Duloxetine in the management of diabetic peripheral neuropathic pain

In silico exploration of venlafaxine, a potential non-tricyclic antidepressant in a liposomal formulation for nose-to-brain drug delivery

OBJECTIVE

Non-tricyclic antidepressants (non-TCAs) work by preventing the intake of norepinephrine and serotonin. Therefore, the aim of this study was to identify a potent non-TCAs and to develop liposomal formulation, characterize and to determine the drug release study across model of dialysis membrane via in vitro and in silico techniques.

METHODS

The in silico docking analysis identified venlafaxine (VLF) as the best non-TCAs with the depressant targets (PDB ID: 3PBL and 4BVN). VLF-loaded liposomal formulation was prepared by the thin-film hydration technique and characterized by physicochemical properties, including entrapment efficacy, in vitro drug release, particle size analysis, and FTIR. Moreover, this article also compares VLF and VLF-loaded with liposome carriers (LPs) based on nose-to-brain drug delivery approaches to treating depression.

RESULTS

Drug release profiles of the optimal liposomal formulation of VLF-LPs were examined in the high entrapment efficiency 94.13 ± 1.20% was attained at 224 nm, composed of spherical particles having a mean particle size of 191 ± 2.0 nm, a polydispersity index of 0.281 ± 0.06 and zeta potential of -20.3 mV. The best formulation of VLF-LPs was more effective than oral VLF treatment, as shown by the in vitro drug release data.

CONCLUSION

The results show that the VLF-LPs formulation is a promising potential platform for application in nose-to-brain drug delivery. Thus, highlighting the robustness of the intranasal drug delivery system with enhanced pharmaceutical properties, efficacy, and bioavailability for the anti-depression effect.

Changes in the central nervous system in diabetic neuropathy

One of the most common chronic complications arising from diabetes is diabetic peripheral neuropathy. Depending on research statistics, approximately half of the people who have diabetes will suffer from diabetic peripheral neuropathy over time, which manifests as abnormal sensations in the distal extremities, and about 25%-50% of these patients have symptoms of neuralgia, called painful diabetic neuropathy. These patients often exhibit adverse emotional conditions, like anxiety or depression, which can reduce their quality of life. The pathogenesis of diabetic peripheral neuropathy is complex, and although persistent hyperglycemia plays a central role in the development of diabetic peripheral neuropathy, strict glycemic control does not eliminate the risk of diabetic peripheral neuropathy. This suggests the need to understand the role of the central nervous system in the development of diabetic peripheral neuropathy to modulate treatment regimens accordingly. Magnetic resonance imaging not only allows for the noninvasive detection of structural and functional alterations in the central nervous system, but also provides insight into the processing of abnormal information such as pain by the central nervous system, and most importantly, contributes to the development of more effective pain relief protocols. Therefore, this article will focus on the mechanisms and related imaging evidence of central alterations in diabetic peripheral neuropathy, especially in painful diabetic neuropathy.

Spinal cord vascular degeneration impairs duloxetine penetration

Introduction

Chronic pain is a prevalent physically debilitating health-related morbidity. Frontline analgesics are inadequate, providing only partial pain relief in only a proportion of the patient cohort. Here, we explore whether alterations in spinal cord vascular perfusion are a factor in reducing the analgesic capability of the noradrenaline reuptake inhibitor, duloxetine.

Method

An established rodent model of spinal cord vascular degeneration was used. Endothelial-specific vascular endothelial growth factor receptor 2 knockout mouse was induced via hydroxytamoxifen administered via intrathecal injection. Duloxetine was administered via intraperitoneal injection, and nociceptive behavioural testing was performed in both WT and VEGFR2KO mice. LC-MS/MS was performed to explore the accumulation of duloxetine in the spinal cord in WT and VEGFR2KO mice.

Results

Spinal cord vascular degeneration leads to heat hypersensitivity and a decline in capillary perfusion. The integrity of noradrenergic projections (dopa - hydroxylase labelled) in the dorsal horn remained unaltered in WT and VEGFR2KO mice. There was an association between dorsal horn blood flow with the abundance of accumulated duloxetine in the spinal cord and analgesic capacity. In VEGFR2KO mice, the abundance of duloxetine in the lumbar spinal cord was reduced and was correlated with reduced anti-nociceptive capability of duloxetine.

