Systemic amyloidosis

Insights into the interaction and inhibitory action of palmatine on lysozyme fibrillogenesis: Spectroscopic and computational studies

Interaction under amyloidogenic condition between naturally occurring protoberberine alkaloid palmatine and hen egg white lysozyme was executed by adopting spectrofluorometric and theoretical molecular docking and dynamic simulation analysis. In spetrofluorometric method, different types of experiments were performed to explore the overall mode and mechanism of interaction. Intrinsic fluorescence quenching of lysozyme (Trp residues) by palmatine showed effective binding interaction and also yielded different binding parameters like binding constant, quenching constant and number of binding sites. Synchronous fluorescence quenching and 3D fluorescence map revealed that palmatine was able to change the microenvironment of the interacting site. Fluorescence life time measurements strongly suggested that this interaction was basically static in nature. Molecular docking result matched with fluorimetric experimental data. Efficient drug like interaction of palmatine with lysozyme at low pH and high salt concentration prompted us to analyze its antifibrillation potential. Different assays and microscopic techniques were employed for detailed analysis of lysozyme amyloidosis.Thioflavin T(ThT) assay, Congo Red (CR) assay, 8-anilino-1-naphthalenesulfonic acid (ANS) assay, Nile Red (NR) assay, anisotropy and intrinsic fluorescence measurements confirmed that palmatine successfully retarded and reduced lysozyme fibrillation. Dynamic light scattering (DLS) and atomic force microscopy (AFM) further reiterated the excellent antiamyloidogenic potency of palmatine.

Atypical Presentation of Amyloidosis in a Female Patient with Muscle Weakness

Muscle involvement represents a well-recognized but rare manifestation of amyloidosis. Here, we report a 40-year-old female who presented with muscle weakness, musculoskeletal pain, and proteinuria, which was eventually diagnosed as myopathic amyloidosis based on muscle biopsy results. A multidisciplinary approach appears to be the cornerstone of the diagnostic work up for recognizing the unusual amyloid myopathy.

Comparing neuropathy in multiple myeloma and AL amyloidosis

Peripheral neuropathy (PN) is frequent in patients with monoclonal gammopathy due to plasma cell dyscrasia, but little is known about the comparative impact of nerve dysfunction in different disorders. We compared clinical and laboratory results between two diagnostic groups. We recruited 76 untreated multiple myeloma (MM) and 27 AL amyloidosis (ALA) patients for evaluation of symptoms, clinical findings and nerve conduction studies (NCS). We diagnosed significant PN using total neuropathy scores (TNS > 7) in 17.6% of MM and 48.1% of ALA patients and in 27.7% of MM and 35.7% of ALA patients using NCS findings. TNS score grades were significantly higher in the AL amyloidosis patients (Fisher's exact test: P = .02) but a NCS based PN diagnosis was not significantly different (Fisher's exact test: P = .13). A significantly higher TNS vibration (P = .04) and pin (P = .02) sensory sign and TNS reflex (P = .04) sign score was found in amyloidosis patients. Likewise, quantitative sensory thresholds for vibration was higher in amyloidosis patients (Welsh ANOVA: P = .01). NCS revealed signs of more frequent axonal tibial neuropathy with significantly lower motor response amplitudes (P = .02) and resulting higher TNS scores (P = .002), while sural nerve sensory response amplitudes were without significant difference (P = .86). We found more severe TNS grades of PN in AL amyloidosis patients compared with MM patients. We also found higher sensory symptoms scores and higher thresholds for vibration but similar sensory involvement using NCS. The NCS exclusively showed signs of an axonal neuropathy.

Amyloidosis: diagnosis and new therapies for a misunderstood and misdiagnosed disease

Amyloidosis is a group of diseases characterized by extracellular deposition of amyloid fibril complexes. Fibril deposition results in organ dysfunction and possible failure. Amyloidosis is regarded as a rare disease, but in general is underdiagnosed. The two main types of systemic amyloidosis are immunoglobulin light chain and transthyretin amyloidosis. The increased availability of noninvasive cardiac imaging, genetic testing and improved laboratory assays and protein identification methods have led to increased diagnosis. However, in many cases, the diagnosis is not made until the patient develops organ impairment. Earlier diagnosis is required to prevent irreversible organ failure. Novel treatments for immunoglobulin light chain and transthyretin amyloidosis that halt disease progression, prolong and increase quality of life have recently become available.

