart, kidney and thyroid gland, where amyloid deposition is commonly observed in FAP patients. In double transgenic mice, onset, progression and tissue distribution of amyloid deposition were the same as those in single transgenic mouse. These results clearly suggest that SAP is not important for the initiation and progression of amyloid deposition.

Transgenic mouse model of familial amyloidotic polyneuropathy

Familial amyloidotic polyneuropathy (FAP) is a dominantly inherited disorder, characterized by the extracellular deposition of amyloid fibrils composed of variant transthyretin (TTR), and by prominent peripheral nerve involvement. We demonstrate that the main cause of this disease is the presence of a point mutation in the TTR gene. However, neither the time of onset nor the clinical course is predictable. To elucidate the molecular pathogenesis of this disease, we constructed transgenic mice carrying and expressing the human mutant TTR gene. In these mice, amyloid is deposited in the alimentary tract as early as age six months, and becomes more remarkable with aging. These transgenic mice should be useful in elucidating factors which modulate the time of onset and the clinical course of FAP, and in establishing therapy for this intractable disorder.

[A case of motor and sensory neuropathy with elevated serum lactate and pyruvate which responded to large dose of coenzyme Q10 therapy]

A 16-year-old high school male student was admitted to our hospital with complaints of difficulty in walking and muscle atrophy of the lower legs. He noticed his gait disturbance when he was about 12 years old and his symptoms had gradually increased. On examination, he was unable to walk on his heels and on his toes. He had mild pes cavus and marked muscle wastes of the lower legs. The weakness was limited to the feet, lower legs, and hands. Mild sensory losses were demonstrated inside of the feet. Autonomic dysfunction was not present. The deep tendon reflexes were diminished. Nerves were not enlarged or excessively firm. On laboratory examinations, pyruvate and lactate were elevated in both serum and cerebrospinal fluid. The serum level of coenzyme Q10 (CoQ10) was low (0.57 micrograms/ml). Nerve conduction velocities were normal or just below normal except sural nerves and amplitudes of M waves were decreased. The sural nerve finding revealed marked reduction in number of large myelinated fibers and no onion bulb formation. The teased myelinated fiber analysis suggested ongoing axonal degeneration. Electron microscopy showed no mitochondrial abnormalities in muscle and nerve. The therapeutic trial of large dose of CoQ10 (120 mg/day) was dramatically effective to muscle weakness and atrophy at about third week after therapy. His gait disturbance disappeared after about 16 months. These findings may indicate an alteration of mitochondrial function in this case.

[A case of malignant rheumatoid arthritis with severe peripheral neuropathy]

A 72-year-old woman of definite type of malignant rheumatoid arthritis (MRA) with severe peripheral neuropathy. She has often noted pain of both shoulders or knee joints since some years ago. At the age of 71, she noticed numbness of the feet with pain and swelling of knee joints. She was diagnosed as definite type of rheumatoid arthritis by one podiatrist. Although she took some medications, she subsequently developed general fatigue, appetite loss, exacerbation of arthritis, drop feet and hands with prominent coldness. She was admitted to our hospital on March 22, 1985. On examination, she revealed purpura, decubitis, heart murmur, arthritis of knee joints, and fingers necrosis with skin ulcer. She had severe muscle weakness, and wasting of four limbs. Moderate impairment of all-modality sensations were noted in all extremities. Distal involvement was greater than proximal. Laboratory data during administration of prednisolone (60 mg/day) were as follows: glucose in urine, 2+; occult blood in urine, 1+; white blood cells count, 18600 with 92% polymorphonuclear leukocytes; erythrocyte sedimentation rate, 60 mm in an hour; CRP, 14.62 mg/dl (normal 0.5 greater than); RA test, 2+; RAHA, 10240; CH50, 10 U/ml (normal 32-42); C3, 37 mg/dl (normal 55-75); C4, 9 mg/dl (normal 15-28); immune complex, 4.4 micrograms/ml (normal 3.0): Chest X-ray film showed cardiomegaly (CTR, 57%). ECG disclosed atrial premature contraction, and echo cardiography suggested epicarditis with aortic valve insufficiency. 99mTc RI angiogram revealed impairment of peripheral circulation. SCV on sural nerve was not elicited. Sural nerve biopsy showed obliterans type of endoarteritis and axonal degeneration with loss of myelinated fiber.

Complicating systemic amyloidosis in dystrophic epidermolysis bullosa, recessive type

An autopsy case of dystrophic epidermolysis bullosa, recessive type, complicated by systemic secondary amyloidosis is described. The patient had developed multiple bullous lesions and erosions from birth, followed by repeated infection. At autopsy, chronic persistent inflammation was observed in the skin and in various visceral organs, accompanied by systemic amyloidosis. By the peroxidase-antiperoxidase (PAP) method, amyloid deposits stained positively for anti-AA-protein antiserum. In the present case, we concluded that the systemic amyloidosis was of the AA type, and developed secondarily to the chronic persistent inflammation in the prolonged course of dystrophic epidermolysis bullosa, recessive type.

Infant visual habituation as a function of exposure time and stimulus similarity

The course of visual response integration was examined in four-month-old infants (N = 32 boys and girls) by presenting a bull's eye pattern pair and a striped pattern pair on a single display board. On the basis of Jeffrey's serial habituation hypothesis it was predicted that in the early period of exposure the infant's scanning behavior would be limited to two like pairs, but that as attention waned to the similar pairs one or more of the less preferred stimuli would be integrated into the attending response. A measure of three consecutive looks indicated that attention confined to one similar pair decreased significantly over time, whereas the initially lower three-look sequences to two similar and one dissimilar stimuli increased significantly.