Discussion

Here, we show that an impaired vascular network in the spinal cord impairs the anti-nociceptive action of duloxetine. This highlights that the spinal cord vascular network is crucial to maintaining the efficacy of analgesics to provide pain relief.

Application of Sygen® in Diabetic Peripheral Neuropathies-A Review of Biological Interactions

This study investigates the role of Sygen® in diabetic peripheral neuropathy, a severe disease that affects the peripheral nervous system in diabetic individuals. This disorder often impacts the lower limbs, causing significant discomfort and, if left untreated, progresses into more serious conditions involving chronic ulcers and even amputation in many cases. Although there are management strategies available, peripheral neuropathies are difficult to treat as they often present multiple causes, especially due to metabolic dysfunction in diabetic individuals. Gangliosides, however, have long been studied and appreciated for their role in neurological diseases. The monosialotetrahexosylganglioside (GM1) ganglioside, popularly known as Sygen, provides beneficial effects such as enhanced neuritic sprouting, neurotrophism, neuroprotection, anti-apoptosis, and anti-excitotoxic activity, being particularly useful in the treatment of neurological complications that arise from diabetes. This product mimics the roles displayed by neurotrophins, improving neuronal function and immunomodulation by attenuating exacerbated inflammation in neurons. Furthermore, Sygen assists in axonal stabilization and keeps nodal and paranodal regions of myelin fibers organized. This maintains an adequate propagation of action potentials and restores standard peripheral nerve function. Given the multifactorial nature of this complicated disorder, medical practitioners must carefully screen the patient to avoid confusion and misdiagnosis. There are several studies analyzing the role of Sygen in neurological disorders. However, the medical literature still needs more robust investigations such as randomized clinical trials regarding the administration of this compound for diabetic peripheral neuropathies, specifically.

Diabetic neuropathy: A narrative review of risk factors, classification, screening and current pathogenic treatment options (Review)

Diabetic neuropathy (DN) is a frequent complication of diabetes mellitus (DM) with severe consequences as it progresses and influences all human body systems. This review discusses the risk factors for DN, the main characteristics of the clinical forms of DN, the screening methods and the current therapeutic options. Distal symmetric DN is the primary clinical form, and DM patients should be screened for this complication. The most important treatment of DN remains good glucose control, generally defined as HbA1c ≤7%. Symptomatic treatment improves life quality in diabetic patients. Pharmacological agents such as alpha (α)-lipoic acid and benfotiamine have been validated in several studies since they act on specific pathways such as increased oxidative stress (α-lipoic acid exerts antioxidant effects) and the excessive production of advanced glycosylation products (benfotiamine may inhibit their production via the normalization of glucose). Timely diagnosis of DN is significant to avoid several complications, including lower limb amputations and cardiac arrhythmias.

Epidemiology of Peripheral Neuropathy and Lower Extremity Disease in Diabetes

PURPOSE OF REVIEW

Diabetic peripheral neuropathy eventually affects nearly 50% of adults with diabetes during their lifetime and is associated with substantial morbidity including pain, foot ulcers, and lower limb amputation. This review summarizes the epidemiology, risk factors, and management of diabetic peripheral neuropathy and related lower extremity complications.

RECENT FINDINGS

The prevalence of peripheral neuropathy is estimated to be between 6 and 51% among adults with diabetes depending on age, duration of diabetes, glucose control, and type 1 versus type 2 diabetes. The clinical manifestations are variable, ranging from asymptomatic to painful neuropathic symptoms. Because of the risk of foot ulcer (25%) and amputation associated with diabetic peripheral neuropathy, aggressive screening and treatment in the form of glycemic control, regular foot exams, and pain management are important. There is an emerging focus on lifestyle interventions including weight loss and physical activity as well. The American Diabetes Association has issued multiple recommendation statements pertaining to diabetic neuropathies and the care of the diabetic foot. Given that approximately 50% of adults with diabetes will be affected by peripheral neuropathy in their lifetime, more diligent screening and management are important to reduce the complications and health care burden associated with the disease.

