Preventive Nutrient Company



Several studies have suggested that diabetes is associated with defective insulin degrading enzyme (IDE) production and stimulation of IDE may improve blood sugar control. PNC has proven that Cyclo-Z (also known as Glucometa) is a potent stimulator of IDE synthesis. We have examined anti-diabetic activities of Cyclo-Z in five different animal models: 1) Streptozotocin-induced diabetic rats (Type 1 model); 2) ob/ob mice (Type 2 diabetes with obesity); 3) Goto-Kakizaki (G-K) rats (Type 2 diabetes without obesity); 4) aging Sprague-Dawley rats (naturally induced human insulin resistance-like or mild-Type 2 diabetes) and 5) high carbohydrate fed mice (over eating induced diabetes). 

Our colleagues at the VA Greater Los Angeles Healthcare System demonstrated that Cydo-Z treatment increased IDE synthesis in human Amyloid protein transgenic mice and stimulated degradation of Amyloid b protein and insulin. A 3 month pilot study of human subjects who used Pro-Z which contains various zinc metabolism stimulating agents showed significantly improved oral glucose tolerance test (OG1T) (measurement of insulin sensitivity) and decreased Hemoglobin A1c levels (measurement of average blood glucose concentration during the last three months).  Urine glucose levels (indication of improved blood glucose control) were significantly decreased, while fasting blood glucose insignificantly decreased. In our formal FDA standard phase 1 clinical trial, acute high dose of Cyclo-Z before breakfast in 12 healthy subjects significantly reduced blood glucose levels at 8 hours even after breakfast and lunch. In a pilot efficacy study, postprandial blood glucose levels, Hemoglobin A1c levels, and insulin requirement significantly decreased in 17 out of 18 diabetic subjects during 6 months. However, the physician noted that the remaining subject showed signs of improvement after more than 7 months of treatment. Some subjects stopped insulin injections completely after the 6 month treatment period. 

Blood Glucose Control
IDE, a zinc enzyme, plays a major role in the degradation of internalized insulin, which is needed to maintain insulin sensitivity. If endosomal IDE levels are inadequate, un-degraded insulin will remain in the cytosol and interfere with insulin signal transduction to translocation glucose transporter-4 to the cell membrane for glucose uptake. Diabetic animals and humans are zinc deficient due to impaired intestinal zinc absorption and hyperzincuria. This zinc deficiency is likely to contribute to insulin resistance by decreasing IDE synthesis and thereby accumulating un-degraded insulin in the cells. Genetically type 2 diabetic GatoKakizaki (G-K) rats are defective in IDE gene expression. Polymorphism in the IDE gene is also associated with type 2 diabetes in Europeans and in Asians. Insulin downstream targeting of insulin receptor signaling in the brain is associated with IDE function. Cyclo (his-pro) (CHP) plus zinc enhanced IDE synthesis in brain tissues and stimulated insulin degradation. It has been proven that Cyclo-Z significantly stimulated intestinal zinc absorption and muscles tissue zinc uptake in rats and glucose uptake in isolated muscle tissue. CHP or zinc alone is somewhat effective, but Cyclo-Z treatment significantly reduced blood glucose levels and improved oral glucose tolerance (while reducing plasma insulin levels in a CHP concentration dependent manner in genetically IDE deficient diabetic G-K rats, in insulin resistant aged obese Sprague-Dawley rats, and in obese diabetic ob/ob mice. These available literatures and our preliminary data suggest a strong potentiality that Cyclo-Z ameliorates insulin resistant humans mainly by stimulating IDE synthesis.

Background Studies
Specifically, our background studies with animal models indicate that the optimal dose of Cyclo-Z for the improvement of three hour Average above Fasting blood Glucose Concentration (TAFGC)=accurate measurement of OGTT is 0.5 mg CHP plus 10 mg zinc/kg BW for acute treatment. The optimal daily dose for blood glucose lowering rate for 2 weeks is 0.5 mg CHP plus 10 mg zinc/l in the drinking water for genetically diabetic G-K rats, which is equivalent to 0.1 mg CHP plus 2 mg zinc/Kg BW/day based on the calculation of the known amount of CHP and zinc containing water intake per day. Blood glucose levels also significantly decreased in obese ob/ob mice with the same dose (0.1 mg CHP plus 2 mg zinc /kg BW/day). Therefore, Cyclo-Z dose for the treatment of diabetes must be carefully monitored depending on the need of diabetes treatment. When insulin resistant aged S-D rats were given acute bolus of 1.0 mg CHP plus 10 mg zinc/kg BW, improved TAFGC was maintained at least one week, while the improvement of TAFGC was lost within 24 hours in G-K rats. These data suggest that the blood glucose lowering effect of Cyclo-Z treatment may be more effective and better maintained in obesity induced diabetic subjects. These pre-clinical studies with various animal models and human studies suggest that Cyclo-Z may be a very effective diabetes treatment agent.

