Inhibition of serotonin synthesis in gut - a new way of treating osteoporosis ?

A crucial clue uncovered in Dr. Karsenty’s lab turned his attention to the small intestine, wherein his research team found that the gene Lrp5, (previously linked to a rare form of osteoporosis) controls the production of serotonin in the gut, and that serotonin is an inhibitor of bone formation. By inactivating Lrp5 in the small intestine of mice and thereby turning on the production of serotonin, bone mass decreased. While in contrast, the deletion of the same gene in the bone cells of mice, on the other hand, had no effect on bone mass. As per the claim by the researcher, these findings demonstrate that serotonin from the gut is acting as a hormone to regulate bone mass (1). 

Most osteoporosis drugs, including those currently under clinical investigation  do not generate new bone but prevent the breakdown of old bone and the only drug currently in  the market which can generate new bone   has its limited application (due to its reported increased risk of bone cancer,is restricted for short-term and  that too in women with severe osteoporosis). Researchers  read about an investigational drug, known as LP533401  which is able to inhibit serotonin in the gut they synthesized and used LP533401, a small molecule inhibitor of tryptophan hydroxylase-1 (Tph-1)  the initial enzyme in GDS biosynthesis.

Results demonstrated that osteoporosis was prevented from developing, or when already present, could be fully cured (in mice). Interestingly  levels of serotonin were normal in the brain, which indicated that the compound did not enter the general circulation and was unable to cross the blood-brain barrier, thereby avoiding many potential side effects. Dr. Karsenty and his colleagues did not find any gastrointestinal problems in mice unable to produce serotonin in their guts, suggesting that a serotonin inhibitor would not produce any such side effects in humans. The authors conclude that these results provide a proof of principle that inhibiting GDS biosynthesis could become a new anabolic treatment for osteoporosis.

Ref : http://www.nature.com/nm/journal/vaop/ncurrent/full/nm.2098.html

New cyclopropane derivative as better antidepressant ?

We know that most of the antidepressants have side effects such as  constipation, dry mouth, drowsiness and hypotension, or low blood pressure. Amongst various trypes TCAs, tricyclic antidepressants also have  the above mentioned side effects. 

In recent times, the TCAs have been largely replaced in clinical use in most parts of the world by newer antidepressants such as the selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs), among others, though they are still sometimes prescribed for certain indications.

Duloxetine, is a serotonin-norepinephrine reuptake inhibitor manufactured and marketed by Eli Lilly. It is effective for major depressive disorder and it is as effective as venlafaxine in generalized anxiety disorder. Duloxetine failed the US approval for stress urinary incontinence amidst the concerns about liver toxicity and suicidal events; however, it was approved for this indication in Europe and Canada.

Interestingly, chemists at Oregon State University have discovered and synthesized a new compound  (see the structure) that in laboratory and animal tests appears to be similar to, but may have advantages over Duloxetine. As per the claim by the  lead researcher Dr. James White (Professor Emeritus of Chemistry at OSU),  the new compound has properties similar to (Cymbalta) Duloxetine in some ways, but in laboratory and animal studies does a better job at balancing body chemistry. New compound is 10 times better than Duloxetine at inhibiting the re-uptake of norepinephine and comes close to the perfectly balanced antidepressant with fewer side effects, such as concerns with constipation and hypotension. Though clinical studies are essential to substantiate the claims its a good achievement...

Ref : http://pubs.acs.org/doi/abs/10.1021/jm900847b

Celastrol Inhibiting Hsp90 Chaperoning - a new way to treat cancer?

Celastrol, derived from trees and shrubs called celastracaea,  (Thunder of God Vine) has been used for centuries in China to treat symptoms such as fever, chills, joint pain and inflammation.Celastrol has been shown to possess antioxidant, anti-inflammatory activities. The same compound has been tried for Alzheimer's disease and anticancer activity  also.

Now Dr. Ahmed Chadli, has come up with an interesting findings i.e., Celastrol may play a role in cancer treatment by inactivating a protein required for cancer growth.  Protein, P23, is one of many proteins helping the heat shock protein 90. Dr. Chadli claims that,  "scientists are just beginning to realize the potential of controlling inflammation-related diseases, including cancer, by inhibiting HSP90".

As per  claim by Dr. Chadli, cancer cells need HSP90 more than normal cells because cancer cells have thousands of mutations. They need chaperones all the time to keep their mutated proteins active. By taking heat shock proteins away from cells, the stabilization is taken away and cell death occurs. 

