Alcohol Consumption Post-Liver Transplantation: A Cross-Sectional Study.

Background: Listing patients with alcohol-associated liver disease (ALD) for liver transplant (LT) remains challenging especially due to the risk of alcohol resumption post-LT. We aimed to evaluate post-LT alcohol consumption at a Portuguese transplant center. Methods: We conducted a cross-sectional study including LT recipients from 2019 at Curry Cabral Hospital, Lisbon, Portugal. A pretested survey and a validated Portuguese translation of the Alcohol Use Disorder Identification Test (AUDIT) were applied via a telephone call. Alcohol consumption was defined by patients' self-reports or a positive AUDIT. Results: In 2019, 122 patients underwent LT, and 99 patients answered the survey (June 2021). The mean (SD) age was 57 (10) years, 70 patients (70.7%) were males, and 49 (49.5%) underwent ALD-related LT. During a median (IQR) follow-up of 24 (20-26) months post-index LT, 22 (22.2%) recipients consumed any amount of alcohol: 14 had a drink monthly or less and 8 drank 2-4 times/month. On drinking days, 18 patients usually consumed 1-2 drinks and the remainder no more than 3-4 drinks. One patient reported having drunk ≥6 drinks on one occasion. All post-LT drinking recipients were considered low risk (score <8) as per the AUDIT score (median [IQR] of 1 [1-2]). No patient reported alcohol-related problems, whether self-inflicted or toward others. Drinking recipients were younger (53 vs. 59 years, p = 0.020), had more non-ALD-related LT (72.7 vs. 44.2%, p = 0.018) and active smoking (31.8 vs. 10.4%, p = 0.037) than abstinent ones. Conclusion: In our cohort, about a quarter of LT recipients consumed alcohol early posttransplant, all with a low-risk pattern according to the AUDIT score.

Introdução: Incluir doentes com doença hepática associada ao álcool (DHA) em lista ativa de transplante hepático (TH) é desafiante, especialmente pelo risco de recidiva de consumo de álcool pós-TH. O objetivo foi avaliar o consumo de álcool pós-TH num centro de transplantação português. Métodos: Realizamos um estudo transversal incluindo doentes submetidos a TH em 2019 no Hospital Curry Cabral, Lisboa, Portugal. Foi realizado um questionário previamente testado e uma tradução validada para o português do Alcohol Use Disorder Identification Test (AUDIT), através de uma chamada telefónica. O consumo de álcool foi definido pelo autorrelato do doente ou por um AUDIT positivo. Resultados: Durante 2019, 122 doentes foram submetidos a TH e 99 responderam ao questionário (junho de 2021). A idade média (SD) foi de 57 (10) anos, 70 doentes (70,7%) eram do sexo masculino e 49 (49,5%) foram submetidos a TH relacionado com DHA. Com uma mediana (IQR) de follow-up de 24 (20­26) meses após o TH-índex, 22 (22,2%) doentes admitiram algum consumo de álcool: 14 beberam mensalmente ou menos e oito beberam 2­4 vezes/mês. Nos dias em que bebiam, 18 consumiam normalmente 1­2 bebidas e os restantes não mais do que 3­4 bebidas. Um doente reportou o consumo de ≥6 bebidas em uma ocasião. Todos os doentes transplantados com consumo alcoólico pós-TH foram considerados de baixo risco (pontuação >8) de acordo com o AUDIT (mediana [IQR] de 1 [1­2]). Nenhum doente reportou problemas relacionados com o álcool, tanto autoinfligido como a terceiros. Os indivíduos transplantados com consumo alcoólico eram mais jovens (53 vs. 59 anos, p = 0,020), o motivo de TH era mais frequentemente não relacionado com DHA (72,7 vs. 44,2%, p = 0,018) e apresentavam mais tabagismo ativo (31,8 vs. 10,4%, p = 0,037) quando comparado com os abstinentes. Conclusão: Na nossa coorte, cerca de um quarto dos doentes transplantados hepáticos consumiram álcool no período pós-transplante precoce, todos com um padrão de baixo risco, de acordo com o AUDIT.

The Impact of Donor Risk Index, Recipients' and Operative Characteristics on Post Liver Transplant One-Year Graft Failure: A Cohort Analysis.