Glucometa (also known as Cyclo-Z) contains Cyclo (his-pro) plus zinc and has demonstrated to be significantly effective in the prevention and natural treatment of diabetes. While Pro-Z contains a lesser amount of Cyclo (his-pro), it contains other components that influence zinc metabolism and diabetes.

Body Weight Control 

Glucometa (or Cyclo-Z) treatment also significantly decreased body weight (BW) or BW gain in obese and overweight animals while decreasing plasma leptin levels. Although obese subjects generally develop hyperinsulinemia (pre-diabetic), only 22% of diabetic subjects are not directly associated with Body Mass Index. Thus, obese diabetic subjects are also expected to benefit from the Glucometa treatment as evidenced in the animal study. IDE deficiency causes hyperinsulinemia and hyperinsulinemia is one of the major causes of obesity, since insulin increases fat accumulation in adipocytes. Hyperinsulinemia in obesity is caused mainly by decreased insulin clearance in the plasma. Impaired internalized insulin digestion induces accumulation of inactive insulin fragments in the cells, which is associated with significant impairment of insulin receptor signal transduction mechanisms, resutting in insulin resistant, hyperinsulinemia, and obesity. Monocyte insulin levels from obese patients were more than fourfold higher compared to cells from normal subjects. Similarly, plasma insulin levels in obese subjects are about 69% higher than in normal subjects. The impaired insulin clearance in obese humans and the contrasting increase in insulin clearance with weight loss have been demonstrated. The decreased insulin clearance in obese subjects is mainly due to the elevated free fatly acids which inhibit insulin degrading enzyme (IDE) synthesis. Therefore, it appears that one of the plausible methods to treat obesity may be to reduce plasma and cellular insulin levels by stimulating IDE synthesis.

Alzheimer’s disease (AD)

Amyloid beta protein accumulation in the brain is the main cause of AD. Although several kinds of mutations in the Amyloid protein precursor (APP) gene and apoE genes have been identified to be the cause of AD development, the majority of AD incidence is induced by age-related undefined cause, which is mostly related to the metabolic diseases. Numerous epidemiological studies suggest that type 2 diabetes characterized as glucose intolerance, obesity, and hyperinsulinemia is associated with a 2- to 6 -fold increased risk for AD. 

There is some evidence that insulin itself may significantly accelerate APP/Aβ trafficking from the trans-Golgi network to plasma membrane for Aβ generation. However, the most important approach in understanding the mechanisms of AD induction is to establish the relationship IDE with Aβ, which is now intensely studied by many researchers from the evidence that IDE activity in the brain is negatively correlated with Aβ content and that IDE expression is decreased In the AD brain. There is now general consensus that insulin may provoke Amyloid accumulation by limiting Aβ degradation via direct competition for IDE which is the only enzyme that degrades both insulin and Aβ. 

Immune System

Diabetes refers to a group of metabolic diseases affecting various interrelated processes including glucose uptake, energy utilization, immune function, weight control, and inflammation and is characterized by excessive amounts of glucose in the blood.  This condition is triggered by the body’s defect(s) in insulin production, insulin action, or both.  Recently,  correlations between the immune system and diabetes have been established.  High blood sugar levels can weaken the patient's immune system.  Viardot et al (1) reported that energy restriction after gastric banding attenuates activation of circulating immune cells of both the innate and adaptive immune system.  Defects in the deletion of autoactive T-cells and in the function of T regulatory cells contribute to the autoimmune response characteristic of Type 1 diabetes or T1D (2).  In T1D, autoimmune destruction of the pancreatic β-cells, which produce insulin, results in insulin deficiency directly inducing the diabetic condition.  Circulating immune cells from T1D subjects also displayed many aspects of a pro-inflammatory state, as indicated by primed or activated monocyte CD111b (3).  In Type 2 diabetes (T2D), it has been proposed that problems with immune function in response to bacterial and viral infections may cause resistance to insulin action and induce T2D.  Patients with diabetes are known to have infections more often than those of with normal glucose metabolism (4). Thus, it is not uncommon for diabetes to cause a decrease in immune function and an increase in susceptibility to certain infections. 