Systemic Amyloidosis and Cardiac Autonomic Neuropathy Associated with Waldenstrom's Macroglobulinemia

A 73-year-old male with long-standing Waldenstrom's macroglobulinemia complicated with systemic amyloidosis presented with a witnessed syncopal episode. He had complaints of orthostatic dizziness and palpitations for few months. Orthostatic hypotension and peripheral neuropathy were demonstrated on physical examination. EKG, 24-hour Holter monitoring, and 2D echocardiogram were unremarkable. MRI of the brain ruled out stroke. Patients with amyloidosis can develop cardiovascular disease through amyloid cardiomyopathy, small vessel disease, conduction defects, pericardial effusion, or autonomic denervation. After ruling out other life-threatening causes, Ewing's battery of tests was done to rule out cardiac autonomic neuropathy. Two heart rate tests and one blood pressure test were abnormal which indicated severe cardiac autonomic neuropathy. Cardiac autonomic neuropathy can mask symptoms of acute coronary syndrome and hence early diagnosis using the simple bedside maneuver is beneficial. The test is also important for prognostication. Absence of augmentation of cardiac output from inadequate autonomic stimulation will lead to postural hypotension, exercise intolerance, and tachycardia. There may be no change in heart rate with Valsalva or deep breathing both of which increase parasympathetic tone. As the condition progresses, it may result in cardiac denervation which can result in silent myocardial infarction, syncope, and sudden death.

Paraproteinemic neuropathy: a practical review

The term paraproteinemic neuropathy describes a heterogeneous set of neuropathies characterized by the presence of homogeneous immunoglobulin in the serum. An abnormal clonal proliferation of B-lymphocytes or plasma cells, which may or may not occur in the context of a hematologic malignancy, produces the immunoglobulins in excess. If malignancy is identified, treatment should be targeted to the neoplasm. Most cases, however, occur as monoclonal gammopathy of undetermined significance. Few prospective, randomized, placebo-controlled trials are available to inform the management of paraproteinemic neuropathies. Clinical experience combined with data from smaller, uncontrolled studies provide a basis for recommendations, which depend on the specific clinical setting in which the paraprotein occurs. In this review, we provide a clinically practical approach to diagnosis and management of such patients.

Association of skin with the pathogenesis and treatment of neurodegenerative amyloidosis

Amyloidosis are a large group of conformational diseases characterized by abnormal protein folding and assembly which results in the accumulation of insoluble protein aggregates that may accumulate systemically or locally in certain organs or tissue. In local amyloidosis, amyloid deposits are restricted to a particular organ or tissue. Alzheimer’s, Parkinson’s disease, and amyotrophic lateral sclerosis are some examples of neurodegenerative amyloidosis. Local manifestation of protein aggregation in the skin has also been reported. Brain and skin are highly connected at a physiological and pathological level. Recently several studies demonstrated a strong connection between brain and skin in different amyloid diseases. In the present review, we discuss the relevance of the “brain–skin connection” in different neurodegenerative amyloidosis, not only at the pathological level, but also as a strategy for the treatment of these diseases.

Vitreous amyloidosis in two large mainland Chinese kindreds resulting from transthyretin variant Lys35Thr and Leu55Arg

OBJECTIVE

To describe the clinical and pathological findings of two large mainland Chinese kindreds with vitreous amyloidosis and associated transthyretin mutation.

METHODS

Twenty individuals from two kindreds with vitreous amyloidosis were ascertained. The transtheretin (TTR) gene of each individual was analyzed, and a clinical examination was obtained on the index patient.

RESULTS

Vitreous amyloidosis and radiculopathy were the significant findings in affected individuals. Vitrectomy was performed on the severely affected individuals, with resulting postoperative visual acuity of 20/80 to 20/25. Congo red staining demonstrated amyloid in the vitreous specimen. In Case A, DNA sequencing of exon 2 in the TTR gene revealed a base-pair substitution at codon 35, AAG > ACG (Lys35Thr). In Case B, a missense mutation of leucine-to-arginine substitution was identified at amino acid position 55 in exon 3, CTG > CGG (Leu55Arg).

CONCLUSIONS

TTR Lys35Thr and Leu55Arg mutations are associated with vitreous amyloidosis. The phenotype is variable, with vitreous opacities occurring earlier, and sometimes as the sole signs of amyloidotic polyneuropathies (FAPs). Vitrectomy improves vision in some patients with vitreous amyloidosis.

