Gerardo Guillen

Background/Objective: Long-term nucleos(t)ide analog (NUC) therapy effectively suppresses hepatitis B virus (HBV) replication, but it rarely achieves a functional cure and typically requires lifelong administration. A major unmet need in chronic hepatitis B (CHB) is the development of safe and effective strategies to discontinue NUCs without compromising viral control or hepatic safety. This exploratory, randomized pilot study evaluated therapeutic immunization in the context of discontinuation of antiviral therapy in HBeAg-negative CHB. Methods: Twenty-six HBeAg-negative CHB patients receiving long-term therapy with NUCs were randomized to either discontinue NUCs and switch to HeberNasvac (NASVAC), a therapeutic vaccine (n = 13), or receive NASVAC in addition to NUCs (n = 13). Virological, serological, biochemical, and safety parameters were assessed during a 52-week primary follow-up. In particular, ALT and AST were evaluated every 2 weeks during the first 6 months after NUC discontinuation. An extended monitoring period from weeks 96 to 192 was designed to assess virological and biochemical variables. Results: At week 48, HBV DNA remained below 2000 IU/mL in 92.3% of patients who discontinued NUCs and received NASVAC and in 100% of those who received both NUCs and NASVAC. During extended follow-up, HBV DNA < 2000 IU/mL persisted in 84.6% and 76.9% of patients in the NUC discontinuation group at weeks 96 and 192, respectively, and in 100% of patients in the continuation group (NASVAC added to NUCs) at both time points. In the first 48 weeks after NUC discontinuation, NASVAC induced a limited but significant decline in serum quantitative HBsAg. Liver function, renal, and hematological parameters remained stable, without significant ALT abnormalities, biochemical exacerbations, fibrosis progression, or severe adverse events during primary or extended follow-up. None of the patients required restarting treatment. Conclusions: NASVAC-based immunotherapy demonstrated durable virological control, a limited but progressive reduction in qHBsAg, and a strong long-term safety profile following the complete withdrawal of antiviral therapy. This exploratory study suggests that NASVAC can be administered in the context of NUC discontinuation with an acceptable short- and long-term safety profile, but controlled trials are required to determine whether therapeutic vaccination contributes independently to sustained off-treatment viral control.

Introduction: Evolutionary divergence between regeneration competent and regeneration incompetent species reflects distinct tissue repair programs. While aquatic and semi aquatic vertebrates activate a highly coordinated regenerative cascade-involving rapid re-epithelialization, apical epidermal cap formation and blastema proliferation supported by mesenchymal cell plasticity, permissive immune modulation and efficient senescenT-cell clearance-mammalian wound repair is usually fibrotic. Aims: This review discusses current evidence and hypotheses explaining why mammals, despite retaining many regeneration associated genetic pathways, tend to follow a fibrotic healing program. Translational strategies to restore regenerative capacity are also explored. Methods: This narrative synthesis integrates comparative evidence on wound re epithelialization, blastema biology, immune regulation, fibroblast activation and senescence associated constraints on tissue repair. Results: In mammals, transforming growth factor beta and mechanical stress drive fibroblast to myofibroblast differentiation, collagen deposition, wound contraction and expansion of scar promoting lineages such as Engrailed 1 positive and paired related homeobox 1 expressing fibroblasts. Keratinocytes fail to generate a functional apical epidermal cap, while robust tumor suppressor activity and persistent senescenT-cells further restricT-cellular plasticity-prioritizing rapid wound closure and pathogen defense over structural restoration. The immune inflammatory response is a critical determinant of divergent outcomes: regeneration competent species mount a tightly regulated, pro resolving response with T-lymphocytes and regulatory T-cells fostering progenitor activation, whereas mammals exhibit prolonged, maladaptive immune activity that sustains fibrosis. Conclusions: Many regeneration-related pathways remain conserved in mammals, but appear to be dormant. This suggests that regenerative repair may still be biologically accessible if the right epithelial, mesenchymal and immune signals can be restored. Approaches based on stem cells, biomaterial scaffolds and immune reprogramming may therefore help shift repair away from fibrosis and toward regeneration, addressing pressing unmet needs in wound care, fibrosis and organ transplantation.