Background and Aims: The donor risk index (DRI) quantifies donor-related characteristics potentially associated with increased risk of early graft failure. We aimed to assess the impact of the DRI, recipient and perioperative factors on post liver transplant (LT) outcomes. Methods: This was a single-center retrospective cohort study including all adult (≥18 years) patients who underwent LT from 01/2019 to 12/2019 at Curry Cabral Hospital, Lisbon, Portugal. Primary endpoint was 1-year graft failure post LT. Associations were studied with logistic regression. Results: A total of 131 cadaveric donor LT procedures were performed in 116 recipients. Recipients' median (IQR) age was 57 (47-64) years and 101/131 (77.1%) were males. Cirrhosis was the underlying etiology in 95/131 (81.2%) transplants. Based on 8 predefined donors' characteristics, median (IQR) DRI was 1.96 (1.67-2.16). Following adjustment for MELDNa score pre LT and SOFA score (adjusted odds ratio [aOR], 95% confidence interval [CI] = 0.91 [0.56-1.47]) or lactate (aOR [95% CI] = 2.76 [0.71-10.7]) upon intensive care unit (ICU) admission post LT, DRI was not associated with 1-year graft failure. However, higher SOFA score (aOR [95% CI] = 1.20 [1.05-1.37]) or lactate (aOR [95% CI] = 1.27 [1.10-1.46]) upon ICU admission post LT were independently associated with higher odds of 1-year graft failure. Conclusions: In a recent cohort of patients who underwent LT, DRI, despite being high, was not associated with 1-year graft failure, but SOFA score or lactate upon ICU admission post LT were.

Introdução: O índice de risco do dador (DRI) quantifica as características relacionadas com o dador potencialmente associadas com risco acrescido de falência precoce do enxerto. Procurou-se avaliar o impacto do DRI e factores relacionados com os receptores e cirurgia nos resultados clínicos após transplante hepático (LT). Materiais e Métodos: Estudo coorte retrospectivo de centro único incluindo todos os doentes adultos (≥18 anos) que receberam LT entre 01/2019 e 12/2019 no Hospital Curry Cabral, Lisboa, Portugal. O endpoint primário foi a falência do enxerto após um ano do LT. As associações foram estudadas com regressão logística. Resultados: Um total de 131 transplantes de dadores cadavéricos foram realizados em 116 receptores. A idade mediana (IQR) destes foi 57 (47­64) anos e 101/131 (77.1%) eram homens. A cirrose foi a etiologia subjacente em 95/131 (81.2%) transplantes. Com base nas 8 características dos dadores predefinidas, o DRI mediano (IQR) foi 1.96 (1.67­2.16). Após ajuste para o score MELDNa pre LT e o score SOFA (odds ratio ajustado [aOR], intervalo de confiança 95% [CI] = 0.91 [0.56­1.47]) ou o lactato (aOR [95% CI] = 2.76 [0.71­10.7]) após admissão na unidade de cuidados intensivos (ICU) pós LT, o DRI não se associou com a falência do enxerto um ano depois do LT. Contudo, um maior score SOFA (aOR [95% CI] = 1.20 [1.05­1.37]) ou lactato (aOR [95% CI] = 1.27 [1.10­1.46]) após admissão na ICU depois do LT associaram-se independentemente com a falência do enxerto um ano depois do LT. Conclusões: Num coorte recente de doentes submetidos a LT, o DRI, apesar de alto, não se associou com a falência precoce do enxerto precoce. Contudo, o score SOFA ou lactato após admissão na ICU depois do LT associaram-se com a falência precoce do enxerto.

A 5-Year Follow-Up of The Benefits of an Exercise Training Program in Liver Recipients Transplanted Due to Familial Amyloidotic Polyneuropathy.

