Variation in thermally induced taste response across thermal tasters.

Thermal tasters (TTs) perceive thermally induced taste (thermal taste) sensations when the tongue is stimulated with temperature in the absence of gustatory stimuli, while thermal non tasters (TnTs) only perceive temperature. This is the first study to explore detailed differences in thermal taste responses across TTs. Using thermal taster status phenotyping, 37 TTs were recruited, and the temporal characteristics of thermal taste responses collected during repeat exposure to temperature stimulation. Phenotyping found sweet most frequently reported during warming stimulation, and bitter and sour when cooling, but a range of other sensations were stated. The taste quality, intensity, and number of tastes reported greatly varied. Furthermore, the temperature range when thermal taste was perceived differed across TTs and taste qualities, with some TTs perceiving a taste for a small temperature range, and others the whole trial. The onset of thermal sweet taste ranged between 22 and 38°C during temperature increase. This supports the hypothesis that TRPM5 may be involved in thermal sweet taste perception as TRPM5 is temperature activated between 15 and 35°C, and involved in sweet taste transduction. These findings also raised questions concerning the phenotyping protocol and classification currently used, thus indicating the need to review practices for future testing. This study has highlighted the hitherto unknown variation that exists in thermal taste response across TTs, provides some insights into possible mechanisms, and importantly emphasises the need for more research into this sensory phenomenon.

An automated method to detect and quantify fungiform papillae in the human tongue: Validation and relationship to phenotypical differences in taste perception.

Determination of the number of fungiform papillae (FP) on the human tongue is an important measure that has frequently been associated with individual differences in oral perception, including taste sensitivity. At present, there is no standardised method consistently used to identify the number of FP, and primarily scientists manually count papillae over a small region(s) of the anterior tip of a stained tongue. In this study, a rapid automated method was developed to quantify the number of FP across the anterior 2cm of an unstained tongue from high resolution digital images. In 60 participants, the automated method was validated against traditional manual counting, and then used to assess the relationship between the number of FP and taste phenotype (both 6-n-propylthiouracil (PROP) and Thermal Taster Status). FP count on the anterior 2cm of the tongue was found to correlate significantly with PROP taster status. PROP supertasters (PSTs) had a significantly higher FP count compared with PROP non-tasters (PNTs). Conversely, the common approach used to determine the number of FP in a small 6mm diameter circle on the anterior tongue tip, did not show a significant correlation irrespective of whether it was determined via automated or manual counting. The regional distribution of FP was assessed across PROP taster status groups. PSTs had a significantly higher FP count within the first centimetre of the anterior tongue compared with the PNT and PROP medium-tasters (PMT), with no significant difference in the second centimetre. No significant relationship was found with Thermal Taster Status and FP count, or interaction with PROP taster status groups, supporting previous evidence suggesting these phenomena are independent. The automated method is a valuable tool, enabling reliable quantification of FP over the anterior 2cm surface of the tongue, and overcomes subjective discrepancies in manual counting.

A longitudinal evaluation of health-related quality of life in patients with AL amyloidosis: associations with health outcomes over time.

Light chain (AL) amyloidosis is a rare disease associated with significant, irreversible organ dysfunction and high case fatality. An observational study was conducted to assess health-related quality of life (HRQoL) in patients treated for AL amyloidosis between 1994 and 2014 with both high dose melphalan and stem cell transplantation (HDM/SCT) or non-SCT chemotherapy regimens. The SF-36v1® Health Survey (SF-36) was administered to assess HRQoL during clinic visits. Analysis of variance was used to compare pre- and post-treatment HRQoL within each treatment group to an age- and gender-adjusted general population (GP) normative sample. Cox proportional hazard models were fit to examine associations between pre-treatment levels of HRQoL and mortality within 1 and 5 years after initiating specific treatment regimens (HDM/SCT: n = 402; non-SCT chemotherapy regimens: n = 172). Among patients who received HDM/SCT, there were significant improvements following treatment in vitality, social functioning, role-emotional and mental health. Worse pre-treatment SF-36 physical component scores were associated with a greater risk of mortality in both treatment groups and follow-up periods (P ≤ 0·005 for both). [Correction added on 20 October 2017, after first online publication: This P value has been corrected]. Using HRQoL assessments in every physician visit or treatment may provide valuable insights for treating rare conditions like AL amyloidosis.