Cognitive decline is a hallmark of neurodegenerative diseases. The complex pathophysiology of these diseases has limited the efficacy of current therapies. The co-administration of epidermal growth factor (EGF) and growth hormone-releasing peptide 6 (GHRP6) emerges as a promising neuroprotective candidate. The present study evaluated the therapeutic potential of this combination in two preclinical models of cognitive impairment: (i) age-related decline and (ii) impairment induced by intracerebroventricular administration of streptozotocin (STZ). In both experiments, C57BL/6 mice were used and distributed into three experimental groups, each comprising 14-15 animals per group. Cognitive and motor function was assessed through gait pattern, Y-maze and novel object recognition tests. Differential gene expression was analyzed using qPCR. Both models reproduced hallmark features of cognitive decline, including deficits in working and spatial memory and changes in the expression of genes associated with oxidative stress, neuroinflammation and synaptic plasticity. In aged animals, EGF + GHRP6 treatment increased step length (p = 0.04). In the forced alternation Y-maze test, aged-EGF + GHRP6 animals made more visits to the novel arm than to the familiar arm 1 (p = 0.001) or to the familiar arm 2 (p = 0.04). Cognitive benefits were also observed in the STZ-induced model. STZ-EGF + GHRP6 group exhibited an alternation percentage higher than the STZ-vehicle group (p = 0.03). Moreover, EGF + GHRP6 treatment significantly increased the expression of genes associated with antioxidant defense (Hmox1), synaptic plasticity (Creb1), and oligodendrocyte differentiation (Olig1) while concurrently reducing the expression of Nfkb1. These findings highlight the therapeutic potential of EGF + GHRP6 co-administration as a neuroprotective strategy to mitigate neurodegeneration and preserve cognitive function.

Combined therapy with epidermal growth factor (EGF) and growth hormone-releasing peptide 6 (GHRP6) has demonstrated neuroprotective effects in models of global and focal brain ischemia. Clinical studies in ischemic stroke patients have confirmed the safety and preliminary efficacy of this combined treatment. This study aimed to elucidate the molecular mechanisms underlying the effects of EGF+GHRP6 co-administration. Male Wistar rats were subjected to endothelin-1 (ET-1)-induced middle cerebral artery (MCA) occlusion and randomly assigned to three experimental groups: EGF+GHRP6‑treated ischemic, vehicle‑treated ischemic, and sham-operated controls (n = 12 per group). Label-free quantitative proteomic analysis of the ischemic penumbra was performed at 3 and 24 h post-treatment. Functional enrichment and pathway analysis of differentially modulated proteins were performed using bioinformatics tools. Proteomic profiling validated the ischemic model and revealed 40 and 223 proteins differentially modulated by EGF+GHRP6 at 3 and 24 h, respectively. Proteins involved in neurotransmitter transport were consistently overrepresented in the EGF+GHRP6-regulated proteome at both time points. At 24 h post-treatment, proteins associated with reactive oxygen species (ROS) detoxification, heat shock factor 1 (HSF1) activation, and negative regulation of cellular hypoxia response were significantly modulated. Additionally, anti-apoptotic and mitochondrial proteins were modulated in the ischemic penumbra, supporting the neuroprotective effects of EGF+GHRP6. Notably, proteins known to attenuate brain damage after stroke were up-regulated, while those promoting ischemic injury were down-regulated following the combined treatment. These findings provide molecular evidence supporting the neuroprotective mechanism of action of EGF+GHRP6 co-administration and reinforce its potential as a therapeutic strategy for ischemic stroke.

