RMRP-related short stature: A report of six additional Japanese individuals with cartilage hair hypoplasia and literature review

Biallelic pathogenic variants in RMRP, the gene encoding the RNA component of RNase mitochondrial RNA processing enzyme complex, have been reported in individuals with cartilage hair hypoplasia (CHH). CHH is prevalent in Finnish and Amish populations due to a founder pathogenic variant, n.71A > G. Based on the manifestations in the Finnish and Amish individuals, the hallmarks of CHH are prenatal-onset growth failure, metaphyseal dysplasia, hair hypoplasia, immunodeficiency, and other extraskeletal manifestations. Herein, we report six Japanese individuals with CHH from four families. All probands presented with moderate short stature with mild metaphyseal dysplasia or brachydactyly. One of them had hair hypoplasia and the other immunodeficiency. By contrast, the affected siblings of two families showed only mild short stature. We also reviewed all previously reported 13 Japanese individuals. No n.71A > G allele was detected. The proportions of Japanese versus Finnish individuals were 0% versus 70% for birth length < -2.0 SD, 84% versus 100% for metaphyseal dysplasia and 26% versus 88% for hair hypoplasia. Milder manifestations in the Japanese individuals may be related to the difference of genotypes. The mildest form of CHH phenotypes is mild short stature without overt skeletal alteration or extraskeletal manifestation and can be termed "RMRP-related short stature".

GR-KLF15 pathway controls hepatic lipogenesis during fasting

During periods of fasting, the body undergoes a metabolic shift from carbohydrate utilization to the use of fats and ketones as an energy source, as well as the inhibition of de novo lipogenesis and the initiation of gluconeogenesis in the liver. The transcription factor sterol regulatory element-binding protein-1 (SREBP-1), which plays a critical role in the regulation of lipogenesis, is suppressed during fasting, resulting in the suppression of hepatic lipogenesis. We previously demonstrated that the interaction of fasting-induced Kruppel-like factor 15 (KLF15) with liver X receptor serves as the essential mechanism for the nutritional regulation of SREBP-1 expression. However, the underlying mechanisms of KLF15 induction during fasting remain unclear. In this study, we show that the glucocorticoid receptor (GR) regulates the hepatic expression of KLF15 and, subsequently, lipogenesis through the KLF15-SREBP-1 pathway during fasting. KLF15 is necessary for the suppression of SREBP-1 by GR, as demonstrated through experiments using KLF15 knockout mice. Additionally, we show that GR is involved in the fasting response, with heightened binding to the KLF15 enhancer. It has been widely known that the hypothalamic-pituitary-adrenal (HPA) axis regulates the secretion of glucocorticoids and plays a significant role in the metabolic response to undernutrition. These findings demonstrate the importance of the HPA-axis-regulated GR-KLF15 pathway in the regulation of lipid metabolism in the liver during fasting.

Qualitative and Quantitative Study on Components of Future Time Perspective and Their Association with Persistent Treatment for Type 2 Diabetes

INTRODUCTION

Future time perspective (FTP) means the capacity to foresee, anticipate, and plan for future desired outcomes, and it contributes to persistent treatment for type 2 diabetes mellitus (T2DM). However, the components of FTP specific to T2DM patients have not been clarified. This study aimed to explore the components of FTP and to examine the associations between such components and persistent/impersistent diabetes treatment.

METHODS

In this cross-sectional study, using qualitative and quantitative methods, 106 T2DM patients were enrolled by purposive sampling. The participants were interviewed in October and November 2018 by public health nurses in Koriyama City Public Health Center, Japan. In addition to the participants' status of treatment engagement (persistent/impersistent), their responses regarding reasons for persistent/impersistent treatment were collected and then summarized into nine subthemes, which were then merged into two main themes according to the presence or absence of FTP with a sense of T2DM ownership for analysis.

RESULTS

The main theme, "presence of FTP with a sense of T2DM ownership," included subthemes such as "securing social independence," "planning on living a long and healthy life," "prioritizing avoiding being a burden on family and friends," "valuing improvement of diabetes," "avoiding tragic results," "optimistically viewing treatment as a form of self-development," and "improving mental health," whereas the main theme, "absence of FTP with a sense of T2DM ownership," included "lack of consciousness of disease" and "living a dissipated life." The association between the presence of FTP with a sense of T2DM ownership and persistent treatment for T2DM was found using Fisher's exact test (p < 0.001).

CONCLUSION

Health care professionals should support T2DM patients in having an FTP with a sense of T2DM ownership and purpose in life instead of treatment goals when such patients mention their dissipated life or lack of insight into the disease.

Quality of Life and Utility Values for Cost-Effectiveness Modeling in Japanese Patients with Type 2 Diabetes

INTRODUCTION

Reliable quality of life (QoL) measures and utility values are needed for patients with type 2 diabetes mellitus (T2DM) with a variety of comorbid conditions to help facilitate cost-effectiveness modeling. This study aimed to evaluate the Diabetes Treatment-Related Quality of Life (DTR-QOL) and EuroQol 5-dimension 5-level (EQ-5D-5L) questionnaires in patients with T2DM with and without diabetes complications and comorbidities in Japan.

METHODS

This was an observational survey study involving 1000 patients with T2DM, at least 20 years old, receiving treatment at Nara University Hospital or Takamura Internal Medicine Clinic in Japan. Patients completed the DTR-QOL and EQ-5D-5L questionnaires and clinicians completed an accompanying case report form. The DTR-QOL and EQ-5D-5L are scored on a scale of 0-100 and 0-1, with 100 and 1 representing the best possible scores, respectively.

