High cryo-resistance of SARS-CoV-2 virus: Increased risk of re-contamination at transplantation of cryopreserved ovarian tissue after COVID-19 pandemic

Abstract

Cryopreservation and re-transplantation of ovarian tissue after anticancer treatment is important medical technology. Today, during a pandemic, the risk of contamination of transplanted cells with SARS-CoV-2 virus is extremely high. Data about cryo-resistance (virulence and/or infectivity) of SARS-CoV-2 are limited. Analysis and systematization of literature data allow us to draw the following conclusions: 1) The cytoplasmic membrane of somatic cell, like envelope of corona viruses, consists of lipid bilayer and this membrane, like envelope of corona virus, contains membrane proteins. Thus, we can consider the cytoplasmic membrane of an ordinary somatic cell as a model of the envelope membrane of SARS-CoV-2. It is expected that the response of the virus to cryopreservation is similar to that of a somatic cell. SARS-CoV-2 is more poor-water and more protein-rich than somatic cell, and this virus is much more cryo-resistant. 2) The exposure of somatic cells at low positive temperatures increases a viability of these cells. The safety of the virus is also in direct proportion to the decrease in temperature: the positive effect of low temperatures on SARS-CoV-2 virus has been experimentally proven. 3) Resistance of SARS-CoV-2 to cryoprotectant-free cryopreservation is extremely high. The high viability rate of SARS-CoV-2 after freezing-drying confirms its high cryo-resistance. 4) The risk of SARS-CoV-2 infection after transplantation of cryopreserved ovarian tissues that have been contaminated with this virus, increases significantly. Our own experimental data on the increase in the viability of cancer cells after cryopreservation allow us to formulate a hypothesis about increasing of viability (virulence and/or infectivity) of SARS-CoV-2 virus after cryopreservation.

Stability of SARS-CoV-2 in cold-chain transportation environments and the efficacy of disinfection measures

“…Researchers have shown that salt enhances the thermostability of viruses by increasing van der Waals forces( Meister et al., 2020 ). Although SARS-CoV-2, with a lipid envelope, is more tolerant to low temperatures than viruses without an envelope ( Yao et al., 2020 ; Isachenko et al., 2021 ), it still can freeze. Without cryoprotectants, the protein activity will be affected by the freezing and thawing rate, and the structural protein on the virus envelope may change due to freezing and thawing ( Cao et al., 2003 ).…”

Impact of the COVID-19 pandemic on ovarian tissue cryopreservation planning in the Bologna clinical center

“…A relevant risk in cryopreservation is the potential transmission of pathogens during preparation and cryopreservation procedures. Although, the transmission of pathogens in samples stored in fertility cryobanks has never been reported ( 21 ), the cryo-resistance of SARS-CoV-2 is extremely high ( 22 ). So it is important to understand and mitigate these risks through safety and precautionary measures.…”

Oncofertility and COVID-19: At the Crossroads between Two Time-Sensitive Fields

“…For fertility preservation purposes, reproductive cells and tissues are treated with specific cryoprotectants and immersed in liquid nitrogen (LN2) at ultra-low cooling temperatures of −196 °C [ 68 , 69 , 70 ]. Due to its high protein structure and low water content, the SARS-CoV-2 virus has an increased cryo-resistance, being stable at 4 °C, reaching maximum viability [ 71 ]. It is known that due to the presence of cryoprotectants, viruses can survive the freezing and thawing procedures, and hence one of the main concerns surrounding FP was the possibility of SARS-CoV-2 indefinite survival in LN2 and transmission at the moment of fertility restoration [ 72 ].…”