Heart Failure Resulting From Age-Related Cardiac Amyloid Disease Associated With Wild-Type Transthyretin: A Prospective, Observational Cohort Study.

BACKGROUND: Heart failure caused by wild-type transthyretin amyloidosis (ATTRwt) is an underappreciated cause of morbidity and mortality in the aging population. The aims of this study were to examine features of disease and to characterize outcomes in a large ATTRwt cohort. METHODS AND RESULTS: Over 20 years, 121 patients with ATTRwt were enrolled in a prospective, observational study. Median age at enrollment was 75.6 years (range, 62.6-87.8 years); 97% of patients were white. The median survival, measured from biopsy diagnosis, was 46.69 months (95% confidence interval, 41.95-56.77); 78% of deaths were attributable to cardiac causes. By Kaplan-Meier analysis, 5-year survival was 35.7% (95% confidence interval, 25-46). Impaired functional capacity (mean Vo2max, 13.5 mL·kg(-1)·min(-1)) and atrial fibrillation (67%) were common clinical features. Multivariate predictors of reduced survival were elevated serum brain natriuretic peptide (482 ± 337 pg/mL) and uric acid (8.2 ± 2.6 mg/dL), decreased left ventricular ejection fraction (50% median; range, 10%-70%), and increased relative wall thickness (0.75 ± 0.19). CONCLUSIONS: In this series of patients with biopsy-proven ATTRwt, poor functional capacity and atrial arrhythmias were common clinical features. Elevated brain natriuretic peptide and uric acid, decreased left ventricular ejection fraction, and increased relative wall thickness were associated with limited survival of only 35.7% at 5 years for the group as a whole. These data establish the natural history of ATTRwt, provide statistical basis for the design of future interventional clinical trials, and highlight the need for more sensitive diagnostic tests and disease-specific treatments for this disease.

Repurposing diflunisal for familial amyloid polyneuropathy: a randomized clinical trial.

IMPORTANCE: Familial amyloid polyneuropathy, a lethal genetic disease caused by aggregation of variant transthyretin, induces progressive peripheral nerve deficits and disability. Diflunisal, a nonsteroidal anti-inflammatory agent, stabilizes transthyretin tetramers and prevents amyloid fibril formation in vitro. OBJECTIVE: To determine the effect of diflunisal on polyneuropathy progression in patients with familial amyloid polyneuropathy. DESIGN, SETTING, AND PARTICIPANTS: International randomized, double-blind, placebo-controlled study conducted among 130 patients with familial amyloid polyneuropathy exhibiting clinically detectable peripheral or autonomic neuropathy at amyloid centers in Sweden (Umeå), Italy (Pavia), Japan (Matsumoto and Kumamoto), England (London), and the United States (Boston, Massachusetts; New York, New York; and Rochester, Minnesota) from 2006 through 2012. INTERVENTION: Participants were randomly assigned to receive diflunisal, 250 mg (n=64), or placebo (n=66) twice daily for 2 years. MAIN OUTCOMES AND MEASURES: The primary end point, the difference in polyneuropathy progression between treatments, was measured by the Neuropathy Impairment Score plus 7 nerve tests (NIS+7) which ranges from 0 (no neurological deficits) to 270 points (no detectable peripheral nerve function). Secondary outcomes included a quality-of-life questionnaire (36-Item Short-Form Health Survey [SF-36]) and modified body mass index. Because of attrition, we used likelihood-based modeling and multiple imputation analysis of baseline to 2-year data. RESULTS: By multiple imputation, the NIS+7 score increased by 25.0 (95% CI, 18.4-31.6) points in the placebo group and by 8.7 (95% CI, 3.3-14.1) points in the diflunisal group, a difference of 16.3 points (95% CI, 8.1-24.5 points; P < .001). Mean SF-36 physical scores decreased by 4.9 (95% CI, -7.6 to -2.2) points in the placebo group and increased by 1.5 (95% CI, -0.8 to 3.7) points in the diflunisal group (P < .001). Mean SF-36 mental scores declined by 1.1 (95% CI, -4.3 to 2.0) points in the placebo group while increasing by 3.7 (95% CI, 1.0-6.4) points in the diflunisal group (P = .02). By responder analysis, 29.7% of the diflunisal group and 9.4% of the placebo group exhibited neurological stability at 2 years (<2-point increase in NIS+7 score; P = .007). CONCLUSIONS AND RELEVANCE: Among patients with familial amyloid polyneuropathy, the use of diflunisal compared with placebo for 2 years reduced the rate of progression of neurological impairment and preserved quality of life. Although longer-term follow-up studies are needed, these findings suggest benefit of this treatment for familial amyloid polyneuropathy. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00294671.

