Objectives To study the basic mechanism of cell death (autophagy, apoptosis and necrosis) typical of patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and systemic scleroderma (SSD). During systemic connective tissue diseases and especially in SLE, a close relationship between various types of cellular death is observed.

Methods 7 SLE-, 10 RA-, 10 SSD patients’ and 5 donors’ sera were studied. The level of Ca ions was registered by the method of atomic absorption spectrometry. Adenosine monophosphate-activated protein kinase (AMPK) was estimated by the Western blotting method. The activity of ATP-ase was measured spectrophotometrically. In order to find out the level of p53 protein, the immune-enzyme “Human p53 Platinum ELISA” method was employed. The quantity of hemoprotein (Cyt c) and the level of 8-hydroxy-2’-deoxyguanosine (8-OH-dG) was measured by employing the immune-enzyme method.

Results Assessing the functional activity of AMPK is an specific marker and a strategic biopower regulator of autophagy, as well as a specific indicator of red-ox cellular potential. In systemic connective tissue diseases, the oxidative stress is matched by urinary calcium and a decrease in the level of calcium in the blood. It reflects the level of seriousness of osteoporosis especially in case of RA. Molecular chaperones (HSP) play a key role in the changing of the way of cellular death. The family of chaperones HSP60 – HSP 100 shows ATPase activity which is most distinct during SLE and RA. The de-energisation of cells during systemic connective tissue diseases and the disappearing of the link between respiration and oxidative phosphorylation lead to proapoptotic protein – Cyt c is being released from mitochondria. High levels of Cyt c reflect cellular mitochondrial apoptosis and show the growing of hypoxia in SLE and RA. The level of protein p53 – a biological marker of apoptosis – is expressed when the DNA is destroyed. It reflects a higher level of the oxidative damage done to the DNA and the extent of the oxidative stress in SLE. This is also evidenced by the data collected by finding out the level of 8-OH-dG which is a biological marker of the free-radical damage of the DNA.

Comparison of markers of autophagy, apoptosis and necrosis in sera in SLE, RA and SSD: AMPK activity (units·mg of protein), the total level of ATP-ase active of HSP-60 – HSP-100 (nmol Pi/min·mg protein), (mM/l), quantity of (ng/ml): Cyt c, p53-protein, 8-OH-dG

Conclusions Chaperone-mediated induction of the immune response by autophagy, an evolutionary enshrined only in mammals, perhaps, is the central link in the pathogenesis of systemic connective tissue diseases.

Reference [1] Shishkin VI, et al. Ann Rheum Dis2017;76:6–507.

Disclosure of Interest None declared