BACKGROUND: Supervised (SE) and home-based exercise (HBE) training regimes are effective on reconditioning patients with familial amyloidotic polyneuropathy (FAP) after liver transplantation, but research of the long-term retention of the benefits attained in patients with FAP has not yet been conducted. PURPOSE: In this 5-year follow-up study, we aimed to determine whether the exercise training gains in body composition, physical activity, and function promoted by a 24-week SE or HBE training regimes are retained in patients with FAP who resume normal activity. METHODOLOGY: Sixteen liver-transplanted patients with FAP were reassessed for body composition (dual X-ray absorptiometry), physical activity (questionnaire), and function (handgrip strength and 6-minute walk test). RESULTS: Total body fat increased with both exercise regimes during follow-up ( P < .05; η2 = 0.432-0.625) as well as femoral neck bone density ( P = .048; η2 = 0.119). However, gains in upper limbs muscle quality during follow-up ( P < .001; η2 = 0.597) were only found in the SE group ( P = .042; η2 = 0.245). Both exercise regimes showed retaining aptitudes in walking capacity ( P < .05; η2 = 0.329-0.460) and muscle mass ( P = .05; η2 = 0.245). Still, none could retain the physical activity levels. CONCLUSION: Long-term resumption of normal activity following a 24-week SE or HBE regime in patients with FAP resulted in loss of exercise induced increases in physical activity but counterweighted postoperative losses in bone mineral density and substantially retained the benefits in walking capacity, muscle mass, and quality, in particular, in the SE group.

Acute-on-Chronic Liver Failure: A Portuguese Single-Center Reference Review.

Acute-on-chronic liver failure (ACLF) is a syndrome characterized by an acute deterioration of a patient with cirrhosis, frequently associated with multi-organ failure and a high short-term mortality rate. We present a retrospective study that aims to characterize the presentation, evolution, and outcome of patients diagnosed with ACLF at our center over the last 3 years, with a comparative analysis between the group of patients that had ACLF precipitated by infectious insults of bacterial origin and the group of those with ACLF triggered by a nonbacterial infectious insult; the incidence of acute kidney injury and its impact on the prognosis of ACLF was also analyzed. Twenty-nine patients were enrolled, the majority of them being male (89.6%), and the mean age was 53 years. Fourteen patients (48.3%) developed ACLF due to a bacterial infectious event, and 9 of them died (64.2%, overall mortality rate 31%); however, no statistical significance was found (p < 0.7). Of the remaining 15 patients (51.7%) with noninfectious triggers, 11 died (73.3%, overall mortality rate 37.9%); again there was no statistical significance (p < 0.7). Twenty-four patients (83%) developed acute kidney injury (overall mortality rate 65.5%; p < 0.022) at the 28-day and 90-day follow-up. Twelve patients had acute kidney injury requiring renal replacement therapy (41.37%; overall mortality rate 37.9%; p < 0.043). Hepatic transplant was performed in 3 patients, with a 100% survival at the 28-day and 90-day follow-up (p < 0.023). Higher grades of ACLF were associated with increased mortality (p < 0.02; overall mortality 69%). CONCLUSIONS: ACLF is a heterogeneous syndrome with a variety of precipitant factors and different grades of extrahepatic involvement. Most cases will have some degree of renal dysfunction, with an increased risk of mortality. Hepatic transplant is an efficient form of therapy for this syndrome.

A Doença Hepática Crónica Agudizada/Falência é um síndrome caracterizado por uma deterioração aguda de um doente com cirrose, frequentemente associada com falência multiorgânica e elevada mortalidade a curto prazo. Apresentamos estudo retrospetivo que teve como objetivo caracterizar a apresentação, evolução e prognóstico de doentes diagnosticados com Doença Hepática Crónica Agudizada/Falência no nosso Centro nos últimos 3 anos, comparando o grupo de doentes que tiveram Doença Hepática Crónica provocada por infeções bacterianas e os doentes com Doença Hepática Crónica Agudizada/Falência desencadeada por precipitantes que não a infeção bacteriana; foi também analisada a incidência de lesão renal aguda e o seu impacto no prognóstico na Doença Hepática Crónica Agudizada/Falência. Vinte e nove doente foram incluídos no estudo, a maioria do género masculino (89.6%), idade media de 53 anos. Catorze doentes (48.3%) desenvolveram Doença Hepática Crónica Agudizada devido a infeção bacteriana, 9 dos quais faleceram (64.2%, mortalidade global 31%), contudo, sem significado estatístico (p < 0.7); dos restantes 15 (51.7%) sem infeção bacteriana, 11 faleceram (73.3%, mortalidade global 37.9%), também sem significado estatístico (p < 0.7%). Vinte e quatro doentes (83%) desenvolveram lesão renal, mortalidade global de 65.5% (p < 0.022) aos 28 e 90 dias de seguimento. Doze doentes desenvolveram lesão renal aguda com necessidade de terapêutica de substituição da função renal (41.37%), mortalidade global de 37.9% (p < 0.043). O transplante hepático foi realizado em 3 doentes, com uma sobrevida de 100% aos 28 e 90 dias de seguimento (p < 0.023); Graus elevados de Doença Hepática Crónica Agudizada estão associadas a mortalidade mais elevada (p < 0.02); mortalidade global de 69%. CONCLUSIONS: A Doença Hepática Crónica Agudizada é um síndrome heterogéneo, com uma variedade de fatores precipitantes e diferentes graus de envolvimento extra-hepático; a maioria das situações estará associada a disfunção renal, com aumento do risco de mortalidade; O transplante hepático será uma eficaz de tratamento deste síndrome.

