ABSTRACT Objectives: To evaluate the effect of sitagliptin treatment in early type 2 diabetes mellitus (T2DM) and the impact of different macronutrient compositions on hormones and substrates during meal tolerance tests (MTT). Materials and methods: Half of the drug-naive patients with T2DM were randomly assigned for treatment with 100 mg of sitagliptin, q.d., or placebo for 4 weeks and then submitted to 3 consecutive MTT intercalated every 48 h. The MTTs differed in terms of macronutrient composition, with 70% of total energy from carbohydrates, proteins, or lipids. After 4 weeks of washout, a crossover treatment design was repeated. Both patients and researchers were blinded, and a repeated-measures ANOVA was employed for statistical analysis. Results: Sitagliptin treatment reduced but did not normalize fasting and post-meal glucose values in the three MTTs, with lowered area-under-glucose-curve values varying from 7% to 15%. The sitagliptin treatment also improved the insulinogenic index (+86%) and the insulin/glucose (+25%), glucagon-like peptide-1/glucose (+46%) incremental area under the curves. Patients with early T2DM maintained the lowest glucose excursion after a protein- or lipid-rich meal without any major change in insulin, C-peptide, glucagon, or NEFA levels. Conclusion: We conclude that sitagliptin treatment is tolerable and contributes to better control of glucose homeostasis in early T2DM, irrespective of macronutrient composition. The blood glucose excursion during meal ingestion is minimal in protein- or fat-rich meals, which can be a positive ally for the management of T2DM. Clinical trial no: NCT00881543

O risco de doença arterial coronariana (DAC) nos pacientes com diabetes melito tipo 1 (DM1) é conhecido desde o final dos anos 1970, sendo atualmente a principal causa de mortalidade na população adulta com diabetes tipo 1 de longa duração. A patogênese do processo aterosclerótico nesta doença ainda é obscura, acreditando-se que a hiperglicemia desenvolva aí um papel importante, entretanto vários estudos epidemiológicos mostraram que a associação entre doença coronariana e glicemia, em pacientes com DM1 seja fraca. Dados recentes do estudo DCCT/EDIC mostram que o grupo que recebeu tratamento insulínico intensificado durante o DCCT desenvolveu graus menores de aterosclerose, relacionado aos valores reduzidos de HbA1c durante a fase ativa do estudo, com melhor proteção nos pacientes mais jovens e com menor duração da doença. Há também evidências de que os benefícios são maiores nos pacientes sem nefropatia quando comparados aos com doença renal. Outros fatores de risco importante para o desenvolvimento de DAC em pacientes com DM1 são os mesmos descritos para DM2, incluindo os componentes da síndrome metabólica e marcadores de resistência insulínica. Sugere-se que pacientes com DM1 devam ter o melhor controle glicêmico possível, desde o início da sua doença acrescido de vigilância e tratamento rígido dos fatores de riscos clássicos para DAC, principalmente naqueles com história familiar de DM2.

The association between type 1 diabetes and coronary heart disease has become very clear since the late 1970. It has been demonstrated that there is an important increased risk in morbidity and mortality caused by coronary artery disease in young adults with type 1 diabetes compared with the non diabetic population. The underlying pathogeneses is still poorly understood. While the role of glycemic control in the development of microvascular disease complication is well established its role in CVD in patients with DM1 remains unclear with epidemiologic studies reporting conflicting data. Recent findings from the DCCT/EDIC showed that prior intensive diabetes treatment during the DCCT was associated with less atherosclerosis, largely because of reduced level of HbA1c during the DCCT. The improvement of glycemic control itself appeared to be particularly effective in younger patients with shorter duration of the disease. Other analyses suggested the glycemia may have a stronger effect on CAD in patients without than in those with albuminúria. Other major determinants of coronary artery disease are the components of metabolic syndrome and the surrogate measure of insulin resistence: eGDR. It is proposed that patients with DM1 should have aggressive medical therapy, risk factor modification and careful monitoring not only of his blood sugar but also of the other processes involved in the atherosclerotic process, mostly the ones with family history of type 2 diabetes.

A retinopatia é das complicações mais comuns e está presente tanto no diabetes tipo 1 quanto no tipo 2, especialmente em pacientes com longo tempo de doença e mau controle glicêmico. Quando culmina em perda visual é considerada trágica e constitui fator importante de morbidade de elevado impacto econômico, uma vez que a retinopatia diabética é a causa mais freqüente de cegueira adquirida. A fisiopatologia das alterações microvasculares do tecido retiniano está relacionada à hiperglicemia crônica, que leva a alterações circulatórias como a perda do tônus vascular, alteração do fluxo sangüíneo, aumento da permeabilidade vascular e conseqüentemente extravasamentos e edemas e, por fim, obstrução vascular que leva à neovascularização, com vasos frágeis que se rompem, levando a hemorragias e descolamento da retina. O controle metabólico e pressórico estritos podem retardar a progressão da retinopatia. Até o momento, nenhum agente farmacológico se mostrou eficaz em prevenir, retardar ou reverter a retinopatia diabética.O tratamento disponível no momento é a fotocoagulação a laser de argônio e, em alguns casos, a vitrectomia. O sucesso do tratamento depende da detecção precoce das lesões. Muitos estudos têm revelado mecanismos, assim como antagonistas importantes na evolução da retinopatia.

Diabetic retinopathy is a frequently observed complication in both type 1 and type 2 diabetes, specially in patients with long term disease and poor glicemic control. Irreversible visual loss appears at the final stages of diabetic retinopathy and it is considered one of the most tragic of diabetic complications. It is also considered an important factor of morbidity and has a high economical impact once it is the leading cause of blindness. The pathophysiology of the retinal microvascular alterations is related to the chronic hyperglycemia that leads to the following circulatory disturbances: loss of vascular tonus, increase in vascular permeability, edema and exudation, with vascular obstruction and ischemia that stimulates neovascularization, which may lead to fibrous retraction and vitreous hemorrhages with retinal detachment. Recent studies have indicated that the strict glicemic and blood pressure controls are effective in reducing or blocking the progression of retinopathy. Up to now no pharmacological agents have shown to be effective in preventing or reducing neovascularization and visual loss. Presently, the most effective available treatment for proliferative retinopathy is laser photocoagulation. Further studies are needed to obtain new products and technologies that could effectively prevent or block retinopathy progression.