Insulin: its role in the central control of reproduction

Insulin has long been recognized as a key regulator of energy homeostasis via its actions at the level of the brain, but in addition, plays a role in regulating neural control of reproduction. In this review, we consider and compare evidence from animal models demonstrating a role for insulin for physiological control of reproduction by effects on GnRH/LH secretion. We also review the role that insulin plays in prenatal programming of adult reproduction, and consider specific candidate neurons in the adult hypothalamus by which insulin may act to regulate reproductive function. Finally, we review clinical evidence of the role that insulin may play in adult human fertility and reproductive disorders. Overall, while insulin appears to have a significant impact on reproductive neuroendocrine function, there are many unanswered questions regarding its precise sites and mechanisms of action, and their impact on developing and adult reproductive neuroendocrine function.

Normal-range albuminuria does not exclude nephropathy in diabetic children

Clinically detectable diabetic nephropathy (DN) begins with the development of microalbuminuria (MA). However, early renal dysfunction may be overlooked despite using that method. On the other hand, the gold standard in DN detection-that is, renal biopsy-is highly invasive. The aim of this study was to evaluate the level of neutrophil-gelatinase-associated lipocalin (NGAL) and interleukin (IL)-18 and their relations to albumin excretion rate (AER) in children with normal-range albuminuria, e.g. in those considered as not presenting diabetic nephropathy. The study group consisted of 22 children (age 12.7 +/- 3.5 years) with type 1 diabetes mellitus (T1DM). Long-term glycemic control was assessed on hemoglobin A1c (HbA1c) levels (8.52 +/- 1.78%). All patients presented normal estimated glomerular filtration rate (eGFR) (141 +/- 23 ml/min/1.73 m(2)) and normal urinary albumin excretion (13.09 +/- 7.63 mg/24 h). Fourteen healthy children served as a control group. Children with T1DM showed increased NGAL values with respect to controls-interestingly, both in serum (sNGAL) (867.43 +/- 341.98 vs. 655.29 +/- 196.17 ng/ml; p = 0.04) and in urine (uNGAL) (420.04 +/- 374.16 vs. 156.53 +/- 185.18 ng/ml, p = 0.04). IL-18 levels were not different in both groups both in serum (58.52 +/- 20.11 vs. 69.79 +/- 58.76 ng/ml; NS) and in urine (14.53 +/- 12.74 vs. 14.60 +/- 10.92 ng/ml; NS). Despite the relatively small study group, the positive correlation between sNGAL and AER was found [AER (mg/24 h) = 3.1893 + 0.01141 x sNGAL (ng/ml); r = 0.51; p = 0.014] as well as between uNGAL and AER [AER (mg/24 h) = 8.7538 + 0.01032 x uNGAL (ng/ml); r = 0.51; p = 0.016]. No relationship between sNGAL and uNGAL, and GFR and HbA1c were found. Normal-range albuminuria does not exclude diabetic nephropathy defined as increased sNGAL and uNGAL concentration. NGAL measurement can be more sensitive than MA and may become a useful tool for evaluating renal involvement in diabetic children.

miR-487a-3p upregulated in type 1 diabetes targets CTLA4 and FOXO3

AIMS

Type 1 diabetes (T1D) is an autoimmune disorder caused by the T-cell mediated destruction of the insulin-producing pancreatic beta cells. T1D is a consequence of complex processes, influenced by genetic, epigenetic and environmental factors. MicroRNAs (miRNAs) are small non-coding RNAs that target multiple mRNAs and regulate gene expression. The implication of miRNAs in T1D pathogenesis, as potential modulators of immune response genes, remains poorly defined. The aim of this study was to investigate the expression profile of miRNAs in new onset T1D and the impact of deregulated miRNAs on target genes.

METHODS

Total RNA from peripheral blood mononuclear cells of newly diagnosed T1D pediatric patients and age-matched controls was screened for disease-associated miRNAs by a microarray analysis, with subsequent validation by quantitative reverse-transcription polymerase chain reaction (qRT-PCR). miRNA targets were identified by luciferase reporter assays.

RESULTS

The microarray analysis revealed 91 deregulated miRNAs (P < 0.05) in T1D group compared to non-diabetic controls. Within this group we observed one upregulated and seven downregulated miRNAs with fold change >2.0. qRT-PCR validation revealed overexpression of miR-487a-3p which has not been previously reported in the context of T1D. Luciferase reporter assays indicated CTLA4 and FOXO3 genes as miR-487a-3p targets.

CONCLUSION

Our study suggests that miR-487a-3p might repress CTLA4 and FOXO3 by binding to their 3'UTRs and contribute to the development of T1D.

