Clinical associations of an increased transthyretin band in routine serum and urine protein electrophoresis

Hypoglycemia, Malnutrition and Body Composition

Hypoglycemia is one of the most significant factors to affect prognosis, and is detrimental to patients regardless of diabetes mellitus (DM) status. The classical paradigms dictate that hypoglycemia is a result of overtreatment with glucose lowering agents (iatrogenic hypoglycemia), or, as among patients without DM, this condition is attributed to disease severity. New information shows that hypoglycemia occurs among patients that have a tendency for it. Incident hypoglycemia is very prevalent in the hospital setting, occurring in 1:6 patients with DM and in 1:17 patients without DM (Leibovitz E, Khanimov I, Wainstein J, Boaz M; Diabetes Metab Syndr Clin Res Rev. 13:222-226, 2019).One of the major factors associated with incidence of hypoglycemia is the nutritional status on hospital admission and during the hospitalization. Assessment of nutritional status using questionnaires and biomarkers might be helpful in determining risk of hypoglycemia. Moreover, administration of oral nutritional supplements was shown to decrease this risk.It is also well known that a high burden of comorbidities is associated with an increased risk of hypoglycemia. For example, kidney disease, whether acute or chronic, was shown to increase the risk for hypoglycemia, as well as some endocrine disorders.In this review we elaborate on specific findings that are characteristic of patients at risk for developing hypoglycemia, as well as treatment aimed at preventing its occurrence.

Association between vitamin C deficiency and dialysis modalities

AIM

  We designed a cross-sectional study to investigate plasma vitamin C level in patients who underwent maintenance haemodialysis (MHD) and continuous ambulatory peritoneal dialysis (CAPD) to explore whether there is a difference in vitamin C deficiency between MHD patients and CAPD patients.

METHODS

  This investigation included 382 dialysis patients without vitamin C supplement before the study. Demographic characteristics, laboratory tests, ascorbic acid and total plasma vitamin C level were measured. A linear regression model was built to explore the association between vitamin C deficiency and dialysis modalities after adjusting for age, dialysis vintage, gender, Charlson index, modality of dialysis and hsCRP.

RESULTS

  The range of plasma vitamin C level was from 0.48 µg/mL to 31.16 µg/mL. 35.9% (n = 137) patients had severe vitamin C deficiency (<2 µg/mL). Plasma vitamin C level was inversely associated with age and dialysis vintage. After age and dialysis vintage were adjusted, vitamin C deficiency was associated with MHD. R square for model fitting was relatively low, which implied that there were other vitamin C influencing factors not included in the model.

CONCLUSIONS

  Vitamin C deficiency is common in dialysis patients, especially in patients treated with MHD.

Urinary proteomic analysis of chronic allograft nephropathy

The pathogenesis of progressive renal allograft injury, which is termed chronic allograft nephropathy (CAN), remains obscure and is currently defined by histology. Prospective protocol-biopsy trials have demonstrated that clinical and standard laboratory tests are insufficiently sensitive indicators of the development and progression of CAN. The study aim was to determine if CAN could be characterized by urinary proteomic data and identify the proteins associated with disease. The urinary proteome of 75 renal transplant recipients and 20 healthy volunteers was analyzed using surface enhanced laser desorption and ionization MS. Patients could be classified into subgroups with normal histology and Banff CAN grades 2-3 with a sensitivity of 86% and a specificity of 92% by applying the classification algorithm Adaboost to urinary proteomic data. Several urinary proteins associated with advanced CAN were identified including α1-microglobulin, β2-microglobulin, prealbumin, and endorepellin, the antiangiogenic C-terminal fragment of perlecan. Increased urinary endorepellin was confirmed by ELISA and increased tissue expression of the endorepellin/perlecan ratio by immunofluoresence analysis of renal biopsies. In conclusion, analysis of urinary proteomic data has further characterized the more severe CAN grades and identified urinary endorepellin, as a potential biomarker of advanced CAN.

Serum prealbumin is higher in peritoneal dialysis than in hemodialysis: a meta-analysis

BACKGROUND

Although not widely appreciated, the reported concentration of serum prealbumin, like that of serum cholesterol, tends to be higher in patients on peritoneal dialysis (PD) than on hemodialysis (HD), despite the substantial loss of protein during PD.

METHODS

The mean difference in serum prealbumin was quantified by meta-analysis of the mean differences found in six cohorts with both PD and HD patients (set 1; N = 639) using a fixed-effects model, and meta-analysis of the mean prealbumin values reported in 23 cohorts of unselected dialysis patients on a single modality (set 2; 9 PD cohorts, 14 HD cohorts; N = 12,256) using a mixed model. For comparison, the mean difference in serum albumin concentration between PD and HD also was estimated in sets 1 and 2 using the same methods.