The neuromuscular manifestations of amyloidosis

Amyloidosis is a systemic disease that may be acquired or hereditary and which results in the deposition of amyloid fibrils in a variety of tissues causing their progressive dysfunction. Although the clinical presentation often is dominated by cardiac or renal failure, peripheral neuropathy may be a significant or the initial manifestation, resulting in presentation to the neurologist. Diagnosis often is challenging and may require multiple diagnostic procedures, including more than one biopsy. Acquired and hereditary amyloidosis can be definitively distinguished from one another only by immunohistochemical staining or molecular genetic testing. Treatment remains a challenge, although chemotherapy and autologous stem cell transplantation offer hope for those with primary systemic amyloidosis, whereas liver transplantation is effective for some forms of hereditary amyloid neuropathy. Much less commonly, myopathy may be a clinically significant manifestation of amyloidosis.

Amyloid myopathy: a diagnostic challenge

Amyloid myopathy (AM) is a rare manifestation of primary systemic amyloidosis (AL). Like inflammatory myopathies, it presents with proximal muscle weakness and an increased creatine kinase level. We describe a case of AL with severe, rapidly progressive myopathy as the initial symptom. The clinical manifestation and muscle biopsy were suggestive of inclusion body myositis. AM was not suspected until amyloidosis was seen in the gastric mucosal biopsy. The muscle biopsy was then re-examined more specifically, and Congo red staining eventually showed vascular and interstitial amyloid accumulation, which led to a diagnosis of AM. The present case illustrates the fact that the clinical picture of AM can mimic that of inclusion body myositis.

Biochemical characterisation of amyloid by endomyocardial biopsy

Cardiomyopathy is a major cause of death in patients with systemic amyloidosis. There are several forms of systemic amyloidosis which cause cardiomyopathy and determination of the exact type of amyloid in each affected patient is essential for treatment and determination of prognosis. In this study, we tested the feasibility of determining the type of amyloidosis by biochemical analysis of endomyocardial biopsies. Right ventricular endomyocardial biopsies were obtained from 10 patients with restrictive cardiomyopathy. Three patients had monoclonal protein demonstrated in serum or urine and all three had bone marrow findings consistent with monoclonal gammopathy. Seven patients had isolated cardiomyopathy without evidence of monoclonal gammopathy. A portion of each myocardial biopsy was submitted for histologic evaluation and all demonstrated amyloid by Congo red staining. Each biopsy was analysed biochemically by isolation of amyloid fibrils and the protein characterised by amino acid sequence analysis. Four amyloid isolates were characterised as immunoglobulin light chain proteins. Two specimens obtained from patients with transthyretin (TTR) DNA mutations contained TTR peptides proving the hereditary nature of the disease. Biopsies from four patients without a TTR mutation contained TTR and were consistent with the diagnosis of senile cardiac amyloidosis (SCA). All endomyocardial biopsy specimens that were analysed had sufficient amyloid fibril subunit protein to allow characterisation by amino acid sequence analysis. This methodology is particularly useful in differentiating SCA with TTR amyloid fibrils from immunoglobulin light chain amyloidosis which also occurs in the elderly age group.

The molecular biology and clinical features of amyloid neuropathy

Neuropathy is often a major manifestation of systemic amyloidosis. It is most frequently seen in patients with hereditary transthyretin (TTR) amyloidosis, but is also present in 20% of patients with systemic immunoglobulin light chain (primary) amyloidosis. Familial amyloid polyneuropathy (FAP) is the most common form of inherited amyloidotic polyneuropathy, with clinical and electrophysiologic findings similar to neuropathies with differing etiologies (e.g., diabetes mellitus). Hereditary amyloidosis is an adult-onset autosomal-dominant disease with varying degrees of penetrance. It is caused by specific gene mutations, but demonstration that a patient has one such mutation does not confirm the diagnosis of amyloidosis. Diagnosis requires tissue biopsy with demonstration of amyloid deposits either by special histochemical stains or electron microscopy. Transthyretin amyloidosis is treated by liver transplantation, which eliminates the mutated transthyretin from the blood, but for some patients continued amyloid deposition can occur from wild-type (normal) transthyretin. Presently, a study is ongoing to determine whether amyloid deposition can be inhibited by small organic molecules that are hypothesized to affect the fibril-forming ability of transthyretin. Proposed gene therapy with antisense oligonucleotides (ASOs) to suppress hepatic transthyretin synthesis is effective in a transgenic mouse model but has not yet been tested in humans.