The effect of pregabalin and duloxetine treatment on quality of life of breast cancer patients with taxane-induced sensory neuropathy: A randomized clinical trial

Background:

The primary side effect of adjuvant chemotherapy with taxanes is the taxane-induced peripheral neuropathy (TIPN), which may have substantial negative impacts on patients’ quality of life (QOL). We investigated the effect of pregabalin and duloxetine on QOL of breast cancer patients who experienced TIPN.

Materials and Methods:

This was a randomized, double-blind clinical trial conducted at a chemotherapy center of Mazandaran University of Medical Sciences, Sari, Iran. Breast cancer patients 18 or more years old were included if they received paclitaxel or docetaxel and experienced neuropathy grade one or higher; and neuropathic pain score of four or more. Patients were treated with pregabalin or duloxetine until 6 weeks. Assessment of sensory neuropathy and QOL was performed at baseline, and 6 weeks after the initiation of the treatment.

Results:

At baseline, the mean score of global health status/QOL scale for pregabalin and duloxetine groups were 61 (standard deviation [SD]; 5.11) and 60.28 (SD; 5.44), respectively (P = 0.54). After 6 weeks, both interventions were associated with improvement of global QOL compared to baseline. The global health status/QOL score was not different between two groups after 6 weeks. While the emotional functioning was improved more favorably with duloxetine (P < 0.001); pregabalin was associated with more improvement in insomnia and pain scores (P = 0.05 and P < 0.001, respectively).

Conclusion:

Pregabalin as well as duloxetine improve the global QOL of breast cancer patients with TIPN. Different effects of treatments on subscale of QLQ-C30 could help clinicians to select the appropriate agent individually.

Suppressive Effects of Bee Venom Acupuncture on Paclitaxel-Induced Neuropathic Pain in Rats: Mediation by Spinal α₂-Adrenergic Receptor

Paclitaxel, a chemotherapy drug for solid tumors, induces peripheral painful neuropathy. Bee venom acupuncture (BVA) has been reported to have potent analgesic effects, which are known to be mediated by activation of spinal α-adrenergic receptor. Here, we investigated the effect of BVA on mechanical hyperalgesia and spinal neuronal hyperexcitation induced by paclitaxel. The role of spinal α-adrenergic receptor subtypes in the analgesic effect of BVA was also observed. Administration of paclitaxel (total 8 mg/kg, intraperitoneal) on four alternate days (days 0, 2, 4, and 6) induced significant mechanical hyperalgesic signs, measured using a von Frey filament. BVA (1 mg/kg, ST36) relieved this mechanical hyperalgesia for at least two hours, and suppressed the hyperexcitation in spinal wide dynamic range neurons evoked by press or pinch stimulation. Both melittin (0.5 mg/kg, ST36) and phospholipase A2 (0.12 mg/kg, ST36) were shown to play an important part in this analgesic effect of the BVA, as they significantly attenuated the pain. Intrathecal pretreatment with the α₂-adrenergic receptor antagonist (idazoxan, 50 µg), but not α₁-adrenergic receptor antagonist (prazosin, 30 µg), blocked the analgesic effect of BVA. These results suggest that BVA has potent suppressive effects against paclitaxel-induced neuropathic pain, which were mediated by spinal α₂-adrenergic receptor.

A Guide to Medications Inducing Salivary Gland Dysfunction, Xerostomia, and Subjective Sialorrhea: A Systematic Review Sponsored by the World Workshop on Oral Medicine VI

BACKGROUND

Medication-induced salivary gland dysfunction (MISGD), xerostomia (sensation of oral dryness), and subjective sialorrhea cause significant morbidity and impair quality of life. However, no evidence-based lists of the medications that cause these disorders exist.

OBJECTIVE

Our objective was to compile a list of medications affecting salivary gland function and inducing xerostomia or subjective sialorrhea.