Most HSP90 inhibitors lack selectivity, disabling the functions of all proteins activated by HSP90 rather than only the ones implicated in a specific tumor and proteins vary from one tumor to another. Dr. Chadli and colleagues at the Mayo Clinic believe celastrol holds the key to specificity, targeting the HSP90-activated protein required for folding steroid receptors.

Celastrol inhibits the Hsp90 chaperoning machinery by inactivating the co-chaperone p23, resulting in a more selective destabilization of steroid receptors compared with kinase clients. Both in vitro and in vivo results demonstrate that celastrol disrupts p23 function by altering its three-dimensional structure, leading to rapid formation of amyloid-like fibrils. This study reveals a unique inhibition mechanism of p23 by a small molecule that could be exploited in the dissection of protein fibrillization processes as well as in the therapeutics of steroid receptor-dependent diseases....

Ref : http://www.jbc.org/content/285/6/4224.abstract

Metformin helps dieting teens to lose weight....

We know that Metformin  (see structure), is a  biguanide hypoglycemic  agent used in the treatment of non-insulin-dependent diabetes mellitus not responding to dietary modification. Metformin improves glycemic control by improving insulin sensitivity and decreasing intestinal absorption of glucose. Metformin's pharmacologic mechanisms of action are different from other classes of oral antihyperglycemic agents. Metformin decreases hepatic glucose production, decreases intestinal absorption of glucose and improves insulin sensitivity by increasing peripheral glucose uptake and utilization. In my earlier blogs, I have covered the recent (findings)  updates on metformin.

Now researchers  lead by Dr. Darrell Wilson (from Division of Pediatric Endocrinology and Diabetes, Stanford University)  have found that metformin appears to help overweight teenagers lose weight when combined with a program designed to help them change their lifestyle habits.

As per the claim by the authors though metformin hydrochloride is  used as a primary or adjunctive treatment in obese  nondiabetic adolescents there are limited short-term data to support this therapy  and also it is unclear whether any observed effects of metformin on body mass index. Therefore  the researchers conducted a 48-week randomized, double-blind, placebo-controlled trial of extended-release (XR) metformin therapy in nondiabetic obese adolescents  followed by a 48-week monitoring period after completion of treatment.

Researchers found that the addition of metformin to a lifestyle change intervention for a period of 12 months resulted in a significant improvement of BMI regardless of baseline fasting insulin levels, that persisted for 12 to 24 weeks after cessation of drug treatment. The mean (SE) reduction in BMI of –1.1 (0.5) at 1 year was comparable with that observed in other randomized controlled trials of metformin treatment in obese adolescents, although these randomized controlled trials involved shorter treatment duration (about 6 months), targeted obese children with additional diabetes risks, and had smaller sample sizes.

The mechanisms of action for these effects have not fully been elucidated but may involve beneficial effects on carbohydrate and lipid metabolism, mediated through adenosine monophosphate kinase.

Researchers conclude that  "metformin  in combination with lifestyle modification, had a small but statistically significant effect to reduce BMI in obese adolescents; this effect waned within 12 to 24 weeks of discontinuing metformin treatment". These results indicate that metformin may have an important role in the treatment of adolescent obesity. Longer-term studies will be needed to define the effects of metformin treatment on obesity-related disease risk in this population....

Ref : http://archpedi.ama-assn.org/cgi/content/full/164/2/116?home

7,8-Dihydroxyflavone (a selective TrkB agonist) as new class of brain protecting drugs ?

In recent days, I have seen many groups working on the diverse activities of  flavonoid family of chemicals. In my earlier blog, have mentioned about Quercetin   (quercetin a flavonoid has been reported for diverse activities). Now interestingly  investigators at Emory University School of Medicine,  have reported that '7,8-Dihydroxyflavone' (see structure - also a  member of the flavonoid family of chemicals, abundant in fruits and vegetables-cherries to soybeans)   can partially prevent the death of neurons in experimental models of three neurological diseases" and  this  selective effect suggest that it could be  a new class of brain-protecting drugs.

Investigators at Emory University School of Medicine, led by Dr. Keqiang Ye, (Associate professor of pathology and laboratory medicine), were searching for a way to mimic a protein found in the brain called BDNF (brain-derived neurotrophic factor).

BDNF has been studied extensively for its ability to protect neurons vulnerable to degeneration in several diseases, such as ALS, Parkinson's and Alzheimer's disease,  Ye, one of the authors says, "the trouble with BDNF is one of delivery. It's a protein, so it can't cross the blood-brain barrier and degrades quickly". 

