The role of spexin in energy metabolism

Association between serum spexin levels and diabetic nephropathy in patients with type 2 diabetes: a cross-sectional study

BACKGROUND

Diabetic nephropathy (DN) is a serious complication of diabetes, with a high prevalence ranging from 21.8% in China, 35.3% in African countries, and an overall prevalence of 20-40% worldwide. This study investigated serum spexin levels in patients with type 2 diabetes, comparing those with and without DN, and explored its association with metabolic parameters.

METHODS

This cross-sectional study was conducted among patients with type-2 diabetes according to ADA guidelines. After obtaining informed consent, urine albumin-to-creatinine-ratio (ACR) was determined and patients were categorized into two groups: with-nephropathy (ACR ≥ 30) and without-nephropathy (ACR < 30). The correlation between spexin and demographic, anthropometric, and biochemical variables was further determined. Logistic regression analysis was used to assess the relationship between spexin and the likelihood of DN. Receiver Operating Characteristic (ROC) curve analysis determined the optimal serum spexin cutoff for distinguishing between groups.

RESULTS

A total of 97 diabetic individuals (33 with DN, 64 without) participated in the study. Serum spexin was significantly lower in patients with DN compared to those without DN (p < 0.001). Spexin concentrations showed an inverse correlation with LDL and ACR levels. Lower spexin levels were associated with a reduced likelihood of DN (OR 0.46, 95% CI 0.31-0.69; p < 0.001). ROC curve analysis identified a cutoff value of 81.10 ng/ml, with an area under the curve of 0.986, demonstrating 95.3% sensitivity and 94.1% specificity for diagnosing DN.

CONCLUSION

Lower serum spexin levels are associated with impaired kidney function, indicating its potential as a predictive biomarker for diabetic nephropathy. However, further validation in larger and more diverse cohorts is needed to address limitations such as sample size and unmeasured confounders.

Immunohistochemical investigation of transient receptor potential melastatin-2 and spexin immunoreactivity in atopic dermatitis and mycosis fungoides

BACKGROUND

Atopic dermatitis (AD) is a chronic, pruritic, and inflammatory dermatosis seen in individuals with an atopic predisposition. This study aimed to examine the immunoreactivity of spexin and TRPM2 in skin samples from patients with AD and MF lesions using immunohistochemical methods.

MATERIALS AND METHODS

The study utilized a total of 60 skin samples, comprising 20 from AD patients, 20 from MF patients, and 20 from control subjects. Skin samples from patients diagnosed with other dermatological diseases, malignancies, and diabetes mellitus were excluded from the study. During staining, the prevalence (0.1: <25%, 0.4: 26-50%, 0.6: 51-75%, 0.9: 76-100%) and intensity (0: none, + 0.5: very low, + 1: low, + 2: moderate, + 3: intense) of immunoreactivity were used as criteria to establish a histo-score. Calculations employed the formula histo-score = prevalence x intensity.

RESULTS

Statistically significant higher spexin histoscores were observed in both the AD and MF patient groups compared to the control group (1.30 ± 0.46, 1.04 ± 0.29, and 0.20 ± 0.07, respectively; p = 0.000). Similarly, TRPM2 histoscores were significantly higher in the AD and MF patient groups compared to the control group (1.12 ± 0.28, 1.02 ± 0.30, and 0.20 ± 0.07, respectively; p = 0.000).

CONCLUSION

It is hypothesized that the increase in the neuropeptide spexin in both AD and MF is triggered by inflammation and contributes to itching mechanisms via galanin receptors. TRPM2, an ion channel, is speculated to be a marker of Reactive Oxygen Species (ROS) in chronic inflammatory dermatoses like AD, but it may not serve as a potential biomarker for distinguishing chronic inflammatory dermatoses from MF.

Investigation of serum spexin concentrations in pregnant women diagnosed with hyperemesis gravidarum

OBJECTIVE

We aimed to investigate the serum concentration of the spexin, which has been shown to have an anorexic effect in animal models, in pregnant women with hyperemesis gravidarum (HG).

METHODS

This case-control study was conducted with 80 pregnant women who applied to the Umraniye Training and Research Hospital Gynecology and Obstetrics Clinic between April 2022 and September 2022. The HG group consisted of 40 pregnant women who were diagnosed with HG in the first 14 weeks of pregnancy, and the control group consisted of 40 healthy pregnant women matched with the HG group in terms of age, BMI, and gestational week.

RESULTS

Both groups were similar in terms of demographic characteristics and gestational age at blood sampling for spexin (p > 0.05). While maternal serum spexin concentration was 342.4 pg/ml in the HG group, it was 272.8 pg/ml in the control group (p = 0.003). ROC analysis was performed to determine the value of maternal serum spexin concentration in terms of predicting HG. AUC analysis of maternal serum spexin for HG estimation was 0.693 (p = 0.003, 95% CI =0.577 - 0.809). The optimal cutoff value for maternal serum spexin concentration was determined as 305.90 pg/ml with 65% sensitivity and 65% specificity.

