Changes of protein kinetics in nephrotic patients

Utility of muscle ultrasound in nutritional assessment of children with nephrotic syndrome

BACKGROUND

Nutritional status assessment in children with nephrotic syndrome (NS) is critical for identifying patients who are at risk of protein-energy wasting (PEW) and for determining their nutritional needs and monitoring nutritional intervention outcomes.

METHODS

In a case-control study, we enrolled 40 children (age range: 2-16 years) with NS and 40 apparently healthy children (age and sex-matched) as a control group. Anthropometric data, as well as demographic, clinical, and laboratory data, were collected. A dietary intake assessment using a 3-day food intake record was done, and the quadriceps rectus femoris thickness (QRFT) and quadriceps vastus intermedius thickness (QVIT) were assessed using B-mode ultrasound and compared between both groups.

RESULTS

Children with NS had lower QRFT and QVIT measurements than control groups (p < 0.001). Inadequacy in protein intake occurred in 62.5% and 27.5% of the NS and control groups, respectively (p = 0.002). The thickness of the rectus and vastus muscles by ultrasound was significantly associated with the percentage of protein intake (p < 0.001). The ROC curve revealed that the best cutoff value of QRFT for the prediction of the patient at risk of malnutrition was ≤ 1.195 with an area under curve of 0.907, with p < 0.001.

CONCLUSION

In children with NS, skeletal muscle ultrasound is a simple and easy-to-use bedside technique for the identification of patients at risk of malnutrition. A higher resolution version of the Graphical abstract is available as Supplementary information.

Protein energy-wasting associated with nephrotic syndrome - the comparison of metabolic pattern in severe nephrosis to different stages of chronic kidney disease

Background

Nephrotic syndrome (NS) is associated with a hypercatabolic state expressed as an exacerbated degradation of muscle mass. However, the clinical significance of this phenomenon has not yet been investigated.

The aim of the study was to evaluate the nutritional status of patients with severe NS (defined as nephrotic range proteinuria with hypoalbuminemia ≤2.5 g/dL) and estimated glomerular filtration rate (eGFR) ≥45 mL/min/1.73 m² in comparison to patients in different stages of chronic kidney disease (CKD).

Methods

Twenty men with severe NS (NS group) and 40 men without proteinuria similar in term of serum creatinine (control group) were included into the study. A retrospective cohort of 40 men with CKD stage G4 (PreD group) and 20 haemodialysis men (HD group) were added to the analysis after matching for age, height and weight using propensity score matching. The bioimpedance spectroscopy and biochemical nutritional markers were evaluated.

Results

Nephrotic patients had a significantly lower lean tissue mass (LTM; p = 0.035) and index (a quotient of LTM over height squared, LTI; p = 0.068), with an expected deficiency of LTM by 3.2 kg, and LTI by 0.9 kg/m² when compared to the control group. A significant lean tissue deficit (defined as LTI below the lower limit of the reference range by 1.0 kg/m²) was observed in 12.5% of patients in the control group in comparison to 31.7% with advanced CKD (PreD+HD; p = 0.032) and 50% with NS (p = 0.003). NS group presented with higher phosphorus (p = 0.029), uric acid (p = 0.002) and blood urea (p = 0.049) than the control group. Blood urea was strongly negatively correlated with LTM in NS (r = − 0.64, p = 0.002). Nine nephrotic patients (45%) were identified as hypercatabolic based on severe hyperphosphatemia (> 5.0 mg/dL) and/or hyperuricemia (> 8.0 mg/dL), and were characterized by higher blood urea and lower prealbumin, as well as LTM lower by 5.6 kg than in less catabolic individuals.

Conclusions

In term of lean tissue amount, NS group was more similar to advanced CKD than to the control group. We concluded that specific metabolic pattern with elevated phosphorus, uric acid and blood urea, and lean tissue deficiency may be defined as protein-energy wasting associated with nephrotic syndrome (neph-PEW).

Serum levels of cancer biomarkers in diabetic and non-diabetic proteinuric patients: a preliminary study

BACKGROUND

Cancer biomarkers (CBs) can be used in early detection of several cancers as well as in detection of recurrence and following response to treatment. We aimed to investigate the levels of CBs in proteinuric patients with primary glomerular disease (PGD) and diabetes mellitus, and compare them with healthy controls.

METHODS

One hundred and two patients with untreated PGD, 62 proteinuric patients with diabetic nephropathy, and 84 healthy controls were enrolled. Levels of cancer antigen 125 (CA 125), cancer antigen 15-3 (CA 15-3), carcinoembriogenic antigen (CEA), α-fetoprotein (AFP), total prostate specific antigen (TPSA), free prostate specific antigen (FPSA) and carbohydrate antigen 19-9 (CA 19-9) were measured.