Researchers tried a a library of chemicals to find those that could stimulate one of the proteins on the surfaces of neurons that BDNF binds to. They could show that, 7,8-dihydroxyflavone sends survival signals to brain cells by pulling together two TrkB receiver-dish molecules, just like BDNF does. Interesting part of this research is that, 7,8-Dihydroxyflavone is active in the brain when injected into the body cavity (meaning that it can cross the blood-brain barrier). As claimed by the co-author Ye, many experimental "neuroprotectant" drugs have been unsuccessful in clinical trials for diseases such as stroke and Parkinson's over the last decade and 7,8-Dihydroxyflavone is the first molecule that specifically triggers TrkB. To show the effects of 7,8-dihydroxyflavone depended on TrkB,  authors used mice with a modified TrkB gene and were successful in doing so. Detailed animal studies to substantiate the claim  are essential , still  in my opinion its a good achievement... (details...)

FDAs approval of Lapatinib in combination with Letrozole to treat breast cancer...

In my earlier blog, I mentioned about the combination of Lapatinib and Trastuzumab for breast cancer treatment. Now FDA has  approved Lapatinib in combination with Letrozole (see structure ; Letrozole trade name Femara, an oral non-steroidal aromatase inhibitor for the treatment of hormonally-responsive breast cancer after surgery)  to treat hormone positive and HER2-positive advanced breast cancer in postmenopausal women for whom hormonal therapy is indicated. This drug combination of  Lapatinib  & Letrozole provides women being treated for advanced breast cancer with an important treatment option. 

The entirely oral treatment regimen works by targeting both HER2 and the hormone receptors, thereby slowing the cancer cells' ability to grow or spread. As per the claim by  Dr. Richard Pazdur, (Director, Office of Oncology Drug Products, FDA's Center for Drug Evaluation and Research) women with HER2-positive disease receiving the Lapatinib plus Letrozole combination more than doubled the time they lived without the cancer progressing compared with those receiving Letrozole alone (35 weeks vs. 13 weeks).

Lapatinib, was initially approved in combination with a chemotherapy drug, Xeloda (capecitabine) in 2007. This combination was used to treat women with advanced breast cancer tumors with the HER2 protein who had received prior treatment with chemotherapy drugs, including an anthracycline and a taxane, and Herceptin (trastuzumab), an anti-cancer antibody used to treat HER2-positive advanced breast cancer. Safety information from this study was consistent with previous Lapatinib clinical studies in advanced breast cancer. The most commonly reported side effects of the combination were diarrhea, rash, nausea and fatigue. Still clinical trials are to be carried out, in my opinion its a good achievement...

Ref : http://www.prnewswire.com/news-releases/fda-expands-use-of-approved-breast-cancer-drug-83072502.html

Green tea might help to treat Uterine Fibroids....

In continuation of my update on green tea   (pic : source : greenteatruth.org ).......  

We have seen many research groups  trying to explore the  usefulness of  green tea for reduction in heart disease (bad cholesterol),  increase in metabolic rate (fat oxidization) prevention  of Alzheimer’s or Parkinson’s diseases, lowering incidence of cancers and  weight reduction.

 Now researchers from Meharry Medical College in Nashville, Tenn lead  Dr. Ayman Al-Hendy ,   have found that green tea extract shows promise as a treatment for uterine fibroids. The key ingredient responsible for this activity is  "epigallocatechin gallate (EGCG)". The researchers investigated  the effect of epigallocatechin gallate  on rat leiomyoma (ELT3) cells in vitro and in a nude mice model. ELT3 cells were treated with various concentrations of EGCG. Cell proliferation, proliferation cell nuclear antigen (PCNA), and cyclin-dependent kinase 4 (Cdk4) protein levels were evaluated. As per the claim by the researchers, EGCG significantly decreased PCNA and Cdk4 protein levels. The authotrs conclude that EGCG effectively inhibits proliferation and induces apoptosis in rat ELT3 uterine leiomyoma cells in vitro and in vivo.

Ref : http://www.ajog.org/article/S0002-9378%2809%2902102-4/fulltext

Pomegranate extract (β-Sitosterol) stimulates uterine contractions.........

In continuation of my update on pomegranate and its importance in the diet, I found this info interesting to share with...

Earlier studies have suggested that the pomegranate’s antioxidant and anti-inflammatory properties have a positive impact on health. Scientists at the University of Liverpool   and the Suranaree University of Technology, Thailand, wanted to understand its effect on uterine contractions to explore new ways of treating women who may experience difficult labours.  Currently the only available drug to treat women with a poorly contracting uterus is oxytocin, a hormone which only works approximately 50% of the time,  so there is need of a good  drug.

