Lipoatrophic diabetes and other related syndromes

Genetic perspectives on childhood monogenic diabetes: Diagnosis, management, and future directions

Monogenic diabetes is caused by one or even more genetic variations, which may be uncommon yet have a significant influence and cause diabetes at an early age. Monogenic diabetes affects 1 to 5% of children, and early detection and gene-tically focused treatment of neonatal diabetes and maturity-onset diabetes of the young can significantly improve long-term health and well-being. The etiology of monogenic diabetes in childhood is primarily attributed to genetic variations affecting the regulatory genes responsible for beta-cell activity. In rare instances, mutations leading to severe insulin resistance can also result in the development of diabetes. Individuals diagnosed with specific types of monogenic diabetes, which are commonly found, can transition from insulin therapy to sulfonylureas, provided they maintain consistent regulation of their blood glucose levels. Scientists have successfully devised materials and methodologies to distinguish individuals with type 1 or 2 diabetes from those more prone to monogenic diabetes. Genetic screening with appropriate findings and interpretations is essential to establish a prognosis and to guide the choice of therapies and management of these interrelated ailments. This review aims to design a comprehensive literature summarizing genetic insights into monogenetic diabetes in children and adolescents as well as summarizing their diagnosis and mana-gement.

The subtleties of insulin treatment in patients with lipodystrophy

In the treatment of Diabetes Mellitus (DM), which develops on the basis of insulin resistance in patients with lipodystrophy (LD) often require high doses of insulin. Traditionally in practice is to gradually increase the insulin doses to achieve blood glucose normalization. The fact that high insulin doses require a larger injection volume, which causes impairment in the absorption of insulin from the subcutaneous tissue to the circulation. In this article, we discussed the clinical approach to insulin practice in the treatment of DM in patients with LD and reviewed systematically the literature.

Application of Nanoparticles: Diagnosis, Therapeutics, and Delivery of Insulin/Anti-Diabetic Drugs to Enhance the Therapeutic Efficacy of Diabetes Mellitus

Diabetes mellitus (DM) is a chronic metabolic disorder of carbohydrates, lipids, and proteins due to a deficiency of insulin secretion or failure to respond to insulin secreted from pancreatic cells, which leads to high blood glucose levels. DM is one of the top four noncommunicable diseases and causes of death worldwide. Even though great achievements were made in the management and treatment of DM, there are still certain limitations, mainly related to the early diagnosis, and lack of appropriate delivery of insulin and other anti-diabetic agents. Nanotechnology is an emerging field in the area of nanomedicine and NP based anti-diabetic agent delivery is reported to enhance efficacy by increasing bioavailability and target site accumulation. Moreover, theranostic NPs can be used as diagnostic tools for the early detection and prevention of diseases owing to their unique biological, physiochemical, and magnetic properties. NPs have been synthesized from a variety of organic and inorganic materials including polysaccharides, dendrimers, proteins, lipids, DNA, carbon nanotubes, quantum dots, and mesoporous materials within the nanoscale size. This review focuses on the role of NPs, derived from organic and inorganic materials, in the diagnosis and treatment of DM.

An overview of lipodystrophy and the role of the complement system

The complement system is a major component of innate immunity playing essential roles in the destruction of pathogens, the clearance of apoptotic cells and immune complexes, the enhancement of phagocytosis, inflammation, and the modulation of adaptive immune responses. During the last decades, numerous studies have shown that the complement system has key functions in the biology of certain tissues. For example, complement contributes to normal brain and embryonic development and to the homeostasis of lipid metabolism. However, the complement system is subjected to the effective balance between activation-inactivation to maintain complement homeostasis and to prevent self-injury to cells or tissues. When this control is disrupted, serious pathologies eventually develop, such as C3 glomerulopathy, autoimmune conditions and infections. Another heterogeneous group of ultra-rare diseases in which complement abnormalities have been described are the lipodystrophy syndromes. These diseases are characterized by the loss of adipose tissue throughout the entire body or partially. Complement over-activation has been reported in most of the patients with acquired partial lipodystrophy (also called Barraquer-Simons Syndrome) and in some cases of the generalized variety of the disease (Lawrence Syndrome). Even so, the mechanism through which the complement system induces adipose tissue abnormalities remains unclear. This review focuses on describing the link between the complement system and certain forms of lipodystrophy. In addition, we present an overview regarding the clinical presentation, differential diagnosis, classification, and management of patients with lipodystrophy associated with complement abnormalities.