RESULTS

In set 1, the mean prealbumin difference (PD-HD) in the individual cohorts ranged from 3.6 to 14.7 mg/dL (P < 0.05 in five cohorts), and the weighted mean difference was 5.4 mg/dL (95% CI, 3.8 to 7.0 mg/dL). In set 2, weighted mean prealbumin was 8.1 mg/dL (95% CI, 5.2 to 10.9 mg/dL) higher in PD than in HD in the entire data set, and 6.9 mg/dL (95% CI, 5.2 to 8.6 mg/dL) higher in a sensitivity analysis that excluded two outlying HD studies. By contrast, weighted mean serum albumin concentration was significantly lower in PD than in HD in both sets 1 and 2; the mean difference was 0.25 g/dL (95% CI, 0.14 to 0.36 g/dL) in set 1 and 0.28 g/dL (95% CI, 0.14 to 0.42 g/dL) in set 2.

CONCLUSIONS

Serum prealbumin level is approximately 6 mg/dL higher in PD than HD, perhaps due to the stimulation of hepatic synthesis by PD albumin loss, while serum albumin is approximately 0.3 g/dL lower in PD. Different reference ranges and clinical targets (such as, K/DOQI guidelines) are needed for PD and for HD.

Rise in serum albumin and creatinine in the first half year on hemodialysis

Rise in serum albumin and creatinine in the first half year on hemodialysis.

BACKGROUND

Serum albumin and creatinine have been reported to rise in new hemodialysis patients; however, these trends have not been quantitated in a stable cohort, and their determinants and prognostic value are unknown.

METHODS

This study examined the changes in monthly values of serum albumin and creatinine over the first half year of hemodialysis in 115 patients who survived to the start of the sixth month. After verifying that the trends were approximately linear, we calculated the rates of rise (slope) of six predialysis values of serum albumin (months 1 through 6) and of creatinine (months 2 through 7) and examined their associations with age, diabetes, race, baseline 24-hour urine protein and creatinine excretion, and survival during the latter half of the first year.

RESULTS

Serum albumin rose by 13% over months 1 through 6 [0.08 +/- 0.12 (SD) g/dl/month, P < 10-9 vs. zero slope]. Patients who survived the entire year had higher mean values for both serum albumin (month 1, P < 0.003; months 3 through 6, P < 10-3) and rate of rise of albumin (0.09 +/- 0.11 g/dl/month vs. 0.01 +/- 0.13 g/dl/month, P < 0.005) than patients who died during months 6 through 12, but the slope was not an independent predictor of survival after adjusting for serum albumin concentration. Baseline proteinuria correlated inversely with serum albumin measured at the first and second months (P < 0.005) and directly with the albumin slope (r = 0.49, P < 10-5). Serum creatinine rose by 12% between months 2 through 7 (0.12 +/- 0.47 mg/dl/month, P < 0.02). Survivors had a significantly higher mean baseline creatinine excretion (P < 0. 03) and serum creatinine (month 2, P < 0.03; months 3 through 7, P < 0.01) but only a marginally higher rate of rise of serum creatinine (0.16 +/- 0.47 mg/dl/month vs. -0.07 +/- 0.48 mg/dl/month, P < 0.06) than patients who died during the second half of the year. Baseline urinary creatinine excretion correlated directly with serum creatinine at month 2 (P < 0.01) and more strongly at months 3 through 7 (P < 10-3), as well as correlating with the creatinine slope (r = 0.26, P < 0.03).

CONCLUSIONS

Serum albumin and creatinine rose by 12 to 13% during the first half year of hemodialysis in a stable cohort. The slope of serum albumin versus time predicted survival, but it was not as predictive as the absolute albumin concentration. The pattern of correlations of baseline urinary protein and creatinine excretion with the respective monthly serum values of albumin and creatinine and their slopes is consistent with the hypothesis that as residual renal function declines, progressive retention of protein and creatinine contributes to the respective rises in serum albumin and creatinine.

Urine Protein Electrophoresis of End-Stage Diabetic Nephropathy Patients on Dialysis Using Room Temperature Precipitation Technique

Proteinuria is one of the markers of renal diseases. Its quantitative measurement alone has limited diagnostic conclusions. Electrophoresis procedures have been applied for further differentiation. To determine the extent of precipitated proteinuria as a diagnostic and clinical marker tool, I have used the precipitated urine proteins without any chemical or heat for protein precipitation utilizing a new feasible and practicable approach. Two samples of urine (5 c.c. each) after 24 hours of dialysis were collected from 10 end-stage renal failure diabetic nephropathy patients (Salmaniya Medical Center) and 5 normal healthy persons without any history of renal and diabetic involvement. The samples were dried at room temperature without adding any chemical for 24 hours and precipitated urine was diluted in distilled water. They were run on Beckman apparatus Paragon Electropheresis System and scanned for electrophoresis bands for the following proteins in BDF hospital: albumin, alpha 1, alpha 2, beta, and gamma. The pattern of electrophoresis graph and bands were different in the urine of patients compared to the urine of healthy persons. There were alterations in alpha 1 and 2 proteins in the urine of patients with ESRF. This technique illustrates a feasible approach to estimate the protein alteration in ESRF of diabetic nephropathy patients and to develop a marker for clinical development of diabetic nephropathy patients, that could be used as a tool for further studies with, for example, diabetic nephropathy patients without ESRF and diabetic patients without nephropathy of both IDDM and NIDDM.