Amyloidosis of the gastrointestinal tract: a 13-year, single-center, referral experience.

Amyloidosis of the gastrointestinal tract, with biopsy-proven disease, is rare. We reviewed a series of patients who presented with biopsy-proven gastrointestinal amyloidosis and report their clinical characteristics, treatments, and survival. This is a retrospective review of data prospectively collected from January 1998 to December 2011 in a tertiary referral center; 2,334 patients with all types of amyloidosis were evaluated during this period. Seventy-six patients (3.2%) had biopsy-proven amyloid involvement of the gastrointestinal tract. Their median age was 61 years (range, 34-79). Systemic amyloidosis with dominant gastrointestinal involvement was present in 60 (79%) patients, whereas the other 16 (21%) patients had amyloidosis localized to the gastrointestinal tract without evidence of an associated plasma cell dyscrasia or other organ involvement. Of the 60 systemic cases, 50 (83%) had immunoglobulin light-chain, five (8%) had familial lysozyme, three (5%) had wild-type transthyretin, and two (3%) had mutant transthyretin amyloidosis. The most frequent symptoms for all patients were weight loss in 33 (45%) and gastrointestinal bleeding in 27 (36%). Incidental identification of amyloidosis on routine endoscopic surveillance played a role in the diagnosis of seven patients with systemic immunoglobulin light-chain, and four patients with immunoglobulin light-chain localized to the gastrointestinal tract. Amyloid protein subtyping was performed in 12 of the cases of localized disease, and all had lambda light chain disease. Of the 50 patients with systemic immunoglobulin light-chain amyloidosis, 45 were treated with anti-plasma cell therapy. The median survival has not been reached for this group. For the 16 patients with localized gastrointestinal amyloidosis, supportive care was the mainstay of treatment; none received anti-plasma cell therapy. All 16 are alive at a median follow-up of 36 months (range, 1-143). Patients with biopsy-proven gastrointestinal amyloidosis often present with weight loss and bleeding. In localized cases, all that underwent typing were due to lambda light chain amyloidosis and none progressed to systemic disease during the period of follow-up. Most patients with systemic disease had immunoglobulin light-chain, and their tolerance of therapy and median survival were excellent. Although a rare manifestation of amyloidosis, staining for amyloid should be considered in patients undergoing gastrointestinal biopsy who have unexplained chronic gastrointestinal symptoms.

A new lysozyme tyr54asn mutation causing amyloidosis in a family of Swedish ancestry with gastrointestinal symptoms.