Cumulative effect of IFIH1 variants and increased gene expression associated with type 1 diabetes

AIMS

IFIH1 (Interferon Induced with Helicase C domain 1) gene encodes a sensor of double-stranded RNA, which initiates antiviral activity. Recent studies have indicated the association of rare and common IFIH1 variants with type 1 diabetes mellitus (T1D). The aim of this study was to investigate whether polymorphisms in the IFIH1 locus are a risk factor for T1D in Caucasian patients from Poland.

METHODS

We genotyped 514 T1D patients and 713 healthy control individuals for rs3747517, rs1990760, rs2111485 and rs13422767 variants. Cumulative genetic risk score (CGRS) was calculated using unweighted and weighted approaches. We also examined the expression of IFIH1 gene in a cohort of 90 T1D patients.

RESULTS

All studied polymorphisms showed significant association with type 1 diabetes. The risk alleles G of rs3747517, rs2111485, rs13422767 and A of rs1990760 were observed more frequently in T1D group with P values and allelic odds ratio OR (95%CI) < 0.0001, 1.742 (1.428-2.126); 0.001, 1.336 (1.125-1.588); < 0.0001, 1.799 (1.416-2.285); 0.0005, 1.359 (1.144-1.616), respectively. The risk for type 1 diabetes increased with the growing number of the risk alleles. OR (95%CI) for carriers of ≥ 6 risk alleles reached 2.387 (1.552-3.670) for unweighted CGRS and 3.132 (1.928-5.089) for weighted CGRS. Furthermore, IFIH1 gene expression levels in unstimulated peripheral blood mononuclear cells of T1D patients were significantly higher compared to healthy individuals (mean ± SEM mRNA copy number 163.8 ± 15.7 vs. 117.8 ± 7.2; P = 0.046).

CONCLUSIONS

This study confirms the association of the IFIH1 locus with susceptibility to T1D in the Polish population. The cumulative effect of rs3747517, rs1990760, rs2111485 and rs13422767 variants on type 1 diabetes risk was observed.

Urinary angiotensinogen and urinary sodium are associated with blood pressure in normoalbuminuric children with diabetes

BACKGROUND

The aim of this study was to evaluate the association between blood pressure (BP) and urinary angiotensinogen excretion (uAGT) and renal sodium excretion (uNa) in children with type 1 diabetes mellitus (DM1).

METHODS

The study group consisted of 52 children with DM1 (28 males and 24 females) with albumin/creatinine ratio (ACR) below 30 mg/g and glomerular filtration rate (eGFR) above 90 ml/min/1.73 m(2). BP was assessed by 24-h ambulatory blood pressure monitoring (ABPM).

RESULTS

The patients showed significantly increased uAGT values with respect to controls (median 0.00 and range 1.76 vs. 0.00 and 0.00 ng/mg, respectively). The significant increase of uAGT was observed even in prehypertensive patients. uAGT concentrations showed positive correlation with systolic and diastolic 24-h BP and with mean arterial pressure (MAP) (r = 0.594). uNa values were negatively correlated with BP parameters, uAGT, ACR and eGFR.

CONCLUSIONS

An increase in uAGT precedes hypertension (HTN) in normoalbuminuric children with DM1 and may be considered as a new marker of HTN. Decreased sodium excretion seems to be involved in the development of HTN and early renal injury. Both uAGT and uNa are associated with BP in normoalbuminuric diabetic children.

Missense mutations and polymorphisms of the MC4R gene in Polish obese children and adolescents in relation to the relative body mass index

Extensive studies of the MC4R gene polymorphism showed that, among numerous variants, there are mutations responsible for monogenic obesity, as well as polymorphisms negatively correlated with the risk of obesity. In this report, we present the first studies of the whole coding sequence of the MC4R gene in 243 Polish obese children and adolescents (the mean relative body mass index [RBMI] was 163.6). In addition, 101 non-obese adults were also analyzed. Direct sequencing facilitated the identification of six missense (K73R, V103I, T112M, S127L, M215L, and I251L) and one silent (c.756 C > T) single-nucleotide polymorphisms (SNPs). Two non-synonymous polymorphisms (K73R and M215L) appeared to be novel and one was found in obese patients (M215L, one patient) and one in non-obese adults (K73R, one person). The overall frequency of non-synonymous variant carriers reached 4.1% and 6.9% in obese patients and non-obese adults, respectively. Only one obesity-associated variant (127L) was found in two obese patients (0.82%) and in two non-obese adults (1.98%). The obesity-protecting variants (103I and 251L) appeared to be the most common in both groups: 3.3% and 4.0%, respectively. It was also observed that the RBMI in obese children and adolescents carrying the minor variants did not differ significantly from the non-carriers; however, the expected trends for the associated and protecting variants were observed. We conclude that the contribution of the MC4R gene variants to the pathogenesis of obesity in Polish children and adolescents is low.

