Alzheimer’s disease is the most common cause of dementia globally. The pathogenesis is multifactorial and includes deposition of amyloid-β in the central nervous system, presence of intraneuronal neurofibrillary tangles and a decreased amount of synapses. It remains uncertain what causes the progression of the disease. Nowadays, it is suggested that the brain is connected to the gastrointestinal tract, especially the enteric nervous system and gut microbiome. Studies have found a positive association between AD and gastrointestinal diseases such as periodontitis, Helicobacter pylori infection, inflammatory bowel disease and microbiome disorders. H. pylori and its metabolites can enter the CNS via the oropharyngeal olfactory pathway and may predispose to the onset and progression of AD. Periodontitis may cause systemic inflammation of low severity with high levels of pro-inflammatory cytokines and neutrophils. Moreover, lipopolysaccharide from oral bacteria accompanies beta-amyloid in plaques that form in the brain. Increased intestinal permeability in IBS leads to neuronal inflammation from transference. Chronic inflammation may lead to beta-amyloid plaque formation in the intestinal tract that spreads to the brain via the vagus nerve. The microbiome plays an important role in many bodily functions, such as nutrient absorption and vitamin production, but it is also an important factor in the development of many diseases, including Alzheimer’s disease. Both the quantity and diversity of the microbiome change significantly in patients with AD and even in people in the preclinical stage of the disease, when symptoms are not yet present. The microbiome influences the functioning of the central nervous system through, among other things, the microbiota–gut–brain axis. Given the involvement of the microbiome in the pathogenesis of AD, antibiotic therapy, probiotics and prebiotics, and faecal transplantation are being considered as possible therapeutic options.

Obesity is a global problem. It affects every age group and is associated with many negative health effects. As an example, there is a relationship between obesity and allergic and immunological diseases, such as asthma, psoriasis, food allergies, allergic rhinitis and atopic dermatitis. Obesity undeniably affects their development. In addition, it causes adverse changes in the course and response to therapy in relation to patients without excessive body weight. The treatment of diseases associated with obesity is difficult; drugs are less effective and must be used in higher doses, and their use in patients with obesity is often associated with higher risks. The main form of treatment of all obesity-related diseases is a change in eating habits and increased physical activity, which leads to a decrease in body fat mass. The positive effect of reducing BMI has been confirmed in many independent studies. This paper reviews various types of research documents published since 2019. It aims to systematize the latest knowledge and highlight the need for further research for effective and sustainable treatment options for obesity, its complications and obesity-related diseases.

Food allergy (FA) has become a common global public health issue, with a growing prevalence in the modern world and a significant impact on the lives of patients, their families, and caregivers. It affects every area of life and is associated with elevated costs. Food allergy is an adverse immune reaction that occurs in response to a given food. The symptoms vary from mild to severe and can lead to anaphylaxis. This is why it is important to focus on the factors influencing the occurrence of food allergies, specific diagnostic methods, effective therapies, and especially prevention. Recently, many guidelines have emphasized the impact of introducing specific foods into a child’s diet at an early age in order to prevent food allergies. Childhood allergies vary with age. In infants, the most common allergy is to cow’s milk. Later in life, peanut allergy is more frequently diagnosed. Numerous common childhood allergies can be outgrown by adulthood. Adults can also develop new IgE-mediated FA. The gold standard for diagnosis is the oral provocation test. Skin prick tests, specific IgE measurements, and component-resolved diagnostic techniques are helpful in the diagnosis. Multiple different approaches are being tried as possible treatments, such as immunotherapy or monoclonal antibodies. This article focuses on the prevention and quality of life of allergic patients. This article aims to systematize the latest knowledge and highlight the differences between food allergies in pediatric and adult populations.

Alzheimer’s disease, a neurodegenerative brain disorder leading to the progressive decline in cognitive functions, is the most common type of dementia. The main risk factor for its development is aging. Recent studies indicate that cellular senescence mechanisms are among the major factors in a heterogeneous aging process. Cellular senescence is characterized by a permanent proliferative arrest. Many factors might initiate senescence, for example, damage of DNA, shortening of telomeres, dysfunction of mitochondria, and oncogene activation. These processes lead to alterations in the morphology and function of senescent cells. Research is still ongoing to identify one universal marker that could detect senescent cells and distinguish them from other non-proliferating cells. Those cells are involved in age-related pathologies through many heterogeneous processes, including secretion of pro-inflammatory senescence-associated secretory phenotype factors, which affect the brain differently. Alzheimer’s disease is an example of a neurodegenerative condition connected to cellular senescence. Senescent cells have been demonstrated to accumulate near Aβ plaques and neurofibrillary tangles. In this review, the multifactorial connection between Alzheimer’s disease and cellular senescence is discussed, including topics such as senescence of astrocytes, defective mitochondria, dysregulation of cellular autophagy, and the role of senescent microglia.

The human endogenous retroviruses (HERVs) are ancient exogenous retroviruses that were embedded in the germline over 30 million years ago and underwent an endogenization process. They make up roughly 8% of the human genome. HERVs exhibit many physiological and non-physiological functions; for example, they play a role in the development of many diseases. They have been shown to affect carcinogenesis by modifying the expression of host genes through their functions as enhancers and promoters. Additionally, some molecules derived from HERVs may stimulate the immune system. Recently research has been focused on the effect of human endogenous retroviruses on the development of neurodegenerative diseases, including Alzheimer’s disease (AD), which is the most common cause of dementia. AD is also linked to a significant deterioration in quality of life. The article aims to highlight the potential role of HERVs in neurodegenerative diseases such as Alzheimer’s disease and senescence. Moreover, it is estimated that HERVs may be potential targets for diagnosis and therapy of AD.

In recent years, there has been a noticeable development in oncological treatment, including chemotherapy and biological treatment. Despite their significant effectiveness, they are not free from side effects, such as allergic and dermatological reactions. These reactions can vary in severity and outcome, including potential death. Examples, among others, are type I-IV hypersensitivity reactions of various origins and skin reactions including rashes, itching and redness, but also severe cutaneous syndromes. Due to the therapy used, these may include Stevens–Johnson syndrome, toxic epidermal necrolysis, drug rash with eosinophilia and systemic symptoms, drug-induced hypersensitivity syndrome and acute generalized exanthematous pustulosis. In some cases, it is necessary to interrupt therapy, which may result in a poorer outcome and shorten the patient’s survival. This paper reviews various types of research documents published since 2016. It aims to systematize the latest knowledge and highlight the need for further research into ways to avoid adverse reactions.