Endocrine approaches to treatment of Alzheimer's disease and other neurological conditions: Part I: Some recollections of my association with Dr. Abba Kastin: A tale of successful collaboration

Extracorporeal apheresis therapy for Alzheimer disease-targeting lipids, stress, and inflammation

Current therapeutic approaches to Alzheimer disease (AD) remain disappointing and, hence, there is an urgent need for effective treatments. Here, we provide a perspective review on the emerging role of "metabolic inflammation" and stress as a key factor in the pathogenesis of AD and propose a novel rationale for correction of metabolic inflammation, increase resilience and potentially slow-down or halt the progression of the neurodegenerative process. Based on recent evidence and observations of an early pilot trial, we posit a potential use of extracorporeal apheresis in the prevention and treatment of AD. Apolipoprotein E, lipoprotein(a), oxidized LDL (low density lipoprotein)'s and large LDL particles, as well as other proinflammatory lipids and stress hormones such as cortisol, have been recognized as key factors in amyloid plaque formation and aggravation of AD. Extracorporeal lipoprotein apheresis systems employ well-established, powerful methods to provide an acute, reliable 60-80% reduction in the circulating concentration of these lipid classes and reduce acute cortisol levels. Following a double-membrane extracorporeal apheresis in patients with AD, there was a significant reduction of proinflammatory lipids, circulating cytokines, immune complexes, proinflammatory metals and toxic chaperones in patients with AD. On the basis of the above, we suggest designing clinical trials to assess the promising potential of such "cerebropheresis" treatment in patients with AD and, possibly, other neurodegenerative diseases.

P53, GHRH, inflammation and cancer

P53 is a transcription factor very often mutated in malignancies. It functions towards the regulation of important cellular activities, such as cell cycle, senescence and apoptosis. Since inflammation and cancer are strongly associated through common pathways, P53 can suppress inflammation in a plethora of human tissues. Growth Hormone - Releasing Hormone is a hypothalamic peptide with a great capacity to affect the complex networks of cellular regulation via GHRH - specific receptors. GHRH antagonistic and agonistic analogs have been developed for clinical applications, including treatment of benign prostatic hyperplasia, breast, prostate and lung cancers, diabetes and neurodegenerative diseases. The epicenter of the current manuscript is the protective role of P53 against inflammation and cancer and emphasizes the p53 – mediated beneficial effects of GHRH antagonists in various human diseases.

•

Inflammation is tightly associated with cancer.

•

GHRH antagonists induce P53 expression.

•

P53 exerts a protective effect against cancer and inflammation.

Peripheral activities of growth hormone-releasing hormone

Growth hormone (GH)-releasing hormone (GHRH) is produced by the hypothalamus and stimulates GH synthesis and release in the anterior pituitary gland. In addition to its endocrine role, GHRH exerts a wide range of extrapituitary effects which include stimulation of cell proliferation, survival and differentiation, and inhibition of apoptosis. Accordingly, expression of GHRH, as well as the receptor GHRH-R and its splice variants, has been demonstrated in different peripheral tissues and cell types. Among the direct peripheral activities, GHRH regulates pancreatic islet and β-cell survival and function and endometrial cell proliferation, promotes cardioprotection and wound healing, influences the immune and reproductive systems, reduces inflammation, indirectly increases lifespan and adiposity and acts on skeletal muscle cells to inhibit cell death and atrophy. Therefore, it is becoming increasingly clear that GHRH exerts important extrapituitary functions, suggesting potential therapeutic use of the peptide and its analogs in a wide range of medical settings.