DATA SOURCES

Electronic databases were searched for relevant articles published until June 2013. Of 3867 screened records, 269 had an acceptable degree of relevance, quality of methodology, and strength of evidence. We found 56 chemical substances with a higher level of evidence and 50 with a moderate level of evidence of causing the above-mentioned disorders. At the first level of the Anatomical Therapeutic Chemical (ATC) classification system, 9 of 14 anatomical groups were represented, mainly the alimentary, cardiovascular, genitourinary, nervous, and respiratory systems. Management strategies include substitution or discontinuation of medications whenever possible, oral or systemic therapy with sialogogues, administration of saliva substitutes, and use of electro-stimulating devices.

LIMITATIONS

While xerostomia was a commonly reported outcome, objectively measured salivary flow rate was rarely reported. Moreover, xerostomia was mostly assessed as an adverse effect rather than the primary outcome of medication use. This study may not include some medications that could cause xerostomia when administered in conjunction with others or for which xerostomia as an adverse reaction has not been reported in the literature or was not detected in our search.

CONCLUSIONS

We compiled a comprehensive list of medications with documented effects on salivary gland function or symptoms that may assist practitioners in assessing patients who complain of dry mouth while taking medications. The list may also prove useful in helping practitioners anticipate adverse effects and consider alternative medications.

The Suppressive Effects of Cinnamomi Cortex and Its Phytocompound Coumarin on Oxaliplatin-Induced Neuropathic Cold Allodynia in Rats

Oxaliplatin, a chemotherapy drug, induces acute peripheral neuropathy characterized by cold allodynia, spinal glial activation and increased levels of pro-inflammatory cytokines. Herein, we determined whether Cinnamomi Cortex (C. Cortex), a widely used medicinal herb in East Asia for cold-related diseases, could attenuate oxaliplatin-induced cold allodynia in rats and the mechanisms involved. A single oxaliplatin injection (6 mg/kg, i.p.) induced significant cold allodynia signs based on tail immersion tests using cold water (4 °C). Daily oral administration of water extract of C. Cortex (WECC) (100, 200, and 400 mg/kg) for five consecutive days following an oxaliplatin injection dose-dependently alleviated cold allodynia with only a slight difference in efficacies between the middle dose at 200 mg/kg and the highest dose at 400 mg/kg. WECC at 200 mg/kg significantly suppressed the activation of astrocytes and microglia and decreased the expression levels of IL-1β and TNF in the spinal cord after injection with oxaliplatin. Furthermore, oral administration of coumarin (10 mg/kg), a major phytocompound of C. Cortex, markedly reduced cold allodynia. These results indicate that C. Cortex has a potent anti-allodynic effect in oxaliplatin-injected rats through inhibiting spinal glial cells and pro-inflammatory cytokines. We also suggest that coumarin might play a role in the anti-allodynic effect of C. Cortex.

Involvement of spinal muscarinic and serotonergic receptors in the anti-allodynic effect of electroacupuncture in rats with oxaliplatin-induced neuropathic pain

This study was performed to investigate whether the spinal cholinergic and serotonergic analgesic systems mediate the relieving effect of electroacupuncture (EA) on oxaliplatin-induced neuropathic cold allodynia in rats. The cold allodynia induced by an oxaliplatin injection (6 mg/kg, i.p.) was evaluated by immersing the rat's tail into cold water (4℃) and measuring the withdrawal latency. EA stimulation (2 Hz, 0.3-ms pulse duration, 0.2~0.3 mA) at the acupoint ST36, GV3, or LI11 all showed a significant anti-allodynic effect, which was stronger at ST36. The analgesic effect of EA at ST36 was blocked by intraperitoneal injection of muscarinic acetylcholine receptor antagonist (atropine, 1 mg/kg), but not by nicotinic (mecamylamine, 2 mg/kg) receptor antagonist. Furthermore, intrathecal administration of M₂ (methoctramine, 10 µg) and M₃ (4-DAMP, 10 µg) receptor antagonist, but not M₁ (pirenzepine, 10 µg) receptor antagonist, blocked the effect. Also, spinal administration of 5-HT₃ (MDL-72222, 12 µg) receptor antagonist, but not 5-HT_1A (NAN-190, 15 µg) or 5-HT_2A (ketanserin, 30 µg) receptor antagonist, prevented the anti-allodynic effect of EA. These results suggest that EA may have a signifi cant analgesic action against oxaliplatin-induced neuropathic pain, which is mediated by spinal cholinergic (M₂, M₃) and serotonergic (5-HT₃) receptors.

