The term ‘inflammaging’ has been coined to describe the chronic state of inflammation derived from ongoing cycles of tissue damage and the subsequent immune responses. This inflammatory status contributes to the decline of organs and physiological functions, accelerates the aging process, and increases the risk of age-related illnesses and death. During aging, the gut microbiota (GM) undergoes significant changes, including a decreased diversity of species, a decline in beneficial bacteria, and a rise in proinflammatory ones, resulting in persistent low-grade inflammation. Moreover, environmental factors, such as diet and medications, contribute to age-related changes in GM and immune function, preventing or promoting inflammaging. This narrative review aims to clarify the underlying mechanisms of inflammaging and to specifically investigate the influence of GM and several environmental factors on these mechanisms, while also exploring potential differences related to sex. Moreover, lifestyle and pharmacological interventions will be suggested to promote healthy aging.

In recent years, there has been a growing interest in the concept of the “gut–brain axis”. In addition to well-studied diseases associated with an imbalance in gut microbiota, such as cancer, chronic inflammation, and cardiovascular diseases, research is now exploring the potential role of gut microbial dysbiosis in the onset and development of brain-related diseases. When the function of the intestinal barrier is altered by dysbiosis, the aberrant immune system response interacts with the nervous system, leading to a state of “neuroinflammation”. The gut microbiota–brain axis is mediated by inflammatory and immunological mechanisms, neurotransmitters, and neuroendocrine pathways. This narrative review aims to illustrate the molecular basis of neuroinflammation and elaborate on the concept of the gut–brain axis by virtue of analyzing the various metabolites produced by the gut microbiome and how they might impact the nervous system. Additionally, the current review will highlight how sex influences these molecular mechanisms. In fact, sex hormones impact the brain–gut microbiota axis at different levels, such as the central nervous system, the enteric nervous one, and enteroendocrine cells. A deeper understanding of the gut–brain axis in human health and disease is crucial to guide diagnoses, treatments, and preventive interventions.

Non-communicable diseases (NCDs), including cancer, cardiovascular, neurodegenerative, autoimmune, and allergic diseases, account for a significant amount of global morbidity and mortality. Chronic viral infections have not been recognized as NCDs, despite the availability of several therapeutic vaccination strategies against oncogenic viruses, such as the hepatitis B virus (HBV) and the human papillomavirus (HPV). Indeed, chronic viral infection leads to the development and progression of malignancies directly linked to the viruses. These considerations support a connection between NCDs, infectious diseases, and therapeutic vaccination. Recent advances in technology have paved the way to the use of vaccines beyond the prevention of infectious diseases, heralding innovative therapeutic and preventative strategies for a variety of chronic NCDs. Here we will review the state of the art of personalized vaccine strategies for NCDs, with an emphasis on the diverse technological platforms used to develop them, including mRNA and DNA vaccines, viral vectors, dendritic cell-based vaccines, nanoparticle delivery systems, and next-generation adjuvants. The review intends to make the case for personalized and antigen-specific vaccination strategies as a compelling option for precision immunotherapy primarily in oncology, where neoantigen-based vaccines are being developed. In addition, we will also review tolerogenic vaccination strategies, vaccination strategies targeting pathological proteins and pathways in neurodegenerative and cardiovascular diseases, and vaccine-based treatment of chronic viral infections. Current evidence about vaccines suggests that several ways are available to induce an immune response or create tolerance to a disease, and possibly altering its course instead of simply controlling the symptoms. However, many challenges are still to be overcome, including disease variability, how to identify appropriate target antigens, the complexity of manufacturing process, long-term safety, and integration with already established treatments. By virtue of the convergence of multiple fields—immunology, genomics, bioinformatics, and new delivery systems—precision vaccinology is gaining momentum. Thus, it is envisaged that personalized vaccines will be an increasingly essential component of future preventive and therapeutic approaches for non-communicable diseases.