IGF-I deficiency and enhanced insulin sensitivity due to a mutated growth hormone receptor gene in humans

Divergent metabolic phenotypes in two genetic syndromes of low insulin secretion

AIMS

We examined the effect of growth hormone (GH) counter-regulation on carbohydrate metabolism in individuals with life-long diminished insulin secretion (DIS).

METHODS

Adults homozygous for the E180 splice site mutation of GHR [Laron syndrome (LS)], adults with a gain-of-function mutation in CDKN1c [Guevara-Rosenbloom syndrome (GRS)], and controls were evaluated for body composition, leptin, total and high molecular weight (HMW) adiponectin, insulin-like growth factor (IGF) axis molecules, and a 5-hour oral glucose tolerance test (OGTT), with measurements of glucose, insulin, glucagon, ghrelin, pancreatic polypeptide, gastric inhibitory peptide, glucagon-like peptide-1, peptide YY, and islet amyloid polypeptide (IAPP).

RESULTS

Both syndromic cohorts displayed DIS during OGTT. LS subjects had higher serum concentrations of total and HMW adiponectin, and lower levels of IGF-I, IGF-II, and IGF-Binding Protein-3 than individuals in other study groups. Furthermore, they displayed normal glycemic responses during OGTT with the lowest IAPP secretion. In contrast, individuals with GRS had higher levels of protein glycation, deficient glucose control during OGTT, and increased secretion of IAPP.

CONCLUSIONS

A distinct metabolic phenotype depending on GH counter-regulatory status, associates with diabetes development and excess glucose-induced IAPP secretion.

Growth hormone modulates Trypanosoma cruzi infection in vitro

OBJECTIVE

Chagas disease (CD) is caused by the protozoan parasite, Trypanosoma cruzi. It affects 7 to 8 million people worldwide and leads to approximately 50,000 deaths per year. In vitro and in vivo studies had demonstrated that Trypanosoma cruziinfection causes an imbalance in the hypothalamic-pituitary-adrenal (HPA) axis that is accompanied by a progressive decrease in growth hormone (GH) and prolactin (PRL) production. In humans, inactivating mutations in the GH receptor gene cause Laron Syndrome (LS), an autosomal recessive disorder. Affected subjects are short, have increased adiposity, decreased insulin-like growth factor-I (IGFI), increased serum GH levels, are highly resistant to diabetes and cancer, and display slow cognitive decline. In addition, CD incidence in these individuals is diminished despite living in highly endemic areas. Consequently, we decided to investigate the in vitro effect of GH/IGF-I on T. cruzi infection.

DESIGN

We first treated the parasite and/or host cells with different peptide hormones including GH, IGFI, and PRL. Then, we treated cells using different combinations of GH/IGF-I attempting to mimic the GH/IGF-I serum levels observed in LS subjects.

RESULTS

We found that exogenous GH confers protection against T. cruzi infection. Moreover, this effect is mediated by GH and not IGFI. The combination of relatively high GH (50 ng/ml) and low IGF-I (20 ng/ml), mimicking the hormonal pattern seen in LS individuals, consistently decreased T. cruzi infection in vitro.

CONCLUSIONS

The combination of relatively high GH and low IGF-I serum levels in LS individuals may be an underlying condition providing partial protection against T. cruzi infection.

Differential Diagnosis of the Short IGF-I-Deficient Child with Apparently Normal Growth Hormone Secretion

The current differential diagnosis for a short child with low insulin-like growth factor I (IGF-I) and a normal growth hormone (GH) peak in a GH stimulation test (GHST), after exclusion of acquired causes, includes the following disorders: (1) a decreased spontaneous GH secretion in contrast to a normal stimulated GH peak ("GH neurosecretory dysfunction," GHND) and (2) genetic conditions with a normal GH sensitivity (e.g., pathogenic variants of GH1 or GHSR) and (3) GH insensitivity (GHI). We present a critical appraisal of the concept of GHND and the role of 12- or 24-h GH profiles in the selection of children for GH treatment. The mean 24-h GH concentration in healthy children overlaps with that in those with GH deficiency, indicating that the previously proposed cutoff limit (3.0-3.2 μg/L) is too high. The main advantage of performing a GH profile is that it prevents about 20% of false-positive test results of the GHST, while it also detects a low spontaneous GH secretion in children who would be considered GH sufficient based on a stimulation test. However, due to a considerable burden for patients and the health budget, GH profiles are only used in few centres. Regarding genetic causes, there is good evidence of the existence of Kowarski syndrome (due to GH1 variants) but less on the role of GHSR variants. Several genetic causes of (partial) GHI are known (GHR, STAT5B, STAT3, IGF1, IGFALS defects, and Noonan and 3M syndromes), some responding positively to GH therapy. In the final section, we speculate on hypothetical causes.