Preoperative metabolic status is associated with different evolution of resting energy expenditure after liver transplant in adults.

INTRODUCTION: The resting energy expenditure (REE) evolution after liver transplantation is not fully understood. OBJECTIVE: To assess longitudinally the REE evolution in adults undergoing liver transplantation, in association with other nutritional measurements that characterize the metabolic profile. METHODS: A single-center cohort of consecutive end-stage liver disease patients with indication for liver transplantation was recruited. REE, subjective global assessment (SGA), handgrip strength and body composition measurements were assessed before transplantation (T0) and at median nine (T1) and 36 (T2) days after transplantation. Mixed effects regression models were used for analysis. RESULTS: Fifty-six patients with a mean age of 53.7 (8.5) years were included; 87.5% were males. In T0, 41% of patients were normometabolic, 37.5% were hypometabolic and 21.4% were hypermetabolic. After transplantation, the mean REE decreased progressively in patients initially hypermetabolic and the opposite occurred in those initially hypometabolic. The REE evolution was positively associated with body weight (ß = 9.6, p < 0.001) and energy intake (ß= 13.6, p = 0.005) in the whole sample; it was positively associated with body weight (ß= 7.1, p = 0.018) and percentage of energy intake from lipids (ß= 18.9, p = 0.003) in initially hypometabolic patients, and positively associated with body weight (ß= 14.1, p < 0.001) and negatively associated with SGA-undernourishment (ß = -171, p = 0.007) in initially normometabolic patients. CONCLUSION: Different REE evolutions after liver transplantation are associated with the preoperative metabolic status. In patients initially hypometabolic, the REE evolution is positively associated with body weight and percentage of energy intake from lipids, and in those initially normometabolic, it is positively associated with body weight and negatively associated with SGA-undernourishment.

Tuberculosis in Liver Transplant Recipients: A Report of Eight Cases During a Five Year Period.

INTRODUCTION: Tuberculosis incidence in Portugal ranged from 20 to 22 cases per 100 000 inhabitants between 2010 and 2014. Tuberculosis incidence in liver transplant recipients is not precisely known, but it is estimated to be higher than among the general population. Tuberculosis in liver transplant recipients is particularly challenging because of the atypical clinical presentation and side effects of the antibacillary drugs and their potential interactions with immunosuppressive therapies. MATERIAL AND METHODS: We retrospectively reviewed the clinical records of liver transplant recipients with post-transplant tuberculosis occurring from January 2010 to December 2014 at a liver transplantation unit in Lisbon, Portugal. Demographic data, baseline and clinical features, as well as treatment regimen, toxicities and outcomes, were analyzed. RESULTS: Among 1005 recipients, active tuberculosis was diagnosed in eight patients between January 2010 and December 2014 (frequency = 0.8%). Late onset tuberculosis was more frequent than early tuberculosis. Mycobacterium tuberculosis complex was isolated from cultures in almost every case (7; 87.5%). Extra-pulmonary involvement and disseminated tuberculosis were frequent. Two patients developed rejection without allograft loss. Crude mortality was 37.5%, with 2 deaths being related to tuberculosis. DISCUSSION: Despite the uncertainty regarding treatment duration in liver transplant recipients, disease severity, as well as number of active drugs against TB infection, should be taken into account. There was a need for a rifampin-free regimen and immunosuppression adjustment in patients who experienced acute graf rejection. CONCLUSION: Although the number of cases of tuberculosis is low, its post-transplant frequency is significant and the observed mortality rate is not to be neglected. The cases of hepatotoxicity and graft rejection seen in this case series demonstrate the challenges associated with tuberculosis diagnosis in liver transplant recipients and management of the interactions between immunosuppressors and rifampin. This study strengthens the recommendation of latent tuberculosis infection screening and treatment in liver transplant candidates or recipients.

