Ganoderma lucidum spore powder is a traditional Chinese medicine with a variety of health benefits. Sporoderm-removed Ganoderma lucidum spores (RGLS) can be more effectively absorbed and utilized by the body. Due to the extensive clinical application and lack of long-term (>30 days) safety evaluation of RGLS, it is necessary to evaluate its repeated dose toxicity during a longer administration period. Here, we conducted a 26-week repeated dose toxicity test of RGLS in Sprague‒Dawley (SD) rats. The male and female rats were orally administered RGLS at doses of 0, 0.4, 1.2, and 4.0 g/kg once daily for a period of 26 weeks. The safety profile of RGLS was assessed through in vivo observations of survival, body weight, and food consumption; hematological, biochemical, and urine analyses; immunotoxicity assays; and histopathological examinations. The results showed that no significant systemic toxicity was observed following 26 weeks of repeated RGLS administration. Our data showed a no-observed adverse effect level (NOAEL) of 4.0 g/kg, which is approximately 20 times higher than the human equivalent dose. Our results support that RGLS can be considered a safe medicinal or food product that can be added to a healthy diet.

Human umbilical cord mesenchymal stem cells (hUC-MSCs) are proposed for the treatment of acute lung injury and atopic dermatitis. To advance hUC-MSC entry into clinical trials, the effects of hUC-MSCs on the general toxicity, immune perturbation and toxicokinetic study of hUC-MSCs in cynomolgus monkeys were assessed. hUC-MSCs were administered to cynomolgus monkeys by intravenous infusion of 3.0 × 10⁶ or 3.0 × 10⁷cells/kg or by subcutaneous injection of 3.0 × 10⁷cells/kg twice a week for 3 weeks followed by withdrawal and observation for 6 weeks. Toxicity was assessed by clinical observation, clinical pathology, ophthalmology, immunotoxicology and histopathology. Moreover, toxicokinetic study was performed using a validated qPCR method after the first and last dose. After 3rd or 4th dosing, one or three the monkeys in the intravenous high-dose group exhibited transient coma, which was eliminated by slow-speed infusion after 5th or 6th dosing. In all dose groups, hUC-MSCs significantly increased NEUT levels and decreased LYMPH and CD3⁺ levels, which are related to the immunosuppressive effect of hUC-MSCs. Subcutaneous nodules and granulomatous foci were found at the site of administration in all monkeys in the subcutaneous injection group. Other than above abnormalities, no obvious systemic toxicity was observed in any group. The hUC-MSCs was detectable in blood only within 1 h after intravenous and subcutaneous administration. The present study declared the preliminary safety of hUC-MSCs, but close monitoring of hUC-MSCs for adverse effects, such as coma induced by intravenous infusion, is warranted in future clinical trials.

Although the new coronavirus disease 2019 (COVID-19) outbreak occurred in late 2019, it is still endemic worldwide, and has become a global public health problem. Vaccination against SARS-CoV-2 is considered to be the most effective intervention to prevent the spread of COVID-19. ZF2001 is a recombinant protein vaccine based on SARS-CoV-2 receptor-binding domain (RBD) subunit which contains aluminum adjuvant. In order to advance our research on ZF2001 into clinical trial, we investigated the general toxicity and immunogenicity of ZF2001 in cynomolgus monkeys and assessed the possible target organs for vaccine-induced toxicity. In the present research, we observed no significant systemic toxicities and abnormal cardiovascular and respiratory events following four times injections of intramuscular ZF2001 in cynomolgus monkeys. Histological examination revealed recoverable inflammatory changes in quadricep muscle and adjacent lymph node at the vaccine injection site. As expected, the vaccine can produce a strongly specific binding antibody and neutralizing antibodies in cynomolgus monkeys after inoculation. Taken together, our regulatory toxicology research proves the safety and immunogenicity of the ZF2001 vaccine, supporting its entry into large scale clinical trials.

Atopic dermatitis (AD) management is significantly challenging due to the high prevalence, chronicity, and recurrent nature of the disease, and limited options for its treatment. Human umbilical cord mesenchymal stem cells (hUC-MSCs) exhibit potential effects against AD; however, the mechanisms underlying these effects remain largely unexplored. AD mouse models were established using 1-chloro-2,4-dinitrobenzene (DNCB) and ovalbumin (OVA). The therapeutic effects of subcutaneously administered hUC-MSCs and their conditioned medium (hUC-MSC-CM) were evaluated through histopathology, western blotting, PCR, ELISA, and flow cytometry. Mechanistic studies included RNA sequencing, cytokine arrays, and exosome characterization. Both hUC-MSCs and hUC-MSC-CM significantly alleviated AD-like symptoms, including erythema, epidermal thickening, and inflammatory cell infiltration in DNCB- and OVA-induced models. There was a decrease in serum IgE levels and histological analyses confirmed attenuated skin damage in these models. Moreover, neither hUC-MSCs nor hUC-MSC-CM induced weight loss. Mechanistically, hUC-MSC-CM suppressed neutrophil migration in the skin and inhibited keratinocyte-derived chemokine (e.g., CCL5 and CXCL11) secretion. Additionally, hUC-MSC-derived exosomes reduced chemokine production in keratinocytes, mediated by the STAT3 signaling pathway. This study demonstrated that hUC-MSCs and hUC-MSC-CM ameliorate AD-like symptoms, possibly through exosome-dependent suppression of the STAT3 signaling pathway and chemokine expression. Furthermore, hUC-MSC-CM serves as a cell-free alternative to whole-cell therapy, with comparable efficacy, offering novel mechanistic insights and a potential translational strategy for AD treatment.

Coronavirus disease 19 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), had given rise to a massive epidemic. Owing to the high morbidity and mortality of COVID-19 and the lack of effective therapies, safe and effective vaccination is the optimum choice for controlling this epidemic and preventing infection. The protein subunit vaccine ZF2001, which targets the receptor-binding domain (RBD) protein of SARS-CoV-2, has a significant protective effect against COVID-19. At the beginning of the COVID-19 epidemic, to promote the early approval of ZF2001 for clinical trials by the National Medical Products Administration of China (NMPA), a comprehensive evaluation of its toxicity in vivo was warranted. In the present study, a major part of the above series of studies, we evaluated the safety, immunogenicity and efficacy of the ZF2001 vaccine for the first time in adult Sprague Dawley (SD) rats. The male and female rats were administered three doses of the ZF2001 vaccine (25 μg or 50 μg NCP-RBD protein/dose, containing the aluminum-based adjuvant). The safety profile of ZF2001 was assessed by observing the general health status, local toxicity at the site of administration, immunotoxicity, immunogenicity, blood chemistry and hematology parameters in SD rats. In general, our results indicated that the ZF2001 vaccine did not induce significant systemic toxicity in rats, with a no-observed adverse effect level (NOAEL) of 50 μg NCP-RBD protein/rat. Moreover, the ZF2001 vaccine showed good immunogenicity by inducing the production of specific IgG antibodies in rats after three consecutive immunizations. In addition, histological examination revealed recoverable inflammatory changes in quadricep muscles and adjacent lymph nodes at the vaccine injection site. In summary, our systematic toxicology study proves the safety, tolerability and immunogenicity of the ZF2001 vaccine, which further supports the results of clinical trials of ZF2001.