The differentiation and stress response factor XBP-1 drives multiple myeloma pathogenesis

Multiple myeloma (MM) evolves from a highly prevalent premalignant condition termed MGUS. The factors underlying the malignant transformation of MGUS are unknown. We report a MGUS/MM phenotype in transgenic mice with Emu-directed expression of the XBP-1 spliced isoform (XBP-1s), a factor governing unfolded protein/ER stress response and plasma-cell development. Emu-XBP-1s elicited elevated serum Ig and skin alterations. With age, Emu-xbp-1s transgenics develop features diagnostic of human MM, including bone lytic lesions and subendothelial Ig deposition. Furthermore, transcriptional profiles of Emu-xbp-1s lymphoid and MM cells show aberrant expression of known human MM dysregulated genes. The similarities of this model with the human disease, coupled with documented frequent XBP-1s overexpression in human MM, serve to implicate XBP-1s dysregulation in MM pathogenesis.

Autonomic Peripheral Neuropathy

Most generalized peripheral polyneuropathies are accompanied by clinical or subclinical autonomic dysfunction. There is a group of peripheral neuropathies in which the small or unmyelinated fibers are selectively targeted. In these neuropathies, autonomic dysfunction is the most prominent manifestation. The features associated with an autonomic neuropathy include impairment of cardiovascular, gastrointestinal, urogenital, thermoregulatory, sudomotor, and pupillomotor autonomic function.

Paraproteinemic neuropathies

Paraproteinemic neuropathies comprise a diverse group of disorders that includes monoclonal gammopathy of undetermined significance, primary amyloidosis, multiple myeloma, cryoglobulinemia, POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal protein and skin changes) syndrome, and Waldenstrom macroglobulinemia. Various factors including hepatitis C virus, vascular endothelial growth factor, and an array of cytokines are implicated in the pathogenesis of these conditions. More recently, a variety of novel antibody specificities, and vasculitis, have also been described as contributory factors in the development of these neuropathies. Therapeutic approaches for paraproteinemic neuropathies have included administration of cytotoxic agents, steroids, interferon-alpha, intravenous immunoglobulin, radiation, bone marrow transplantation, and more recently, drugs such as rituximab and bevacizumab. In this article, we review some of the well-known features of these diseases, and highlight some of the more recent findings from the vast literature for these diseases.

Autonomic peripheral neuropathy

The autonomic neuropathies are a group of disorders in which the small, lightly myelinated and unmyelinated autonomic nerve fibres are selectively targeted. Autonomic features, which involve the cardiovascular, gastrointestinal, urogenital, sudomotor, and pupillomotor systems, occur in varying combination in these disorders. Diabetes is the most common cause of autonomic neuropathy in more developed countries. Autonomic neuropathies can also occur as a result of amyloid deposition, after acute infection, as part of a paraneoplastic syndrome, and after exposure to neurotoxins including therapeutic drugs. Certain antibodies (eg, anti-Hu and those directed against neuronal nicotinic acetylcholine receptor) are associated with autonomic signs and symptoms. There are several familial autonomic neuropathies with autosomal dominant, autosomal recessive, or X-linked patterns of inheritance. Autonomic dysfunction can occur in association with specific infections. The availability of sensitive and reproducible measures of autonomic function has improved physicians' ability to diagnose these disorders.

The hereditary amyloidoses

Hereditary amyloidosis is, in general, a systemic condition related to multiple organ system involvement by beta-structured protein deposits. As such, it often mimics the more common forms of systemic amyloidosis: immunoglobulin light chain (AL, primary) and reactive (AA, secondary). The challenge diagnostically is to recognize hereditary amyloidosis as a distinct entity and then to determine the specific type of genetic disease. There are several types of hereditary amyloidosis and precise diagnosis is essential for proper therapy and genetic counselling. This chapter strives to present the subject of hereditary amyloidosis in a way which facilitates understanding of the disease, of the means for diagnosis, of the present and possible future therapies, and of the importance of combined basic and medical research.

Atypical presentations of primary amyloid neuropathy

Primary amyloidosis (AL) may be complicated by peripheral neuropathy in 15-35% of cases. We report on four patients with atypical neurological presentations of AL neuropathy, whose diagnoses were delayed due to varied clinical presentations. The clinical presentation included painful sensory neuropathy (two patients), mononeuropathy multiplex (one patient), and primary demyelinating polyneuropathy (one patient). The latter two types of presentation have not been reported previously. The diagnosis was established by fat pad biopsy in two patients, lymph node biopsy in one, and sural nerve biopsy in one. Two patients were treated with high-dose melphalan followed by stem cell rescue, and one was treated with oral melphalan and prednisone. All three cases experienced stabilization of neuropathic symptoms. We report these cases in order to raise awareness of the varied clinical presentation of AL neuropathy.