Introdução: A incidência de tuberculose em Portugal entre 2010 - 2014 foi de 20 a 22 casos por 100 000 habitantes. A incidência de tuberculose em transplantados hepáticos não é conhecida, estimando-se que seja mais elevada do que a da população em geral. O manejo da tuberculose em transplantados hepáticos constitui um desafio, não só pela apresentação clínica frequentemente atípica, mas também pelos efeitos secundários da terapêutica antibacilar e suas interações farmacológicas com a medicação imunossupressora, necessária no período pós-transplante. Material e Métodos: Os autores fizeram uma revisão retrospetiva dos casos de doentes transplantados hepáticos com tuberculose pós- transplante diagnosticada durante o período entre janeiro 2010 e dezembro 2014 num centro de transplantação hepática em Lisboa, Portugal. Foram analisados os dados demográficos, características clínicas, a par do regime antibacilar, toxicidade e evolução. Resultados: Num total de 1005 transplantados foi diagnosticada tuberculose ativa em oito doentes entre janeiro de 2010 e dezembro de 2014 (frequência de 0,8%). O desenvolvimento de tuberculose tardia foi mais frequente do que a doença precoce. Foi isolado Mycobacterium tuberculosis complex no exame cultural de sete doentes (87,5%). Foram frequentes a presença de envolvimento extrapulmonar, assim como doença tuberculosa disseminada. Dois doentes desenvolveram rejeição aguda, sem perda de enxerto. A taxa de mortalidade global foi de 37,5%, com duas mortes directamente atribuíveis à tuberculose. Discussão: Apesar da incerteza quanto à duração do tratamento da tuberculose em transplantados hepáticos, deverão ser tidos em conta a gravidade da doença, assim como o número de fármacos com actividade antibacilar. Nesta série, os doentes que desenvolveram rejeição aguda necessitaram da utilização de um regime sem rifampicina, e ajuste da terapêutica imunossupressora. Conclusão: Apesar do baixo número de casos de tuberculose, a sua frequência pós-transplante é significativa e a mortalidade associada não é negligenciável. Os casos de hepatotoxicidade e rejeição de enxerto demonstram os desafios no diagnóstico da tuberculose em transplantados hepáticos e a dificuldade do manejo das interações entre imunossupressores e a rifampicina. Este estudo reforça a recomendação de rastreio e tratamento de tuberculose latente em transplantados ou candidatos a transplante hepático.

Factors Associated With Changes in Body Composition Shortly After Orthotopic Liver Transplantation: The Potential Influence of Immunosuppressive Agents.

BACKGROUND: This study aimed to determine factors associated with body composition changes shortly after liver transplantation (LTx), including the influence of immunosuppressive agents. The combined resting energy expenditure (REE) and handgrip strength provided a valuable assessment in data interpretation of body composition. METHODS: This observational single-center study included a cohort of consecutive end-stage liver disease patients with indications for LTx over 2 years. Cyclosporine was preferred for diabetic, hepatitis C-infected, and human immunodeficiency virus-infected patients per the transplant center protocol. Subjective Global Assessment, handgrip strength, multifrequency bioelectrical impedance analysis, and REE measurements were collected. The assessments were performed before LTx (T0) and at medians of 9 (T1) and 36 (T2) days after LTx. The fat mass index (FMI) and lean mass index (LMI) were surrogates of adiposity and skeletal muscle, respectively. Multiple linear regression analysis was used. RESULTS: Fifty-six patients with a mean age of 53.7 (8.5) years were included; 87.5% were men. Preoperative Subjective Global Assessment undernourishment (ß-estimate = 17.9; P = 0.004) and of drug addiction absence (ß estimate = 14.6; P = 0.049) were associated with FMI increase. Higher REE at T1 (per 100 kcal) was associated with LMI increase (ß estimate = 1.70; P = 0.012) and body cell mass increase (ß estimate = 1.60; P = 0.049). The cyclosporine-based regimen was associated with FMI decrease (ß estimate = -25.64; P < 0.001) and LMI increase (ß estimate = 23.76; P < 0.001) when compared with a tacrolimus-based regimen. Steroids did not affect body composition. CONCLUSIONS: The cyclosporine-based regimen was independently associated with decreased adiposity and increased skeletal muscle compared with the tacrolimus-based regimen. Future randomized controlled trials are needed to confirm these findings.