Long-term effectiveness and safety of metreleptin in the treatment of patients with partial lipodystrophy

PURPOSE

To evaluate the effects of metreleptin in patients with partial lipodystrophy (PL).

METHODS

Patients aged ≥ 6 months with PL, circulating leptin < 12.0 ng/mL, and diabetes mellitus, insulin resistance, or hypertriglyceridemia received metreleptin doses (once or twice daily) titrated to a mean of 0.124 mg/kg/day. Changes from baseline to month 12 in glycated hemoglobin (HbA1c) and fasting serum triglycerides (TGs; co-primary endpoints), fasting plasma glucose (FPG), and liver volume were evaluated. Additional assessments included the proportions of patients achieving target decreases in HbA1c or fasting TGs at month 12, long-term treatment effects, and treatment-emergent adverse events (TEAEs).

RESULTS

Significant (p < 0.05) reductions in HbA1c (-0.6%), fasting TGs (-20.8%), FPG (-1.2 mmol/L), and liver volume (-13.4%) were observed in the overall PL population at month 12. In a subgroup of patients with baseline HbA1c ≥ 6.5% or TGs ≥ 5.65 mmol/L, significant (p < 0.05) reductions were seen in HbA1c (-0.9%), fasting TGs (-37.4%), FPG (-1.9 mmol/L), and liver volume (-12.4%). In this subgroup, 67.9% of patients had a ≥ 1% decrease in HbA1c or ≥ 30% decrease in fasting TGs, and 42.9% had a ≥ 2% decrease in HbA1c or ≥ 40% decrease in fasting TGs. Long-term treatment in this subgroup led to significant (p < 0.05) reductions at months 12, 24, and 36 in HbA1c, fasting TGs, and FPG. Metreleptin was well tolerated with no unexpected safety signals. The most common TEAEs were abdominal pain, hypoglycemia, and nausea.

CONCLUSIONS

In patients with PL, treatment with metreleptin was well tolerated and resulted in improvements in glycemic control, hypertriglyceridemia, and liver volume.

Long-term effectiveness and safety of metreleptin in the treatment of patients with generalized lipodystrophy

PURPOSE

The purpose of this study is to summarize the effectiveness and safety of metreleptin in patients with congenital or acquired generalized lipodystrophy.

METHODS

Patients (n = 66) aged ≥6 months had lipodystrophy, low circulating leptin, and ≥1 metabolic abnormality (diabetes mellitus, insulin resistance, or hypertriglyceridemia). Metreleptin dose (once or twice daily) was titrated to a mean dose of 0.10 mg/kg/day with a maximum of 0.24 mg/kg/day. Means and changes from baseline to month 12 were assessed for glycated hemoglobin (HbA1c), fasting triglycerides (TGs), and fasting plasma glucose (FPG). Additional assessments included the proportions of patients achieving target decreases in HbA1c or fasting TGs at months 4, 12, and 36, medication changes, and estimates of liver size. Treatment-emergent adverse events (TEAEs) were recorded.