Familial amyloidoses are a group of inherited disorders that cause deposition of misfolded amyloidogenic proteins in various tissues, resulting in organ dysfunction. Point mutations in the coding region of seven different genes are known to cause clinically significant systemic amyloid disease. We describe a new mutation in exon 2 of the lysozyme gene associated with amyloidosis (ALys) in a 61-year-old woman with a 7-year history of non-bloody, watery diarrhea, and weight loss. Biopsies of the duodenum and stomach were positive for amyloid deposits in the lamina propria and blood vessels. Direct DNA sequencing of the lysozyme gene revealed a single base nucleotide transversion from T to A at the first position of codon 54, resulting in replacement of Tyr by Asn in the mature lysozyme protein (pTyr54Asn). Immunoblot analysis of amyloid fibrils extracted from a fat tissue sample confirmed lysozyme as the amyloid protein. Clinically, the phenotype associated with this lysozyme mutation featured chronic abdominal pain, diarrhea, weight loss, malabsorption, and sicca syndrome. There was no associated nephropathy as has been reported for other ALys mutations. We describe a new mutant lysozyme that presents with abdominal discomfort, diarrhea, weight loss, and sicca syndrome.

Prospective evaluation of the morbidity and mortality of wild-type and V122I mutant transthyretin amyloid cardiomyopathy: the Transthyretin Amyloidosis Cardiac Study (TRACS).

BACKGROUND: TRACS sought to describe the clinical outcomes and disease progression of transthyretin (TTR) cardiac amyloidosis (ATTR) in an observational study. Clinical course is largely determined by disease type with ATTR categorized as wild-type (ATTRwt) or genetic-variant protein (ATTRm). Prospective data are lacking in the most common TTR mutation, V122I, present in approximately 3.5% of African Americans. METHODS: Patients with ATTRwt (n = 18) and V122I ATTRm (n = 11) were longitudinally assessed every 6 months for up to 2 years by functional class assessments, biochemical markers, and echocardiography. RESULTS: At baseline, no differences in clinical characteristics, biomarkers, or echocardiographic parameters were noted between patients with ATTRwt and patients with ATTRm. After 15.5 ± 8 months, there were 11 deaths and 1 cardiac transplant, with higher mortality (73% vs 22%, P = .03) and cardiovascular hospitalization (64% vs 28%, P = .02) among patients with ATTRm. The median survival from diagnosis was 25.6 months for ATTRm vs 43.0 months for ATTRwt (P = .04). Univariate predictors of mortality included disease duration, heart rate ≥ 70 beats/min, baseline stroke volume, left ventricular ejection fraction <50%, and ATTRm status. For each 6-month increment, the mean 6-minute walk distance declined by 25.8 m, N-terminal pro b-type natriuretic peptide increased by 1,816 pg/mL, and left ventricular ejection fraction fell by 3.2%, for the entire cohort. CONCLUSIONS: In this prospective study, disease progression, morbidity, and mortality were observed in ATTR cardiomyopathy, particularly due to V122I, over a short duration. Given the prevalence of this mutation, further study of V122I in at-risk African American patients is warranted.

Amyloid deposits in the bone marrow of patients with immunoglobulin light chain amyloidosis do not impact stem cell mobilization or engraftment.

Amyloid deposits are often found in the bone marrow in patients with Immunoglobulin light chain (AL) amyloidosis. We sought to determine whether this affects stem cell collection or engraftment after high-dose melphalan and autologous stem cell transplantation (HDM-SCT). We reviewed data on 361 patients with AL amyloidosis who had Congo red staining of pretreatment bone marrow biopsy specimens and underwent HDM-SCT between July 1994 and December 2011. We analyzed data on stem cell yield, days of stem cell collection, and days to neutrophil and platelet engraftment posttransplantation. Bone marrow amyloid deposits were found in 65% of patients (n = 233). There were no significant differences in median number of stem cells collected and days to neutrophil or platelet engraftment between patients with bone marrow amyloid deposits and those without these deposits. Thus, our data indicate that although amyloid involvement of the bone marrow is common, it does not negatively affect stem cell mobilization or neutrophil and platelet engraftment after HDM-SCT.