Long-term positive and negative psychosocial outcomes in young childhood cancer survivors, type 1 diabetics and their healthy peers

OBJECTIVE

This study examined posttraumatic growth (PTG) in young childhood cancer survivors (CCS) and type 1 diabetics (DM), with physically healthy peers as the control group (CG). Anxiety and depression as negative mental outcomes in the three groups, as well as fear of progression in DM and CCS were examined.

METHODS

A total of 107 participants with ages ranging from 18 to 35 years were examined: CCS (n=33), type 1 diabetics (n=39) and peers without a history of chronic disease (n=35). PTG and negative psychosocial outcomes were assessed with self-report questionnaires.

RESULTS

There was a significant difference between the groups regarding PTG. On a subscale level DM reported higher appreciation of life (p=0.024), higher personal strength (p=0.010), and more new possibilities (p=0.010) compared to CG. CCS experienced higher spiritual changes than DM (p=0.050). DM reported higher levels of anxiety compared to CCS (p=0.026) and CG (p=0.049). Depression was higher in DM compared to CG (p=0.003). Fear of progression was higher in DM compared to CCS (p<0.001).

CONCLUSION

These findings show that psychological growth was experienced by young CCS and participants with DM. Furthermore, these findings highlight that adolescents with a significant health diagnosis in childhood or youth can undergo a similar or even more positive psychosocial development as peers without a history of chronic disease. However, young type 1 diabetics seem to be a more vulnerable group in terms of anxiety, depression and fear of progression.

Combined Effects of Bee Venom Acupuncture and Morphine on Oxaliplatin-Induced Neuropathic Pain in Mice

Oxaliplatin, a chemotherapeutic drug for colorectal cancer, induces severe peripheral neuropathy. Bee venom acupuncture (BVA) has been used to attenuate pain, and its effect is known to be mediated by spinal noradrenergic and serotonergic receptors. Morphine is a well-known opioid used to treat different types of pain. Here, we investigated whether treatment with a combination of these two agents has an additive effect on oxaliplatin-induced neuropathic pain in mice. To assess cold and mechanical allodynia, acetone and von Frey filament tests were used, respectively. Significant allodynia signs were observed three days after an oxaliplatin injection (6 mg/kg, i.p.). BVA (0.25, 1, and 2.5 mg/kg, s.c., ST36) or morphine (0.5, 2, and 5 mg/kg, i.p.) alone showed dose-dependent anti-allodynic effects. The combination of BVA and morphine at intermediate doses showed a greater and longer effect than either BVA or morphine alone at the highest dose. Intrathecal pretreatment with the opioidergic (naloxone, 20 μg) or 5-HT3 (MDL-72222, 15 μg) receptor antagonist, but not with α2 adrenergic (idazoxan, 10 μg) receptor antagonist, blocked this additive effect. Therefore, we suggest that the combination effect of BVA and morphine is mediated by spinal opioidergic and 5-HT3 receptors and this combination has a robust and enduring analgesic action against oxaliplatin-induced neuropathic pain.

Neuroplasticity underlying the comorbidity of pain and depression

Acute pain induces depressed mood, and chronic pain is known to cause depression. Depression, meanwhile, can also adversely affect pain behaviors ranging from symptomology to treatment response. Pain and depression independently induce long-term plasticity in the central nervous system (CNS). Comorbid conditions, however, have distinct patterns of neural activation. We performed a review of the changes in neural circuitry and molecular signaling pathways that may underlie this complex relationship between pain and depression. We also discussed some of the current and future therapies that are based on this understanding of the CNS plasticity that occurs with pain and depression.