RESULTS

Compared to healthy controls, levels of CA 125, CA 15-3 and CA 19-9 were higher in patients with PGD and diabetic patients (all p<0.05), while levels of TPSA, FPSA, AFP and CEA were lower (all p<0.05). There was no correlation between levels of cancer biomarkers and serum fibrinogen and serum amyloid A protein levels (all p>0.05). Both urinary protein excretion rate and serum albumin levels were correlated with all CBs (all p<0.05).

CONCLUSIONS

CBs levels seem to be changed in different proteinuric patients. This condition should be kept in mind when evaluating CBs levels in proteinuric patients.

In vivo effects of hyperthermia on the functional and conformational characteristics of antithrombin

BACKGROUND

High temperatures produce in vitro transitions of antithrombin to its inactive latent and polymeric forms. Accordingly, high body temperatures might contribute in vivo to conformational changes in antithrombin associated with increased thrombotic risk.

METHODS

We assessed the in vivo effects of different hyperthermic stimuli on antithrombin. We studied two mouse models of hyperthermia. (i) Febrile syndrome induced by turpentine. (ii) Heat stroke generated by exposure to 42 degrees C. Body temperatures were measured. Antigen, anti-factor Xa activity and conformational features of plasma antithrombin were studied. Furthermore, structural and ultrastructural features from livers were analyzed. Intracellular retention of serpins (antithrombin and alpha1-antitrypsin) was studied by western-blotting, immunohistochemistry, and immunogold-labeling-electron microscopy.

RESULTS

Hyperthermic stimuli caused a moderate deficiency of circulating antithrombin and a slight increase in its latent form. Moreover, hyperthermia caused intracellular retention of antithrombin into aggregates within the lumen of the endoplasmic reticulum of hepatocytes. This effect was similar for alpha1-antitrypsin.

CONCLUSION

Hyperthermia causes minor conformational changes on circulating antithrombin in vivo, although it has severe consequences for intracellular antithrombin and other hepatic serpins, inducing the intracellular retention of the nascent protein. These effects may contribute to the moderate plasma deficiency of antithrombin and the increased thrombotic risk detected in hyperthermic conditions.

Dynamics of albumin synthesis after major rectal operation

BACKGROUND

Major abdominal operations were found to be associated with long-lasting metabolic changes, such as accelerated release of stress hormones and carbohydrate turnover. It is unknown currently whether acute changes of hepatic protein metabolism persist in a similar way. We wanted to determine the long-term dynamics of albumin synthesis and its relationship to whole body protein breakdown and albumin concentration after major rectal operations.

METHODS

We used stable isotope tracer techniques to determine albumin synthesis and whole body protein breakdown (rate of appearance of leucine, Ra) in postoperative patients about 1 week after low anterior rectal resection and also during convalescence (about 4 months after operation), and in healthy controls. Consecutive blood sampling was carried out during continuous isotope infusion (1-[(13)C]-leucine, 0.16 micromol/kg min).

RESULTS

Serum albumin concentrations were close to the lower normal limit in patients early after operation but were comparable to controls in convalescent patients. Simultaneously, albumin synthesis was increased in the early postoperative phase (0.53 +/- 0.0.5%/h) compared with convalescent patients (0.32 +/- 0.04) and controls (0.28 +/- 0.04) (P < .01 each). A significant inverse correlation could be found between plasma albumin concentration and corresponding rates of albumin synthesis. Early after operation patients showed an increased leucine Ra (3.25 +/- 0.23 micromol/kg min) that was greater than that of convalescent patients (2.37 +/- 0.06 micromol/kg min, P < .05). Leucine Ra in both patient groups were greater than the rates in controls (2.01 +/- 0.07 micromol/kg min, P < .01) Albumin synthesis correlated weakly with whole body protein breakdown rate.

CONCLUSIONS

Albumin synthesis and total body protein breakdown are increased after major abdominal operation, but albumin synthesis returns to control values only during convalescence. Hypoalbuminemia after rectal operations may be associated with high rates of albumin synthesis and is, therefore, not necessarily an indicator of insufficient hepatic function or poor nutritional status in that particular situation.

A Case Report of a Diabetic Nephropathy Patient With Cirrhotic Ascites Treated by Peritoneal Dialysis

A 64-year-old man was admitted because of abdominal fullness, edema and anorexia. He had come to our hospital for treatment of liver cirrhosis and diabetic nephropathy for 1 year. We started diuretics and human albumin intravenous administration. Although the edema disappeared and abdominal fullness improved a little, blood urea nitrogen (BUN) and serum creatinine became elevated, hepatic function deteriorated and he lost his appetite. We consequently started continuous ambulatory peritoneal dialysis (CAPD) in order to control ascites and uremia. Abdominal fullness, appetite and BUN and serum creatinine improved without hepatic function deterioration. It might be important to start CAPD to control ascites although serum creatinine levels might be slightly elevated.