Insulin-like growth factor in Parkinson's disease is related to nonmotor symptoms and the volume of specific brain areas

Early diagnosis of Parkinson's disease: biomarker study

Parkinson's disease (PD) is a common chronic degenerative disease with age-dependent increasing prevalence in the elderly. Non-motor symptoms include sensory deficiencies, autonomic dysfunction, psychological and cognitive abnormalities; while motor symptoms are bradykinesia, myotonia, resting tremor, and postural balance difficulties. The clinical diagnosis of PD depends mainly on patients' medical history and physical examination. It is highly important to realize early detection of PD, and biomarkers are a valuable tool in this regard. The present study reviewed the findings of researches from the last few years, involving the advancements in the study of PD biomarkers in blood, cerebrospinal fluid, saliva, urine, tears, imaging, and pathology.

The Insulin-like Growth Factor Family as a Potential Peripheral Biomarker in Psychiatric Disorders: A Systematic Review

Psychiatric disorders (PDs), including schizophrenia (SZ), major depressive disorder (MDD), bipolar disorder (BD), autism spectrum disorder (ASD), among other disorders, represent a significant global health burden. Despite advancements in understanding their biological mechanisms, there is still no reliable objective and reliable biomarker; therefore, diagnosis remains largely reliant on subjective clinical assessments. Peripheral biomarkers in plasma or serum are interesting due to their accessibility, low cost, and potential to reflect central nervous system processes. Among these, the insulin-like growth factor (IGF) family, IGF-1, IGF-2, and IGF-binding proteins (IGFBPs), has gained attention for its roles in neuroplasticity, cognition, and neuroprotection, as well as for their capability to cross the blood-brain barrier. This review evaluates the evidence for IGF family alterations in PDs, with special focus on SZ, MDD, and BD, while also addressing other PDs covering almost 40 years of history. In SZ patients, IGF-1 alterations have been linked to metabolic dysregulation, treatment response, and hypothalamic-pituitary-adrenal axis dysfunction. In MDD patients, IGF-1 appears to compensate for impaired neurogenesis, although findings are inconsistent. Emerging studies on IGF-2 and IGFBPs suggest potential roles across PDs. While promising, heterogeneity among studies and methodological limitations highlights the need for further research to validate IGFs as reliable psychiatric biomarkers.

Metabolic biomarkers of appetite control in Parkinson's disease patients with and without cognitive impairment

BACKGROUND

Appetite dysregulation in Parkinson's Disease (PD) appears to be linked to physical and cognitive deterioration. PD patients with and without cognitive impairment (CI) were compared to an age-matched control group to explore predictors of appetite control in fasting and post-prandial conditions.

METHODS

Fifty-five patients were recruited and divided into three groups: twenty controls (age: 74 y, BMI: 25.8 kg/m2), nineteen PD patients without CI (72.5 y, 25.1 kg/m2) and sixteen PD patients with CI (74.3 y, 24.0 kg/m2). Self-reported appetite perception and circulating blood metabolic biomarkers were measured in fasting and over a 3-h post-prandial period. Biomarkers included glucose, insulin, tumour necrosis factor alpha (TNF-α), leptin, acyl-ghrelin, total ghrelin, peptide YY (PYY), glucagon like peptide 1 (GLP-1), insulin growth factor 1 (IGF-1), growth factor (GF) and triglycerides. Patients were then provided with a mixed meal to eat ad libitum with the aim to evaluate links between metabolic biomarkers and control of energy intake.

RESULTS

PD patients with CI had a significant lower protein intake (7.4 ± 2.5 g, p = 0.01) compared to controls (21.9 ± 3.1 g) and PD patients without CI (14.3 ± 3.0 g). Post-prandial plasma GLP-1 concentrations were associated with decreased hunger perception (B±SE, -5.3 ± 2.4  mm·h-1, p = 0.04). PYY concentrations were significantly associated with GLP-1 in fasting (r = 0.40, p = 0.005) and post-prandial (r = 0.46, p < 0.001) conditions. In a multivariate model, post-prandial PYY concentrations were a significant predictor of ad libitum energy intake in all subjects (B±SE, -87.5 ± 34.9 kcal, p = 0.01) and in patients with PD (B±SE, -106.8 ± 44.9 kcal, p = 0.04).

CONCLUSIONS

PYY and GLP-1 appeared to influence appetite control in PD patients and their roles merit further investigation.

Association between serum insulin-like growth factor 1 and osteoporosis risk in Parkinson's disease: a cross-sectional study

OBJECTIVE

To examine the correlation between serum insulin-like growth factor 1 (IGF-1) and osteoporosis (OP) in Parkinson's disease (PD).