Auraptenol attenuates vincristine-induced mechanical hyperalgesia through serotonin 5-HT1A receptors

Common chemotherapeutic agents such as vincristine often cause neuropathic pain during cancer treatment in patients. Such neuropathic pain is refractory to common analgesics and represents a challenging clinical issue. Angelicae dahuricae radix is an old traditional Chinese medicine with demonstrated analgesic efficacy in humans. However, the active component(s) that attribute to the analgesic action have not been identified. This work described the anti-hyperalgesic effect of one coumarin component, auraptenol, in a mouse model of chemotherapeutic agent vincristine-induced neuropathic pain. We reported that auraptenol dose-dependently reverted the mechanical hyperalgesia in mice within the dose range of 0.05–0.8 mg/kg. In addition, the anti-hyperalgesic effect of auraptenol was significantly blocked by a selective serotonin 5-HT_1A receptor antagonist WAY100635 (1 mg/kg). Within the dose range studied, auraptenol did not significantly alter the general locomotor activity in mice. Taken together, this study for the first time identified an active component from the herbal medicine angelicae dahuricae radix that possesses robust analgesic efficacy in mice. These data support further studies to assess the potential of auraptenol as a novel analgesic for the management of neuropathic pain.

Synergistic analgesia of duloxetine and celecoxib in the mouse formalin test: a combination analysis

Duloxetine, a serotonin and noradrenaline reuptake inhibitor, and celecoxib, a non-steroidal anti-inflammatory drug, are commonly used analgesics for persistent pain, however with moderate gastrointestinal side effects or analgesia tolerance. One promising analgesic strategy is to give a combined prescription, allowing the maximal or equal efficacy with fewer side effects. In the current study, the efficacy and side effects of combined administration of duloxetine and celecoxib were tested in the mouse formalin pain model. The subcutaneous (s.c.) injection of formalin into the left hindpaw induced significant somatic and emotional pain evaluated by the biphasic spontaneous flinching of the injected hindpaw and interphase ultrasonic vocalizations (USVs) during the 1 h after formalin injection, respectively. Pretreatment with intraperitoneal (i.p.) injection of duloxetine or celecoxib at 1 h before formalin injection induced the dose-dependent inhibition on the second but not first phase pain responses. Combined administration of duloxetine and celecoxib showed significant analgesia for the second phase pain responses. Combination analgesia on the first phase was observed only with higher dose combination. A statistical difference between the theoretical and experimental ED₅₀ for the second phase pain responses was observed, which indicated synergistic interaction of the two drugs. Concerning the emotional pain responses revealed with USVs, we assumed that the antinociceptive effects were almost completely derived from duloxetine, since celecoxib was ineffective when administered alone or reduced the dosage of duloxetine when given in combination. Based on the above findings, acute concomitant administration of duloxetine and celecoxib showed synergism on the somatic pain behavior but not emotional pain behaviors.

Comorbidity of depression and anxiety: association with poor quality of life in type 1 and 2 diabetic patients

BACKGROUND

Diabetes is associates with depression and impairment in Quality of Life (QoL).

OBJECTIVE

The objective is to define the frequencies of depressive and anxiety symptoms in a sample of patients diagnosed with type 1 and 2 diabetes, the amount of impairment of QoL and the weight of depression and anxiety in determining the QoL in such of patients.

METHODS

A total of 210 patients were divided into two groups (type 1 and type 2). Patients completed the HADS and WHOQoL-bref.

RESULTS

Groups showed a high prevalence of anxiety (type 1 = 60%, type 2 = 43.8%) and depression (type 1 = 52.4%, type 2 = 38.1%), both measures were significantly higher (p < 0.05) in diabetes type 1 patients. Type 1 patients also showed a QoL in the overall assessment and the physical, psychological and social relations domains. In both Type 1 and 2 diabetes poor QoL was found associated by anxiety and depression comorbidity.

CONCLUSION

In overall diabetes patients depression and anxiety seems to be a determinant of poor QoL.