Effect of three common SNPs in 5'-flanking region of LEP and ADIPOQ genes on their expression in Polish obese children and adolescents

Genes encoding adipokines are considered as candidates for human obesity. In this study we analyzed the expression of leptin (LEP) and adiponectin (ADIPOQ) genes in relation to common 5′-flanking or 5′UTR variants: -2548G>A (LEP), 19A>G (LEP) and -11377C>G (ADIPOQ) in Polish obese children and adolescents. Relative transcription levels in the subcutaneous adipose tissue (real time RT–PCR) and serum protein concentrations (RIA) were measured in 48 obese subjects with known genotypes at three polymorphic sites and in five non-obese controls. None of the studied polymorphisms altered significantly the expression. Significantly elevated relative transcription levels of the LEP gene (P < 0.05) and serum leptin concentrations (P < 0.01) were recorded in obese patients, when compared with the non-obese controls, but such differences were not found for the ADIPOQ gene. Interestingly, the leptin to adiponectin protein concentration ratio (L/A) was approximately sevenfold higher in obese children and adolescents when compared with the non-obese controls (P < 0.001). Taking into consideration the observed relationship between the genotypes and the gene expression level we suggest that these SNPs are not conclusive markers for predisposition to obesity in Polish children and adolescents. On the other hand, we confirmed that the leptin to adiponectin gene expression ratio (L/A) is an informative index characterizing obesity.

Neuropeptide Y and Peptide YY in Association with Depressive Symptoms and Eating Behaviours in Adolescents across the Weight Spectrum: From Anorexia Nervosa to Obesity

Neuropeptide Y (NPY) and peptide YY (PYY) are involved in metabolic regulation. The purpose of the study was to assess the serum levels of NPY and PYY in adolescents with anorexia nervosa (AN) or obesity (OB), as well as in a healthy control group (CG). The effects of potential confounders on their concentrations were also analysed. Eighty-nine adolescents were included in this study (AN = 30, OB = 30, and CG = 29). Anthropometric measurements and psychometric assessment of depressive symptoms, eating behaviours, body attitudes, and fasting serum levels of NPY and PYY were analysed. The AN group presented severe depressive symptoms, while the OB group held different attitudes towards the body. The levels of NPY were lower in the AN and OB groups as compared with the CG. The PYY levels were higher in the OB group than in the AN group and the CG. The severity of eating disorder symptoms predicted fasting serum concentrations of NPY. Lower levels of NPY in AN, as well as in OB suggests the need to look for a common link in the mechanism of this effect. Higher level of PYY in OB may be important in explaining complex etiopathogenesis of the disease. The psychopathological symptoms may have an influence on the neurohormones regulating metabolism.

Next- generation sequencing is an effective method for diagnosing patients with different forms of monogenic diabetes

AIM

Monogenic diabetes (MD) represents 5-7% of antibody-negative diabetes cases and is a heterogeneous group of disorders.

METHODS

We used targeted next-generation sequencing (NGS) on Illumina NextSeq 550 platform involving the SureSelect assay to perform genetic and clinical characteristics of a study group of 684 individuals, including 542 patients referred from 12 Polish Diabetes Centers with suspected MD diagnosed between December 2016 and December 2019 and their 142 family members (FM).

RESULTS

In 198 probands (36.5%) and 66 FM (46.5%) heterozygous causative variants were confirmed in 11 different MD-related genes, including 31 novel mutations, with the highest number in the GCK gene (206/264), 22/264 in the HNF1A gene and 8/264 in the KCNJ11 gene. Of the 183 probands with MODY1-5 diabetes, 48.6% of them were diagnosed at the pre-diabetes stage and most of them (68.7%) were on diet only at the time of genetic diagnosis, while 31.3% were additionally treated with oral hypoglycaemic drugs and/or insulin.

CONCLUSIONS

In summary, the results obtained confirm the efficacy of targeted NGS method in the molecular diagnosis of patients with suspected MD and broaden the spectrum of new causal variants, while updating our knowledge of the clinical features of patients defined as having MD.

Early kidney damage in diabetic adolescents with increased blood pressure and glomerular hyperfiltration

BACKGROUND

The early impact of type-1 diabetes mellitus (DM1), increased blood pressure and glomerular hyperfiltration (GHF) on kidney damage in adolescents using two urinary markers of kidney injury - neutrophil gelatinase-associated lipocalin (uNGAL) and transferrin (uTransf) was assessed.