Endothelial dysfunction precedes C-fiber abnormalities in primary (AL) amyloidosis

Primary (AL; immunoglobulin light-chain associated) amyloidosis is characterized by the deposition of pathological proteins in the extracellular matrix of tissues and organs. Autonomic and sensory peripheral neuropathy is a common feature of this disorder. The pathogenesis of the neuropathy is poorly defined. The aims of this study were to investigate vascular and neural function in the cutaneous microcirculation of AL amyloidosis patients. Seven patients with AL amyloidosis and controls were studied. Acetylcholine and sodium nitroprusside were iontophoresed into the forearm skin. Endothelial, smooth muscle, and C-fiber-mediated cutaneous blood flow (CuBF) were recorded by laser Doppler flowmetry. Endothelial vasodilation in the forearm skin was attenuated in AL amyloidosis patients (p = 0.007). Maximum endothelium-mediated CuBF in the patient group was reduced (p = 0.047). No group differences could be detected in the C-fiber response or smooth muscle vasodilation (p value not significant). Maximum C-fiber and endothelium-independent CuBF did not differ between the two groups (p value not significant). Early in the disease, AL amyloidosis patients present with impaired endothelial function. At this stage, C-fiber and smooth muscle function are still preserved. These data suggest that endothelial abnormalities precede and may contribute to the pathogenesis of the neuropathy associated with AL amyloidosis.

Symptomatic ischemic heart disease resulting from obstructive intramural coronary amyloidosis

PURPOSE

Obstructive intramural coronary amyloidosis is an unusual complication of systemic amyloidosis.

SUBJECTS AND METHODS

We review the characteristics of 11 patients seen at the Mayo Clinic (Rochester, Minnesota) from January 1, 1960, to June 1, 1999, with intramural cardiac amyloidosis diagnosed at autopsy or after examination of an explanted heart.

RESULTS

Symptomatic ischemic heart disease resulting from obstructive intramural coronary amyloidosis was found in 11 patients (8 men, 3 women). The mean (+/-SD) age at the diagnosis of primary amyloidosis was 62 +/- 12 years. All patients had angina pectoris; angina was the presenting symptom of primary amyloidosis in 6 patients. Unstable coronary syndromes occurred in 7 patients and congestive heart failure in 8. New electrocardiographic abnormalities after the development of angina were common and included ischemic changes, bundle branch block, and dysrhythmias. Low voltage was seen in only 2 patients. All 7 patients who underwent coronary angiography had normal or clinically insignificant findings. Endomyocardial biopsy was performed on 4 patients; amyloid was found in 3 patients, none of whom had obstructive intramural coronary amyloidosis. The diagnosis of obstructive intramural coronary amyloidosis with associated myocardial injury was established only at autopsy or after examination of the explanted heart after cardiac transplantation. The mean time to death or cardiac transplantation after symptoms of cardiac ischemia developed was 18 +/- 20 months.

CONCLUSIONS

The diagnosis of ischemic heart disease resulting from obstructive intramural coronary amyloidosis is difficult to establish before death or cardiac transplantation. Although the condition has a poor prognosis, its accurate recognition may have therapeutic implications, because some patients may benefit from treatment, including systemic chemotherapy or cardiac transplantation.

Cutaneous manifestations of cancer

The appearance of skin lesions in patients with occult or obvious malignancy may be of extreme value in the detection and management of cancer because the skin is readily accessible to examination and biopsy. Examination of the skin of our patients can provide important insights into underlying malignant processes or possible complications from cancer treatment. The range of cutaneous abnormalities is wide, and include cutaneous paraneoplastic syndromes such as xanthomas, acanthosis nigricans, carcinoid syndrome, unusual erythematous eruptions such as erythema gyratum repens, and a number of genetic syndromes associated with malignancies and inherited dermatoses.

Twenty-one years survival with systemic AL-amyloidosis

AL-amyloidosis has a poor prognosis, typically with cardiac or renal failure ensuing some months after diagnosis. However, sporadically there have been reports of long-term survivors, either with unusual manifestations of amyloidosis, or after concerted chemotherapy to suppress the overt or occult pathological monoclonal plasma cell population responsible for the elaboration of immunoglobulin light chains. We report the case of a 46-year-old man who has survived 21 years after the histological diagnosis of renal amyloidosis was made, after he had presented with severe nephrotic syndrome. This patient was given intensive chemotherapy but came to end-stage renal failure some 10 years later, was dialysed for 1 year, and then was the successful recipient of a cadaveric renal transplant, which is working excellently some 10 years later, with little evidence of recurrent renal or systemic amyloidosis. There is renewed interest in therapy for systemic amyloidosis, and this case demonstrates that with this approach the prognosis can be more favorable than is commonly assumed.