RESULTS

Out of 1000 recruited patients, 978 were included in the final analysis. Patients reported an average EQ-5D-5L value of 0.92 ± 0.11. Utility values corresponded to the degree of severity of health conditions while few differences were observed when stratified by the HbA1c 7% threshold, age, or BMI level, nor did the values correspond to the degree of clinical risk factors. Patients reported an average total DTR-QOL score of 79.26 ± 13.26. The DTR-QOL was sensitive to detect differences in patients with T2DM with a variety of complications and comorbidities, risk factors, and treatments.

CONCLUSION

This is the largest study to report QOL values for patients with diabetes in Japan and the first to include a variety of comorbid diabetic conditions. These findings may be useful for cost-effectiveness modeling of patients with T2DM in Japan.

Contribution of pancreatic α-cell function to insulin sensitivity and glycemic variability in patients with type 1 diabetes

AIMS/INTRODUCTION

To evaluate the contribution of pancreatic α-cell function to the dawn phenomenon, insulin sensitivity, hepatic glucose uptake and glycemic variability in patients with type 1 diabetes.

MATERIALS AND METHODS

In 40 patients with type 1 diabetes, arginine stimulation tests were carried out, and the area under the curve (AUC) of glucagon was measured using radioimmunoassays (AUCglc RIA ) and enzyme-linked immunosorbent assays (AUCglc ELISA ). The ratio of the insulin dose delivered by an artificial pancreas to maintain euglycemia between 04.00 and 08.00 hours or between 00.00 and 04.00 hours was measured as the dawn index. The glucose infusion rate and hepatic glucose uptake were measured using hyperinsulinemic euglycemic clamp and clamp oral glucose loading tests. Glycemic variability in 96 h was measured by continuous glucose monitoring.

RESULTS

The median dawn index (1.7, interquartile range 1.0-2.8) was not correlated with AUCglc RIA (R2  = 0.03, P = 0.39) or AUCglc ELISA (R2  = 0.04, P = 0.32). The median glucose infusion rate (7.3 mg/kg/min, interquartile range 6.4-9.2 mg/kg/min) was significantly correlated with AUCglc RIA (R2  = 0.20, P = 0.02) and AUCglc ELISA (R2  = 0.21, P = 0.02). The median hepatic glucose uptake (65.3%, interquartile range 40.0-87.3%) was not correlated with AUCglc RIA (R2  = 0.07, P = 0.26) or AUCglc ELISA (R2  = 0.26, P = 0.79). The standard deviation of glucose levels measured by continuous glucose monitoring was significantly correlated with AUCglc RIA (R2  = 0.11, P = 0.049), but not with AUCglc ELISA (R2  = 0.01, P = 0.75).

CONCLUSIONS

Pancreatic α-cell function contributed to insulin sensitivity in patients with type 1 diabetes.

Response to "Preserved" glucagon secretion in fulminant type 1 diabetes

We compared the glucagon responses to arginine stimulation in five patients with fulminant type 1 diabetes and five age- and diabetes duration-matched acute-onset type 1 diabetes, and the curves of the glucagon responses were similar. In our study, we measured the glucagon levels by not only radioimmunoassay, but also novel enzyme-linked immunosorbent assay.

Impact of Reduced Renal Function on the Glucose-Lowering Effects of Luseogliflozin, a Selective SGLT2 Inhibitor, Assessed by Continuous Glucose Monitoring in Japanese Patients with Type 2 Diabetes Mellitus

INTRODUCTION

We investigated the impact of reduced renal function on 24-h glucose variability in Japanese patients with type 2 diabetes mellitus (T2DM) treated with luseogliflozin.

METHODS

In this double-blind, placebo-controlled, crossover study, 37 Japanese patients with T2DM [glycated hemoglobin (HbA1c) 7.0-10.0%] and estimated glomerular filtration rate (eGFR) ≥45 mL/min/1.73 m(2) were randomized into two groups in which patients first received luseogliflozin then placebo, or vice versa, for 7 days each. Twenty-four-hour glucose variability was measured on day 7 in each period and was compared among patients divided into three groups according to their baseline eGFR (mL/min/1.73 m(2)): normal (≥90; n = 13; normal group), normal-to-mildly reduced renal function (≥75 to <90; n = 12; normal-mild group), and mild-to-moderately reduced renal function (<75; n = 9; mild-moderate group).

RESULTS

The mean [95% confidence interval (CI)] placebo-subtracted 24-h cumulative urinary glucose excretion (g) was 82.1 (72.7, 91.5), 82.5 (73.4, 91.5), and 62.2 (51.2, 73.3); the placebo-subtracted 24-h mean glucose concentration (mg/dL) was -24.39 (-32.53, -16.26), -28.28 (-39.35, -17.22), and -11.53 (-23.93, 0.86); and the placebo-subtracted peak postprandial glucose (mg/dL) was -26.9 (-46.9, -6.9), -38.1 (-59.6, -16.6), and 1.5 (-25.5, 28.4) in the normal, normal-mild, and mild-moderate groups, respectively. The mean lowest glucose concentrations (placebo vs. luseogliflozin, mg/dL) decreased to similar levels in the normal (115.4 vs. 93.4), normal-mild (121.0 vs. 97.9), and mild-moderate (104.0 vs. 91.1) groups.

CONCLUSION

This post hoc subanalysis revealed that although mild-to-moderately reduced renal function attenuated the glucose-lowering effects of luseogliflozin on peak postprandial glucose, it did not attenuate the effects of luseogliflozin on fasting glucose. These findings may explain the smaller increase in urinary glucose excretion in these patients relative to patients with normal renal function or normal-to-moderately reduced renal function. Further studies may be needed to examine these findings in large populations of patients with T2DM and reduced renal function.

TRIAL REGISTRATION

JapicCTI-142548.

FUNDING

Taisho Pharmaceutical Co., Ltd.