The Diflunisal Trial: study accrual and drug tolerance.

Familial amyloidotic polyneuropathy (FAP) is a protein folding disorder that induces neuropathy and cardiomyopathy, leading to death within 7-15 years after onset of clinical disease. In vitro, small ligands binding the thyroid hormone docking site stabilize tetrameric transthyretin, inhibiting amyloid fibril formation. We undertook a randomized, placebo-controlled clinical trial to determine whether diflunisal, a well-known non-steroidal anti-inflammatory drug (NSAID) alters neurologic disease progression in FAP. We enrolled 130 subjects with wide age and FAP mutation representation. To date, few recognized complications of NSAIDs have occurred in the study cohort. Data collection will be completed by November 2012.

Outcome of AL amyloidosis after high-dose melphalan and autologous stem cell transplantation: long-term results in a series of 421 patients.

Previous studies have suggested that, in patients with AL amyloidosis treated with high-dose melphalan and autologous stem-cell transplantation (HDM/SCT), the greatest benefit is seen in those patients achieving a hematologic complete response (CR). We analyzed a series of 421 consecutive patients treated with HDM/SCT at a single referral center and compared outcomes for patients with and without CR. Treatment-related mortality was 11.4% overall (5.6% in the last 5 years). By intention-to-treat analysis, the CR rate was 34% and the median event-free survival (EFS) and overall survival (OS) were 2.6 and 6.3 years, respectively. Eighty-one patients died within the first year after HDM/SCT and were not evaluable for hematologic and organ response. Of 340 evaluable patients, 43% achieved CR and 78% of them experienced an organ response. For CR patients, median EFS and OS were 8.3 and 13.2 years, respectively. Among the 195 patients who did not obtain CR, 52% achieved an organ response, and their median EFS and OS were 2 and 5.9 years, respectively. Thus, treatment of selected AL patients with HDM/SCT resulted in a high organ response rate and long OS, even for those patients who did not achieve CR.

Localized amyloidosis of the breast: a case series.

We report on the clinical presentation and histopathology of a series of seven patients with localized amyloidosis of the breast. These patients were diagnosed by biopsy performed to rule out malignancy because of calcifications seen by mammography, and represented 0.5% of patients referred to the Amyloid Treatment and Research Program at Boston University Medical Campus in an 18-year period. The patients ranged in age from 35 to 75, median 63 years. None of these seven patients had evidence of a systemic plasma cell dyscrasia or amyloidosis in other organs, nor did systemic disease develop with a median follow-up of 6 years. Thus, other than excisional biopsy to exclude malignancy, no systemic therapy is indicated for this disorder.

Macroglossia - not always AL amyloidosis.

AL amyloidosis and transthyretin (ATTR) amyloidosis are the most frequent forms of systemic amyloidosis diagnosed in the United States. Macroglossia is considered to be a pathognomonic feature of AL amyloidosis. We report on two cases of systemic amyloidosis with macroglossia that defied routine clinical diagnosis, in which the deposits were typed as ATTR in one case and AL in the other using immunoelectron microscopy. These cases highlight: (1) the difficulty of typing amyloidosis on clinical criteria alone; (2) the utility of immunoelectron microscopy and (3) that macroglossia, while occurring much more frequently in AL, can also accompany ATTR amyloidosis.

Oral cyclic melphalan and dexamethasone for patients with AL amyloidosis.