Background/Objective: GHRP-6 is a GH secretagogue hexapeptide with expanding and promising cardioprotective effects. Having determined 0.4 mg/kg as the minimum effective dose for enhancing inotropy based on echocardiographic parameters in healthy rats, we implemented a non-reperfusion myocardial infarct model, with its consequent left ventricle wall thinning and ballooning, via permanent left descending coronary artery ligation. Methods: Rats were assigned to three groups: sham-operated/normal rats, infarcted + saline-treated control rats, and infarcted + GHRP-6-administration rats. Treatments were initiated post-surgery and continued for 7 days. On day 7, the animals were echocardiographically and histologically evaluated. For mitochondrial proteomic analysis, an additional 12 healthy rats were used. Six animals received GHRP-6 or normal saline and were observed for 6 h after the inoculation. Results: Here, we show that GHRP-6 attenuated myocardial tissue demise, reduced myocardial interstitial fibrosis/scarring, and integrally improved left ventricle physiology. The proteomic analysis indicated that the GHRP-6 cardioprotective effects may be theoretically mediated by the concerted upregulation of proteins/pathways involved in fatty acid beta-oxidation, apoptosis prevention pathways, antioxidant defenses, and mitochondrial metabolic reprogramming. Conclusions: GHRP-6 is a potent cardioprotective candidate attenuating morphological and functional outcomes caused by late ischemia.

The COVID-19 pandemic has had a profound impact on the world. While the disease is currently under control, the emergence of new coronavirus variants with pandemic potential underscores the need for more universal coronavirus vaccines. This study evaluates the immunogenicity in non-human primates of two broad-spectrum nasal vaccine candidates called PanCoV. The vaccine preparations are based on highly conserved regions of SARS-CoV-2, specifically the nucleocapsid (N) and the S2 subunit from Spike protein, which include several relevant T-cell epitopes and have the potential to form virus-like particles. PanCoV1 candidate contains the N protein, while the PanCoV2 comprises a chimeric protein containing the C-terminal domain of N protein fused to a fragment of S2 subunit. Both vaccine candidates also include the receptor-binding domain (RBD) from Spike protein and the ODN-39M as CpG adjuvant. The results demonstrate that both nasal vaccine candidates can boost the anti-RBD immune response and induce anti-N immunity, this systemic response shows cross-reactivity with SARS-CoV, MERS-CoV, and H-CoV antigens. In addition, a neutralizing response against SARS-CoV-2 that persisted for almost three months after the last dose was induced. A mucosal-specific and cross-reactive IgA response was also observed, mainly in monkeys vaccinated with PanCoV2. Furthermore, the specific IFNγ-secreting response observed in the vaccinated groups peripheral blood mononuclear cells highlights the ability of these candidates to stimulate cellular immunity with a Th1 bias. PanCoV vaccines emerge as promising candidates for use as a booster alternative, with the potential to amplify and broaden the scope of the immune response against coronaviruses.

Jusvinza is an immunomodulatory drug composed of an altered peptide ligand (APL) designed from a novel CD4+ T cell epitope of human heat shock protein 60 (HSP60), an autoantigen involved in the pathogenesis of rheumatoid arthritis (RA). The peptide induces regulatory T cells and decreases levels of TNF-α and IL-17; pre-clinical and phase I clinical studies support its use for the treatment of RA. This peptide was repositioned for the treatment of COVID-19 patients with signs of hyperinflammation. Neutrophils play a pathogenic role in both RA and severe forms of COVID-19. To add novel evidence about the mechanism of action of Jusvinza, the proteomic profile regulated by this peptide of neutrophils isolated from four RA patients was investigated using LC-MS/MS and bioinformatics analysis. A total of 149 proteins were found to be differentially modulated in neutrophils treated with Jusvinza. The proteomic profile regulated by Jusvinza is characterized by the presence of proteins related to RNA splicing, phagocytosis, endocytosis, and immune functions. In response to Jusvinza treatment, several proteins that regulate the NF-κB signaling pathway were differentially modulated, supporting the peptide’s anti-inflammatory effect. Proteins related to metabolic pathways that supply ATP for cellular functions or lipid metabolites with immunoregulatory properties were also identified. Additionally, several structural components of neutrophil extracellular traps (NETs) were decreased in Jusvinza-treated cells, supporting its impairment of this biological process. Of note, these findings were validated by in vitro experiments which confirmed that Jusvinza decreased NET formation. Such results provide evidence of the molecular mechanism of action and support the therapeutic potentialities of Jusvinza to treat other diseases characterized by hyperinflammation besides RA and COVID-19.