Zinc is known to play an important role in the immune system.  These findings indicated that zinc levels must be taken into account whenever alterations of immune functions are observed in vitro or in vivo.  Zinc deficient patients have increased susceptibility to a variety of pathogens (5) and the deficiency may be responsible for decreased cell mediated immune functions (6).   The specific interaction of zinc with immunologically important proteins, signal transduction components, and membrane functions has been summarized by Wellinghausen and Rink (7).  Zinc also has a profound effect on immunosuppression and inflammation leading to the therapeutic use of it as a treatment for many immune system disorders (8).  Zinc has a crucial effect for development and normal functions of neutrophils and natural killer cells (9).  In zinc deficiency patients, B-lymphocyte development and antibody production, particularly immunoglobulin G production, is compromised.  Macrophage functions are also adversely affected by zinc deficiency, which can result in abnormal intracellular killing, cytokine production, and phagocytosis.  In human studies in India, zinc supplementation has been shown to improved cellular immune status (10).  Thus, improvement of zinc nutriture in children or zinc deficient subjects may provide an important preventive intervention for high infectious disease morbidity and associated mortality in developing countries.

Cyclo (his-pro) (CHP) is a naturally occurring cyclic dipeptide that is a metabolite of thyrotropin-releasing hormone (TRH) and functions as a transporter of zinc into cells.  CHP is proven to have antibacterial and antifungal activities (11) and can inhibit the growth of Saccharomyces cerevisae by inhibiting chitinase (12).  It has a protective and therapeutic effect on streptozocin (STZ)-induced cytotoxicity and apoptosis, and exerts anti-inflammatory effects by suppressing pro-inflammatory NF-κB signaling via Nrf2-mediated heme oxygenase-1 activation (13).  CHP has also been shown to protect against glial inflammation and against other neuro-inflammatory diseases including lipopolysaccharide neurotoxicity (14).  STZ-induced cytotoxicity and apoptosis was prevented in rat insulinoma cells (RINm5F) (15).  CHP also exhibited anti-diabetic effects on STZ-induced diabetic mice (16). Oral glucose tolerance test (OGTT) values significantly decreased and plasma glucose levels dropped 60% as compared to the STZ-induced diabetic control group without CHP treatment.  Thus, CHP exhibits anti-diabetic and anti-toxicity effects on STZ-induced diabetic rats and cells. 

We have previously demonstrated that Cyclo-Z (CHP+zinc) is effective in improving diabetes in STZ-induced T1D rats (17), in T2D Goto-Kakizaki (G-K) rats (18), and in T2D ob/ob mice (19).  In addition, Cyclo-Z improved body weight control in diabetic G-K rats and obese and overweight Sprague-Dawley rats (20).  All of these studies indicated that the combination of CHP+zinc in the Cyclo-Z formulation is much more effective than zinc or CHP alone.  Based on the previous studies showing link between zinc and immune functions, we hypothesized that Cyclo-Z treatment may improve basic immune system parameters in both STZ-induced diabetic rats and possibly in normal rats.  Thus, we examined the effect of Cyclo-Z on the levels and activation of several major immune system cell components in STZ-induced diabetic and in normal control rats.

Our research date indicated that the clinical manifestation of T1D is expected to be associated with changes in activation -related biomarkers in the circulating immune cells.  Cyclo-Z treatment invariably increased immune cell levels and activities involved in the innate (dendritic cells, monocytes, natural killer cells), adaptive (cytotoxic CD8+ and helper CD4+ T-cells, antigen presenting cells), and humoral (B-cells) immune system when the rats were young and the immune system still immature (3 months old) in both diabetic and normal rats.  Thus, Cyclo-Z is effective in the stimulation of cell growth and immune system components which may be helpful in fighting infectious agents earlier than possible in young untreated individuals.  In older normal animals,  Cyclo-Z treatment modulates levels of several components involved in inflammation (decreasing monocytes, CD8+T-cells levels) and autoimmune diseases (increasing CD4+helper T-cells levels) suggesting potential benefits in treatment of allergies or psoriasis and other autoimmune disease (such as Lupus and arthritis). 


