beta 2-Microglobulin and the kidney: an overview

The clinical significance and prognostic value of serum beta-2 microglobulin in adult lymphoma-associated hemophagocytic lymphohistiocytosis: a multicenter analysis of 326 patients

To investigate the prognostic impact of serum beta-2 microglobulin (B2M) in adult lymphoma-associated hemophagocytic lymphohistiocytosis (HLH). The clinical and laboratory characteristics of 326 adult patients in a multicenter cohort with lymphoma-associated HLH with available baseline serum B2M levels were retrospectively analyzed. A total of 326 cases were included in this study, and the median serum B2M level was 5.19 mg/L. The optimal cut-off of serum B2M was 8.73 mg/L, and the cases with serum B2M level >8.73 mg/L were older and had a more advanced stage, lower levels of platelets, albumin, and fibrinogen, and higher creatinine level. The serum B2M >8.73 mg/L, creatinine ≥133 μmol/L, fibrinogen ≤1.5 g/L, agranulocytosis (<0.5 × 109/L), severe thrombocytopenia (<50 × 109/L), and high Epstein-Barr virus DNA copy number were found to have independent prognostic values in all patients, and the serum B2M >8.73 mg/L was also an independent prognostic factor in patients with creatinine <133 μmol/L. Finally, a prognostic scoring system was established based on independent prognostic factors of all patients and categorized the patients into three groups with significant prognostic differences. This study confirmed that the serum B2M level can be an independent prognostic factor in lymphoma-associated HLH and established a prognostic scoring system to predict patients' survival.

Urine β2-Microglobulin and Retinol-Binding Protein and Renal Disease Progression in IgA Nephropathy

Background: Tubulointerstitial involvement has been reported to have a decisive influence on the progression of IgA nephropathy (IgAN). High levels of urine β2-microglobulin (β2-MG) and retinol-binding protein (RBP) were observed in patients with IgAN with tubulointerstitial lesions. However, their roles in disease progression remain unclear. This study aimed to evaluate the associations of urine β2-MG and RBP with the progression of IgAN.

Methods: We retrospectively investigated a cohort of 2,153 patients with IgAN. Clinical and pathological features, outcomes, and urine β2-MG, and RBP at the time of biopsy were collected. The associations, of urine β2-MG and RBP with the composite renal outcome, defined as a decline in estimated glomerular filtration rate (eGFR) of ≥50% from baseline or end-stage renal disease (ESRD), were examined using restricted cubic splines and the Cox proportional hazards models.

Results: During a median follow-up of 20.40 months, 140 (6.50%) patients reached the composite renal outcomes. Restricted cubic splines showed that patients with higher urinary β2-MG and RBP levels had worse renal outcomes. The Cox regression analysis revealed that urine β2-MG and RBP were associated with a risk of the composite renal outcome in the multivariate adjusted model [+1 SD for log β2-MG, hazard ratio (HR) = 1.462, 95% CI: 1.136–1.882, p = 0.003; +1 SD for log RBP, HR = 1.972, 95% CI: 1.486–2.617, p = 0.001]. The associations were detectable within patients with baseline eGFR <90 ml/min/1.73 m² (+1 SD for log β2-MG, HR = 1.657, 95% CI: 1.260–2.180, p < 0.001; +1 SD for log RBP, HR = 1.618, 95% CI: 1.199–2.183, p = 0.002), but not among patients with eGFR ≥90 ml/min/1.73 m².

Conclusion: Higher levels of urine β2-MG and RBP were independent risk factors for renal disease progression in IgAN.

Reference genes for mesangial cell and podocyte qPCR gene expression studies under high-glucose and renin-angiotensin-system blocker conditions

BACKGROUND

Real-time PCR remains currently the gold standard method for gene expression studies. Identification of the best reference gene is a key point in performing high-quality qPCR, providing strong support for results, and performing as a source of bias when inappropriately chosen. Mesangial cells and podocytes, as essential cell lines to study diabetic kidney disease (DKD) physiopathology, demand accurate analysis of the reference genes used thus far to enhance the validity of gene expression studies, especially regarding high glucose (HG) and DKD treatments, with angiotensin II receptor blockers (e.g., losartan) being the most commonly used. This study aimed to evaluate the suitability and define the most stable reference gene for mesangial cell and podocyte studies of an in vitro DKD model of disease and its treatment.

METHODS

Five software packages (RefFinder, NormFinder, GeNorm, Bestkeeper, and DataAssist) and the comparative ΔCt method were selected to analyze six different candidate genes: HPRT, ACTB, PGAM-1, GAPDH, PPIA, and B2M. RNA was extracted, and cDNA was synthesized from immortalized mouse mesangial cells and podocytes cultured in 4 groups: control (n = 5; 5 mM glucose), mannitol (n = 5; 30 mM, as osmotic control), HG (n = 5; 30 mM glucose), and HG + losartan (n = 5; 30 mM glucose and 10-4 mM losartan). Real-time PCR was performed according to MIQE guidelines.

RESULTS

We identified that the use of 2 genes was the best combination for qPCR normalization for both mesangial cells and podocytes. For mesangial cells, the combination of HPRT and ACTB presented higher stability values. For podocytes, HPRT and GAPDH showed the best results.

CONCLUSION

This analysis provides support for the use of HPRT and ACTB as reference genes in mouse mesangial cell studies of gene expression via real-time PCR, while for podocytes, HPRT and GAPDH should be chosen.

Gossypol as a male antifertility agent--why studies should have been continued

It has been nearly three decades since the beginning of nationwide research into gossypol as a male antifertility agent in China. Several lines of data implicating some side effects of gossypol were published which led to the termination of this area of research in China. The present review re-examines these data and points out the confusion surrounding issues such as hypokalaemia, irreversible azoospermia and other side effects. The prospects and related difficulties for gossypol as a potential male contraceptive are also discussed.