METHODS

The study group consisted of 80 adolescents with DM1, of whom 42 were patients with increased blood pressure (IBP), and 38 were patients with normal blood pressure (NBP). Blood pressure was assessed by 24-hour ambulatory bloodpressure monitoring. All patients showed estimated glomerular-filtration rates (eGFRs) above 90 ml/min/1.73m2. The control group consisted of 19 healthy, age and gender-matched adolescents.

RESULTS

All diabetic children showed a significant increase in uNGAL (p<0.001). This increase was not related to blood pressure. The uNGAL was elevated in all patients with normal albuminuria, normal eGFR and NBP. The concentration of uTransf was not increased in the entire studied group and was not related to blood pressure. Children with GHF had significantly higher levels of both uTransf (p=0.010) and uNGAL (p<0.001). In patients with GHF, blood pressure was normal. Patients with IBP showed a significantly higher value for triglycerides (r=0.247; p=0.032) and a longer duration of diabetes (r=0.264; p=0.019).

CONCLUSIONS

Diabetes is the leading risk factor for early kidney injury. However, increased blood pressure does not lead to kidney damage, at least in the early stage of DM1. The uNGAL is the early indicator of kidney injury and increases in patients with normal albuminuria, normal glomerular filtration and normal blood pressure. Glomerular hyperfiltration seems to be a marker of diabetic-kidney involvement.

Three-dimensional high-resolution anorectal manometry: cut-off values for diagnosis of dyssynergic defecation in children

OBJECTIVE

Dyssynergic defecation (DD) may be one of the most important causes of constipation, but its diagnostic criteria have not been formally validated in children. This study aims to evaluate constipated children with 3DHRAM (three-dimensional high-resolution anorectal manometry) and determine a new pediatric cut-off for DD variables.

PATIENTS AND METHODS

205 patients diagnosed with functional constipation (FC) based on Rome III criteria were prospectively enrolled. Data were compared to a historical control group (C). Initially, the diagnosis of DD was based on adult criteria and divided into 4 types. A new cut-off value for percent anal relaxation was determined based on ROC curve analysis.

RESULTS

The FC group presented significantly lower values of percent anal relaxation during straining compared to the C group (9.5% vs. 20%, respectively, p=0.03). Based on adult criteria, DD was found in 53% of the FC group and 46% of the C group (p=0.3), with type II occurring most frequently (35.8%). New cut-off value of 31% for percent anal relaxation in children was derived based on the ROC curve analysis. Based on this new cut-off value, DD was diagnosed in 69.3% of constipated children, with type IV occurring most frequently (28.9%). The analysis of segmental pressure showed significant influence of segments at the locations of the puborectalis muscle and external anal sphincter.

CONCLUSIONS

We found that during bear down maneuver the percent anal relaxation variable significantly differed between patients and controls. The higher cut-off value should be used when 3DHRAM and the standard four-type classification are used to diagnose DD in children.

Early kidney damage in diabetic adolescents with increased blood pressure and glomerular hyperfiltration

BACKGROUND

The early impact of type 1 diabetes mellitus (DM1), increased blood pressure and glomerular hyperfiltration (GHF) on kidney damage in adolescents using two urinary markers of kidney injury - neutrophil gelatinase-associated lipocalin (uNGAL) and transferrin (uTransf) - was assessed.

METHODS

The study group consisted of 80 adolescents with DM1, of whom 42 were patients with increased blood pressure (IBP), and 38 were patients with normal blood pressure (NBP). Blood pressure was assessed by 24-hour ambulatory blood-pressure monitoring. All patients showed estimated glomerular-filtration rates (eGFRs) above 90 mL/min/1.73 m2. The control group consisted of 19 healthy, age and gender-matched adolescents.

RESULTS

All diabetic children showed a significant increase in uNGAL (P<0.001). This increase was not related to blood pressure. The uNGAL was elevated in all patients with normal albuminuria, normal eGFR and NBP. The concentration of uTransf was not increased in the entire studied group and was not related to blood pressure. Children with GHF had significantly higher levels of both uTransf (P=0.010) and uNGAL (P<0.001). In patients with GHF, blood pressure was normal. Patients with IBP showed a significantly higher value for triglycerides (r=0.247; P=0.032) and a longer duration of diabetes (r=0.264; P=0.019).

CONCLUSIONS

Diabetes is the leading risk factor for early kidney injury. However, increased blood pressure does not lead to kidney damage, at least in the early stage of DM1. The uNGAL is the early indicator of kidney injury and increases in patients with normal albuminuria, normal glomerular filtration and normal blood pressure. Glomerular hyperfiltration seems to be a marker of diabetic-kidney involvement.