Myopathy in primary systemic amyloidosis

OBJECTIVE

To define the natural history of primary systemic amyloidosis when muscle involvement is prominent at presentation.

METHODS

A retrospective review was carried out of all patients seen at the tertiary referral practice of the Mayo Clinic between 1 January 1960 and 31 December 1994. All patients with primary systemic amyloidosis and proof of amyloid deposits by muscle biopsy were included for analysis. No patients were lost to follow up.

RESULTS

Twelve patients were identified with amyloidosis in muscle. Muscle involvement was the most prominent symptom in patients who had widespread visceral involvement, which included the heart, peripheral nerve, and tongue. Of the 12, three had skeletal muscle pseudohypertrophy. All patients had a demonstrable dysproteinaemia by the finding of free light chain in the serum or urine, a discrete monoclonal peak on serum or urine protein electrophoresis, or a monoclonal population of plasma cells in the bone marrow. Measurement of creatine kinase was not a useful test. Of eight patients treated with chemotherapy based on alkylating agents, three responded. The median survival for the entire group was 12 months.

CONCLUSIONS

The finding of a monoclonal protein in a patient with muscle weakness is an important clue to the diagnosis of primary systemic amyloidosis. Most patients have visceral involvement outside the musculoskeletal system. A subset of patients seems to respond to systemic chemotherapy. The overall survival, however, remains poor, with most patients dying of cardiac failure. Immunoelectrophoresis of serum and urine should be a routine diagnostic test during the evaluation of myopathy of unknown cause.

Neuropathies associated with monoclonal gammopathies

Approximately 10% of patients with idiopathic peripheral neuropathy have an associated serum monoclonal gammopathy or M-protein. This represents six times the incidence of M-proteins found in the general population. In 5% of idiopathic peripheral neuropathy patients the M-protein is associated with an identifiable plasma cell dyscrasia. Sclerotic myeloma is particularly important to recognize because treatment may result in amelioration of the neuropathy and remission of the tumor. Patients with primary systemic amyloidosis often have preferential small fiber involvement with a dissociated sensory loss and autonomic dysfunction. The nerve root infiltration of lymphoproliferative disorders may simulate a polyradiculoneuropathy. In cases without an identifiable cause for the M-protein, referred to as monoclonal gammopathy of undetermined significance (MGUS), the pathophysiologic basis for the neuropathy is poorly defined in most cases. A role for M-proteins with antibody activity to myelin-associated glycoprotein is provocative. This review summarizes current knowledge of this important group of disorders.

Tertiary structure of an amyloid immunoglobulin light chain protein: a proposed model for amyloid fibril formation

An immunoglobulin light chain protein was isolated from the urine of an individual (BRE) with systemic amyloidosis. Complete amino acid sequence of the variable region of the light chain (VL) protein established it as a kappa I, which when compared with other kappa I amyloid associated proteins had unique residues, including Ile-34, Leu-40, and Tyr-71. To study the tertiary structure, BRE VL was expressed in Escherichia coli by using a PCR product amplified from the patient BRE's bone marrow DNA. The PCR product was ligated into pCZ11, a thermal-inducible replication vector. Recombinant BRE VL was isolated, purified to homogeneity, and crystallized by using ammonium sulfate as the precipitant. Two crystal forms were obtained. In crystal form I the BRE VL kappa domain crystallizes as a dimer with unit cell constants isomorphous to previously published kappa protein structures. Comparison with a nonamyloid VL kappa domain from patient REI, identified significant differences in position of residues in the hypervariable segments plus variations in framework region (FR) segments 40-46 (FR2) and 66-67 (FR3). In addition, positional differences can be seen along the two types of local diads, corresponding to the monomer-monomer and dimer-dimer interfaces. From the packing diagram, a model for the amyloid light chain (AL) fibril is proposed based on a pseudohexagonal spiral structure with a rise of approximately the width of two dimers per 360 degree turn. This spiral structure could be consistent with the dimensions of amyloid fibrils as determined by electron microscopy.

