Pineal peptides restore the age-related disturbances in hormonal functions of the pineal gland and the pancreas

Thymus-Pineal Gland Axis: Revisiting Its Role in Human Life and Ageing

For years the thymus gland (TG) and the pineal gland (PG) have been subject of increasingly in-depth studies, but only recently a link that can associate the activities of the two organs has been identified. Considering, on the one hand, the well-known immune activity of thymus and, on the other, the increasingly emerging immunological roles of circadian oscillators and the rhythmically secreted main pineal product, melatonin, many studies aimed to analyse the possible existence of an interaction between these two systems. Moreover, data confirmed that the immune system is functionally associated with the nervous and endocrine systems determining an integrated dynamic network. In addition, recent researches showed a similar, characteristic involution process both in TG and PG. Since the second half of the 20th century, evidence led to the definition of an effectively interacting thymus-pineal axis (TG-PG axis), but much has to be done. In this sense, the aim of this review is to summarize what is actually known about this topic, focusing on the impact of the TG-PG axis on human life and ageing. We would like to give more emphasis to the implications of this dynamical interaction in a possible therapeutic strategy for human health. Moreover, we focused on all the products of TG and PG in order to collect what is known about the role of peptides other than melatonin. The results available today are often unclear and not linear. These peptides have not been well studied and defined over the years. In this review we hope to awake the interest of the scientific community in them and in their future pharmacological applications.

Streptozotocin-induced diabetes disrupts the body temperature daily rhythm in rats

BACKGROUND

In mammals, the temperature rhythm is regulated by the circadian pacemaker located in the suprachiasmatic nuclei, and is considered a "marker rhythm". Melatonin, the pineal gland hormone, is a major regulator of the endogenous rhythms including body temperature. Its production is influenced by many factors, such as type 1 diabetes mellitus. In rats, diabetes leads to hypothermia and reduced melatonin synthesis; insulin treatment reestablishes both.

AIM

To study the body temperature daily rhythm of diabetic animals and the effects of insulin and/or melatonin treatment on its structure.

METHODS

We studied the effects of streptozotocin-induced diabetes (60 mg/kg) on the body temperature rhythm of Wistar rats and the possible modifications resulting from early and late treatments with insulin (6U/day) and/or melatonin (daily 0.5 mg/kg). We monitored the daily body temperature rhythm, its rhythmic parameters (MESOR, amplitude and acrophase), glycemia and body weight for 55 days. Data were classified by groups and expressed as mean ± SEM. One-way ANOVA analysis was performed followed by Bonferroni posttest. Statistical significance was set at p < 0.05.

RESULTS

Diabetes led to complete disruption of the temperature rhythm and hypothermia, which were accentuated over time. All early treatments (insulin or/and melatonin) prevented the temperature rhythm disruption and hypothermia. Insulin plus melatonin restored the body temperature rhythm whereas insulin alone resulted less efficient; melatonin alone did not restore any of the parameters studied; however, when supplemented close to diabetes onset, it maintained the temperature rhythmicity. All these corrective effects of the early treatments were dependent on the continuous maintenance of the treatment.

CONCLUSIONS

Taken together, our findings show the disruption of the body temperature daily rhythm, a new consequence of insulin-dependent diabetes, as well as the beneficial effect of the complementary action of melatonin and insulin restoring the normal rhythmicity.

Molecular cellular mechanisms of peptide regulation of melatonin synthesis in pinealocyte culture

The effects of epithalone and vilone peptides on the synthesis of melatonin and factors involved in this process, arylalkylamine-N-acetyltransferase (AANAT) enzyme and pCREB transcription protein, were studied in rat pinealocyte culture. Epithalone stimulated AANAT and pCREB synthesis and increased melatonin level in culture medium. Simultaneous addition of norepinephrine and peptides into the culture potentiated the expression of AANAT and pCREB.

Biogerontology in Russia: from past to future

The paper presents major steps of gerontology development in Russia. The issues of training in gerontology and geriatrics, institutional infrastructure within the Gerontological Society of the Russian Academy of Sciences and its activities have been considered therein. Some results of Russian researchers obtained during 2005-2010 have been summarized as well. Special attention is given to the prospects of gerontology in Russia.

Role of melatonin in metabolic regulation

Although the human genome has remained unchanged over the last 10,000 years, our lifestyle has become progressively more divergent from those of our ancient ancestors. This maladaptive change became apparent with the Industrial Revolution and has been accelerating in recent decades. Socially, we are people of the 21st century, but genetically we remain similar to our early ancestors. In conjunction with this discordance between our ancient, genetically-determined biology and the nutritional, cultural and activity patterns in contemporary Western populations, many diseases have emerged. Only a century ago infectious disease was a major cause of mortality, whereas today non-infectious chronic diseases are the greatest cause of death in the world. Epidemics of metabolic diseases (e.g., cardiovascular diseases, type 2 diabetes, obesity, metabolic syndrome and certain cancers) have become major contributors to the burden of poor health and they are presently emerging or accelerating, in most developing countries. One major lifestyle consequence is light at night and subsequent disrupted circadian rhythms commonly referred to as circadian disruption or chronodisruption. Mounting evidence reveals that particularly melatonin rhythmicity has crucial roles in a variety of metabolic functions as an anti-oxidant, anti-inflammatory chronobiotic and possibly as an epigenetic regulator. This paper provides a brief outline about metabolic dysregulation in conjunction with a disrupted melatonin rhythm.

Peptide bioregulation of aging: results and prospects

The review comprises the results of author's long-term investigation in the mechanisms of aging and a role of peptide bioregulators in prevention of age-related pathology. A number of small peptides have been isolated from different organs and tissues and their analogues (di-, tri-, tetrapeptides) were synthesized from the amino acids. It was shown that long-term treatment with some peptide preparations increased mean life span by 20-40%, slow down the age-related changes in the biomarkers of aging and suppressed development of spontaneous and induced by chemical or radiation carcinogens tumorigenesis in rodents. Possible mechanisms of the biological effects of small peptides are discussed in the paper. The results of clinical applications of peptide preparation during the period of 6-12 years are presented as well.