The team identified   β-Sitosterol,   which inhibit the absorption of cholesterol in the intestine  (as the main constituent of pomegranate seed extract) could be used as a natural stimulant to encourage the uterus to contract during  labour.

        I would say this activity (stimulation of  uterine contractions) is an interesting out come from the research group, because β-Sitosterol has been (earlier) reported ;

a) in treatment of hypercholesterolemia;
b) to possess  anticancer activity (prostate & breast);
c) in a small study, it shows a positive effect on male hair loss in combination with Saw palmetto.

Researchers,  also found that β-Sitosterol concentration  is more in the  pomegranate seed extract  rather  than pomegranate juice itself  and by adding this seed extract to the uterus tissue samples from animals they found that the muscle cells increased their activity. 

The reason for this activity,  (as claimed by the researchers) is due to a rise in calcium, which is necessary in order for any muscle to contract (which is usually affected by hormones, nerve impulses and some drug treatments) . So further studies  like how β-Sitosterol  in pomegranate extract could increase calcium are essential and might lead to  an interesting step towards identifying new ways of treating dysfunctional labour ..more..

Pazopanib for the treatment of advanced renal cell carcinoma.......

In continuation of my update on Pazopanib, I found this interesting info. In my earlier blog , I mentioned that lots of research groups are trying the same drug for other forms of cancer.  Dr. Cora Sternberg and co authors (Chief of the medical oncology department at the San Camillo and Forlanini Hospital in Rome, Italy), have come up with interesting results from a phase 3 study included 233 patients with previously untreated kidney cancer (also known as renal cell carcinoma) that was locally advanced or had spread, and 202 patients with renal cell carcinoma who had previously been treated with cytokine therapy (interferon or interleukin). The patients were randomly assigned to take pazopanib tablets (290 patients) or a placebo drug (145 patients).

As per the claim by the authors, in the pazopanib group, it took an average 9.2 months for the cancer to progress, vs. an average 4.2 months in the placebo group. The difference was greatest in previously untreated patients (11.1 months for the pazopanib group and 2.8 months for the placebo group), but also was found among patients previously treated with cytokines (7.4 months in the pazopanib group vs. 4.2 months in placebo group). 

Common side effects of pazopanib treatment included diarrhea (52 percent), high blood pressure (40 percent), hair color changes (38 percent), nausea (26 percent), weight loss (22 percent) and vomiting (21 percent).

Ref : http://jco.ascopubs.org/cgi/content/abstract/JCO.2009.23.9764v1 

FDA approves Liraglutide for Type 2 Diabetes, with a warning.....

Liraglutide, marketed under the brand name Victoza, is a long-acting glucagon-like peptide-1 (GLP-1) analog that has been developed by Novo Nordisk for the treatment of type 2 diabetes. The product was approved by the European Medicines Agency (EMEA) on July 3, 2009, Now the same drug has been approved  by the FDA.

The interesting part of this approval lies in the fact that, Liraglutide was reviewed by an FDA advisory panel which expressed serious concerns that the drug may cause thyroid tumors. Whereas based on the studies and consistent with the relevant literature it is obvious that the rodent C-cell tumors induced by dosing of liraglutide were caused by a non-genotoxic, specific receptormediated mechanism to which rodents are particularly sensitive whereas non-human primates and humans are not. Liraglutide improves control of blood glucose.  It reduces meal-related hyperglycaemia (for 12 hours after administration) by increasing insulin secretion, delaying gastric emptying, and suppressing prandial glucagon secretion.

As per the claim by the company, the advantages are:

a) acts in a glucose-dependent manner, and  stimulate insulin secretion only when blood glucose levels are

    higher than normal. Consequently, it shows negligible risk of hypoglycemia;

b) has the potential for inhibiting apoptosis and stimulating regeneration of beta cells;

c) decreases appetite and maintains body weight, as shown in a head-to-head study versus glimepiride;

d) lowers blood triglyceride levels and only mild and transient side effects, mainly gastrointestinal &
e) has a half-life after subcutaneous injection of 11–15 hours and hence once-daily GLP-1 derivative.

But the FDA, warned that the once-daily injection shouldn't be used as an initial (first-line) treatment until additional studies are completed, since the drug may cause thyroid tumors or a rare disease called medullary thyroid cancer. People at risk for this type of cancer shouldn't use the drug, the FDA stressed. Hope the further studies will rule out the possibility of the drug causing thyroid tumors..

For details, one can read the press release....