The role of fibrinogen glycation in ATTR: evidence for chaperone activity loss in disease.

Transthyretin amyloidosis (ATTR) belongs to a class of disorders caused by protein misfolding and aggregation. ATTR is a disabling disorder of autosomal dominant trait, where transthyretin (TTR) forms amyloid deposits in different organs, causing dysfunction of the peripheral nervous system. We previously discovered that amyloid fibrils from ATTR patients are glycated by methylglyoxal. Even though no consensus has been reached about the actual role of methylglyoxal-derived advanced glycation end-products in amyloid diseases, evidence collected so far points to a role for protein glycation in conformational abnormalities, being ubiquitously found in amyloid deposits in Alzheimer's disease, dialysis-related amyloidosis and Parkinson's diseases. Human fibrinogen, an extracellular chaperone, was reported to specifically interact with a wide spectrum of stressed proteins and suppress their aggregation, being an interacting protein with TTR. Fibrinogen is differentially glycated in ATTR, leading to its chaperone activity loss. Here we show the existence of a proteostasis imbalance in ATTR linked to fibrinogen glycation by methylglyoxal.

Long-term Results of Domino Liver Transplantation for Hepatocellular Carcinoma Using the "Double Piggy-back" Technique: A 13-Year Experience.

OBJECTIVES: The aim of this study was to evaluate the long-term outcome of liver transplantation (LT) for hepatocellular carcinoma (HCC) with Domino LT (DLT) using the "Double Piggy-back" technique. BACKGROUND DATA: DLT using livers from familial amyloidotic polyneuropathy (FAP) patients is a well-described technique and useful for expanding the donor pool. However, data on long-term results for HCC are limited, particularly regarding the use of the "Double Piggy-back" technique. METHODS: Between 2001 and 2014, a total of 260 patients undergoing LT for HCC were analyzed from a prospective database. Of those, 114 were submitted to DLT. Comparisons between groups were performed using propensity score matching. RESULTS: Median follow-up was 34 months (1-152). Overall and disease-free 5-year survival rates for the whole population were 58% and 56%, respectively. There were 177 (68%) patients within Milan Criteria and an additional 26 (10%) within University of California San Francisco (UCSF) criteria. Patients older than 50 years were more likely to receive an FAP liver [odds ratio (OR) 1.94, confidence interval (CI) 1.02-3.69]. DLT patients had more major complications (23.7% vs 13.0%, P = 0.025). Only patients undergoing DLT presented with piggy-back syndrome (7% vs 0%, P = 0.001). After adjusting for potential confounders, DLT and cadaveric LT had a similar 5-year survival rate (59% vs 44%, respectively, P = 0.117). Thirteen patients (11.4%) evidenced FAP disease but not before 6 years after DLT. CONCLUSIONS: DLT for HCC is feasible and achieves equivalent results to cadaveric LT. The benefit of expanding the donor pool must be balanced against higher morbidity and a real risk of disease transmission.

Transthyretin Amyloidosis: Chaperone Concentration Changes and Increased Proteolysis in the Pathway to Disease.

Transthyretin amyloidosis is a conformational pathology characterized by the extracellular formation of amyloid deposits and the progressive impairment of the peripheral nervous system. Point mutations in this tetrameric plasma protein decrease its stability and are linked to disease onset and progression. Since non-mutated transthyretin also forms amyloid in systemic senile amyloidosis and some mutation bearers are asymptomatic throughout their lives, non-genetic factors must also be involved in transthyretin amyloidosis. We discovered, using a differential proteomics approach, that extracellular chaperones such as fibrinogen, clusterin, haptoglobin, alpha-1-anti-trypsin and 2-macroglobulin are overrepresented in transthyretin amyloidosis. Our data shows that a complex network of extracellular chaperones are over represented in human plasma and we speculate that they act synergistically to cope with amyloid prone proteins. Proteostasis may thus be as important as point mutations in transthyretin amyloidosis.