RESULTS

Significant mean reductions from baseline were seen at month 12 for HbA1c (-2.2%, n = 59) and FPG (-3.0 mmol/L, n = 59) and mean percent change in fasting TGs (-32.1%, n = 57) (all p ≤ 0.001). Reductions from baseline over time in these parameters were also significant at month 36 (all p < 0.001, n = 14). At month 4, 34.8% of patients had a ≥1% reduction in HbA1c and 62.5% had a ≥30% reduction in fasting TGs; at month 12, 80% of patients had a ≥1% decrease in HbA1c or ≥30% decrease in TGs, and 66% had a decrease of ≥2% in HbA1c or ≥40% decrease in TGs. Of those on medications, 41%, 22%, and 24% discontinued insulin, oral antidiabetic medications, or lipid-lowering medications, respectively. Mean decrease in liver volume at month 12 was 33.8% (p < 0.001, n = 12). Most TEAEs were of mild/moderate severity.

CONCLUSIONS

In patients with generalized lipodystrophy, long-term treatment with metreleptin was well tolerated and resulted in sustained improvements in hypertriglyceridemia, glycemic control, and liver volume.

Thigh circumference and low ankle brachial index in US adults: results from the National Health and Nutrition Examination Survey 1999-2004

OBJECTIVE

Recent studies have suggested that smaller thighs are a disadvantage for health and survival, but the association of thigh circumference with atherosclerosis remains uncertain. The purpose of this study was to investigate the association between thigh circumference and peripheral arterial disease (PAD), as measured by ankle brachial index (ABI).

METHODS

This study used data from the National Health and Nutrition Examination Survey (1999-2004), in which participants' ABI and thigh circumference were measured simultaneously. A total of 5716 participants (2959 men and 2757 women) were included in the final analysis. A diagnosis of PAD was determined on the basis of ABI <0.9.

RESULTS

The overall prevalence of PAD in this sample was 6.6%. Thigh circumference of those with PAD was 50.1cm compared to 52.2 cm for those without PAD (p < 0.0001). After adjusting for potential covariates, the prevalence of PAD generally decreased as thigh circumference increased up to 55 cm. In the first quantile (smallest thigh circumference), men and women had as much as a 4.8-fold (95% CI, 2.28-10.29) and a 3-fold (95% CI, 1.45-6.18) increased risk of PAD, respectively. Above 55 cm, PAD was no longer related to thigh circumference.

CONCLUSIONS

Small thigh circumference may be associated with PAD, as measured by ABI.

Lipoatrophic diabetes: a case report with a brief review of the literature

Lipoatrophy syndromes are characterized by an absence of adipose tissue and low leptin levels. Metabolic derangements associated with these syndromes can include diabetes mellitus, insulin resistance, and hyperlipidemia.

Metabolic fuel and clinical implications for female reproduction

Reproduction is a physiologically costly process that consumes significant amounts of energy. The physiological mechanisms controlling energy balance are closely linked to fertility. This close relationship ensures that pregnancy and lactation occur only in favourable conditions with respect to energy. The primary metabolic cue that modulates reproduction is the availability of oxidizable fuel. An organism's metabolic status is transmitted to the brain through metabolic fuel detectors. There are many of these detectors at both the peripheral (e.g., leptin, insulin, ghrelin) and central (e.g., neuropeptide Y, melanocortin, orexins) levels. When oxidizable fuel is scarce, the detectors function to inhibit the release of gonadotropin-releasing hormone and luteinizing hormone, thereby altering steroidogenesis, reproductive cyclicity, and sexual behaviour. Infertility can also result when resources are abundant but food intake fails to compensate for increased energy demands. Examples of these conditions in women include anorexia nervosa and exercise-induced amenorrhea. Infertility associated with obesity appears to be less related to an effect of oxidizable fuel on the hypothalamic-pituitary-ovarian axis. Impaired insulin sensitivity may play a role in the etiology of these conditions, but their specific etiology remains unresolved. Research into the metabolic regulation of reproductive function has implications for elucidating mechanisms of impaired pubertal development, nutritional amenorrhea, and obesity-related infertility. A better understanding of these etiologies has far-reaching implications for the prevention and management of reproductive dysfunction and its associated comorbidities.