METHODS

We retrospectively analyzed clinical data from 105 PD patients (PD group) and 78 individuals in the health examination group (HC group). We compared general clinical data and serum IGF-1 levels between the two groups. PD patients were further categorized into PD with OP (50 cases) and PD without OP (55 cases) based on dual-energy X-ray absorptiometry (DXA) results for bone density. We compared general clinical data and serum IGF-1 levels between these two subgroups. Pearson correlation coefficient analysis was conducted to assess the relationship between serum IGF-1 levels and bone density at the lumbar spine and left femoral neck. Multifactorial logistic regression analysis was performed to identify risk factors for PD with OP.

RESULTS

Serum IGF-1 levels were significantly lower in the PD group compared to the HC group (P < 0.05). Pearson correlation analysis revealed a positive association between serum IGF-1 levels and both lumbar spine and left femoral neck bone densities (r = 0.653, P < 0.001; r = 0.625, P < 0.001). Multivariate logistic regression analysis identified decreased serum IGF-1 levels, lower uric acid levels, and higher H-Y stage as risk factors for PD with OP (P < 0.05).

CONCLUSION

Reduced levels of serum IGF-1, uric acid, and an increased H-Y stage are closely linked to osteoporosis in PD. Elevating serum levels of IGF-1 and uric acid may potentially offer therapeutic avenues for PD with osteoporosis.

Insulin-Like Growth Factor Binding Protein 2 Drives Neurodegeneration in Parkinson's Disease: Insights From In Vivo and In Vitro Studies

AIMS

Insulin-like growth factor binding protein 2 (IGFBP2) is implicated in various neurodegenerative diseases. However, its role in Parkinson's disease (PD) is unclear.

METHODS

PD rat model was established by 6-OHDA injection. After 3 weeks, mRNA-seq was conducted. Rats received rIGFBP2 via intra-MFB injection 6 h prior to 6-OHDA infusion, and the effect of IGFBP2 in PD rats was investigated by western blotting, IHC, specific kits, JC-1 staining, and TUNEL analysis. In vitro, PC12 cells were treated with 6-OHDA, and CCK-8, specific kits, Hoechst 33258 staining, Western blotting, and JC-1 staining were performed to assess the IGFBP2's role.

RESULTS

mRNA-seq revealed DEGs in PD, with attention to downregulated IGFBP2. rIGFBP2 treatment aggravated neurobehavioral deficits, decreased TH expression, Ψm, ATP level and SOD, GSH-Px activities but increased α-synuclein, ROS, MDA, mitochondrial cytochrome c contents, cell apoptosis in 6-OHDA-lesioned rats, which might be mediated through inactivating IGF-1R/AKT pathway. In 6-OHDA-treated PC12 cells, rIGFBP2 aggravated cell injury, demonstrated by decreased cell viability and increased apoptosis, oxidative stress, and mitochondrial dysfunction. Co-treatment with rIGFBP2 and rIGF-1 partially reversed the effect of rIGFBP2 on cell damage.

CONCLUSION

IGFBP2 exacerbates neurodegeneration in PD through increasing oxidative stress, mitochondrial dysfunction, and apoptosis via inhibiting IGF-1R/AKT pathway.

Harnessing IGF-1 and IL-2 as biomarkers for calcineurin activity to tailor optimal FK506 dosage in α-synucleinopathies

Introduction: Rise in Calcium (Ca2+) and hyperactive Ca2+-dependent phosphatase calcineurin represent two key determinants of a-synuclein (a-syn) pathobiology implicated in Parkinson's Disease (PD) and other neurodegenerative diseases. Calcineurin activity can be inhibited with FK506, a Food and Drug Administration (FDA)-approved compound. Our previous work demonstrated a protective effect of low doses of FK506 against a-syn pathology in various models of a-syn related pathobiology. Methods: Control and a-syn-expressing mice (12-18 months old) were injected with vehicle or two single doses of FK506 administered 4 days apart. Cerebral cortex and serum from these mice were collected and assayed using a meso scale discovery quickplex SQ 120 for cytokines and Enzyme-linked immunosorbent assay for IGF-1. Results: In this study we present evidence that reducing calcineurin activity with FK506 in a-syn transgenic mice increased insulin growth factor (IGF-1), while simultaneously decreasing IL-2 levels in both cerebral cortex and serum. Discussion: The highly conserved Ca2+/calcineurin signaling pathway is known to be affected in a-syn-dependent human disease. FK506, an already approved drug for other uses, exhibits high brain penetrance and a proven safety profile. IL-2 and IGF-1 are produced throughout life and can be measured using standard clinical methods. Our findings provide two potential biomarkers that could guide a clinical trial of FK506 in PD patients, without posing significant logistical or regulatory challenges.