Fatigue in Patients on Chronic Hemodialysis: The Role of Indoleamine 2,3-Dioxygenase (IDO) Activity, Interleukin-6, and Muscularity.

Fatigue is a frequent symptom in hemodialysis (HD), and the indolamine-2,3-dioxygenase (IDO) metabolic trap has been hypothesized in the pathogenesis of fatigue. The association between IDO activity according to fatigue and its relationship with muscle mass and function in HD patients was verified. Chronic HD patients were considered, and fatigue was assessed. The plasma kynurenines and tryptophan ratio (Kyn/Trp), as surrogate of IDO activity, and interleukin (IL)-6 were measured. Muscularity was assessed by BIA and muscle strength by hand-grip dynamometer. 50 HD patients were enrolled, and fatigue was present in 24% of the cohort. Patients with fatigue showed higher Kyn/Trp (p = 0.005), were older (p = 0.007), and IL-6 levels resulted higher than in non-fatigue patients (p < 0.001). HD patients with fatigue showed lower intracellular water (surrogate of muscle mass) (p < 0.001), as well as lower hand grip strength (p = 0.02). The Kyn/Trp ratio positively correlated with IL-6 and ECW/ICW (p = 0.004 and p = 0.014). By logistic regression analysis, higher ICW/h2 was associated with lower odds of fatigue (OR, 0.10; 95% CI, 0.01 to 0.73). In conclusion, our cohort fatigue was associated with a higher Kyn/Trp ratio, indicating a modulation of IDO activity. The Kyn/Trp ratio correlated with IL-6, suggesting a potential role of IDO and inflammation in inducing fatigue and changes in muscularity.

ATTRv in Lazio-Italy: A High-Prevalence Region in a Non-Endemic Country.

Hereditary transthyretin amyloidosis (ATTRv, v for variant) prevalence in Italy, a non-endemic region, has been established by ATTRv amyloidosis Italian Registry. However, values of prevalence were extremely heterogeneous, considering different regions. To properly establish the prevalence of the disease in the Lazio region, a survey was sent to university regional hospitals and to main regional hospitals, in order to collect all affected patients regularly followed. We identified 100 ATTRv patients and, considering a Lazio population of 5.8/million, we estimated a ATTRv prevalence of 17.2/million. The ATTRv amyloidosis Italian Registry reported a prevalence of 8.0/million in Lazio, while our survey showed a value of double this. Our survey documented a high-prevalence for a non-endemic country. The increased awareness of the disease among general practitioners and medical specialists is a fundamental step to reduce the diagnostic delay and start an effective treatment of this disease.

ATTRv amyloidosis Italian Registry: clinical and epidemiological data.

INTRODUCTION: ATTRv amyloidosis is worldwide spread with endemic foci in Portugal and Sweden, Japan, Brazil, Maiorca, and Cyprus. A national Registry was developed to characterise the epidemiology and genotype-phenotype correlation of ATTRv amyloidosis in Italy and to allow a better planning of diagnostic and therapeutic services. METHODS: Fifteen Italian referral centres for amyloidosis spread all over the country have contributed to the Registry. RESULTS: Four-hundred-forty-seven subjects were enrolled, 187 asymptomatic carriers and 260 affected patients. Thirty-one different mutations were recorded. The seven most represented genetic variants were significantly different in terms of age at onset, clinical features and geographical distribution. National prevalence is 4.33/million with higher values in Southern Italy. Overall symptoms of polyneuropathy were present at disease onset in about half of the patients, symptoms of cardiomyopathy in a quarter of patients, the rest referring carpal tunnel syndrome, dysautonomia or lumbar spinal stenosis. 52.6% of patients were in FAP stage 1, 20.4% in stage 2 and 13.5% in stage 3, while 13.5% patients had no neuropathy, presenting only cardiological symptoms. CONCLUSIONS: We presented an epidemiological study based on collaboration among referral centres for ATTRv amyloidosis spread in all the Italian territory, using web-based Registry. It provided a detailed map of the regional distribution of the disease. The increased awareness of the disease among general practitioners and medical specialists has contributed to reduce the diagnostic delay and the rate of misdiagnosis. The Registry will allow to collect also future information about clinical and instrumental follow-up.

Longitudinal Physical Activity Change During Hemodialysis and Its Association With Body Composition and Plasma BAIBA Levels.

Rationale: Low physical activity is frequent in end stage renal disease. We evaluated the longitudinal change in physical activity and its barriers in hemodialysis (HD) patients and the association between the patterns of physical activity change, body composition, and beta-aminoisobutyric acid (BAIBA), as circulating myokine. Methods: This is an observational study, where HD patients were considered in a 24-month follow-up. We assessed overtime the change of physical inactivity and its barriers by validated questionnaires, body composition by bioimpedance analysis, muscle strength by hand-dynamometer, and plasma BAIBA levels by liquid chromatography spectrometry. Parametric and non-parametric analyses were performed, as appropriate. Results: Out of the 49 patients studied at baseline, 39 completed the first-year follow-up, and 29 completed the second year. At month 12, active patients had higher intracellular water (ICW) (P = 0.001) and cellular mass (P < 0.001), as well as at month 24 (P = 0.012, P = 0.002; respectively) with respect to inactive. A significant reduction in ICW was shown at month 12 (P = 0.011) and month 24 (P = 0.014) in all patients. The barrier "reduced walking ability" was more frequent in inactive patients with respect to active at month 12 (P = 0.003) and at month 24 (P = 0.05). At month 24, plasma BAIBA levels were higher among active patients with respect to inactive (P = 0.043) and a correlation was seen between muscle strength and ICW (r = 0.51, P = 0.005); normalizing BAIBA per body mass index, we found it lower with respect to baseline (P = 0.004), as well as after correcting per ICW (P = 0.001), as marker of muscle mass. Conclusion: A high prevalence of physical inactivity persisted during a 24-month follow-up in this cohort. We found an association between physical activity and a decline in marker of muscularity and reduced plasma BAIBA levels.