Monogenic diabetes in children and young adults: Challenges for researcher, clinician and patient

Monogenic diabetes results from one or more mutations in a single gene which might hence be rare but has great impact leading to diabetes at a very young age. It has resulted in great challenges for researchers elucidating the aetiology of diabetes and related features in other organ systems, for clinicians specifying a diagnosis that leads to improved genetic counselling, predicting of clinical course and changes in treatment, and for patients to altered treatment that has lead to coming off insulin and injections with no alternative (Glucokinase mutations), insulin injections being replaced by tablets (e.g. low dose in HNFalpha or high dose in potassium channel defects -Kir6.2 and SUR1) or with tablets in addition to insulin (e.g. metformin in insulin resistant syndromes). Genetic testing requires guidance to test for what gene especially given limited resources. Monogenic diabetes should be considered in any diabetic patient who has features inconsistent with their current diagnosis (unspecified neonatal diabetes, type 1 or type 2 diabetes) and clinical features of a specific subtype of monogenic diabetes (neonatal diabetes, familial diabetes, mild hyperglycaemia, syndromes). Guidance is given by clinical and physiological features in patient and family and the likelihood of the proposed mutation altering clinical care. In this article, I aimed to provide insight in the genes and mutations involved in insulin synthesis, secretion, and resistance, and to provide guidance for genetic testing by showing the clinical and physiological features and tests for each specified diagnosis as well as the opportunities for treatment.

The classification of diabetes mellitus: a conceptual framework

Diabetes is the extreme manifestation of a spectrum conditions in which the balance of insulin secretion and insulin action (or insulin resistance) has been altered. Loss of euglycemia is caused by relative insulin deficiency in the presence of insulin resistance, or by absolute insulin deficiency. There are related conditions in which an alteration of insulin resistance or beta-cell dysfunction exists, but because of compensation glucose homeostasis has not been lost. The elucidation of the causes of insulin resistance and -cell failure and the attention to the different degrees of insulin deficiency and insulin resistance allow for better diagnosis, treatment, and prevention of diabetes and its related conditions.

Monogenic and other unusual causes of diabetes mellitus

This article covers some unusual or rare causes of diabetes mellitus chosen not necessarily on the basis of frequency or rarity, but rather on the basis of how well the disease and its implications in diabetes management is understood. A specific diagnosis is of help in these rare syndromes but not absolutely necessary for optimal management. The basic principles of diabetes management are well-defined, regardless of etiology. What is important is to understand the relative contribution of insulin resistance versus insulin deficiency, regardless of etiology, as the most important guide to management.

Lipin expression preceding peroxisome proliferator-activated receptor-gamma is critical for adipogenesis in vivo and in vitro

We recently identified mutations in the lipin gene, Lpin1, as the cause of lipodystrophy in the fatty liver dystrophy (fld) mouse. Here we identify impaired adipocyte differentiation as the basis for lipodystrophy in lipin-deficient mice and demonstrate that lipin is required for normal induction of the adipogenic gene transcription program. We found that the reduced adiposity in chow fed fld mice and resistance to obesity in fld mice fed a high-fat diet is associated with reduced adipogenic gene expression. Using primary mouse embryonic fibroblasts isolated from fld mice, we confirmed that lipin deficiency prevents normal lipid accumulation and induction of key adipogenic genes, including peroxisome proliferator-activated receptor (PPAR)gamma and CCAAT enhancer-binding protein (C/EBP)alpha. However, our previous studies of daily gene expression in differentiating 3T3-L1 preadipocytes indicated that lipin expression is undetectable until about day 3 of differentiation, at a point after PPARgamma and C/EBPalpha gene expression is established. This paradox was resolved by examining gene expression at 10-h intervals during 3T3-L1 cell differentiation, leading to detection of transient lipin expression at 10 h into the differentiation program, prior to the induction of PPARgamma and C/EBPalpha. Consistent with a requirement for lipin expression upstream of PPARgamma, differentiation of lipin-deficient mouse embryonic fibroblasts could be rescued by ectopic expression of PPARgamma. Thus, we conclude that lipin expression is required prior to PPARgamma during adipocyte differentiation.