Viardot A, Lord RV, Samaras K. The effects of weight loss and gastric banding on the innate and adaptive immune system in Type 2 diabetes and prediabetes.  J Clin Endocrinol Metab 95:2845-2850, 2010.

Ting C, Bansal V, Batal I, Mounayar M, Chbtimi L, Akiki GE, Azzi J.  Impairment of immune systems in diabetes in Diabetes: an old disease, a new insight. (2012) pg 62-75.

Cifarelli VC, Libman IM, DeLuca A, Becker D, Trucco M, Luppi P.  Increased expression of monocyte CD11b (Mac-1) in overweight recent-onset Type 1 diabetic children. Rev Diabet Stud 4:113-120, 2007.

Geerlings, SE,  Hoepelman AIM.  Immune dysfunction in patients with diabetes mellitus (DM). FEMS Immunol Med Microbiol 26:259-265, 1999.

Prasad AS. Zinc and immunity.  Mol Cell Biochem 188:63-69, 1998. 

Mochegiani E, Muzzioli M, Cipriano C, Giacconi R.  Zinc, T-cell pathways, aging: role of metallothionein.  Mech Aging Dev 106:183-204, 1998. 

Wellghausen N, Rink L.  The significance of zinc for leukocyte biology.  J Leukoc Biol 64:571-577, 1998.

Rink I, Gabriel P.  Zinc and the immune system. Proc Nutr Soc 59:541-552, 2000.

Shankar AH, Prasad AS. Zinc and immune function: The biological basis of altered resistance to infection. Am J Clin Nutr 68:447S-463S, 1998.  

Sazawal S, Jalla S, Mazumder S, Sinha A, Black RE, Bhan MK.  Effect of zinc supplementation on cell-mediated immunity and lymphocyte subsets in preschool children.  Indian Pediatr 34:589-597, 1997.

Fusetani N. Antifungal peptides in marine invertebrates.  Invertebrate Survival J 7:53-66, 2010.

Houston DR, Synstad B, Fijsink VGH, Stark MJR, Eggleston IM, van Alten DMF.  Structure- based exploration of cyclic dipeptide chitinase inhibitors. J Med Chem 47:5713-5720, 2004. 

Minelli A, Grottelli S, Mierla A, Pinnen F, Cacciatore I, Bellezza I.  Cyclo (his-pro) exerts anti-inflammatory effects by modulating NF-κB and Nrf2 signaling.  Int J Biochem Cell Biol 44:525-535, 2012.

Bellezza I, Grottelli S, Mierla AL, Cacciatore I, Fomasari E, Roscini L, Cardinali  G, Minelli A.  Neuroinflammation and endoplasmic reticulum stress are coregulated by Cyclo (His-Pro) to prevent LPS neurotoxicity.  Int J Biochem Cell Biol 51:159-169, 2014.

Koo KB, Suh HJ, Ra KS, Choi JW.  Protective effect of Cyclo (his-pro) on steptozotocin-induced cytotoxicity and apoptosis in vitro.  J Mol Biotechnol. 21:218-227, 2011.

Park Y, Lee HJ, Choi JW, Bae SH, Suh HJ. Anti-diabetic effect of Cyclo-His-Pro (CHP)-enriched yeast hydrolysate in streptozotocin -induced diabetic mice. Afr J Biotech 12:5473-5479, 2013

Song MK, Rosenthal MJ, Hong SJ, Harris DM, Hwang IK, Yip I, Golub MS, Ament ME, Go VLW.  Synergistic anti-diabetic activties of zinc, cyclo(his-pro) and arachidonic acid.  Metabolism 50:53-59, 2001.

Song MK, Hwang IK, Rosenthal MJ, Harris DM, Yamguchi DT, Yip I, Go VLW.  Anti-diabetic actions of arachidonic acid and zinc in genetically diabetic Goto-Kakizaki rats. Metabolism 52:7-12, 2003.

Hwang IK, Go VLW, Harris DM, Yip I, Song MK.  Effects of arachidonic acid plus zinc on glucose disposal in genetically diabetic (ob/ob) mice. Obe.Diabet. Metbol.4:124-131, 2002.

Song MK, Rosenthal MJ, Song AM, Uyemura K, Yang H, Ament ME, Yamaguchi DT, Cornford EM.  Body weight reduction by oral treatment with zinc plus Cyclo (his-pro).  Br J Pharmacol 158:442-450, 2009.