α-Synuclein aggregation in the saliva of familial transthyretin amyloidosis: a potential biomarker.

Familial transthyretin amyloidosis (ATTR) is an autosomal dominant disease characterized by the formation of transthyretin (TTR) amyloid deposits. This crippling and fatal disease is associated with point mutations in TTR, a protein mainly produced in the liver. Hence, liver transplantation is the only treatment capable of halting disease progression. Ideally, liver transplantation should be performed as early as possible in the disease course before significant neurologic disability has been incurred. Early detection of disease before serious pathological lesions occur is crucial for the clinical management of patients and for morbidity delay. Unfortunately, the presence of TTR mutations by itself is not a predictor of disease onset or progression. In the present work, we observed an increased oligomerization of α-synuclein in the saliva of ATTR symptomatic individuals comparatively to asymptomatic carriers of the same TTR mutation and healthy control subjects. Based on this observation, we propose monitoring α-synuclein oligomers in saliva as a biomarker of ATTR progression. Since α-synuclein plays a major role in several neurodegenerative disorders, assessing its oligomerization state in this fluid provides a non-invasive approach to survey these pathologies.

The relative amounts of plasma transthyretin forms in familial transthyretin amyloidosis: a quantitative analysis by Fourier transform ion-cyclotron resonance mass spectrometry.

Familial transthyretin amyloidosis (ATTR) is a fatal autosomal dominant disease characterized by the formation of amyloid fibers, mainly composed of transthyretin (TTR). Protein aggregation and amyloid fiber formation are considered concentration dependent processes and since most ATTR patients are heterozygous it is crucial to determine the ratio between mutant and non-mutant TTR forms in human plasma. Using a high resolution mass spectrometry based approach we determined the ratio of TTR forms in ATTR patients, V30M mutation carriers, symptomatic and asymptomatic ones, as well as ATTR patients that received a wild type cadaveric liver transplant. Domino transplanted patients that received a liver from an ATTR patient were also investigated. We found that although wild type TTR is diminished in the plasma of non-transplanted ATTR patients comparatively to healthy subjects, the relationship with the V30M variant does not change with illness progression. Those who received a wild type liver showed no mutant protein while domino transplanted patients presented the same relative amount of V30M as found in asymptomatic and symptomatic individuals. The V30M to wild type TTR ratio in plasma is the same for all ATTR patients studied, showing no variation with disease clinical progression. Our results point to the involvement of additional non-genetic factors on the pathogenesis of this disease.

Beyond genetic factors in familial amyloidotic polyneuropathy: protein glycation and the loss of fibrinogen's chaperone activity.

Familial amyloidotic polyneuropathy (FAP) is a systemic conformational disease characterized by extracellular amyloid fibril formation from plasma transthyretin (TTR). This is a crippling, fatal disease for which liver transplantation is the only effective therapy. More than 80 TTR point mutations are associated with amyloidotic diseases and the most widely accepted disease model relates TTR tetramer instability with TTR point mutations. However, this model fails to explain two observations. First, native TTR also forms amyloid in systemic senile amyloidosis, a geriatric disease. Second, age at disease onset varies by decades for patients bearing the same mutation and some mutation carrier individuals are asymptomatic throughout their lives. Hence, mutations only accelerate the process and non-genetic factors must play a key role in the molecular mechanisms of disease. One of these factors is protein glycation, previously associated with conformational diseases like Alzheimer's and Parkinson's. The glycation hypothesis in FAP is supported by our previous discovery of methylglyoxal-derived glycation of amyloid fibrils in FAP patients. Here we show that plasma proteins are differentially glycated by methylglyoxal in FAP patients and that fibrinogen is the main glycation target. Moreover, we also found that fibrinogen interacts with TTR in plasma. Fibrinogen has chaperone activity which is compromised upon glycation by methylglyoxal. Hence, we propose that methylglyoxal glycation hampers the chaperone activity of fibrinogen, rendering TTR more prone to aggregation, amyloid formation and ultimately, disease.