[Retrospective clinical and morphological analysis of patients with AL amyloidosis (the 2008 to 2015 nephrobiopsies)]

OBJECTIVE

To study correlations between the clinical signs of dysfunction and pathological structural changes in the renal parenchyma in a group of Russian patients with AL amyloidosis in 2008-2015.

SUBJECTS AND METHODS

A total group (At) including Group 1 with AL (kappa + lambda light chains) (n=46) was divided into subgroups: 2λ) 40 patients with AL-lambda (AL-λ); 3κ) 6 patients with AL-kappa (AL-κ). All the patients underwent standard laboratory and instrumental studies: determinations of the peak systolic and diastolic blood pressures (SBP and DBP, respectively, mm Hg), glomerular filtration rate (GFR) (ml/min/1.73 m²) by the EPI equation, daily protein loss (g/day). Polyclonal antibodies against kappa and lambda light chains, AA component, and transthyretin (DAKO, Denmark) were used as immunomorphological markers. Light optical structural changes were semiquantitatively assessed, by ranking the following analyzed sign: interstitial focal sclerosis (FS), tubular atrophy (TA), interstitial inflammatory infiltration (II) semi-quantitatively (0 - no; 1 - < 25%; 2 - <50%, 3 - >50% of the volume of a histological compartment). Glomerulosclerosis (GS) was defined as the percentage of sclerotic glomeruli. The extent of amyloid depositions in the renal parenchyma structures was estimated according to the procedure proposed by Ying Yao et al., 2013.

RESULTS

The AL group showed a female preponderance (65.21%). The patients' mean age was 62±11 years. There were no significant differences in daily proteinuria and the levels of serum creatinine, GFR, SBP, and DBP between the groups. The predominant clinical manifestation in the patients was nephrotic syndrome. A comparative analysis of the pathomorphological criteria for the spread of amyloid masses and the markers of fibroplastic processes revealed no statistically significant differences in the studied groups. Correlation analysis of the spread of AL deposits in the renal parenchyma in the patients of Group 1 and Subgroup 2λ, as well as laboratory data showed that there were significant (p<0.05) correlations with GFR, serum creatinine, unlike in Subgroup 3κ. At the same time, the analysis demonstrated that daily proteinuria had a significant positive correlation with VA, IA, GA, and TA values in Subgroup 3κ, unlike in Group 1 and Subgroup 2λ. Positive correlations were found between glomerulosclerosis and VA in Subgroup 2 λ and IA in Group 1. Sclerotic (FS and TA) changes in the tubular interstitium (TIN) were significantly positively correlated with all the indicators of AL (GA, VA, IA, TA) in the examinees in Group 1 and Subgroup 2λ, but not in Subgroup 3κ. Inflammatory TIN infiltration showed statistically significant (p<0.05) positive correlations with IA and VA in Group 1 and Subgroup 2λ and their absence in subgroup 3κ.

CONCLUSION

: The retrospective analysis of nephrobiopsy specimens from of patients with AL amyloidosis revealed that kidney damage was mainly associated with the development of λ-associated AL amyloidosis. The clinical and laboratory parameters were correlated with the pathomorphological criteria for loading the renal parenchyma with amyloid masses. The findings suggest that there are clinical and morphological features of the subclasses of AL amyloidosis, which may be of value for predicting the course and progression of the disease.

Cold and distant: structural features of the nucleoprotein complex of a cold-adapted influenza A virus strain

Two influenza A nucleoprotein variants (wild-type: G102R; and mutant: G102R and E292G) were studied with regard to macro-molecular interactions in oligomeric form (24-mers). The E292G mutation has been previously shown to provide cold adaptation. Molecular dynamics simulations of these complexes and trajectory analysis showed that the most significant difference between the obtained models was distance between nucleoprotein complex strands. The isolated complexes of two ribonucleoprotein variants were characterized by transmission electron microscopy and differential scanning fluorimetry (DSF). Presence of the E292G substitution was shown by DSF to affect nucleoprotein complex melting temperature. In the filament interface peptide model, it was shown that the peptide corresponding in primary structure to the wild-type NP (SGYDFEREGYS) is prone to temperature-dependent self-association, unlike the peptide corresponding to E292G substitution (SGYDFGREGYS). It was also shown that the SGYDFEREGYS peptide is capable of interacting with a monomeric nucleoprotein (wild type); this interaction's equilibrium dissociation constant is five orders of magnitude lower than for the SGYDFGREGYS peptide. Using small-angle neutron scattering (SANS), the supramolecular structures of isolated complexes of these proteins were studied at temperatures of 15, 32, and 37 °C. SANS data show that the structures of the studied complexes at elevated temperature differ from the rod-like particle model and react differently to temperature changes. The data suggest that the mechanism behind cold adaptation with E292G is associated with a weakening of the interaction between strands of the ribonucleoprotein complex and, as a result, the appearance of inter-chain interface flexibility necessary for complex function at low temperature.Communicated by Ramaswamy H. Sarma.

COMPARISON OF INFLUENZA A VIRUS INHIBITION IN VITRO BY SIRNA COMPLEXES WITH CHITOSAN DERIVATIVES, POLYETHYLENEIMINE AND HYBRID POLYARGININE-INORGANIC MICROCAPSULES

Anti-influenza drugs and vaccines have a limited effect due to the high mutation rate of virus genome. The direct impact on the conservative virus genome regions should significantly improve therapeutic effectiveness. The RNA interference mechanism (RNAi) is one of the modern approaches used to solve this problem. In this work, we have investigated the antiviral activity of small interfering RNA (siRNA) against the influenza A/PR/8/34 (H1N1), targeting conserved regions of NP and PA. Polycations were used for intracellular siRNA delivery: chitosan's derivatives (methylglycol and quaternized chitosan), polyethyleneimine, lipofectamine, and hybrid organic/non-organic microcapsules. A comparative study of these delivery systems with fluorescent labeled siRNA was conducted. The antiviral activity of three small interfering RNAs targeting the NP (NP-717, NP-1496) and PA (PA-1630) influenza A viruses genes was demonstrated, depending on the chosen carrier. The most effective intracellular delivery and antiviral activity were observed for hybrid microcapsules.