Cardiac immunocyte-derived (AL) amyloidosis: an endomyocardial biopsy study in 11 patients

The objective of this study was to investigate the spectrum of morphologic features in myocardial biopsy specimens from patients with cardiac immunocyte-derived (AL) amyloidosis. Cardiac involvement is the most important predictor of survival in AL amyloidosis. Myocardial biopsy remains the method of choice for diagnosing cardiac amyloidosis when noninvasive studies give equivocal results. Histologic, immunohistochemical, ultrastructural, and morphometric studies were made on myocardial biopsy specimens from 11 patients in whom the diagnosis of AL amyloidosis was based on the demonstration of a monoclonal immunoglobulinopathy and of amyloid deposits in tissues. Histopathologic study showed amyloid in 10 of the 11 biopsies. In one biopsy (Congo red negative), the diagnosis was made by ultrastructural identification of amyloid fibrils. In all patients, the deposits formed perimyocytic layers that measured up to 18 microns in thickness. These layers formed along the basement membranes, which were partially preserved in 5 patients and unrecognizable in 6. Interstitial nodular deposits were also present in 5 patients. Immunohistochemical studies for the characterization of the proteins in the amyloid deposits were diagnostic in 1 patient and confirmatory in 10. Nodular deposits, thick perimyocytic layers of amyloid and small myocyte diameters were associated with shorter survival of the patients. Small-vessel involvement and myofilament loss occurred in all patients. In conclusion, myocardial biopsy serves to (1) establish the diagnosis of cardiac amyloidosis; (2) characterize immunohistochemically the proteins in the amyloid fibrils and (3) assess the degree of myocyte damage and atrophy.

Immunohistochemical classification of 140 autopsy cases with systemic amyloidosis

One hundred and forty autopsy cases of systemic amyloidosis were examined using the potassium permanganate method for distinction of amyloid A protein from other amyloid proteins and an immunohistochemical technique. Of those cases, amyloid proteins were identified in 121 cases. There were 68 cases of amyloid A-related (AA) amyloidosis and these were the most common type among the cases (56.2%). There were 39 cases of immunoglobulin light chain-related (AL) amyloidosis (32.2%), six cases of beta 2-microglobulin-related (A beta 2M) amyloidosis (5%), and five cases of transthyretin-related (ATTR) amyloidosis (4.1%). Minute areas of amyloid deposits in four cases with AA were resistant to potassium permanganate pretreatment. In A beta 2M amyloidosis amyloid deposits were either resistant or sensitive to potassium permanganate pretreatment, from case to case. The coexistence of two different amyloid proteins was seen in three cases: one case had ATTR and A kappa types, and two cases had A beta 2M and AA types. Some discrepancies were seen between the immunohistochemical typing and clinical classification of amyloidosis referred to in the Annual of the Pathological Autopsy Cases in Japan, for example, one case of AA type in myeloma-associated amyloidosis and one case of AL type in secondary amyloidosis. From the present results, the importance of the immunohistochemical method in classifying amyloidosis is stressed.

Amyloidosis

The biochemistry of amyloidosis as it relates to clinical medicine and experimental pathology is presented. Amyloidoses are complex disorders in which normally soluble precursors undergo pathological conformational changes and polymerize as insoluble fibrils with the beta-pleated sheet conformation. Over the past 20 years, 16 biochemically diverse proteins have been identified as fibrillar constituents of amyloid deposits; in all cases the protein-protein interactions that result in amyloid fibril formation appear to be stabilized both by the structure and the microenvironment of the precursor protein. Either genetic predisposition or dysfunctions of the immune system favor amyloid fibril formation. In particular, macrophage function is a factor in the pathogenesis of many of the amyloidoses. The diagnosis of amyloidosis involves acquisition of a tissue biopsy, staining of the specimen with Congo red, and observation of classic green birefringence on polarization microscopy. The subdiagnosis of the systemic amyloidoses involves characterization of variant or monoclonal plasma amyloid precursor proteins in the context of clinical symptoms. Treatment is generally supportive, with the use of antiinflammatory therapy, dialysis, or transplantation and genetic counseling where indicated.

Phase II trial of recombinant interferon alfa-2 in the treatment of primary systemic amyloidosis

Primary systemic amyloidosis (AL) is a rare disorder characterized by production of an aberrant monoclonal light chain. This insoluble light chain, or a fragment thereof, deposits in tissues as amyloid and results in disruption of organ function and, ultimately, death. Although melphalan and prednisone were reported to benefit subsets of patients with the disease, many patients showed no benefit; the median survival with the disease is approximately 2 years. There is a need to develop new agents for patients who fail to respond to a trial of cytotoxic chemotherapy. A study was undertaken of interferon alfa-2 in the treatment of 15 patients with AL because of its reported benefits in the induction and maintenance therapy for patients with multiple myeloma, a disease that has many characteristics in common with AL. None of the patients showed any objective regression of their disease; the median survival of the entire group was 26.3 months. This survival is not superior to that reported with other agents used for this disease. We conclude that interferon alpha-2 is not a valuable agent in the treatment of AL.