PURPOSE: Aggressive treatment of amyloid light chain (AL) amyloidosis with high-dose intravenous melphalan followed by autologous stem cell transplantation (HDM/SCT) is effective in inducing hematologic remission and clinical improvement. However, only selected patients with AL amyloidosis are eligible for HDM/SCT because of amyloid-associated organ dysfunction. PATIENTS AND METHODS: We report on 70 patients with AL amyloidosis treated with oral cyclic melphalan and dexamethasone. RESULTS: Of 48 evaluable patients who survived and returned for follow-up assessment, 6 patients (13%) achieved a complete hematologic response and 12 patients (25%) a partial hematologic response. Responses were non-inferior for patients receiving weekly "low-dose" dexamethasone compared with those receiving 4 day pulses. Median survival for the 70 patients has not yet been reached with a median follow-up of 17 months. Nineteen patients (27%) received additional treatment leading to improvement in survival. CONCLUSION: Melphalan/dexamethasone can lead to hematologic responses and improvement in survival, particularly for those who can receive additional treatment for AL amyloidosis.

The critical role of the constant region in thermal stability and aggregation of amyloidogenic immunoglobulin light chain.

Light chain (LC) amyloidosis (AL) is a fatal disease in which immunoglobulin LC deposit as fibrils. Although the LC amyloid-forming propensity is attributed primarily to the variable region, fibrils also contain full-length LC comprised of variable-joining (V(L)) and constant (C(L)) regions. To assess the role of C(L) in fibrillogenesis, we compared the thermal stability of full-length LC and corresponding V(L) and C(L) fragments. Protein unfolding and aggregation were monitored by circular dichroism and light scattering. A full-length λ6 LC purified from urine of a patient with AL amyloidosis showed irreversible unfolding coupled to aggregation. The transition temperature decreased at slower heating rates, indicating kinetic effects. Next, we studied five recombinant λ6 proteins: full-length amyloidogenic LC, its V(L), germline LC, germline V(L), and C(L). Amyloidogenic and germline proteins showed similar rank order of stability, V(L) < LC < C(L); hence, in the full-length LC, V(L) destabilizes C(L). Amyloidogenic proteins were less stable than their germline counterparts, suggesting that reduction in V(L) stability destabilizes the full-length LC. Thermal unfolding of the full-length amyloidogenic and germline LC required high activation energy and involved irreversible aggregation, yet the unfolding of the isolated V(L) and C(L) fragments was partially reversible. Therefore, compared to their fragments, full-length LCs are more likely to initiate aggregation during unfolding and provide a template for the V(L) deposition. The kinetic barrier for this aggregation is regulated by the stability of the V(L) region. This represents a paradigm shift in AL fibrillogenesis and suggests C(L) region as a potential therapeutic target.

Role of glycosaminoglycan sulfation in the formation of immunoglobulin light chain amyloid oligomers and fibrils.

Primary amyloidosis (AL) results from overproduction of unstable monoclonal immunoglobulin light chains (LCs) and the deposition of insoluble fibrils in tissues, leading to fatal organ disease. Glycosaminoglycans (GAGs) are associated with AL fibrils and have been successfully targeted in the treatment of other forms of amyloidosis. We investigated the role of GAGs in LC fibrillogenesis. Ex vivo tissue amyloid fibrils were extracted and examined for structure and associated GAGs. The GAGs were detected along the length of the fibril strand, and the periodicity of heparan sulfate (HS) along the LC fibrils generated in vitro was similar to that of the ex vivo fibrils. To examine the role of sulfated GAGs on AL oligomer and fibril formation in vitro, a κ1 LC purified from urine of a patient with AL amyloidosis was incubated in the presence or absence of GAGs. The fibrils generated in vitro at physiologic concentration, temperature, and pH shared morphologic characteristics with the ex vivo κ1 amyloid fibrils. The presence of HS and over-O-sulfated-heparin enhanced the formation of oligomers and fibrils with HS promoting the most rapid transition. In contrast, GAGs did not enhance fibril formation of a non-amyloidogenic κ1 LC purified from urine of a patient with multiple myeloma. The data indicate that the characteristics of the full-length κ1 amyloidogenic LC, containing post-translational modifications, possess key elements that influence interactions of the LC with HS. These findings highlight the importance of the variable and constant LC regions in GAG interaction and suggest potential therapeutic targets for treatment.