Pathological lesions in senile diabetes: Possible pathogenetic interpretations

Revision of the ADA-classification of diabetes mellitus type 2 (DMT2): the importance of maturity onset diabetes (MOD), and senile diabetes (DS)

The changing social and economic conditions and the increase of the life span induced a progressive increase of the general prevalence of DMT2, particularly in the elderly population of the highly evoluted countries. Up to now 18 genetic loci have been identified, each of them consisting of several single nucleotide polymorphisms (SNPs). The evidence that the DMT2 is regulated by a high number of genes, demonstrate the pathogenetic complexity of this disease. The onset of diabetes mellitus (DM) in medium age is a consequence of the breakdown of the glycemic homeostasis in correlation with the genetic factors, such as the variants of the TCF7L2, obesity, etc., and the environmental factors, such as the life-style, the evolution of chronic-degenerative diseases, etc. In case of DM that onsets in old age we have to add the deterioration of the anti-aging defense mechanisms, characterized by the antagonistic action of the genes of longevity and aging. One can observe several clinical and therapeutic differences; therefore, the authors of this review propose the reinsertion of three forms into the DMT2 correlated with the age of onset and with the actual age of the subjects: the maturity onset diabetes (MOD), the maturity onset diabetes in elderly (MODE), and the senile diabetes (DS).

Prevalence of diabetes mellitus in a sample of the elderly population of the city of Catania

The prevalence of diabetes mellitus is increasing world-wide, even if it varies markedly in the geographical areas and populations investigated. This study is part of the Progetto Finalizzato Invecchiamento (Aging Project) of the Italian NCR (National Research Council) and is aimed at investigating the prevalence of diabetes and selected clinical characteristics in a study sample aged between 65 and 84 years of age resident in Catania (Italy). The prevalence rate for type II diabetes was 22.8% and it is certainly among the highest values recorded to date in other areas of Italy and abroad. We distinguished between two forms of diabetes in subjects >70 years of age: aged diabetes with onset in middle age (AD); and diabetes of senescence with onset after 70 years of age (DS). Prevalence rate was 18% for AD and 4.8% for DS, respectively. The age-specific rates of AD and DS show the progressive lower prevalence rates of the former and the higher rates of the latter. We assume that DS is mainly caused by atherosclerotic processes and represents the typical form of diabetes in the elderly.

A review on the actual trends of insulin treatment in elderly with diabetes

The diabetes of the elderly subjects has two forms: diabetes of long duration, manifesting itself in younger or medium ages, and senile diabetes, appearing above the age of 65 years. The diabetes of the elderly has usually only modest symptoms: it is not ketosic, but in spite of this, in order to avoid the chronic-degenerative complications, it is important to maintain a good, even if not an optimal compensation. The therapeutic intervention cannot neglect a correct alimentary regime and a programmed physical activity in correlation with the clinical conditions of the patient. If the compensation is not achieved only with these tools, one can add oral antidiabetic treatments. In the elderly patients we usually observe primary or secondary failure of the oral antidiabetic treatments, and in such context we have to apply insulin treatment, even in cases of moderate glycometabolic decompensations. While we are waiting for the gene-therapy or the inhalatory insulin preparations, actually there are at disposal only the insulin analogs in rapid, slow and mixed forms. We propose two treatment schemes: (i) The first one consists of three administrations of rapid insulin with the meals, and on dose of slow insulin 2h after the last meal in the evening. (ii) The second scheme consists of one administration of rapid insulin at lunch, one administration of mixed insulin at dinner, with the addition of oral antidiabetics of peripheric action, in the morning and the evening. A better compliance can be obtained, being a fundamental aspect in the elderly diabetics, and a reduction of the number and severity of the hypoglycemia, which are the most important aspects in the elderly diabetes.

Atherosclerosis and pancreatic damage

The appearance of diabetes in advanced age may be considered as a part of the involutive processes of aging, and as such, it might have a pathogenesis completely different from that of type 2 diabetes of medium age. As a matter of fact, it has been observed that the pancreas undergoes numerous structural and functional alterations with advancing age, both in exocrine and endocrine parts. The present studies have been performed to reveal the quantity and quality of the pancreatic lesions, which may be attributed to atherosclerosis. We have already studied elderly subjects, therefore, we were now looking for further supports in a population of middle age people, died in complications of malignant hypertension. We investigated the pancreas, kidney and heart of 36 subjects (20 males and 16 females) with mean age of 48.6+/-8.9 years. Of this group, eight subjects (22.2%) became diabetic after the appearance of malignant hypertension. Arteriolar atherosclerosis damage (hyalinosis, thickening and stenosis) of the pancreatic arterioles were found in 92.8% of the non-diabetic, and in 87.5% of the diabetic subjects. Lesions of the pancreatic islets were observed in 32% of the non-diabetics, and in 50% of the diabetic subjects. The pancreas is an organ, which tends particularly to develop atherosclerotic damage. The vascular lesion of atherosclerotic origin, independently from the mechanism of its appearance, causes first only a decrease of the blood flux and hypoxia in the pancreatic islets with a consecutive functional decline of the beta-cells. This is then followed by structural modifications of the islets accompanied by the appearance of hyalinosis, loss of beta-cells, and a further decrease of insulin production.