Symptomatic gastric amyloidosis in patients with primary systemic amyloidosis

We reviewed the clinical records of 769 patients with primary systemic amyloidosis who had been examined at Mayo Clinic Jacksonville (Jacksonville, Florida) or Mayo Clinic Rochester (Rochester, Minnesota) during a 12-year period (1978 through 1989). Of these 769 patients, 59 (8%) had biopsy-established gastrointestinal amyloidosis, and 8 (1%) had symptomatic gastric amyloidosis. All eight patients with symptomatic gastric amyloidosis had hematemesis or prolonged nausea and vomiting in association with weight loss. Additional findings were gastroparesis (in three patients), gastric tumor (in one), and gastric outlet obstruction (in one). Macroglossia was present in two patients, and multiple myeloma was diagnosed in three. Six of the eight patients had coexisting small bowel amyloidosis and weight losses of 6.5 to 22.5 kg. Congo red staining identified gastric amyloid in the media of blood vessels in all cases. All cases stained selectively for lambda (seven cases) or kappa (one) light chain. All eight patients died; the median duration of survival after diagnosis was 13.8 months (range, 0.5 to 39.5). Death was due to cardiac failure (three patients), renal failure (two), chronic gastrointestinal obstruction and severe cachexia (two), or hepatic failure (one). Chemotherapy was given to seven patients but was only partially effective for ameliorating symptoms in one.

Familial amyloidosis: a study of 52 North American-born patients examined during a 30-year period

Between 1961 and 1990, 52 patients with biopsy-proven familial amyloidosis born in North America were examined at the Mayo Clinic. At the time of diagnosis of familial amyloidosis, 83% of these patients had peripheral neuropathy, 33% had autonomic neuropathy, and 27% had cardiomyopathy. Renal disease was noted in fewer than 10%, and liver involvement was rare. The median age at diagnosis was 64 years. The sensitivity of various diagnostic biopsies was similar to that for primary amyloidosis: deposits of amyloid were found in 77 and 78% of the subcutaneous fat aspirates or rectal biopsy specimens, respectively, and in 41% of specimens of bone marrow. The median duration of survival of 5.8 years for patients with inherited amyloidosis was superior to that for patients with primary amyloidosis. When patients were stratified by organ involvement, the survival of patients with familial amyloidosis remained superior. The presence of cardiomyopathy and an interactive variable of age and the presence of autonomic neuropathy were powerful predictors of survival. Of the 52 patients, 22 died, 12 (55%) of cardiac failure or cardiac arrhythmia. Nine patients (41%) died of inanition in conjunction with progressive peripheral or autonomic neuropathy. Transthyretin was identified by immunohistochemical studies in 31 of the 34 tissue specimens tested. A transthyretin mutation was identified in 24 of the 31. A transthyretin mutation was found in five additional patients for whom tissue was unavailable for immunostaining.

Systemic diseases affecting the mesenteric circulation

The mesenteric circulation is acutely sensitive to processes that affect the entire body. Such systemic diseases and syndromes are reviewed with particular emphasis on the mechanisms by which they influence the mesenteric vasculature and blood flow.

Serial Doppler echocardiographic follow-up of left ventricular diastolic function in cardiac amyloidosis

A spectrum of left ventricular diastolic filling abnormalities noted on Doppler echocardiography has been demonstrated in patients with cardiac amyloidosis. To determine how these filling abnormalities evolve over time and the significance of any change, serial pulsed wave Doppler studies of left ventricular inflow were performed over 12.6 +/- 4.9 months in 41 consecutive patients (36 men and 15 women, mean age 59 +/- 11 years) with typical two-dimensional echocardiographic features of cardiac involvement. The measurements were peak left ventricular inflow in early diastole (E) and atrial contraction (A) velocities, E/A ratio, deceleration time and isovolumetric relaxation time. Patients were classified by mean left ventricular wall thickness into an early group (less than 15 mm) of 24 patients and an advanced group (greater than or equal to 15 mm) of 17 patients. The total group showed an increased E/A ratio (1.7 +/- 0.9 versus 1.4 +/- 0.9, p = 0.009) and decreased deceleration time (164 +/- 57 versus 174 +/- 51 ms, p = 0.11) at follow-up compared with baseline study. The early group showed significant changes in the E/A ratio (1.6 +/- 1.0 versus 1.2 +/- 0.7, p = 0.001) between the two studies. Seven patients (29%) in the early group showed a change from an abnormal relaxation or "normal" pattern to one of restriction, coincident with increased symptoms in six of these patients. Fifteen (88%) of the 17 patients in the advanced group did not show significant changes in the measures during the follow-up study, but these patients already showed a restrictive pattern.(ABSTRACT TRUNCATED AT 250 WORDS)