CONCLUSIONS

High serum spexin concentration is thought to play a role in the etiopathogenesis of HG, and this should be supported by demonstrating changes in serum spexin concentrations in pregnant women with HG whose symptoms alleviated and weight regain started after treatment.

Exercise training and spexin ameliorate thyroid changes in obese type 2 diabetic rats: the possible interlaying mechanisms

Thyroid dysfunction and diabetes mellitus are prevalent endocrine disorders that often coexist and influence each other. The role of spexin (SPX) in diabetes and obesity is well documented, but its connection to thyroid function is less understood. This study investigates the influence of exercise (EX) and SPX on thyroid hypofunction in obese type 2 diabetic rats. Rats were divided into normal control, obese diabetic sedentary, obese diabetic EX, and obese diabetic SPX groups, with subdivisions for M871 and HT-2157 treatment in the latter two groups. High-fat diet together with streptozotocin (STZ) injection induced obesity and diabetes. The EX group underwent swimming, and the SPX group received SPX injections for 8 wk. Results showed significant improvements in thyroid function and metabolic, oxidative, and inflammatory states with EX and SPX treatment. The study also explored the involvement of galanin receptor isoforms (GALR)2/3 in SPX effects on thyroid function. Blocking GALR2/3 receptors partially attenuated the beneficial effects, indicating their interaction. These findings underscore the importance of EX and SPX in modulating thyroid function in obesity and diabetes. Comprehending this interplay could enable the development of new treatment approaches for thyroid disorders associated with obese type 2 diabetes. Additional research is necessary to clarify the exact mechanisms connecting SPX, EX activity, and thyroid function.NEW & NOTEWORTHY This study proves, for the first time, the beneficial effects of SPX on thyroid dysfunction in obese diabetic rats and suggests that SPX mediates the EX effect on thyroid gland and exerts its effect mainly via GALR2.

Spexin acts as a novel glucose-lowering factor in grass carp (Ctenopharyngodon idella)

At present, the physiological roles of various hormones in fish glucose metabolism have been elucidated. Spexin, a 14-amino acids polypeptide, is highly conserved in many species and has functions such as reducing body weight and improving insulin resistance. In this paper, the open reading frame (ORF) of spx21 in grass carp (Ctenopharyngodon idella) was cloned, and the tissue distribution of spx1 and spx2, their direct and indirect regulatory effects on glucose metabolism of grass carp were investigated. The ORF of spx2 gene in grass carp was 279 bp in length. Moreover, spx1 was highly expressed in the adipose tissue, while spx2 was highly expressed in the brain. In vitro, SPX1 and SPX2 showed opposite effects on the glycolytic pathway in the primary hepatocytes. In vivo, intraperitoneal injection of SPX1 and SPX2 significantly reduced serum glucose levels and increased hepatopancreas glycogen contents. Meanwhile, SPX1 and SPX2 promoted the expression of key genes of glycolysis (pk) and glycogen synthesis (gys) in the hepatopancreas at 3 h post injection. As for indirect effects, 1000 nM SPX1 and SPX2 significantly increased insulin-mediated liver type phosphofructokinase (pfkla) mRNA expression and enhanced the inhibitory effects of insulin on glucose-6-phosphatase (g6pase), phosphoenolpyruvate carboxykinase (pepck), glycogen phosphorylase L (pygl) mRNA expression. Our results show that SPX1 and SPX2 have similar indirect effects on the regulation of glucose metabolism that enhance insulin activity, but they exhibit opposite roles in terms of direct effects.

Recent Research on Mechanisms of Feeding Regulation in Chicks

Food intake affects poultry productivity. A complete understanding of these regulatory mechanisms provides new strategies to improve productivity. Food intake is regulated by complex mechanisms involving many factors, including the central nervous system, gastrointestinal tract, hormones, and nutrients. Although several studies have been conducted to elucidate regulatory mechanisms in chickens, the mechanisms remain unclear. To update the current knowledge on feeding regulation in chickens, this review focuses on recent findings that have not been summarized in previous reviews, including spexins, adipokines, neurosecretory proteins GL and GM, and central intracellular signaling factors.

Normalization of Spexin Levels in Patients with Obesity Submitted to Bariatric Surgery

PURPOSE

Spexin is expressed by white fat tissue and other endocrine organs. A negative correlation between spexin and gluco-lipidic metabolism, energy homeostasis, and food intake has been reported. The objectives of this study are (1) to compare spexin levels between patients with obesity (study group) and normal-weight subjects (control group); (2) to evaluate spexin levels after bariatric surgery; and (3) to identify a correlation between spexin and weight loss/metabolic profile of patients with obesity.

MATERIALS AND METHODS

We examined 53 patients with obesity (mean BMI 48.5 ± 9.4 kg/m2) who underwent bariatric surgery, compared to 55 normal-weight subjects. Serum spexin levels were assessed at baseline (study and control group) and at 3 and 6 months after surgery in patients with obesity.