Regulation of ovarian function by growth hormone: Potential intervention of ovarian aging

Growth hormone (GH) is mainly secreted by eosinophils of anterior pituitary gland. GH plays an important role in regulating the growth and development of many tissues and cells, so it is used in the treatment of many diseases. In recent years, the regulation of GH on ovarian function has attracted much attention. GH has been applied in controlled ovarian hyperstimulation, particularly in the patients with advanced age, diminished ovarian reserve (DOR) and poor ovarian response (POR). GH can directly bind to the growth hormone receptor (GHR) on the ovary to promote the growth, maturation and ovulation of follicles, as well as to inhibit follicular atresia. GH so as to promote the occurrence of early follicles, enhance the sensitivity of follicles to gonadotropins, accelerate the maturation of oocyte nucleus, improve mitochondrial activity and the quality of oocytes through the insulin-like growth factor (IGF) system, which is an indirect regulation. The deep-seated effects of GH on human reproduction and ovarian aging need further basic research and clinical practice.

[Preparation of GH/tPA double transgenic mice and gene expression analysis]

OBJECTIVE

To obtain GH/tPA double transgenic mice, analyze the expression level of tissue plasminogen activator (tPA) in the mammary glands and observe the growth and development of the transgenic mice.

METHODS

We obtained the offspring mice of 2 tPA single transgenic mice (P03 and P05) mated with a female nontransgenic mouse by microinjection of linearized GH plasmid into the fertilized eggs and embryo transfer. PCR was used to detect the gene integration. The expression levels of tPA in single gene and double gene transgenic mice were compared using ELISA and Western blotting. We assessed the effects of GH gene transduction on the growth and development of the transgenic mice by observing body weight changes of the mice at each developmental stage.

RESULTS

A total of 286 fertilized eggs were collected from P03 mice, and after embryo transfer, 77 offspring mice were obtained, including 16 tPA single transgenic mice (7 male, 9 female) and 13 GH/tPA double transgenic mice (8 male, 5 female) as confirmed by PCR. The integration rate of the double genes was 16.9%. A total of 175 fertilized eggs were collected from P05 mice, and 34 offspring mice were obtained including 12 tPA single transgenic mice (5 male, 7 female) and 7 GH/tPA double transgenic mice (3 male, 4 female), in which the integration rate of the double genes was 20.6%. The highest expression level of tPA in the mammary gland was significantly higher in double than in single transgenic mice (674 μg/mL vs 82.5 μg/mL, P < 0.05). In the whole growth cycle of the mice, no significant difference in weight gain was observed in the single or double transgenic mice as compared with the na?ve mice (P>0.05).

CONCLUSION

We successfully prepared GH/tPA double transgenic mice, in which GH gene transduction significantly increases the expression level of target gene tPA without affecting the growth and development of the transgenic mice. This success suggests a promising approach to preparing transgenic animals for producing pharmaceutical proteins and the breeding of the transgenic animals.

Safety and efficacy of ALRV5XR in men with androgenetic alopecia: A randomised, double-blinded, placebo-controlled clinical trial

BACKGROUND

Androgenetic alopecia (AGA) is the most common hair loss disorder seen in men. It can have an early onset but has also been associated with ageing and senescence. It often induces pronounced psychological impact. ALRV5XR, a new hair loss treatment herein evaluated, was designed to target multiple molecular pathways involved in hair growth and hair follicle stem cell biology. The main objectives of the study were the assessment of safety and efficacy profiles of ALRV5XR in men.

METHODS

This 24-week, parallel randomised, placebo-controlled, double-blinded clinical trial was performed in a USA community clinic. Healthy men (age 22-65) with AGA and belonging to the Hamilton-Norwood (HN) classification I-VII and Fitzpatrick skin type (FST) I-VI, were randomly allocated in a 1:1 ratio into ALRV5XR or placebo treatment groups. Dermatologist assessment, phototrichograms, and blood samples were obtained in a blinded fashion at baseline, 12 and 24 weeks. Subjects were given a masked treatment consisting of oral capsules, shampoo, conditioner, and follicle serum, which was intended for daily use. Efficacy was assessed via absolute and per cent changes in terminal hair (TH) density, and response rates. The trial was registered with clinicaltrials.gov (NCT04450589) and is completed.