The metabolite beta-aminoisobutyric acid and physical inactivity among hemodialysis patients.

OBJECTIVE: Physical inactivity is frequent in patients on hemodialysis (HD), and represents a reliable predictor of morbidity and mortality. Beta-aminoisobutyric acid (BAIBA) is a contraction-induced myokine, the plasma levels of which increase with exercise and are inversely associated with metabolic risk factors. The aim of this study was to ascertain whether physical inactivity and clinical parameters relate to plasma BAIBA levels in this patient population. METHODS: Adult patients on HD were included, and the presence of physical inactivity was assessed. BAIBA levels were measured in these patients and in healthy individuals. We assessed barriers to physical activity, including 23 items regarding psychophysical and financial barriers. Body composition was assessed by bioimpedance and muscle strength by handgrip dynamometer. Nonparametric tests and logistic regression analyses were performed. RESULTS: Forty-nine patients on HD were studied; 49% were physically active and 51% were inactive. Of the patients, 43 reported barriers to physical activity and 61% of inactive patients reported three or more barriers. BAIBA levels were lower in patients on HD with respect to controls (P < 0.001). Stratifying HD patients as active and inactive, both groups showed significantly lower BAIBA levels versus controls (P = 0.0005, P < 0.001, respectively). Nondiabetic patients on HD showed increased BAIBA levels compared with diabetic patients (P < 0.001). Patients on HD endorsing the two most frequent barriers showed lower BAIBA levels than those not reporting these barriers (P = 0.006). Active patients showed higher intracellular water (%) (P = 0.008), and active and inactive patients showed significant correlation between total body muscle mass and handgrip strength (P = 0.04, P = 0.005, respectively). CONCLUSIONS: Physical inactivity is highly prevalent among patients on HD and BAIBA correlates with barriers to physical activity reported by inactive patients.

Effect of intensive nutritional counseling and support on clinical outcomes of hemodialysis patients.

OBJECTIVE: Protein-energy wasting is frequently found in patients on hemodialysis (HD). Anorexia and hypophagia contribute to malnutrition and increased morbidity and mortality, but the clinical impact of correcting hypophagia remains uncertain. We evaluated whether the correction of hypophagia influences morbidity and mortality in anorexic patients on HD. METHODS: Thirty-four patients on HD were enrolled in a 2-y follow-up program including regular nutritional assessments. Patients not meeting the nutritional requirements during the follow-up received nutritional counseling, consisting of advice, individually tailored diets, and, for a failed dietary intervention, artificial nutrition. Biochemical, anthropometric, and body composition parameters, morbidity, and mortality were recorded in all patients at 12 and 24 mo. RESULTS: At baseline, 14 patients (41%) were anorexic, and 20 patients (59%) were non-anorexic. Anorexic patients were hypophagic and presented with a decreased fat-free mass. After 12 and 24 mo, cholesterol, albumin, lymphocyte count, and body mass index did not differ between the groups, whereas fat-free mass (percentage) in supplemented anorexic patients significantly improved in no longer differing from non-anorexic patients (65.8 ± 4.4 versus 65.4 ± 8.9, respectively, P = NS; 65.8 ± 4.4 versus 66.7 ± 10.78, respectively, P = NS). Morbidity and mortality were not different between the two groups. CONCLUSION: In patients on HD, nutritional counseling and nutritional support positively affect the nutritional status in hypophagic patients and make the risk of morbidity and mortality in anorexic patients comparable to those of non-anorexic patients.

Anorexia in hemodialysis patients: the possible role of des-acyl ghrelin.

BACKGROUND: Anorexia is frequently found in end-stage renal disease and is a reliable predictor of morbidity and mortality in hemodialysis (HD) patients. The pathogenesis of anorexia is complex and the appetite-modulating hormone ghrelin could be involved. Two forms of circulating ghrelin have been described: acylated ghrelin (<10% of circulating ghrelin) which promotes food intake, and des-acyl ghrelin which induces a negative energy balance. The aim of this cross-sectional study is to clarify whether anorexia and body weight change in HD patients relate to plasma des-acyl ghrelin levels. METHODS: 34 HD patients and 15 healthy controls were studied. The presence of anorexia was assessed by a questionnaire. Serum des-acyl ghrelin was measured in HD patients and in 15 body mass index-, sex- and age-matched controls by ELISA. Energy intake was assessed by a 3-day dietary diary, and fat-free mass (FFM) was evaluated by body impedance analysis. Data have been statistically analyzed and are presented as mean +/- SD. RESULTS: 14 patients (41%) were found to be anorexic, and 20 patients (59%) non-anorexic. Energy intake (kcal/day) was significantly lower in anorexic than in non-anorexic patients (1,682 +/- 241 vs. 1,972.50 +/- 490; p < 0.05). FFM (%) was lower in anorexic than in non-anorexic patients (65.8 +/- 4.4 vs. 70.9 +/- 8.7; p = 0.05). Plasma des-acyl ghrelin levels (fmol/ml) were significantly higher in HD patients than in controls (214.88 +/- 154.24 vs. 128.93 +/- 51.07; p < 0.05), and in anorexic HD patients than in non-anorexic (301.7 +/- 162.4 vs. 159.1 +/- 115.5; p < 0.01). CONCLUSION: Anorexia is highly prevalent among HD patients and des-acyl ghrelin could be involved in its pathogenesis.