RESULTS

Spexin at baseline was significantly lower in the study group (p < 0.0001). At 3 and 6 months after bariatric surgery, spexin significantly increased compared to pre-surgical levels (p < 0.001) reaching control group levels (p = 0.08) at 6 months. In patients with obesity, pre-surgical spexin was similar in patients with and without comorbidities. No correlation between spexin and C-reactive protein (p = 0.8) and HOMA index (p = 0.5) was found. A significant negative correlation between age and pre-surgical spexin was observed (p = 0.03). At multivariable analysis, no correlation between Δ spexin and pre-surgery BMI, HOMA index, age, and 6-month TWL% was found.

CONCLUSION

This study demonstrates that patients with obesity have significantly lower spexin levels than healthy subjects. After surgery, spexin levels of the study group become similar to those observed in the normal-weight group.

Role of Spexin in White Adipose Tissue Thermogenesis under Basal and Cold-Stimulated Conditions

Spexin (SPX) is a novel adipokine that plays an emerging role in metabolic diseases due to its involvement in carbohydrate homeostasis, weight loss, appetite control, and gastrointestinal movement, among others. In obese patients, SPX plasma levels are reduced. Little is known about the relationship between SPX and white adipose tissue (WAT) thermogenesis. Therefore, the aim of the present study was to evaluate the role of SPX in this process. C57BL/6J male mice were treated or not with SPX for ten days. On day 3, mice were randomly divided into two groups: one kept at room temperature and the other kept at cold temperature (4 °C). Caloric intake and body weight were recorded daily. At the end of the protocol, plasma, abdominal (epididymal), subcutaneous (inguinal), and brown AT (EAT, IAT, and BAT, respectively) depots were collected for measurements. We found that SPX treatment reduced Uncoupling protein 1 levels in WAT under both basal and cold conditions. SPX also reduced cox8b and pgc1α mRNA levels and mitochondrial DNA, principally in IAT. SPX did not modulate the number of beige precursors. SPX decreased spx levels in IAT depots and galr2 in WAT depots. No differences were observed in the BAT depots. In conclusion, we showed, for the first time, that SPX treatment in vivo reduced the thermogenic process in subcutaneous and abdominal AT, being more evident under cold stimulation.

An update on galanin and spexin and their potential for the treatment of type 2 diabetes and related metabolic disorders

Spexin (SPX) and galanin (GAL) are two neuropeptides widely expressed in the central nervous system as well as within peripheral tissues in humans and other species. SPX and GAL mediate their biological actions through binding and activation of galanin receptors (GALR), namely GALR1, GALR2 and GLAR3. GAL appears to trigger all three galanin receptors, whereas SPX interacts more specifically with GALR2 and GLAR3. Whilst the biological effects of GAL have been well-described over the years, in-depth knowledge of physiological action profile of SPX is still in its preliminary stages. However, it is recognised that both peptides play a significant role in modulating overall energy homeostasis, suggesting possible therapeutically exploitable benefits in diseases such as obesity and type 2 diabetes mellitus. Accordingly, although both peptides activate GALR's, it appears GAL may be more useful for the treatment of eating disorders such as anorexia and bulimia, whereas SPX may find therapeutic application for obesity and obesity-driven forms of diabetes. This short narrative review aims to provide an up-to-date account of SPX and GAL biology together with putative approaches on exploiting these peptides for the treatment of metabolic disorders.

Spexin may induce mitochondrial biogenesis in white and brown adipocytes via the hypothalamus-pituitary-thyroid (HPT) axis

AIM

The present study aimed to investigate the effect of the intracerebroventricular (icv) administration of spexin on the hypothalamus-pituitary-thyroid (HPT) axis (TRH, TSH, T4 and T3 hormones) and energy expenditure (PGC-1α and UCP1 genes) in white adipose (WAT) and brown adipose tissues (BAT) in rats. Furthermore, the study aimed to determine the effects of spexin on food-water consumption and body weight of rats.

MATERIAL AND METHOD

The study was conducted with 40 male rats that were divided into 4 groups: Control, Sham, Spexin 30 and Spexin 100 (n = 10). Spexin (1 μl/hour) was administered to rats other than those in the control group for 7 days with osmotic minipumps intracerebroventricularly, artificial cerebrospinal fluid (vehicle) was administered to the Sham group, and 30 nMol and 100 nMol spexin was infused to the Spexin 30 and Spexin 100 groups, respectively. Food-water consumption and body weight of the rats were monitored during the experiments. After the seven-day infusion, the rats were decapitated and serum TSH, fT4 and fT3 levels were determined with ELISA on rat blood samples. Also, TRH gene expression levels from the hypothalamus tissues and PGC-1α and UCP1 expression levels from WAT and BAT were determined by real-time PCR.

FINDINGS

It was determined that icv spexin infusion reduced daily food consumption and body weight without leading to a significant change in water consumption (p < 0.05). Icv spexin infusion significantly decreased serum TSH, and increased fT4 and fT3 levels when compared to control and sham groups (p < 0.05). Moreover, icv spexin infusion increased the TRH expressions in the hypothalamus tissues and PGC-1α UCP1 in the WAT and BAT (p < 0.05).

CONCLUSION

Icv Spexin infusion may have effects on food consumption and body weight as well as, thyroid hormones and energy metabolism.