FINDINGS

Forty-six subjects were enroled in the study, 23 allocated to the ALRV5XR treatment and 23 to the placebo group. Enrolment occurred from April 11 to October 23, 2018. Thirty-six subjects completed the trial (17 ALRV5XR, 19 placebo) and 11 subjects in each group were evaluable for TH outcomes. At 24 weeks, the absolute change in TH density improved by 21·0 THs/cm² (95% CI: 9·2-32·8; p = 0·0014), and the relative density increased by 16·4% (95% CI: 7·4%-25·5%; p = 0·0012). The odds ratio for being a responder (≥ 0 change) was 87·4. TH density increased linearly and was not affected by HN, FST, ethnicity, age, or body mass index. All subjects in the ALRV5XR group responded to treatment while 81·8% of the placebo group decreased TH density. ALRV5XR induced statistically significant changes in both decrease in vellus hair (VH) density as well as in concomitant increase of the TH/VH ratio when compared to placebo. ALRV5XR was well tolerated, and no adverse events were observed.

INTERPRETATION

ALRV5XR treatment resulted in clinically significant TH regrowth in men with AGA. Furthermore, it appeared to reverse the characteristic hair miniaturisation seen in this condition. When compared to results of published trials of standard therapy, ALRV5XR showed a multi-fold increase both in efficacy and in response rates. In addition, the continuance of TH regrowth from 12 to 24 weeks suggests that the normal structure and function of non-productive telogen follicles is restored and that a normal hair phenotype may be attained by extended ALRV5XR treatment.

FUNDING

Arbor Life Labs.

Safety and efficacy of ALRV5XR in women with androgenetic alopecia or telogen effluvium: A randomised, double-blinded, placebo-controlled clinical trial

BACKGROUND

Scalp hair loss (alopecia) in women is a common ageing and senescing condition. It usually presents as androgenetic alopecia (AGA) or telogen effluvium (TE) and often has pronounced psychological consequences. ALRV5XR is a novel treatment aiming to regenerate a normal hair phenotype by targeting multiple molecular pathways linked to hair growth promotion and hair follicle stem cell activation. The primary objectives of this 24-week trial were to evaluate the safety and efficacy of ALRV5XR in terminal hair (TH) regrowth in women with AGA or TE.

METHODS

This randomised, double-blind, placebo-controlled trial was performed in a USA community clinic. Healthy women 18-65 years of age with AGA or TE of Ludwig classification I-II and Fitzpatrick skin type I-VI were enrolled. They were allocated in a 1:1 ratio into ALRV5XR or placebo treatment groups using a random number table. Masked dermatologist assessments, phototrichograms and blood samples were obtained at baseline, 12 and 24 weeks. Subjects were given a masked treatment regimen of oral capsules, shampoo, conditioner and follicle serum for daily administration. Main outcomes were absolute and per cent changes in TH density and response rates. The trial was registered with clinicaltrials.gov (NCT04450602) and is completed.

FINDINGS

46 subjects (23 ALRV5XR, 23 placebo) were enrolled between April 3 and October 20, 2018. Five subjects dropped out and two were non-compliant. Thirty-nine subjects completed the trial (18 ALRV5XR, 21 placebo). At 24 weeks, the absolute change in TH density improved by 30·1THs/cm² (95% CI: 15·1-45·1; p=0·0002), and the relative density increased by 19·7% (95% CI: 8·0%-31·4%; p=0·0016). The odds ratio for being a responder (≥0 change) was 2·7. Efficacy increased 133% from week 12 to 24. Efficacy outcomes were similar in AGA and TE subjects. 66·7% of the ALRV5XR group responded by regrowing 40THs/cm² or more hair. No adverse events were reported.

INTERPRETATION

In women with AGA or TE, ALRV5XR treatment significantly increased hair regrowth without adverse events. ALRV5XR displayed a multi-fold improved efficacy and response rate when compared to published trials of standard therapy. Progressive acceleration of TH regrowth suggests regeneration of the structure and function of non-productive telogen follicles and prolonged treatment may restore a normal hair phenotype.