Serum myostatin as a candidate disease severity and progression biomarker of spinal muscular atrophy

The identification of biomarkers for spinal muscular atrophy is crucial for predicting disease progression, severity, and response to new disease-modifying therapies. This study aimed to investigate the role of serum levels of myostatin and follistatin as biomarkers for spinal muscular atrophy, considering muscle atrophy secondary to denervation as the main clinical manifestation of the disease. The study evaluated the differential gene expression of myostatin and follistatin in a lesional model of gastrocnemius denervation in mice, as well as in a meta-analysis of three datasets in transgenic mice models of spinal muscular atrophy, and in two studies involving humans with spinal muscular atrophy. Subsequently, a case-control study involving 27 spinal muscular atrophy patients and 27 controls was conducted, followed by a 12-month cohort study with 25 spinal muscular atrophy cases. Serum levels of myostatin and follistatin were analysed using enzyme-linked immunosorbent assay at a single centre in southern Brazil. Skeletal muscle gene expression of myostatin decreased and of follistatin increased following lesional muscle denervation in mice, consistent with findings in the spinal muscular atrophy transgenic mice meta-analysis and in the iliopsoas muscle of five patients with spinal muscular atrophy type 1. Median serum myostatin levels were significantly lower in spinal muscular atrophy patients (98 pg/mL; 5-157) compared to controls (412 pg/mL; 299-730) (P < 0.001). Lower myostatin levels were associated with greater disease severity based on clinician-rated outcomes (Rho = 0.493-0.812; P < 0.05). After 12 months, there was a further reduction in myostatin levels among spinal muscular atrophy cases (P = 0.021). Follistatin levels did not differ between cases and controls, and no significant changes were observed over time. The follistatin:myostatin ratio was significantly increased in spinal muscular atrophy subjects and inversely correlated with motor severity. Serum myostatin levels show promise as a novel biomarker for evaluating the severity and progression of spinal muscular atrophy. The decrease in myostatin levels and the subsequent favourable environment for muscle growth may be attributed to denervation caused by motor neuron dysfunction.

Quality of life and depression in haemodialysis patients

Chronic kidney disease is associated with a high prevalence of depression, which increases inversely with the glomerular filtration rate. This paper aims to evaluate the factors associated with a low quality of life and depression in patients on haemodialysis. Two hundred patients undergoing haemodialysis answered the Medical Outcomes Study 36 - Item Short - Form Health Survey (SF-36) and Beck Depression Inventory (BDI). Clinical and laboratory variables were analysed and correlated with these two tools. The prevalence of depression was 29%. Anaemia and hypoalbuminemia were independent risk factors for depression. All SF-36 domains showed worse results in patients with depression, and the pain domain presented the highest correlation. Our findings provide evidence that patients on haemodialysis have a low quality of life and a high prevalence of depression. A greater number of comorbidities, an excessive number of medications, diabetes mellitus, anaemia and hypoalbuminemia were associated with a reduced quality of life.

Evaluation of renal function in a specific population of living kidney donors

BACKGROUND

The increase in candidates for kidney transplant has led to growth in the number of living donor transplants. Therefore, studies that adequately evaluate the possible long-term consequences of elective transplant nephrectomy are needed.

OBJECTIVE

To evaluate the possible long-term adverse effects of transplant nephrectomy on the renal function of living kidney donors.

DESIGN

A cross-sectional study.

PARTICIPANTS

Thirty-three living kidney donors registered in the transplant programme of a centre in Alagoas, Brazil.

MEASUREMENTS

Demographic characteristics, anthropometric measures, clinical data and biomarkers (creatinine, eGFR, microalbuminuria, cholesterol and triglycerides) were measured. Creatinine clearance was calculated using the Cockcroft-Gault and Modification of Diet in Renal Disease formulae.

RESULTS

Of the 33 individuals, 63.63% were female, and the median age was 45 years. Additionally, 24.24% of these individuals had altered blood pressure, 39.39% had altered abdominal circumference (AC) and 36.36% were obese, with a body mass index ≥30. Furthermore, 33.33% of these individuals had elevated triglyceride levels. The average eGFR was 97.33 (33.03-175.9) ml/min/1.73 m² (CG) and 84.14 (29.4-131) ml/min/1.73 m² (MDRD). The microalbuminuria level was altered in 12.12% patients.

CONCLUSION

Kidney donation is unquestionably a safe procedure. However, a better understanding of the long-term consequences of living donor kidney transplantation is still needed. This knowledge may have important implications for the follow-up of these patients. Our study has demonstrated a non-negligible presence of an early marker of glomerular injury and a decrease in the GFR of some patients, thereby reinforcing the proposal for long-term follow-up of living kidney donors.