The early expectations about growth factors’ (GFs’) discovery as an undisputed therapeutic solution for chronic wounds progressively eclipsed when they failed to accelerate acute wound closure and restore the healing trajectory of stagnant ulcers. Critical knowledge about chronic wound biology and GF pharmacology was a conundrum at that time. Diabetes undermines keratinocytes’ and fibroblasts’ physiology, impairing skin healing abilities. Diabetic ulcers, as other chronic wounds, are characterized by hyperinflammation, unbalanced proteolytic activity, catabolism, and free radical cytotoxicity. This hostile scenario for the chemical stability, integrity, and functionality of GFs led to the conclusion that topical administration may jeopardize GFs’ clinical effectiveness. Epidermal growth factor (EGF) has a proximal position in tissues homeostasis by activating survival and mitogenic pathways from embryonic life to adulthood. Seminal experiments disclosed unprecedented pharmacological bounties of parenterally administered EGF. Accordingly, the experience accumulated for more than 20 years of EGF intralesional infiltration of diabetic wound bottoms and edges has translated into sustained healing responses, such as low recurrences and amputation rates. This delivery route, in addition to being safe and tolerated, has shown to restore a variety of circulating biochemical markers ordinarily disturbed in diabetic conditions. EGF infiltration triggers a cascade of local fibroblast reactions, supporting its molecular integrity, prolonged mean residence time, and ultimately eliciting its receptor trafficking and nuclear translocation. The intralesional delivery route seems to warrant that EGF reaches wound fibroblasts’ epigenetic core, mitigating the consequences of metabolic memory imprinting.

A phase 1–2, prospective, multicenter, randomized, open-label clinical trial (Code RPCEC00000382), with parallel groups, involving 1161 participants, was designed to assess the safety and immunogenicity of two Cuban COVID-19 vaccines (Mambisa and Abdala) in boosting COVID-19 immunity of convalescent adults after receiving one dose of either vaccine. The main safety outcome was severe vaccination adverse events occurring in 55% of vaccinees in Phase 1 and >70% in Phase 2. Neutralizing antibody titers against SARS-CoV-2 variants were evaluated. Both vaccines were safe—no deaths or severe adverse events occurred. Mild intensity adverse events were the most frequent (>73%); headaches predominated for both vaccines. Phase 1 responders were 83.3% (p = 0.0018) for Abdala. Mambisa showed similar results. Phase 2 responders were 88.6% for Abdala (p < 0.0001) and 74.2% for Mambisa (p = 0.0412). In both phases, anti-RBD IgG titers, inhibition percentages and neutralizing antibody titers increased significantly after the booster dose. Both vaccines were safe and their immunogenicity surpassed the study endpoints.

The immune system is central in controlling acute hepatitis B infection and in patients resolving chronic hepatitis B (CHB). Given that 221 million (75%) of CHB patients reside in low- and middle-income countries, developing a vaccine with therapeutic properties represents a rational and cost-effective approach more than a romantic endeavor. This review systematically analyses the critical variables related to the safety, efficacy, and effectiveness of CHB treatments. HeberNasvac's experience is revisited to address the challenges and potentialities of therapeutic vaccines, as well as the current roadblocks in research and development, registration, and large-scale implementation.